Version 3, 15/12/2016 Christian Gustafsson, leg Sjukhusfysiker, MSc, Skånes Universitetssjukhus, Sweden

Maja Sohlin, leg Sjukhusfysiker, PhD, Sahlgrenska Universitetssjukhuset, Sweden

Lars Filipsson, Siemens Healthcare AB, Work package leader, Gentle Radiotherapy

Method book for the use of

MRI in radiotherapy

www.gentleradiotherapy.se

CONTENTS

Acknowledgements........................................................................................................................................ 5

Purpose ............................................................................................................................................................ 6

General introduction ............................................................................................................................... 7

MRI in radiotherapy ............................................................................................................................ 7

Important differences between MRI in radiotherapy and MRI for diagnosis ............................... 9

Geometric distortion .......................................................................................................................... 10

Patient positioning and immobilization accessories ............................................................................ 11

MRI scanner ......................................................................................................................................... 11

Immobilization and carbon fibre ....................................................................................................... 11

Patient positioning ..................................................................................................................................... 12

Coils – distance to the coil ................................................................................................................. 13

MRI safety ................................................................................................................................................ 13

Background .......................................................................................................................................... 13

Accident risks ....................................................................................................................................... 13

Signage at the MRI scanner ............................................................................................................... 13

Rules for admission to the examination room ............................................................................... 14

Policy for staff ...................................................................................................................................... 14

Policy for patients ................................................................................................................................ 15

Policy for other individuals ................................................................................................................ 15

Helium and emergency stop .............................................................................................................. 15

Fire ......................................................................................................................................................... 16

Practical implementation ........................................................................................................................ 17

General recommendations ................................................................................................................. 17

Matching of images ............................................................................................................................. 17

Practical implementation – Image capture ........................................................................................... 24

Brain ...................................................................................................................................................... 24

Brain – stereotaxy ................................................................................................................................ 29

Head and neck area ................................................................................................................................... 33

Prostate ........................................................................................................................................................ 37

Cervix Brachy ...................................................................................................................................... 48

Quality control ................................................................................................................................................ 53

Geometric accuracy ............................................................................................................................ 53

References ................................................................................................................................................ 61

Appendix A – Supplier-specific sequence suggestions ...................................................................... 62

Brain ...................................................................................................................................................... 62

Brain – Stereotaxy ............................................................................................................................... 65

Head and neck ..................................................................................................................................... 67

Prostate ........................................................................................................................................................ 71

Cervix Brachy ...................................................................................................................................... 75

Appendix B – Safety manual ................................................................................................................. 77

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ACKNOWLEDGEMENTS

The authors would like to thank all the contributing parties in the project collaboration. Your input

and suggestions have been most valuable. The authors would also like to express their gratitude to

the Swedish Innovation Agency VINNOVA who has partially funded the project Gentle

Radiotherapy.

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PURPOSE

This method book serves a number of purposes. The short-term objectives when writing the

method book were:

To increase cooperation between Swedish hospitals using MRI in radiotherapy for target and risk organ delineating. As use of MRI in radiotherapy is relatively new in Sweden(2015), cooperation and knowledge sharing are important aspects of fostering the right skills.

To highlight similarities and differences in how different Swedish hospitals use MRI in radiotherapy. This has served as both a source of inspiration for the hospitals and a catalyst for development and use.

The long-term objectives of this method book are:

To create clarity and help for hospitals and staff beginning to implement MRI in radiotherapy.

For the content of the method book to be both general in nature and concrete enough for application to supplier-specific equipment.

To highlight the differences between radiological MRI and MRI in radiotherapy.

To provide clear procedures and explanatory images that guide the user in the imaging of different anatomies.

To clarify the application area of each MRI sequence and explain how these MR images should or should not be used in radiotherapy.

The method book will primarily serve as a handbook for how MR images should be used with CT

images in the field of radiotherapy. A future version of the method book will also include a

workflow for MRI-based treatment planning (MRI only).

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GENERAL INTRODUCTION

MRI in radiotherapy Integration of MRI in radiotherapy can be divided into two workflows, both of which can exist

simultaneously if the clinic so desires. The first flow involves use of MR images solely for defining

target and risk organs. Treatment planning is thus still done with CT materials (see Figure 1). With

the second flow, MR material is also used for treatment planning and CT is completely eliminated

from the treatment chain (see Figure 2).

This method book will primarily deal with the first flow as it is the flow most relevant to the

majority of clinics as of 2015.

Figure 1. The flow shows how MR and CT material is registered to each other for better definition of target and

risk organs in radiotherapy. Figure from Jonsson, 2013.

Figure 2. The flow shows how MR only (no CT) could be used for both treatment planning and definition of

target and risk organs. Figure from Jonsson, 2013.

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Gentle Radiotherapy The national project “Gentle Radiotherapy” was initiated through Umeå

University Hospital in 2013 and received partial funding from Vinnova.

Vinnova is Sweden’s innovation agency. Their mission is to promote sustainable growth by

improving the conditions for innovation, and to fund needs-driven research. Each year, Vinnova

invests about SEK 2.7 billion in various initiatives (http://www.vinnova.se/sv/Om-

VINNOVA/, 2015).

Many Swedish university hospitals received financial support for participating in this project in

2014. The purpose of the “Gentle Radiotherapy” project was integration of MRI in the

radiotherapy workflow so as to create clinical benefit for the patient in the form of better treatment

with fewer side effects.

“Gentle Radiotherapy” consisted of five work packages.

Work package 1: Optimization of sequences and markers of MRI imaging for RT applications

Work package 2: MR-based treatment planning

Work package 3: Registration and automatic segmentation

Work package 4: QA and geometric distortion

Work package 5: Clinical implementation of Multiparametric MRI (mpMRI) in radiotherapy

One of the desired results of work package 1 was a method book that could summarize and share

knowledge about how to integrate MRI in radiotherapy. The material that served as the basis for

the method book's protocol recommendations was compiled from, inter alia, a survey inventorying

of MR protocols and patient positioning procedures from university hospitals in Stockholm, Umeå,

Lund, Gothenburg, and Uppsala.

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IMPORTANT DIFFERENCES BETWEEN MRI IN RADIOTHERAPY AND

MRI FOR DIAGNOSIS

The quality of an MR image is dependent on several factors, with the most significant factors

being spatial resolution, image contrast, signal-to-noise ratio (SNR), and the presence of artefacts.

In practice, it will never be possible to optimize all of these factors. It will always be necessary to

make a compromise between them as well as between image quality and scan time.

SNR affects both our ability to perceive structures in low-resolution images, and our ability to

distinguish small objects in an image. Image optimization in diagnostics consists largely of

ensuring that there is sufficient SNR in the images for them to be diagnostically useful. In such

cases, the images are examined for pathological changes whose existence or location are unknown.

With MRI in radiotherapy, it works differently. The patient has already been diagnosed and there

is then advance knowledge of what can be expected in the images. This means that it may be

acceptable to have a poorer SNR for MRI in radiotherapy if it means an improvement in other

image quality parameters.

Another factor that affects the visibility of small objects in the image is the spatial resolution in-

plane, i.e. how small the pixels making up the image are. The spatial resolution in MRI is limited

by pixel size, which means that the smallest object that can be visualized is the same size as one

pixel. High spatial resolution is required to be able to distinguish small objects in the image, but

does not guarantee visibility if there is poor image contrast or a poor SNR. In addition to in-

plane spatial resolution, there is also through-plane resolution, i.e. slice thickness. The slice

thickness is generally the largest dimension and is usually most critical when it comes to

visualizing a lesion. If you choose a thicker slice, you get a higher SNR, but are at risk of poorer

image contrast due to partial volume effects. If the slice is to thin, small objects might be missed

because of increased noise in the image, provided that you do not compensate for reduced SNR

by increasing scan time. The same reasoning applies to in-plane resolution, although the

dimensions here are often smaller. An important step of image optimization is defining the

boundary between the spatial resolution required for sufficient SNR and the spatial resolution

required to be able to see small anatomical and pathological details, in relation to a relevant scan

time.

Radiology creates images with the parameters necessary to make an accurate diagnosis, while

oncology must create images with the parameters that enable thorough, effective and safe

treatment. The intended use of diagnostic images is to detect and characterize lesions, while the

intended use of images for radiotherapy is to determine the extent and position of lesions in

relation to critical structures. All image capturing changes required for optimal use of MR images

in radiotherapy are time consuming. A radiotherapy-related MRI scan often takes twice as long as

equivalent diagnostic imaging, and must then often sacrifice SNR. This is because there is a limit

for how long a patient would be able to handle a scan. There is nothing to be gained from

increasing scan time to increase the SNR if the patient begins to move during that time because

they find the long scan time taxing.

In diagnostics, a reduced field of view can be used, which is a time saver. With RT, body contour is

an important part of the matching process and is required for at least one or more image series for

each patient. It takes larger image matrices and thereby a longer scan time to achieve a larger field of

view while maintaining in-plane spatial resolution. In addition, MR images for radiotherapy must

have a thinner slice than diagnostic images to outline the target and risk organs in a satisfactory

manner. It is also preferable for there not to be a gap between the different slices, while gaps are

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commonly used in diagnostic MR imaging to reducescan time. All this means that a much larger

number of slices for the same coverage area are required for radiotherapy-related MRI, which in turn

increases the scan times.

Geometric distortion Geometric distortion is common in MRI and occurs due to inhomogeneities in the static magnetic

field, non-linear magnetic field gradients, or patient-specific susceptibility deviations in the

magnetic field. With diagnostic imaging, geometric distortion is tolerable as long as diagnostic

capability is not affected. Minimal geometric distortion is required for radiotherapy-related MRI

for matching of MR images to CT and because the alignment of the target and risk organs on the

MRI is used for treatment planning.

With radiotherapy-related MRI, use of a higher-order shimming, if available, may be one step

towards trying to minimize the geometric distortion. Another important step is to optimize the

receiver bandwidth for each sequence. A high bandwidth minimizes geometric distortion, but at

the expense of the SNR. With diagnostic MR imaging, where some degree of geometric distortion

is acceptable, it is often possible to use a lower receiver bandwidth and thereby achieve a higher

SNR. One way to minimize distortion caused by non-linear gradients in radiotherapy-related MRI

is to use 3D distortion correction, which is often available from the MR supplier. It is also

particularly important to make sure that the scan volume is in the isocentre, and it may be

beneficial to consider step-and-shoot or continuous table movement techniques, which ensure

that the scan area is always in the isocentre.

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PATIENT POSITIONING AND IMMOBILIZATION ACCESSORIES

MRI scanner A major breakthrough for the introduction of MRI in radiotherapy in recent years has been the

availability of conventional MRI scanners with a 70-cm bore. Although it is only a 10-cm

difference, the extra room is in most cases enough to accommodate the necessary radiotherapy

equipment, while the scanners still have excellent gradient and magnetic performance.

It is preferable to have a dedicated MRI scanner in the Radiotherapy department. This ensures

that there is enough scanner time for radiotherapy-indicated scans; can facilitate scheduling of

patient transports, radiotherapy staff, and immobilization devices; and can help when scheduling

sequential CT and MRI scans. Moreover, there is a large chance that aspects important for

radiotherapy (e.g. field homogeneity, gradient linearity, scanner tunnel, and flexible RF coils)

were not considered during procurement of the diagnostic machine.

An MRI scanner in the Radiotherapy department also makes it possible to install a laser system,

which is helpful when positioning the patient and is a must if the intention is to have an

“MRI only” flow, where the MRI simulator replaces the CT simulator (Figure 2). The major MRI

system manufacturers now also offer the option of pre-fitting the MRI scanner with equipment

such as a flat and indexed table top to enable patient positioning similar to that used during CT

and radiotherapy, an RF coil built into the table, as well as holders and flexible coil solutions for

capturing images of patients in the treatment position.

While it is beneficial to have an MRI system dedicated to radiotherapy, this is not a requirement to

enable use of MR images for radiotherapy planning. However, it is always beneficial to have a

modern MRI system with the latest technology for the highest possible SNR, e.g. a large number

of separate RF channels.

Higher field strengths have higher SNR and an increased chemical shift, which is an advantage for

e.g. spectroscopy and other functional methods, as well as some fat suppression techniques.

Lower field strengths are less expensive, have fewer artefacts, and entail less risk of factors such as

heat rise. In reconstruction of some applicators for brachytherapy applications, a higher field

strength, for example, can produce excessively large artefacts and an increased risk of heat rise.

Immobilization and carbon fibre Many immobilization devices and accessories used in radiotherapy are made of carbon fibre, a

stable material with good strength. Since carbon fibre does not significantly attenuate the radiation,

it is widely used as the material for the table top of radiotherapy CT scanners and radiotherapy

devices.

Use of carbon fibre in MRI is not recommended as it creates image artefacts because carbon fibre

is electrically conductive and therefore interferes with the radio frequency field. To mimic the CT

and radiotherapy table, most MRI suppliers instead offer a flat table top in MRI-compatible

material.

MRI-compatible immobilization accessories for radiotherapy-related MRI are often available from

radiotherapy equipment suppliers. Alternatively, they can be fabricated in-house using suitable

MRI-compatible material. For sequences that are particularly sensitive to susceptibility, one should

also ensure that the equipment does not cause unnecessary susceptibility-induced geometric

distortions.

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Patient positioning Nowadays, radiotherapy is based on a set of CT and MR images collected during the treatment

planning phase. Based on these images, target and risk organs are defined, and a dose distribution

is calculated and optimized based on the position of the organs during the day of imaging. Since

electronic density information from CT images is needed for dose calculation, the MR images

must be registered to the CT images in order to use MRI in radiotherapy. To minimize the

uncertainties introduced through matching between MR and CT images, it is a good idea to

perform the MRI scan with the patient in the treatment position. If possible, it is also a good idea

to perform the MRI scan immediately after the CT scan. The use of contrast medium is governed

by local procedures. It is generally recommended to only use contrast medium on either the CT or

MRI within one day to reduce the renal load of the patient.

If an external laser bridge is available, the patient is positioned using the markings or tattoos made

during the preceding CT. For scans of the head and neck region, the sagittal laser may be helpful

for checking that the patient is squarely positioned in the mask. In pelvic scans, the coronal laser is

also used to ensure correct rotation of the pelvis.

Since immobilization devices for radiotherapy often do not permit use of conventional MRI coils

(e.g. head and head/neck coils), a flexible solution is required for the collection of the MR signal.

Most MRI system suppliers can provide flexible solutions that can be wound around and

combined as needed. Various types of support in the form of coil holders, straps and sand bags

can be of great help in keeping the coil arrangements in place (refer to the relevant anatomical

area for examples of patient positioning).

Coils – distance to the coil When using MRI in radiotherapy, it is often important to include the patient's non-deformed skin

contour in the images as this facilitates matching of the MR image to the CT image. In situations

where only MRI is used (no CT), this is vital and cannot be compromised in connection with

target and risk organ plotting as well as treatment planning. For this reason, bridges or spacers are

often used to create some distance between the patient and the receiver coil when positioning the

patient for image capture. This distance should be as small as possible since the signal that is

collected by the receiver coil decreases as the distance increases. When purchasing coils, the length

of the coil cable should be checked as it could otherwise be limiting depending on the coil

configuration used.

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MRI SAFETY

A general summary of MRI safety information is found below. For more detailed information,

refer to the safety manual in Appendix B – Safety manual.

Background An MRI scanner contains a strong magnet that creates a static magnetic field with a field strength that

is measured in Tesla (T). The clinical MRI scanners found in Sweden generally have a field strength of

1.5 T or 3.0 T. This static magnetic field is always active – 24 hours a day, seven days a week.

To create MR images, you not only need the static magnetic field, but also magnetic field gradients (gradient fields or time-varying magnetic fields) and the ability to send and receive radio waves (radio frequency (RF) fields).

At the levels of magnetic fields, gradient fields, and radio frequency fields used in an MRI scanner, there are no long-term, harmful biological effects reported for patients or for staff. Note that MRI does not use any X-rays and therefore does not provide any dose of radiation.

However, there are other risks associated with MRI activities.

Accident risks One of the biggest hazards of MRI scanners is the risk of accidents. Metal objects may be attracted by the magnetic field and fly towards the scanner, potentially harming the patient, staff,

accompanying persons or equipment found in the examination room (projectile risk). For this

reason, only objects that are guaranteed to be non-magnetic or that have been adapted for the MR environment may be taken into the examination room. Serious accidents and even deaths have been caused by objects flying towards an MRI scanner.

It is important to bear in mind that even some equipment adapted for use in an MRI examination room, such as IV poles and anaesthesia equipment, could be drawn towards the scanner and is therefore only permitted in specially predefined areas of the examination room.

Large metal objects hitting the scanner can not only cause personal injury, but also expensive repairs. Small metal objects, like paper clips or bobby pins, that fly into the scanner could cause

problems with the magnetic field and cause errors in the MR images.

Some medical implants and metal objects in the body could be turned or otherwise affected by the magnetic field and cause injury or death. It is important that absolutely no one is allowed to enter the examination room without being carefully checked and approved by the MR staff.

The magnetic field extends far beyond the actual MRI scanner. Today's MRI scanners are shielded to reduce the magnetic field distribution, but the attractive force increases very rapidly as one approaches the scanner. The attractive force of an MRI scanner is very large. It is not at all possible to physically hold onto an object that is being drawn towards the scanner. The attractive force also increases as the field strength increases.

Signage at the MRI scanner The examination room and/or MRI department must be monitored and/or have limited access

(e.g. require use of an access card) to prevent unauthorized persons from entering the

examination room. Signs must also be posted in the areas. The entrance to the MRI room must

have signs posted to warn about the strong magnetic field and to warn against bringing loose

metal objects into the room. There must also be a warning indicating that people with

pacemakers, other battery-operated implants, or surgically implanted metal objects should not

enter the room. The signage must be visible even when the doors are open.

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The equipment situated in and around the MR environment must also be marked. This applies

in particular to equipment and other objects (racks, tables, etc.) used for monitoring or objects

that might be taken into the examination room during an emergency (e.g. fire extinguishers).

There are three signs at the MRI scanner – MR Safe, MR Conditional, and MR Unsafe (refer to

Appendix B – Safety manual).

It may be a good idea to mark e.g. the 10 mT line on the floor of the examination room. This

boundary marks the maximum field strength for monitoring devices. Note that different field

strengths can be marked in the different MRI scanner rooms. You should therefore always

check what the boundary indicates if conditional equipment is being brought in.

Rules for admission to the examination room All persons must be checked in accordance with the relevant screening form before they enter the examination room (example screening forms can be found in Appendix B – Safety manual).

As a rule, all persons must remove all magnetic metal objects (projectiles), wallets, access cards

(the data on the card could be deleted) and watches (could break) before entering the

examination room. It is a good idea for the MR staff to be the only individuals authorized to

decide who may enter and what may be taken into the examination room. All persons who will

be in the examination room during the image capturing process must wear hearing protection.

The following items must NEVER be taken into the examination room

Private wheelchairs

Patient beds and wheeled walkers

Gas cylinders

General firefighting equipment

Emergency medical bag and defibrillator

Cleaning equipment that is not MRI approved

Tools made of magnetic material

Metal objects like forceps, scissors, pens, paper clips, nail clippers, keys, bobby pins, etc.

Magnetic stripe cards, watches, and electronic equipment

Policy for staff

Everyone working in the MRI scanner room must undergo safety training and confirm that it has been completed. This also applies to external staff, such as anaesthesia, cleaning, and property service staff. Staff from emergency services must also be notified of safety information.

Staff members must be checked in accordance with the relevant screening form before they enter the MRI room for the first time. If the individual has an implant, a medical assessment must be carried out to determine whether the individual can enter/work in the examination room. Each time a staff member enters the examination room, they must remove all metal objects that constitute a projectile risk.

No known damage to foetuses has been reported for MR staff. Pregnant staff members can work as usual during pregnancy, but must not be in the examination room while the images are being captured. This restriction has primarily been set so as not to subject the foetus to high noise levels.

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Policy for patients

All patients must be checked in accordance with the relevant screening form and have undergone a medical assessment before they enter the MRI examination room. The form must be checked by the MR staff at the time of the scan before the patient enters the MRI room. The attending physician is responsible for the medical assessment of patients with implants and pregnant patients.

There are no documented adverse biological effects from the static magnetic fields used clinically in Sweden. However, the gradient fields could cause nerve and muscle stimulation. This may be uncomfortable for the patient, but is not dangerous. The scan methods must be designed to reduce the risk of nerve and muscle stimulation. The radio frequency fields cause the tissue to heat up. The scan methods must be limited so that the rise in heat does not cause damage.

The noise level in the MRI room can get high during image capture. The patients must therefore wear hearing protection during image capture.

When a pregnant patient is being examined, as special assessment is made by the attending physician. The assessment is done as an extra safety precaution since a foetus is more sensitive to

heat rise and to noise than an adult. Examinations that use a contrast medium are normally not

performed on pregnant women.

Policy for other individuals

Other individuals (who are not MR staff or patients) who wish to enter the room (e.g. accompanying persons, building contractors, or students) must be checked in accordance with the relevant screening form before they enter the MRI examination room. If the individual has any type of implant, they must either be medically assessed or refrain from entering the examination room. Note that the restrictions also apply to accompanying staff from other departments (e.g. anaesthesia).

All persons must remove all magnetic metal objects, wallets, access cards and watches before

entering the examination room. All persons who will be in the examination room during the

image capturing process must wear hearing protection. The MR staff is authorized to decide if and when a person is allowed to enter the examination room.

Helium and emergency stop

There is an emergency stop for the magnetic field in both the examination room and the control room. The emergency stop causes a quench, which causes the strong magnetic field to disappear.

A quench can also occur spontaneously, however this is extremely rare. The process to restore the

magnetic field is both expensive and time consuming, so the emergency stop must only be used in cases of serious personal danger or extensive fire. If the magnetic field must be taken down for other reasons, there are procedures to do this in a controlled manner without causing a quench. In such cases, contact the responsible supplier, physicist, or engineer.

Take the following steps if you need to press the quench button or a spontaneous quench occurs:

Inform everyone in the room that the quench button will be activated.

Also press the emergency stop for the electrical supply in the room.

Take the patient out and make sure that everyone leaves the examination room.

Close the door.

Immediately contact a physicist or engineer, as well as the supplier.

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Fire

Because of the strong magnetic field, special restrictions apply in case of fire in the MRI examination room.

The MRI department has special fire extinguishers that are specially marked (with an MR Safe symbol). These can be taken into the MRI room even if the magnetic field is on. Always check the signage on the fire extinguisher before taking it into the room. Other firefighting equipment must never be taken into the MRI room if the magnetic field is on. This is highly dangerous and could even result in death!

If a fire in the MRI examination room is so severe that the fire brigade must be called and/or other firefighting equipment is required, take the following steps:

Evacuate the examination room.

Close the door of the examination room.

Activate a quench, i.e. press the emergency stop for the magnetic field.

Also press the emergency stop for the electrical supply.

Warn those in the surrounding area and activate the alarm.

Wait at least 3 minutes for the magnetic field to disappear.

When the emergency services crew arrives, let them know that the magnetic field is down and let them into the examination room.

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PRACTICAL IMPLEMENTATION

General recommendations Due to the differences between radiological MRI and MRI for radiotherapy, a number of general

recommendations can be given. The following apply for radiotherapy-related MRI.

The system:

The table top of the MRI scanner, CT scanner, and treatment machine should have the same curvature, usually flat.

Coils must be positioned in such a way that they do not alter the skin contour.

The MRI system should be compatible with the same immobilization system used for CT.

The anatomy being imaged should be positioned as close to the isocentre of the MRI

scanner as possible.

MRI protocol:

Think carefully about which sequences are really needed and use the scan time accordingly.

The gap between the image slices should be zero.

Distortion correction should be applied in the slice direction, not just in the image plane. This is usually called 3D distortion correction.

The MR images produced should be angled the same as the CT images. Transverse and unangled are the norm.

The receiver bandwidth of the MRI scanner should be set in such a way that the water-fat shift is made smaller than one pixel. Note that this is dependent on the strength of the magnetic field.

For the MR image (which is matched against the CT), the FOV (field of view) must be large enough to cover the skin contour.

Homogenization of the signal in the MR image may be switched on to improve any segmentation and intensity-dependent matching.

Try to have as short a time as possible between the series used as a basis for matching

againstthe CT and the series used for delineating. If possible, communication with the

patient should be avoided here.

Processing:

The images should be checked for artefacts.

Any reformatting should result in transverse images for matching against the CT.Isotropic voxels are recommended when running 3D sequences.

Matching of images Purpose To perform rigid registration of CT and MR images prior to target definition for external

radiotherapy. The method can be used for matching and registration of MR and CT image series

from image modalities that do not belong to Radiotherapy. It is particularly important to check

the resolution and slice positioning for the image series in question. Always check that the

resolution achieved in the plane being reviewed (tra, sag, cor) is of acceptable quality for the

18

purpose.

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Summary of the work description

Has the CT been loaded? Has the structure set been prepared?

Draw support structures in the CT images; see Table 1.

Import the MR images.

Name the MR image series as indicated in Table 2.

Create a new registration, CT (target image) to MR_T1 (source image).

Perform registration

Name the registration.

Evaluate the results. Write any comments.

RayStation – Work description Preparations

Open the patient in the RayStation module “Patient Data Management”.

Make sure that the patient's current CT image series is loaded.

Before rigid registration is performed, the patient's outer contour must be defined. Go to the

RayStation module Patient Modeling – Structure Definition. In the New ROI geometry menu,

which is located in the ROI toolstab of the toolbar, open the Create external ROI application. In the

dialogue that opens, you can change the threshold level used as the input parameter for the calculation.

The default value is usually suitable. If not, change it by manually entering another value or by dragging

the slider under the histogram. See Figure 3.

Figure 3. Screen and histogram where the threshold level can be changed.

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If you want to make a rigid registration based on gold seeds, you must create points of interest

(POIs) for these. Switch to the POI tools tab in the toolbar. The easiest way to set a POI is to start

by positioning the cross hairs in the centre of the gold seed. Then open the New POI geometry

dialogue and select Point specification: Manual. When defining the equivalent POI in other images,

start by making the image active (Primary). Then select the POI from the POI list, click on Edit

POI geometry and select Point specification: Manual. Note that point-based rigid registration requires

that at least four POIs are defined in both images.

If you want to make a rigid registration based on structures, you must contour these in both

images. This can be done with the manual contouring tools or with the automatic tools in the

form of atlas-based and model-based segmentation. The latter two can be accessed in the New

ROI geometry menu, which is found in the ROI tools tab in the toolbar. For manual contouring, start

by creating a new ROI. Then select it in the ROI list together with the required drawing tool in

the CONTOURING section of the toolbar. When defining the equivalent ROI in other images,

start by making the image active (Primary). Then select the ROI from the ROI list and begin

drawing.

Import the MR images from Radiotherapy's MRI scanner

Import the relevant MR image series via DICOM import – Import to current patient in the Start menu

or the corresponding button in Patient Data Management. There is support for file-based and

query/retrieve-based import.

Name the image series as indicated in Table 2. This is done in Patient Data Management by opening the Image Set Properties dialogue for the corresponding image and change the name as required.

Rigid registration

Switch to the RayStation module Patient Modeling – Image Registration.

Verify that all image series that you want to match, T1 and T2 (MR_T1, MR_T1_GD, MR_T2,

MR_T2_FLAIR), have the same frame of reference (FoR). To do this, go to Image Set Library and

set one of the MR images as Primary and verify that the other MR images have a “FoR” tag; see

Figure 4. Diffusion and perfusion image series generally do not have the same FoR as T1 or T2

image series. This is because these function image series do not have the same geometric integrity

as anatomical image series.

To register the CT image to the various MR images, you must first set the CT as Primary and the T1

image as Secondary. Unless otherwise specified, it is always the CT and the T1 image series (MR_T1,

not MR_T1_GD) that are matched against each other. The T2 image series is designed to image

the anatomy in a good way, e.g. cortical bone, gold seeds, and brain. Since the T1 and T2 image

series (MR_T1, MR_T1_GD, MR_T2, MR_T2_FLAIR) have the same FoR, all of the image series

are registered to the CT image series, not just the T1 image series.

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Figure 4. Image Set Library opens.

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Anatomy registration

When anatomy is being matched, select the Gray level based registration technique. Press the Start

button (/Play symbol) to execute the registration. This is normally all that is required.

Figure 5. Select Gray level based.

For complicated cases, typically with very limited field of view or a large number of artefacts, there

are a number of tools to improve the results.

1. Use the manual tools to move the images to the approximate position, deselect the

Initialize automatically checkbox and press Start.

2. Define an ROI that can be used as the focus region. Select the Focus on region checkbox,

select the ROI, and press Start.

3. Use the Discard rotations checkbox to only consider translations. Point registration (e.g. gold seeds)

When gold seeds are being matched, select the POI based registration technique. Open the Select

POI dialogue, select the POIs you previously defined in Structure Definition (see above) and

press Start. In some cases, registration can be facilitated if the Discard rotations checkbox is ticked.

Structure registration

When structures are being matched, select the ROI based registration technique. Open the Select

ROI dialogue, select the ROI/ROIs you previously defined in Structure Definition (see above)

and press Start. In some cases, registration can be facilitated if the Discard rotations checkbox is

ticked.

Evaluation

Check the matching. How does the patient's outer contour from the CT images look on the MR

images? How much have the images been rotated? Why? Information on rotation and translation

can be found in the toolbar under TRANSFORMATION INFO.

In the Fusion tab of the toolbar or under Visualization in the left-hand panel, you can also find various

Settings for displaying the images fusioned, which can facilitate evaluation. Eclipse – Work description

Preparations

Open up the patient in the Eclipse module “Contouring”.

Make sure that the patient's current CT image series is loaded and prepared with a structure set

before starting registration between the MR and CT images.

To facilitate review of registration (matching), relevant support structures must be drawn into the CT data. A new

structure must be created in the structure set for each support structure. For the name and type of each support

structure, refer to

21

Table 1. The “Segmentation wizard” can be used when plotting the skeleton and brain. The “Segmentation wizard” is executed by right-clicking on the created structure, bones or brain, in the structure set. Click on “Segmentation wizard”, select the organ to be autoaligned, press “next” two times, and then finish with “close”. Autoalignment is not perfect, and it may be necessary to edit the structure. Eyes can often be drawn in as a circular 3D structure with a 2.3-cm diameter. Mark one eye in the structure set at a time. Use the “Brush” function, activate “static” and “3D” brush and define the diameter as 2.3 cm. Position the three slices (tra, cor, sag) so they cross centrally in the eye; click in the centre. Do the same for the other eye. Gold seeds can be outlines using the “Freehand” function.

Table 1. Support structures for evaluating registration of the respective diagnosis group. Never set any structure inside of “Body” to be the type “support”. This creates problems in dose calculation in Eclipse.

Diagnosis group Support structure(s) Name Type Other information

Cervix Skeleton Bones Skeleton

Head&Neck Support structures are used as needed.

Prostate Skeleton

Gold seeds

Bones

Gold

Skeleton

Organ

The skeleton must also be drawn in for patients with gold seeds.

Skull

(all types)

Brain

Eyes

Brain

Eye L

Eye R

Organ

Organ

Organ

Other Support structures are used as needed.

Import the MR images from Radiotherapy's MRI scanner

Import the relevant MR image series (File -> Import->Wizard->Dicom Import) and select node.

This presumes that the images were sent to this Dicom node. Press “next”, select the relevant

patient from the list and then press “next” again. Since you already have the relevant patient open

in ARIA, you can now select “task patient”. Check to make sure it is the open patient that will be

imported; check the name and personal identity number. Press “next” and check that the relevant

MR image series “new and connected” are found in “ARIA data” (column on the right). Press

“Finish”.

Name the MR image series as indicated in Table 2. The full name of the MR image series can be

found under “Comment” in “Properties” for the respective image series.

Table 2. MR image series and their intentions.

Type of MR image series Name of MR image series

T1 MR_T1

T1, fat-sat MR_T1_FATSAT

T1, gadolinium contrast MR_T1_GD

T2 MR_T2

T2, dark fluid MR_T2_FLAIR

Diffusion MR_Diff

Perfusion MR_Perf

Rigid registration (matching)

Switch to the Eclipse module “Registration”.

Verify that all image series that you want to match, T1 and T2 (MR_T1, MR_T1_GD, MR_T2,

MR_T2_FLAIR), have the same frame of reference (FoR). This can be verified by ensuring they are

22

surrounded by a common dashed yellow/orange line in “Registration” or by checking FoR in “Properties” of the respective image series. Diffusion and perfusion image series generally do not have the same FoR as T1 or T2 image series. This is because these function image series do not have the same geometric integrity as anatomical image series.

Create a new rigid registration (Registration -> New Rigid Registration) and name it “CT VS T1”. Unless otherwise specified, it is always the CT and the T1 image series (MR_T1, not MR_T1_GD) that are matched against each other. The T2 image series is designed to image the anatomy in a good way, e.g. cortical bone, gold seeds, and brain. Since the T1 and T2 image series (MR_T1, MR_T1_GD, MR_T2, MR_T2_FLAIR) have the same FoR, all of the image series are registered to the CT image series, not just the T1 image series. Then select MR_T1 as “Source Image” and the CT image series as “Target Image”. During the registration, the MR image series will then be adapted and positioned in relation to the CT image series, and not the other way around. Press “OK”. There is no registration right now, but an arrow appears and points from the MR image series to the CT image series. It is now time for the actual registration.

Anatomy registration If anatomy is being matched, select automatic matching (Registration -> Auto Matching). A

dialogue box will open; see Figure 6. A red box will also appear over the images. Position and edit

the size of the red box so that it passes over the volume you want included in the registration. The

system will only include the volume inside of the red box during registration. For this type of

registration, all six degrees of freedom (“Axes”) must be used (lat, lng, vrt, rot, roll, pitch). Then

press “Start”; see Figure 6. Repeat the process until the MR image no longer moves significantly

during registration.

Figure 6. “Auto matching” dialogue box.

Point registration (e.g. gold seeds) If gold seeds are being matched, select point matching (Registration -> Point Match). Position a

registration point on each gold seed. The registration points are dragged and dropped from the

bottom right corner of the transverse image view; see Figure 7. NOTE! Make sure that

registration points 1, 2 and 3 are used over the same seeds in each image series. Start the

registration once you are satisfied with the positioning of the registration points (Registration ->

Execute Point Match). Repeat the process until the MR image no longer moves significantly

during registration.

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Figure 7. The views for point matching. The points to be positioned are found at the bottom right in the transverse

view of each image series.

Evaluation and approval

Check the matching. How does the Body structure from the CT images look on the MR images?

How much have the images been rotated? Why? Rotation and translation for registration can be

found by right-clicking on the arrow between the MR and CT image series, and then selecting

“Properties” under the “Tech (Reg)” tab.

Enter a comment for the registration if there is anything that does not follow the standard or is

different and new in some other way. In Eclipse, highlight the registration and right-click. Select

the “Properties” tab and use the comment box for “Transformation comment”.

Support structures can be deleted after the registration has been reviewed. The physician who

defines and draws the target is responsible for ensuring that the registration/matching is of an

acceptable quality for the purpose.

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PRACTICAL IMPLEMENTATION – IMAGE

ACQUSITION

To begin using MRI in radiotherapy, a number of adaptations must be made to the protocol and

the choice of peripheral equipment. The following section addresses the practical implementation

of patient positioning and protocol suggestions for different anatomies.

Brain Sequences

Sequence example

Table 3. Sequence recommendations for the brain.

Scan Image use Potential problems

Axial T1W Matching to CT plus anatomy before contrast.

Axial T2W Delineating of target and risk organs.

Axial T2W FLAIR Outlining of vasogenic oedema/infiltrative glioma (bright).

Artefacts from CSF pulsation

Axial T1W with contrast Outlining of areas with defective blood brain barrier and neovascularization (bright).

Postoperative blood products – compare with pre-contrast T1W

Image examples

a b

c d

Figure 8. Images from Siemens Aera 1.5T system in Gothenburg. a) T1 TSE tra (4:54 min), b) T1 TSE Gd tra, (4:54

25

min), c) T2 TSE tra (4:43 min), d) T2 TIRM dark fluid tra (5:45 min).

26

a b

c d

Figure 9. Images from GE Discovery 750W 3.0T system in Lund. a) T1 BRAVO sag reformatted to tra (4:00 min),

b) T1 BRAVO Gd sag reformatted to tra (4:00 min), c) T2 FSE tra (3:52 min), d) T2 FLAIR FatSat tra (3:51 min).

27

a b

c d

Figure 10. Images from GE Signa PET/MR 3.0T system in Umeå. a) T1 FSPGR tra (2:09 min), b) T1 FSPGR Gd tra (2:09 min), c) T2 PROPELLER tra (approx. 5 min), d) T2 Cube FatSat dark fluid sag reformatted to tra (6:57 min).

Positioning and coils

Laser marking

Line things up based on the markings previously made on the immobilizing mask, if such exist. To

ensure that the patient is positioned as straight as possible in the mask, it is particularly important

to check that the sagitel laser follows the previously made marking, or is centred on the patient.

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Coil positioning

Figure 11. Coil positioning for Siemens Aera 1.5T system in Gothenburg with two Flex Large coils enclosing the

head. The coils are inserted and clamped in place under the head area of the flat table top so they also cover the rear

of the head. They are head together in the front with Velcro fasteners. The spine coil elements are not used with this

setup. The coils are supported with sand bags on the sides to get closer to the head and prevent them from pressing

on the patient's nose and face.

Figure 12. Coil positioning for GE Discovery 750W 3.0 T system in Lund. The setup is called GEM RTSuite and

two parts are in use here: 1) GEM RT Open Array, which is an additional panel in the table (not visible), 2) 6-

Channel Flex Coil, which sits to the left and right of the head. The oblong coil located at the bottom is not used.

Figure 13. Coil positioning for Philips Ingenia. The figure is a product image from Philips.

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Spacers

Most major MRI system suppliers have some type of RT-adapted equipment package that often

includes spacers in various forms.

a b c

Figure 14. RT-adapted coil positioning for image capture of the head from a) Siemens, b) GE, and c) Philips.

Scanning If possible, centre the target volume in the isocentre to maximize field homogeneity and

efficiency of any fat suppression and to minimize distortion caused by non-linear gradients.

Coverage area

The T1-weighted image is used for matching to the CT and must therefore cover as large an area

of the head as possible while maintaining correct registration.

Other images must cover the target and any risk organs to be delineated.

Figure 15. Coverage area for image acquisition of the head. FOV covers the entire skin contour of the patient and is

used to enable quality control of registration.

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Brain – stereotaxy Sequences Stereotactic treatment is used for small target areas that often require high-resolution MR images with thin slices for target delineating. This means that it may be advantageous to use 3D sequences for stereotactic patients.

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Sequence example

Table 4. Sequence recommendations for stereotactic brain.

Scan Image use Potential problems

Axial T1W Matching to CT plus anatomy before contrast.

Axial T2W Delineating of target and risk organs.

Axial T2W FLAIR Outlining of vasogenic oedema/infiltrative glioma (bright).

Artefacts from CSF pulsation

Axial T1W with contrast Outlining of areas with defective blood brain barrier and neovascularization (bright).

Postoperative blood products – compare with pre-contrast T1W

Image examples

a b

c d

Figure 16. Images from Siemens Aera 1.5 T system in Gothenburg. a) T1 TSE tra (5:18 min), b) T1 Gd tra (5:18 min), c) T2

TSE tra (6:20 min), d) T2 TIRM dark fluid tra (5:22 min).

32

a b

c d

Figure 17. Images from Siemens Aera 1.5 T system in Gothenburg. a) T1 TSE tra (4:18 min), b) T2 TSE tra (3:09 min), c) T2 SPACE tra (5:57 min), d) coverage area for T2 SPACE tra.

Positioning and coils

Laser marking

Line things up based on the markings previously made on the immobilizing mask, if such exist. To

ensure that the patient is positioned as straight as possible in the mask, it is particularly important

to check that the sagitel laser follows the previously made marking, or is centred on the patient.

Coil positioning

For the Siemens Aera 1.5T MR system at Sahlgrenska University Hospital, a holder was specially

fabricated for the stereotactic frame (CIVCO trUpoint ARCH™ SRS/SRT System). To get the

holder in a stable position, it was made to be fastened below the protruding head section of the flat

table top. Because of this, the patient must be positioned well down on the examination table,

which could potentially be problematic for unusually tall people. The advantage of this setup is that

the spine coil elements can be used to cover the rear part of the cranium. Two Flex Large coils are

wound around the stereotactic frame and are held in place with sand bags on the sides (Figure 18).

33

Image example

Figure 18. Coil positioning for Siemens Aera 1.5 T system in Gothenburg with two Flex Large coils covering the

front part of the head. The rear part of the head is covered by the spine elements in the table.

34

Head and neck area Sequences

Sequence example

Table 5. Head and Neck sequence recommendations.

Scan Image use Anatomic coverage

Potential problems

Axial T2 STIR Differential oedema (bright) Cerebellum to shoulders

Swallow artefacts, flow artefacts

Axial T1 Delineating of nerves and teeth Cerebellum to shoulders

Axial ADC Plotting of hypercellularity (dark) Tumour Geometric distortion

Axial Fat- suppressed postcontrast T1

Plotting of faulty, leaky tissue (bright)

Cerebellum to shoulders

Swallow artefacts, flow artefacts

Image examples

a b

c d

35

Figure 19. Images from Siemens Aera 1.5 T system in Gothenburg. a) T1 TSE tra 3 mm (6:36 min), b) T1 TSE tra

3mm FatSat (6.36 min), c) T1 TSE tra 3mm GD (6.36 min), d) T2 TSE tra 3mm (6.41 min). All run with Neck

Shim and WARP.

a b

Figure 20. Images from GE 750W 3.0 T system in Lund a) T1 CUBE tra 2mm (7:07 min), run coronal 1 mm

isotropic. b) T2 CUBE tra 2 mm (8:31 min), run coronal 1 mm isotropic.

a b

c d

Figure 21. Images from GE 750W 3.0 T Signa MR/PET system in Umeå a) T1 IDEAL Water tra 4 mm (6 min), b) T1 IDEAL INPHASE tra 4 mm (6 min), c) T2 FRFSE Tra 4 mm (4 min). d) T2 Propeller sag 4 mm (5 min).

36

Positioning and coils Laser marking

Line things up based on the markings previously made on the immobilizing mask, if such exist. To

ensure that the patient is positioned as straight as possible in the mask, it is particularly important

to check that the sagitel laser follows the previously made marking, or is centred on the patient.

Coil positioning

Figure 22. Coil positioning for Head & Neck with Body 18 Long on a Siemens Aera 1.5 T system in Gothenburg. There

is also a Flex Small coil positioned posteriorly (under the table top) to increase the SNR from the rear skull parts.

Figure 23. Coil positioning for Head & Neck on a GE Discovery 3.0 T 750W system in Lund. The setup is called

GEM RTSuite and consists of 3 parts. These parts are 1) GEM RT Open Array, which is an additional panel in

the table (not visible), 2) GEM Flex Coil 16-L Array, 3) 6-Channel Flex Coil. Spacers and holders are also visible

in the figure around the visible coils.

37

Figure 24. Coil positioning for Philips Ingenia. The figure is a product image from Philips.

Coverage area

Figure 25. Coverage areas (sag, cor) for head and neck. The large FOV used gives the skin contour of the patient

and is used for better control of the matching.

Image use

Things to consider

If the patient has dental fillings, these will appear as streak artefacts in CT; see Figure 26 a). This

problem is often avoided in MRI as the artefacts instead become small, local, signal-poor parts;

see Figure 26 b). The size of the artefacts in CT depend on what type of material the dental filling

is made out of; see Figure 27 a). The same applies to MRI, but the artefact there can instead take

the form of a geometric distortion, signal loss and/or signal shift; see Figure 27 b). With such

severe geometric distortion, great care should be taken when defining the target and risk organs in

or near the artefact.

38

a b

Figure 26. a) Streak artefacts on a CT image resulting from dental fillings, b) the same anatomy imaged with MRI.

a b

Figure 27. a) Streak artefacts on a CT image that are coarser in nature than in 26, b) the same anatomy imaged with MRI

with large artefact from dental filling, where the artefact exhibits geometric distortion and signal shift (white stripe).

Prostate Preparations The use of contrast medium is governed by local procedures. The procedures for when the patient should drink and/or urinate are governed by local regulations, but the recommendation is to use the same method for CT, MRI and the radiotherapy treatment unit for each radiotherapy fraction.

Umeå provided the following information in November 2015:

New procedures from Umeå for lower abdominal examinations (prostate, rectum, gynaecology).

To reduce motion artefacts from the bowels, the patient is informed that they must fast for the 4

hours immediately preceding the examination, and Glucagon 1 mg s.c. is given right before the

MRI. As previously, the CT and the MRI are performed immediately after each other.

39

Sequences Sequence example

Table 6. Prostate sequence recommendations.

Scan Image use Anatomic coverage Potential problems

Sag T2 Delineating of rectum and bladder Prostate, vesicles

Axial T2 Delineating of prostate and extracapsular disease (dark).

Vesicles down to bulb of penis Post-biopsy haemorrhaging.

Difficult to see the marker.

Axial fat suppressed T2

Delineating of extracapsular disease (dark). Lymph nodes (bright).

Vesicles down to bulb of penis Post-biopsy haemorrhaging

Axial T1 Detection of post-biopsy haemorrhaging (bright). Visualization of markers.

Prostate. Skin and hip bone during anatomy matching.

Axial Diffusion ADC

Delineating of tumour (dark) Prostate Geometric distortion

Image examples

a b

Figure 28. Images from Siemens Aera 1.5 T system in Gothenburg. a) T1 VIBE tra 2 mm (3:38 min), b) T2 TSE tra 2 mm (6:17 min).

40

a b

c d

Figure 29. Images from GE 750W 3.0 T system in Lund a) GRE tra 3 mm (06:03 min), b) T2 Propeller tra 3 mm c) T2

Propeller sag 3 mm d) T2 Propeller cor 3 mm.

41

a b

c d

e

Figure 30. Images from GE 750W 3.0 T Signa MR/PET system in Umeå a) Lava Flex tra 2.5 mm (2:09 min), b) T2

FRFSE tra 3 mm (3:48 min), c) T2 FRFSE Stort FOV 2.5 mm (3:48 min) d) T2 FRFSE sag 3 mm (4:11 min) e)

FOCUS DWI 4 mm (2:24 min).

Positioning and coils Laser marking and ink

If the patient comes in for the MRI after undergoing the CT scan and creating a CT treatment

plan, then there will already be body markings that were applied to the patient's hip during the CT

visit. The position of these body markings are determined by a laser with preset definitions that

are the same as the preset definitions for CT and the treatment unit. By matching this laser system

with these markings, the patient can be positioned the same way in each radiotherapy fraction and

you get a reproducible position for the patient. This avoids rotation of the pelvis, thereby

minimizing the prostate's position deviation between different radiotherapy fractions.

42

When the patient comes in to MRI it is advisable for the same positioning procedure to be used.

There is therefore usually a laser system in the MRI room; see Figure 31. If the laser system does

not align with the body markings, you can rotate the patient's hip by grasping it and rotating.

Once this is done, it is advisable to ask the patient to lift their pelvis straight up in the air slightly

and then lower it again. Then check that the laser aligns with the body markings. See Figures 32 a)

and b).

Figure 31. MRI scanner equipped with flat table top and immobilization system for radiotherapy.

Note the external laser system housed on the arch around the scanner.

a b

Figure 32. a) Patient's position requires correction, b) patient's position is correct.

Because of the manual rotation performed with the hip, there is a risk of the buttocks will end up

slightly asymmetrical. By asking the patient to lift their hips slightly, you avoid having the buttocks

end up in different positions between the CT image and the MR image, which could make

registration between these images more difficult. The separation between the buttocks can be used

as a landmark to check whether any asymmetry has occurred in the position. See Figures 33 a) and

b).

a b

Figure 33. Separation of the buttocks on a) CT image, and b) MR image.

43

Ink type

It is important to pay attention to what type of ink is used for the body markings as certain ink

types have been shown to produce artefacts in the form of signal loss on the MR image; see

Figure 34 and Table 7. This is not acceptable when MRI is used for treatment planning, but in

connection with matching the MR image to a CT image it is not as critical since only a small

proportion of the skin has disappeared. After automatic matching, always check that the results

are correct.

Figure 34. Artefacts from tattoo ink are seen at the arrows.

Table 7. Tattoo ink manufacturers and affect on images.

Name of ink Manufacturer Origin Artefacts

Rotring Switzerland NO

Derma safe pigment color Black 010ds(S)

Lot.no.0002231

PAR SCIENTIFIC Germany MT. DERM GmbH in Berlin. CI 77499.

YES (phantom verified)

www.atomictattooink.com www.atomictattooink.com NO (none found)

Sacred Color Tatoo´s ink Black Liner

Incredible Imported by Lundberg Custom Supplies Sweden AB.

NO (phantom verified)

Drawing ink A P 17 Pelikan Zeichentusche Drawing Ink

NO (none found)

44

Coil positioning

Figure 35. Coil positioning with Body 18 Long on a Siemens Aera 1.5 T system in Gothenburg. The coil arches

prevent the coil from pressing on the skin contour. The knee support sits on a moveable rail created at a workshop.

The knee support should be the same type as in CT to obtain the best reproducible patient positioning.

Figure 36. Coil positioning for prostate on a GE Discovery 3.0 T 750W system in Lund. The knee support should be

the same type as in CT to obtain the best reproducible patient positioning.

45

Figure 37. Coil positioning for Philips Ingenia. The figure is a product image from Philips.

Coverage area

Figure 38. Coverage areas (cor, sag, tra) for a transverse T2-weighted series for the prostate. It is advisable to cover

the entire prostate, approx. 3-4 slices, from above the bladder base down to the penis root.

Figure 39. Coverage areas (cor, sag, tra) for a transverse T1-weighted series for the prostate. The large FOV

used gives the skin contour of the patient and is used for better quality control of the registration.

For patients with MRI-compatible hip prostheses, see Figures 40 a) and b), the protocols can be

adjusted so that metal artefacts are as small as possible. This is best done by applying any metal

artefact reduction functions, if such are available from the supplier. If such are not available, a

higher bandwidth and reduced echo time could limit the spread of metal artefacts. The artefacts are

generally smaller on 1.5 T compared to 3.0 T. On CT, streak artefacts penetrate the prostate, while

the prostate is intact on the MRI; see Figures 40 a) and b). Bear in mind that automatic matching

with CT, if used, may be incorrect. Carefully check the matching manually.

46

a b

Figure 40. a) CT, and b) MR (T1W GRE) on a patient with double hip prostheses.

Visualization of gold seeds In order for a T2-weighted image series to be matched against CT data, you often rely on an image

series where the gold markers are clearly visible and instead register these to the CT. This image

series is often taken with some type of gradient echo-based imaging technique to show the position

of the gold seeds in the prostate more clearly; see Figure 41. We call this image series the

differentiation series. The registration between the T2-weighted image series and the CT data then

follows automatically since the T2-weighted image series and the differentiation series are taken in

the same frame of reference. A disadvantage of this approach is that there is a risk that the patient

and/or the patient's anatomy has moved between the image capture of the T2-weighted image

series and the image capture of the differentiation series. This can be addressed by directly

visualizing the gold markers in the T2-weighted image series.

Figure 41. Image taken with a GE 750W 3.0 T using the gradient echo technique. In the slice, the artefact from a

gold marker is clearly visible as a signal loss (dark) with an area significantly larger than that of the gold marker.

Thus, the susceptibility artefact from the gold seeds is used for localization.

It may be challenging to visualize the gold markers directly on the T2-weighted image series

because the gold markers themselves are small, and the T2-weighted image series is often based

on the turbo spine echo technique (TSE), which automatically minimizes and to some degree

compensates the susceptibility artefacts from the gold markers. In TSE sequences, there is also

smearing in the image as a result of the repeated 180° pulses it uses. On a Siemens Aera

47

1.5T system and a GE 750W 3.0T system, the following adjustments have been shown to visualize

the gold seeds directly on the T2-weighted image series.

Increase the spatial resolution of the image. Approx. 0.7 x 0.7 mm, depending on the size of the gold markers used.

Reduce the slice thickness to reduce partial volume artefacts. Approx. 2.5 mm.

Reduce echo train smearing by reducing the echo train length in the TSE sequence.

Restrict the number of NEX to just 1 to reduce the smearing caused by averaging.

Eliminate imaging acceleration to increase SNR.

Restrict imaging to 1 package.

Use movement correction, if available.

These measures often lead to a reduction in SNR and thereby an increase in scan time to obtain

acceptable image quality.

Figure 42 depicts a large FOV T2 image series taken with a GE 750W 3.0 T system and following

the above imaging recommendations. A close-up of the prostate is shown on the right. In the

close-up, a gold marker can be seen as a small signal loss very locally (see red arrow). Such small

signal losses can also be seen if the patient has calcifications in the prostate or if the patient has

undergone previous biopsies. To differentiate between these objects, the differentiation series (see

Figure 43) can be used to visually (without matching) determine whether it is a gold marker or not;

see red arrow. The artefacts from gold markers often have a symmetrical spread.

Figure 42. Large FOV T2 image and a close-up of the prostate in the image on the right. The gold marker is

seen as a local signal loss (orange arrow).

48

Figure 43. GRE differentiation series where a large susceptibility artefact of the gold marker can be seen (orange arrow).

49

Cervix Brachy Preparations The patient arrives to the MRI scanner on a bed from the Bracytherapy department with the applicator inserted vaginally. The applicator used is made of plastic or another MRI-compatible material; see Figure 44. To optimize the examination, the patient should be lying on a dockable MRI table so as to avoid having to transfer the patient from a standard bed to the examination table.

In order for the applicator to lie in place, it is secured with plugs that are sufficiently moistened

with saline or another liquid to enable the best visualization in the MR image. Saline works best for

MR 3T (Figure 47). For scanners with lower field strength, plug visualization may work better if a

little contrast medium is mixed into the liquid. The plug also helps to shift the rectum and bladder

away from the parts of the applicator that are situated within the vagina.

To reduce motion artefacts from the bowels, the patient is given 1 ml Glucagon i.m. before being

moved to the dockable MRI table. Extreme care is then taken during patient transport so as not to

disturb the applicator position. The same applies once the examination is complete.

The bladder must not be full. The patient will have a catheter inserted in the bladder (IUC); check

the bag if necessary. The recommendation of the GYN-GEC-ESTRO working group is for the

bladder to be moderately full to more easily reproduce the bladder during brachytherapy.

Figure 44. Example of applicator with cervix brachytherapy. The model also shows how needles for interstitial

brachytherapy are positioned in the applicator ring. Plastic model from Electa.

Coverage area

For cervix brachytherapy planning based on MRI, the slices should be positioned relative to the

applicator's ring plane and the applicator plane. This reduces any image interpolation effects when

processing the images.

50

Positioning and coils The patient is placed on the dockable MRI table with diagnostic equipment, i.e. not a flat table top

as in conventional external radiotherapy and no knee support. The examination is done with the feet

entering the scanner first and the abdominal coil positioned directly on the patient's pelvis (Figure

45).

Figure 45. Patient positioning for MRI Cervix Brachy Siemens Skyra 3T. The patient is scanned without a flat

table top and spacers.

The patient will be given an epidural or other sedation, so monitoring with anaesthesia equipment

is necessary. The anaesthesia staff will connect the necessary equipment to the patient before the

MRI scan begins.

Sequences The main purpose of MR imaging is to visualize the tumour. The MR images are then used for

targeting and treatment planning, which is done directly on the MR images. Risk organs, such as

the bladder, vagina, rectum, and sigmoid, as well as relevant anatomical structures are visualized

well on T2-weighted sequences without the use of contrast medium. The T2-weighted sequence is

a base sequence, where turbo spine echo is preferable in view of the scan time. Contrast medium

is not required since urine provides high signal intensity on T2-weighted images. The bladder then

has a high contrast to other anatomy. The applicator provides a low signal on T2-weighted images

and provides sufficient contrast to surrounding anatomy so that it can be visualized and drawn

into the treatment plan at a later time.

The patient will have always undergone a diagnostic MRI scan before brachytherapy and there will

always be an MRI treatment plan for external radiotherapy.

51

Sequence example

Table 8. Cervix sequence recommendations.

Scan Image use Anatomic coverage Potential problems

T1 For interstitial treatment and to visualize glands (where relevant)

Entire uterus included and caudally downwards along the applicator as far as can be covered with the box.

T2 Risk organ and tumour visualization Same coverage as above

Image examples

a b

c d

Figure 46. Images from Siemens Skyra 3T system in Stockholm (Karolinska) a) T2W clear visualization of ring applicator (orange arrow), b) T2W Ring applicator in sagittal plane, c) T2w, and d) T2w with visible plug (orange arrow).

52

a b

c d

Figure 47. Images from Siemens Skyra 3T system in Stockholm (Karolinska) a) T1-weighted visualization of plug (orange arrow), b)T1-weighted sag applicator, c) T1w, and d) T1w.

Figure 48. Coverage area for transverse T2w sequence for cervix.

53

Figure 49. Applicator plotted on T2w image in Oncentra treatment planning system.

Figure 50. Plotting of risk organs and target on T2-weighted image in Oncentra Nucletron treatment planning system.

54

QUALITY CONTROL

As part of Work package 4 of the “Gentle Radiotherapy” project, as of 3 March 2016 work is under way to compile a

QA manual for MRI in radiotherapy.

Geometric accuracy

GE phantom

Before you start

Evaluation software must be installed on the MR control panel in order to get the results from the

phantom measurement. GE may be of assistance in this matter. A research agreement may also be

required. See Torfeh, 2016 as a reference to this phantom.

Phantom setup

1. Make sure the GE system is set to research mode (on the MR control panel, press the

arrow on the Toolbox icon. Then select System Preferences and select mode). A research

agreement with GE may be required to see this alternative.

Figure 51. GE phantom from above.

2. Define a new patient with name SpatAcc SpatAcc, personal identity number 19111111-

1111. Weight 50 kg. Start Exam. Select the protocol Template/QA Geometry Phantom 20XX-XX-XX, Accept. This presumes that a protocol has been defined. If not, continue reading and save a protocol. Select “first level” on SAR and gradient. Accept. Add the plexiglas panel in the recess in the table. See Figure 52.

55

Figure 52. GE phantom from the side. The plexiglas panel is positioned in the table.

3. Position the phantom. It may be good to have two people to do this since the

phantom weighs 50 kg. Make sure that the lower pegs of the phantom engage in the

holes of the plexiglas panel. Make sure that the red laser of the camera is aligned with

the centre ball visible at the top of the phantom (on the black panel; see Figure 53).

Also ensure that the lasers in all directions are aligned with the other balls, i.e. that the

phantom is straight. Do not use the external laser. Make sure this is completely

switched off as it could cause a reduction in the SNR in the images. Lock the position

of the laser and slide the table into the tunnel.

Figure 53. On the black panel, you can see whether the laser is correctly aligned with the position of the phantom.

Scanning the phantom

1. In the protocol you selected, there is a first SURVEY called FGRE Survey.

Scan this. The values should be filled in as follows:

Scan orientation should be “Head First”. Change to 1 slice (at isocentre) per scan plane,

FOV=48cm, Slice thick=3mm. Run auto prescan; if it fails, use manual prescan instead (your

phantom is probably a little bit off the gradient axis). Scan the localizer. Evaluate phantom position

in all 3 localizers and reposition/rescan if needed to centre it “very well”. A sphere along S/I = 0,

R/L = 0 should be at isocentre (A/P position depends on the height of your phantom, and/or

what system you are using). Try to get the LR and SI centring errors < 1mm, and AP < 3 mm.

The overall goal is to align one of the centre spheres at (S/I = 0, L/R = 0) with the gradient

isocentre. The centre sphere is specified in the template.cfg file in spatial distortion analysis directory:

/export/home/signa/tools/spatial_tool/.

2. To learn what the error is in the positioning of the phantom, you can open another

56

survey (double click on FGRE zero check, then press the left arrow at Details) as if you were planning it. Change the figure in the “Center” field for the different directions. Perfect positioning results in 0 in all fields and the cross hairs running through the centre point perfectly in all directions. By changing “Center”, you can see when the cross hairs are aligned and thereby eliminate deviation. Correct the physical position of the phantom if it is not within the specified margins; see above. If the position is OK, this second survey does not have to be run. The distance in AP cannot be changed as it is the height. This must be left as it is. This deviation (approximately 5 mm) is visible in the transverse image, which is shown when you press the left arrow at Details. See Figure 54.

Figure 54. The cross hairs should align with the centre ball in the phantom when the distance is set to 0.

3. Plan the next scan in the protocol, called Fast GRE QA 125 kHz, by double clicking on it.

This scan is a self-compiled scan that is based on efgre3d but also takes into account the

CV changes specified by GE. A complied version that takes these CV changes into

account for DV25 can be obtained from Christian Gustafsson

(christian.k.gustafsson@skane.se) upon request. If it is not possible to obtain this self-

compiled scan, make the following CV changes:

Setting CVs

Click “Save Rx” button.

Scan pull down -> Research -> Download.

The reposition table light may come on, but ignore

it. Scan pull down -> Research -> Display CVs

Set CV ns3d_flag = 1, click Accept (uses non-selective excitation)

Set CV opslblank = 0, click Accept

Set CV rhslblank = 0, click Accept

*note*(CVs opslblank and rhslblank == 0, prevents removal of outermost edges of the 3D slab)

Set CV xlFOV_flag = 1, click Accept (allows FOV>48 cm, valid for 3DFGRE/EPI)

57

Set CV autolock = 1, click Accept (optional, turns ON raw data file save)

Scan pull down -> Research -> Download

The scan should have the following values:

4. Save RX. Press the arrow at Scan. Run Auto Prescan and write down the parameters for

TG, R1, and R2. The centre frequency will be set automatically. Run Manual Prescan,

verify that TG, R1, and R2 are set to R1:13, R2:15, TG:137. If not, change them. Set

Gradshims X,Y,Z = [0,0,0]

5. Scan.

To perform multiple scans

For the first series, use Auto Prescan, and write down prescan parameters. These will need to be the same for all

series within the exam. For the second series, use manual prescan to set TG, R1, R2 and CF to the same values as

for series 1. If auto prescan fails, the phantom may be a little off from isocentre. Use the 3-plane localizer to align.

Otherwise, use manual prescan: Manual prescan parameters: TG=157, R1=13, R2=15, Gradshims X,Y,Z =

[0,0,0]

Scan

Note: TG is the transmit gain of the analogue signal coming from the exciter, and is displayed in 1/10dB; R1 is

the analogue receive gain; R2 is the digital receive gain originating from the reconstruction blade (ICN/VRE).

Gradshims are applicable only for large masses, and can thus be set to zero.

Note: To repeat the scan with alternate parameter(s):

Right click the scanned series, and press “Duplicate and setup” (this retains previous CV mods). Modify protocol

58

parameters (bandwidth and/or NEX)

59

Save Rx

Download

Manual prescan – verify that the manual prescan parameters are the same as for the last series.

Scan

Processing scan data on the control panel

1. Extract data on the MR control panel by opening a terminal window and entering:

cd /export/home/signa/tools/spatial_tool

run_SDA

The evaluation program will then start. Deselect “CT image as reference image”. You must enter the MR exam or MR series number. These can be found in Patient Explorer. See Figure 55.

Figure 55. The evaluation program run on the MR control panel. MR exam and MR series number can be

found in Patient Explorer.

2. Choose the series you want to evaluate. Press Analysis. This will take no more than 5 minutes.

In one of the windows that opens, you can see how many reference points were matched.

Write the number of “marker locations matched in target image set”. See Figure 56.

Figure 56. The evaluation is complete. The number of markers that were matched is shown at the bottom of the log.

60

3. The evaluation of the data is shown in another window. The same evaluation can be run

offline with Matlab. The file used for this this_err.mat and is found in the directory where

you currently are. Rename this to this_err_125khz_2015-XX-XX.mat or a suitable name

for a different bandwidth. This is done by being in the correct directory and writing

mv this_err.mat this_err_125khz_2015-XX-XX.mat

The results file is now on the control panel (see Figure 57) and can be retrieved

through SFTP and then evaluated offline with Matlab.

Figure 57. The evaluation is complete and graphs open on the MR control panel.

Evaluating data offline in Matlab

Retrieve the data using FileZilla or the like

IP: IP address of the MR control panel

USER/PASS is the same as you use when logging in to the MR control panel in the morning

Go to the directory /export/home/signa/tools/spatial_tool

Sort by name

Transfer the correct .mat file.

Evaluating data

The following Matlab code can be used for offline data evaluation: load('this_err_125khz_20XX-XX-XX.mat');

figure;plot(sortrads,sorterr,'.',...

plotmaxrads,plotmaxerr,'r',...

maxrads,avgerr,'g',...

maxrads,avgerr+stderr,'b',...

maxrads,avgerr-stderr,'b');

axis([0 300 0 30]); grid on;

61

legend('Marker Error','Max Error','Average Error','Average Error +/-

STD','Location','NorthWest');

xlabel('\bfdistance from isocenter [mm]');

ylabel('\bflocation error [mm]');

title(['\bf', plotTitle ' Plot 1']);

saveas(gcf, ['TOTAL_error_' plotTitle], 'png');

figure; plot(rad, E(1,:),'.',rad,E(2,:),'.',rad,E(3,:),'.');

axis([0 300 -25 25]); grid on;

legend('\bfx','\bfy','\bfz','Location','NorthWest');

xlabel('\bfdistance from isocenter [mm]');

ylabel('\bflocation error [mm]');

title(['\bf', plotTitle ' Plot 2']);

saveas(gcf, ['XYZ_error_' plotTitle], 'png');

% Use the following variables from your MATLAB workspace: matchT, matchR

and E.

% DEF: matchT = location of identified markers in image data

% DEF: matchR = location of reference markers

% DEF: E = (matchT-matchR)*1000; Vector of errors, unit is mm (vector

poiting from matchR to matchT)

The following files are saved:

TOTAL_error_DISCOVERY MR750w, DATUM, 125 kHz.png

XYZ_error_DISCOVERY MR750w, DATUM, 125 kHz.png

You can then browse between these files to see changes in system performance; see Figure 58 and Figure 59.

Figure 58. Data shows deviation (max, average) to marker as a function of distance to isocentre.

62

Figure 59. Data shows deviation of all points as a function of distance to isocentre.

63

REFERENCES

Dempsey C., Arm J., Best L., Govindaravalu G., Capp A.,O`Brien P. Optimal single 3T MR imaging sequence for

HDR brachyteraphy of cervical cancer. Journal of Contemporary Brachytherapy 2014;6,1:3-9.

Dimopoulos J., Petrow P.,Tanderup K. et al. Recommendations from Gunaecological (GYN) GEC-ESTRO Working

Group (IV): Basic principles and parameters for MR imaging within the frame of image based adaptive cervix cancer

brachytherapy. Radiother Oncol 2012;103: 113-122.

Liney, G. P. and M. A. Moerland (2014). "Magnetic resonance imaging acquisition techniques for radiotherapy

planning." Semin Radiat Oncol 24(3): 160-168.

Paulson, E. S., et al. (2015). "Comprehensive MRI simulation methodology using a dedicated MRI scanner in

radiation oncology for external beam radiation treatment planning." Med Phys 42(1): 28-39.

Integration of MRI into the radiotherapy workflow, PhD thesis, Joakim Jonsson, Umeå Universitet …

61

APPENDIX A – SUPPLIER-SPECIFIC SEQUENCE SUGGESTIONS

The recommendations given in General introduction (page 6) and Prostate (page 36) should be applied to the supplier-specific sequence suggestions.

This can include immobilization, signal homogenization, 3D distortion correction and absence of distance between image slices.

Brain GE

1.5T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

3T – Discovery 750W

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1W 6ch phased-array BRAVO 7.8 3.2 256 1.0 1.0x1.0 244 Sag GRE 3D T2W 6ch phased-array T2 FSE 9265 102 220 4.0 0.4x0.4 195 Tra SE 2D

T2W FLAIR 6ch phased-array T2 FLAIR 11000 90 220 4.0 0.7x0.86 223 Tra SE 2D T1W Gd 6ch phased-array BRAVO 7.8 3.2 256 1.0 1.0x1.0 244 Sag GRE 3D

3T – Signa PET/MR

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1W

HNU

FSPGR

8.5

250

1.0

0.9x1.2

244

Tra

GRE

3D 3D corr. +

intensity corr.

T2W HNU PROPELLER 7898 100 220 2.0 0.5x0.5 223 Tra SE 2D 3D corr. +

intensity corr.

T2W FLAIR HNU FSPGR 8.5 250 1.2 0.9x0.9 244 Sag FatSat + FLAIR SE 3D 3D corr. +

intensity corr.

T1W Gd HNU CUBE 6000 134 240 1.0 0.9x1.2 244 Tra GRE 3D 3D corr. +

intensity corr.

62

Siemens 1.5T – Aera

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1W 2 x Flex L T1 TSE 577 7.5 240 3.0 0.9x0.9 300 Tra SE 2D T2W 2 x Flex L T2 TSE 4265 86 240 3.0 0.9x0.9 191 Tra SE 2D

T2W FLAIR 2 x Flex L T2 TIRM 8180 89 240 3.0 1.2x1.3 180 Tra SE 2D T1W Gd 2 x Flex L T1 TSE 577 7.5 240 3.0 0.9x0.9 300 Tra SE 2D

3T – Skyra

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

Philips – sequence recommendations from manufacturer 1.5T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm) Slice

thickness (mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T2 3D Tra Posterior coil +

2x FlexL

TSE 3D View

2500

213

250 x 200 x 200

2.0

1.0 x 1.0

935.9

Tra

none

Spin Echo

3D Time: 06:33

min

FLAIR 3D Tra

Posterior coil + 2x FlexL

IRTSE 3D View

4800

291

250 x 200 x 200

2.0

1.16 x 1.16

1091.8

Tra

SPIR

Spin Echo Inversion recovery

3D

Time: 6:24 min

T1 3D Tra Posterior coil +

2x FlexL TFE 3D 8.0 3.5 250 x 200 x 200 2.0 1.0 x 1.0 228.6 Tra none GRE 3D

Time: 6:23 min

OPTIONS Metal object detection Tra

Posterior coil + 2x FlexL

b-TFE 3D

6.7

4.6

250 x 200 x 200

2.0

1.5 x 1.5

1417.2

Tra

none

balanced Gradient

Echo (bSSFP)

3D

Time: 1:44 min

T2 FS 3D Tra Posterior coil +

2x FlexL

TSE SPAIR 3D View

2000 202 180 x 180 x 90 2.0 1.15 x 1.14 1014.2 Tra SPAIR Spin Echo 3D Time: 05:22

min

T1 FS 3D Tra Posterior coil +

2x FlexL e-THRIVE 3D 4.6 2.2 180 x 180 x 90 2.0 1.15 x 1.15 432.8 Tra SPAIR

Gradient Echo

3D Time: 05:22

min

T1+FS 2D Ax Posterior coil +

2x FlexL mDixon TSE 2D 594 15 180 x 180 x 90 2.0 1.25 x 1.30 1085.1 Tra mDixon Spin Echo 2D

Time: 06:42 min

T2+FS 2D Ax Posterior coil +

2x FlexL mDixon TSE 2D 2895 90 180 x 180 x 90 2.0 1.25 x 1.26 975.3 Tra mDixon Spin Echo 2D

Time: 08:42 min

63

3T

Sequence Coil Product name

of sequence TR (ms)

TE (ms)

FOV (mm) Slice

thickness (mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T2 3D Tra Posterior coil +

2x FlexL

TSE 3D View

2500

232

250 x 200 x 200

2.0

1.0 x 1.0

935.9

Tra

none

Spin Echo

3D Time: 06:32

min

FLAIR 3D Tra

Posterior coil + 2x FlexL

IRTSE 3D View

4800

322

250 x 200 x 200

2.0

1.16 x 1.16

1091.8

Tra

SPIR

Inversion Recovery Spin Echo

3D

Time: 06:24 min

T1 3D Tra Posterior coil +

2x FlexL TFE 3D 8.0 3.5 250 x 200 x 200 2.0 1.0 x 1.0 455.1 Tra none

Gradient Echo

3D Time: 06:24

min

Option Metal object detection Tra

Posterior coil + 2x FlexL

b-TFE 3D

4.0

1.99

250 x 200 x 200

2.0

1.5 x 1.5

620.0

Tra

SPAIR

balanced Gradient

Echo (bSSFP)

3D

Time: 02:34 min

T1 FS 3D Tra Posterior coil +

2x FlexL e-THRIVE 3D 4.6 2.2 180 x 180 x 90 2.0 1.15 x 1.15 456.6 Tra SPAIR

Gradient Echo

3D Time: 04:54

min

T2 FS 3D Tra Posterior coil +

2x FlexL TSE SPAIR 3D

View 2000 240 180 x 180 x 90 2.0 1.0 x 1.0 879.0 Tra SPAIR Spin Echo 3D

Time: 05:46 min

T1+FS 2D Tra Posterior coil +

2x FlexL mDixon TSE 2D 624 6.7 180 x 180 x 90 2.0 1.05 x 1.07 908.4 Tra mDixon Spin Echo 2D

Time: 06:42 min

T2+FS 2D Tra Posterior coil +

2x FlexL mDixon TSE 2D 2824 100 180 x 180 x 90 2.0 1.10 x 1.16 518.5 Tra mDixon Spin Echo 2D

Time: 08:42 min

64

Brain – Stereotaxy GE

1.5T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

3T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

Siemens 1.5T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm) Slice

thickness (mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family

2D or 3D

Other

T1 without contrast

2 x Flex L

T1_TSE

582

7.5

250 x 87.5%

3

0.8 x 0.8

300 Hz

Tra

SE

2D

T2 T2_TSE 5480 82 250 x 84.4% 2 0.8 x 0.8 191 Hz Tra SE 2D T2 FLAIR T2_TIRM 8490 89 250 * 100% 3 1.3 x 1.3 180 Hz Tra Dark Fluid (IR) SE 2D TI=2438 ms

T1 with contrast

T1_TSE 582 7.5 250 x 87.5% 3 0.8 x 0.8 300 Hz Tra SE 2D

3T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

65

Philips 1.5T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

3T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

66

Head and neck GE

1.5T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

3T – Discovery 750W

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1 Tra

GEMRTSuite = 6 ch phased

array GEM RT Open Array

Gem Flex Coil 16 L array

Cube T1

600

Min

440

1

1x1x1

446 Hz

Cor

SE

3D

Recon Tra 2 mm

with 0.86 mm spacing

T2 Tra

Cube T2

2500

Max

440

1

1x1x1

446 Hz

Cor

SE

3D

Recon Tra 2 mm with 0.86 mm

spacing

T1 Tra Gd

Cube T1

600

Min

440

1

1x1x1

446 Hz

Cor

SE

3D

Recon Tra 2 mm with 0.86 mm

spacing

3T – Signa PET/MR

Sequence Coil Product name

of sequence TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1 Tra FlexLarge +

CMA

IDEAL

718

9.2

240

4

0.68x1.1

355

Tra

DIXON

SE

2D

T2 Tra FRFSE 5624 102 240 4 0.47x0.75 244 Tra SE 2D Sag T2 Propeller 5512 94 240 4 0.625x0625 434 Sag SE 2D

Diffusion FOCUS 6000 70.4 160x80 4 1.14x1.14 238 Tra FAT Special SE 2D

67

Siemens 1.5T – Aera

Sequence

Coil

Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique Sequence family

2D or 3D

Other

T1 TSE

Flex S under extension of table (neck) + Body

18 coil supports (arches)

T1_TSE

577

7.8

480 x 81.3%

3

1.1x1.1

302 Hz

Tra

SE

2D

Neck shim and WARP artefact

reduction

T2 TSE

T2_TSE

3630

80

400 x 81.3%

3

0.9*0.9

302 Hz

Tra

SE

2D

Neck shim and WARP artefact

reduction

T1 TSE Gd

T1_TSE

577

7.8

480 x 81.3%

3

1.1*1.1

302 Hz

Tra

SE

2D

Neck shim and WARP

artefact reduction

T1 TSE Gd

T1_TSE

577

7.8

480 * 81.3%

3

1.1*1.1

302 Hz

Tra

Fat (FatSat)

SE

2D

Neck shim and WARP

artefact reduction

3T – Skyra

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1 Tra Body 18 Vibe 5.56 2.46 300 2.0 0.8*0.8 320 Tra GRE 3D T2 Tse T2_TSE 12000 94 250 3.0 0.7*0.7 246 Tra SE 2D T1 Tra Vibe 907 12 245 3.0 0.5*0.5 399 Tra SE 2D

Philips – Large FOV – sequence recommendations from manufacturer 1.5T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T2 3D Tra

Posterior coil + Anterior coil +

2x FlexL

TSE 3D View

2000

213

260 x 340 x 300

2.4

1.14 x 1.14

870.2

Transaxial

none

Spin Echo

3D

Time: 06:14 min

Option

T1 3D Tra Posterior coil + Anterior coil +

2x FlexL

TFE 3D

6.6

3.2

260 x 340 x 300

2.4

1.14 x 1.14

228.4

Transaxial

none

Gradient Echo

3D

Time: 06:25 min

Metal object detection Tra

Posterior coil + Anterior coil +

2x FlexL

b-TFE 3D

6.6

4.6

260 x 340

x 300

2.4

1.25 x 1.74

615.6

Transaxial

none

balanced Gradient

Echo (bSSFP)

3D

Time:

03:15 min

68

T2+FS 2D Ax Posterior coil + Anterior coil +

2x FlexL

mDixon TSE 2D

3446

90

260 x 340 x 300

2.0

1.25 x 1.34

349.4

Transaxial

mDixon

Spin Echo

2D

Time: 07:39 min

T1+FS 2D Ax

Posterior coil + Anterior coil +

2x FlexL

mDixon TSE 2D

590

15

260 x 340 x 300

2.0

1.25 x 1.32

228.9

Transaxial

mDixon

Spin Echo

2D

Time: 07:04 min

Motion detection

sag/cor/tra

Posterior coil + Anterior coil +

2x FlexL

FFE 2D; 4 frames/sec

3.3

1.65

266 x 300 x 5

5.0

2.14 x 2.14

744.0

3-plane (sag/cor/tra)

none

Gradient Echo

2D

Time: 01:00 min

T1 3D Tra

Posterior coil + Anterior coil +

2x FlexL

TFE 3D

6.6

3.2

260 x 340 x 300

2.4

1.14 x 1.14

228.4

Transaxial

none

Gradient Echo

3D

Time: 06:25 min

3T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T2 3D Tra

Posterior coil + Anterior coil +

2x FlexL

TSE 3D View

2200

303

260 x 340 x 300

2.0

1.0 x 1.0

763.1

Transaxial

none

Spin Echo

3D

Duration 08:28 min

Option

T1 3D Tra Posterior coil + Anterior coil +

2x FlexL

TFE 3D

8.0

3.5

260 x 340 x 300

2.0

1.0 x 1.0

452.6

Transaxial

none

Gradient Echo

3D

Duration 07:31 min

T1 FS 3D Tra

Posterior coil + Anterior coil +

2x FlexL

e-THRIVE 3D

3.9

2.0

260 x 340 x 300

2.4

1.15 x 1.15

721.3

Transaxial

SPAIR

Gradient Echo

3D

Duration 06:38 min

Metal object detection Tra

Posterior coil + Anterior coil +

2x FlexL

b-TFE 3D

7.4

4.6

260 x 340

x 300

2.4

1.25 x 1.74

1071.6

Transaxial

none

balanced Gradient

Echo (bSSFP)

3D

Duration 03:37 min

T2+FS 2D Tra

Posterior coil + Anterior coil +

2x FlexL

mDixon TSE 2D

2819

100

260 x 340 x 300

2.0

1.15 x 1.15

571.1

Transaxial

mDixon

Spin Echo

2D

Duration 08:13 min

T1+FS 2D Tra

Posterior coil + Anterior coil +

2x FlexL

mDixon TSE 2D

624

6.9

260 x 340 x 300

2.0

1.1 x 1.2

840.7

Transaxial

mDixon

Spin Echo

2D

Duration 07:39 min

Motion detection

sag/cor/tra

Posterior coil + Anterior coil +

2x FlexL

FFE 2D; 4 frames/sec

2.6

1.7

257 x 300 x 5

5.0

2.14 x 2.14

1082.3

3-plane (sag/cor/tra)

none

Gradient Echo

2D

Duration 01:00 min

Philips – Small FOV – sequence recommendations from manufacturer 1.5T

Sequence Coil Product name

of sequence TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

69

T2 3D Tra Posterior coil + 2x FlexL/M/S

TSE 3D View 2500 212 220 x 220

x 120 2.0 1.0 x 1.0 947.0 Transaxial none Spin Echo 3D

Duration 06:13 min

Option T1 3D Tra

Posterior coil + 2x FlexL/M/S

TFE 3D 8.0 3.5 220 x 220

x 120 2.0 1.0 x 1.0 228.2 Transaxial none

Gradient Echo

3D Duration 06:28 min

Metal object detection Tra

Posterior coil + 2x FlexL/M/S

b-TFE 3D

7.6

4.6

220 x 220

x 120

2.0

1.25 x 1.26

289.4

Transaxial

none

balanced Gradient

Echo (bSSFP)

3D

Duration 02:54 min

T2 FS 3D Tra Posterior coil + 2x FlexL/M/S

TSE SPAIR 3D View

2000 220 220 x 220

x 120 2.0 1.25 x 1.25 1101.1 Transaxial SPAIR Spin Echo 3D

Duration 6:24 min

T1 FS 3D Tra Posterior coil + 2x FlexL/M/S

e-THRIVE 3D 4.7 2.3 220 x 220

x 120 2.0 1.15 x 1.15 434.0 Transaxial SPAIR

Gradient Echo

3D Duration 05:54 min

T2+FS 2D Ax Posterior coil + 2x FlexL/M/S

mDixon TSE 2D

2988 90 220 x 220

x 120 2.0 1.25 x 1.34 349.9 Transaxial mDixon Spin Echo 2D

Duration 08:22 min

T1+FS 2D Ax Posterior coil + 2x FlexL/M/S

mDixon TSE 2D

537 15 220 x 220

x 120 2.0 1.25 x 1.32 228.7 Transaxial mDixon Spin Echo 2D

Duration 07:02 min

Motion detection

sag/cor/tra

Posterior coil + 2x FlexL/M/S

FFE 2D; 4 frames/sec

3.4

1.66

220 x 220 x 5

5.0

2.14 x 2.14

724.0

3-plane (sag/cor/tra)

none

Gradient Echo

2D

Duration 01:00 min

3T

Sequence

Coil

Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family

2D or 3D

Other

T2 3D Tra Posterior coil + 2x

Flex L/M/S TSE 3D

View

2500

239 220 x 220 x

120

2.0

0.95 x 0.95

898.0

Transaxial

none

Spin Echo

3D Duration 06:33 min

Option T1 3D Tra

Posterior coil + 2x Flex L/M/S

TFE 3D 8.0 3.5 220 x 220 x

120 2.0 1.0 x 1.0 456.4 Transaxial none

Gradient Echo

3D Duration 06:28 min

T2 FS 3D Tra

Posterior coil + 2x Flex L/M/S

TSE SPAIR 3D View

2000 220 220 x 220 x

120 2.0 1.15 x 1.15 1009.3 Transaxial SPAIR Spin Echo 3D

Duration 07:14 min

T1 FS 3D Tra

Posterior coil + 2x Flex L/M/S

e-THRIVE 3D

4.1 2.0 220 x 220 x

120 2.0 1.15 x 1.15 723.4 Transaxial SPAIR

Gradient Echo

3D Duration 07:02 min

Metal object

detection Tra

Posterior coil + 2x

Flex L/M/S

b-TFE 3D

7.4

4.6

220 x 220 x

120

2.0

1.25 x 1.26

578.7

Transaxial

none

balanced Gradient

Echo (bSSFP)

3D

Duration 01:40 min

T1+FS 2D Tra

Posterior coil + 2x Flex L/M/S

mDixon TSE 2D

650 6.5 220 x 220 x

120 2.0 1.25 x 1.34 1101.1 Transaxial mDixon Spin Echo 2D

Duration 05:35 min

T2+FS 2D Tra

Posterior coil + 2x Flex L/M/S

mDixon TSE 2D

2510 100 220 x 220 x

120 2.0 1.25 x 1.26 514.6 Transaxial mDixon Spin Echo 2D

Duration 06:04 min

Motion detection

sag/cor/tra

Posterior coil + 2x Flex L/M/S

FFE 2D; 4 frames/sec

2.7

1.19

220 x 220 x 120

5.0

1.72 x 1.74

1085.1

3-plane (sag/cor/tra)

none

Gradient Echo

2D

Duration 01:00 min

70

Prostate GE

1.5T

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

3T – Discovery 750W

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1 Tra Anterior

Array

GRE 8.2 1.4

280 2.5

1.2 x 1.2

1232

Tra Dixon, use water image

GRE

2D

T2 Sag Anterior

Array FRFSE 6129 102 240 3.0 0.5 x 0.8

450 Sag SE 2D

T2 Tra Anterior

Array FRFSE 5568 102 240 3.0 0.5 x 0.8 450 Tra SE 2D

Diffusion

Anterior

Array

FOCUS

3775

69.4

20

3.6

2 x 2

5208

Tra

2D

b-values 200, 800, 4 8 16 NEX

Diffusion

Anterior Array

Alternatively EPI 2D Diff

4250

73

200

3.6

2 x 1.5

5208

Tra

Fat

2D

b-values 200, 800. Acc 2.

Siemens 1.5T – Aera

Sequence

Coil

Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique Sequence family

2D or 3D

Other

T1 Tra

Body 18

T1_VIBE

7.46

4.77

420

2.0

1.1 x 1.1

330 Hz

Tra

GRE

3D

With hip prosthesis, use WARP for

artefact reduction

T2 Sag Body 18

T2 Tra

Body 18

T2_TSE

12100

102

420

2.0

0.8x0.8

230 Hz

Tra

SE

2D With hip

prosthesis, use WARP artefact

reduction

71

Diffusion Body 18

3T – Skyra

Sequence Coil Product name

of sequence TR

(ms) TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1 Tra Body 18 T1_VIBE 4.57 2.46 390 2.0 1.2 x 1.2 450 Tra GRE 3D T2 Sag Body 18 T2 Tra Body 18 T2_TSE 15880 121 220 3.0 0.7 x 0.7 450 Tra SE 2D

T2 Tra fatsat Body 18 Diffusion Body 18

Philips 1.5T

Sequence Coil Product name

of sequence TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T2 3D Full Contour (M)

Posterior coil + Anterior coil

TSE 3D View

2000

224 350 x 451

x 300

2.4

1.15 x 1.15

763.1

Transaxial

none

Spin Echo

3D Duration 07:02 min

Internal markers (FFE)

Posterior coil + Anterior coil

FFE 3D 7.9 3.9 180 x 180

x 90 2.0 0.95 x 0.95 183.2 Transaxial none

Gradient Echo

3D Duration 01:17 min

Option

MRCAT source (M) Tra

Posterior coil + Anterior coil

FFE 2D mDixon

5.7

1.61

350 x 451 x 300

2.5

1.7 x 1.7

538.0

Transaxial

Dixon

Gradient Echo

2D

For MRI-only simulation – MRCAT generation; Duration 03:20 min

MRCAT source (L) Tra

Posterior coil + Anterior coil

FFE 2D mDixon

5.8

1.62

368 x 552 x 300

2.5

1.7 x 1.7

535.8

Transaxial

Dixon

Gradient Echo

2D

For MRI- only

simulation – MRCAT generation; Duration 04:04 min

T2 3D Full Contour (L)

Posterior coil + Anterior coil

TSE 3D View 2000 244 368 x 552

x 300 2.4 1.15 x 1.15 620.0 Transaxial none Spin Echo 3D

Duration 07:26 min

Metal detection scan Tra

Posterior coil + Anterior coil

FFE 3D 6.7 4.6 340 x 462

x 300 2.4 1.05 x 1.99 612.4 Transaxial none

Gradient Echo

3D Duration 02:33 min

T1 3D Tra Posterior coil +

Anterior coil TFE 3D 6.7 3.3

180 x 180 x 90

2.4 1.1 x 1.1 228.2 Transaxial none Gradient

Echo 3D

Duration 06:14 min

T2 3D Tra Posterior coil +

Anterior coil TSE 3D View 2000 222

180 x 180 x 90

2.4 1.0 x 1.0 879.0 Transaxial none Spin Echo 3D Duration 06:44 min

T1 FS 3D Tra Posterior coil +

Anterior coil e-THRIVE 3D 6.6 3.2

180 x 180 x 90

2.4 1.18 x 1.2 228.4 Transaxial SPAIR Gradient

Echo 3D

Duration 06:04 min

72

T2 FS 3D Tra Posterior coil +

Anterior coil TSE SPAIR 3D

View 2000 192

180 x 180 x 90

2.4 1.25 x 1.25 1098.8 Transaxial SPAIR Spin Echo 3D Duration 05:14 min

T2 2D Tra Posterior coil +

Anterior coil TSE 2D 4174 80

180 x 180 x 90

2.0 1.18 x 1.28 310.3 Transaxial none Spin Echo 2D Duration 06:03 min

T1 2D Tra Posterior coil +

Anterior coil TSE 2D 400 15

180 x 180 x 90

2.0 1.18 x 1.28 303.5 Transaxial none Spin Echo 2D Duration 05:17 min

T2 3D Sag Posterior coil +

Anterior coil TSE 3D View 2000 239

180 x 180 x 90

2.0 1.05 x 1.05 688.9 Sagittal none Spin Echo 3D Duration 06:50 min

Motion detection

sag/cor/tra

Posterior coil + Anterior coil

FFE 2D; 5 frames/sec

3.3

1.66

400 x 400 x 5

5.0

3.03 x 3.03

745.6

3-plane (sag/cor/tra)

none

Gradient Echo

2D

Duration 01:00 min

3T

Sequence

Coil

Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or 3D

Other

T2 3D Full Contour (M)

Posterior coil + Anterior coil

TSE 3D View

2000

258 350 x 451

x 300

2.4

1.15 x 1.15

652.7

Transaxial

none

Spin Echo

3D Duration 07:02 min

Internal marker scan

Ax

Posterior coil + Anterior coil

b-FFE 3D

7.2

3.6

180 x 180 x 90

2.0

0.85 x 0.85

217.2

Transaxial

none

balanced Gradient Echo

(bSSFP)

3D

Duration 01:46 min

Option

MRCAT

source (M) Tra

Posterior coil + Anterior coil

FFE 2D mDixon

3.9

1.21

350 x 451 x 300

2.5

1.7 x 1.7

1071.6

Transaxial

mDixon

Gradient Echo

2D

For MRI- only

simulation – MRCAT generation; Duration 02:17 min

T2 3D Full Contour (L)

Posterior coil + Anterior coil

TSE 3D View 2000 282 368 x 552

x 300 2.4 1.15 x 1.15 620.0 Transaxial none Spin Echo 3D

Duration 07:26 min

MRCAT

source (L) Tra

Posterior coil + Anterior coil

FFE 2D mDixon

3.9

1.21

368 x 552 x 300

2.5

1.7 x 1.7

1071.6

Transaxial

mDixon

Gradient Echo

2D

For MRI- only

simulation – MRCAT generation; Duration 02:48 min

Metal detection scan Tra

Posterior coil + Anterior coil

FFE 3D

6.7

4.6

340 x 462 x 300

2.4

1.05 x 1.99

964.5

Transaxial

none

Gradient Echo

3D

Duration 02:34 min

T1 3D Tra Posterior coil

+ Anterior coil TFE 3D 20 2.4

180 x 180 x 90

2.4 1.1 x 1.1 456.4 Transaxial none Gradient Echo 3D Duration 04:04 min

T2 3D Tra Posterior coil

+ Anterior coil TSE 3D View 2200 240

180 x 180 x 90

2.4 1.0 x 1.0 841.8 Transaxial none Spin Echo 3D Duration 06:43 min

T1 FS 3D Tra

Posterior coil + Anterior coil

e-THRIVE 3D 3.8 1.99 180 x 180

x 90 2.4 1.18 x 1.2 783.2 Transaxial SPAIR Gradient Echo 3D

Duration 03:58 min

73

T2 FS 3D

Tra Posterior coil

+ Anterior coil TSE SPAIR

3D View 2000 217

180 x 180 x 90

2.4 1.18 x 1.19 1040.9 Transaxial SPAIR Spin Echo 3D Duration 04:58 min

T2 2D Tra Posterior coil

+ Anterior coil TSE 2D 4050 100

180 x 180 x 90

2.0 1.25 x 1.33 459.3 Transaxial none Spin Echo 2D Duration 05:16 min

T1 2D Tra Posterior coil

+ Anterior coil TSE 2D 542 8.0

180 x 180 x 90

2.0 1.25 x 1.26 459.3 Transaxial none Spin Echo 2D Duration 05:03 min

T2 3D Sag Posterior coil

+ Anterior coil TSE 3D View 2000 258

180 x 180 x 90

2.0 1.0 x 1.0 688.9 Sagittal none Spin Echo 3D Duration 06:50 min

Motion detection

sag/cor/tra

Posterior coil + Anterior coil

FFE 2D; 5 frames/sec

2.7

1.34

400 x 400 x 5

5.0

3.03 x 3.03

1479.5

3-plane (sag/cor/tra)

none

Gradient Echo

2D

Duration 01:00 min

74

Cervix Brachy GE

1.5T

Sequence Coil Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

3T – Discovery 750W

Sequence Coil Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T2 Sag Anterior Array T2 SE 8854 120 200 3 0.7 x 0.7 289 Hz Sag SE 2D T2 Ring T2 SE 6650 102 300 3 1.0 x 1.3 289 Hz Ring SE 2D T1 Bravo

Ring Bravo 7.7 3.1

300 1 1.2 x 1.2 244 Hz Ring GE 3D

T2 Appl cor T2 SE 4626 102 300 3 1.0 x 1.3 289 Hz Applicator SE 2D T2 Tra T2 SE 5991 120 200 3 0.7 x 0.7 289 Hz Tra SE 2D

Siemens 1.5T – Aera

Sequence

Coil

Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique Sequence family

2D or 3D

Other

3T – Skyra

Sequence Coil Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

T1 Abdome

n

Vibe 4.95 2.46 170 2 mm/ 0 mm gap

530 Tra

GE

3D

75

T2 Abd

omen

TSE 9500 89 170 2 mm/ 0 mm gap

252 Tra SE 2D

Philips 1.5T

Sequence Coil Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

3T

Sequence Coil Product name of sequence

TR (ms)

TE (ms)

FOV (mm)

Slice thickness

(mm)

Pixel size (mm)

Bandwidth per pixel

Angling of slice

Tissue suppression and technique

Sequence family 2D or

3D Other

Version 1, 10 March 2016 Appendix to: Method book for the use of MRI in radiotherapy Version 3, 10 March 2016

APPENDIX B – SAFETY MANUAL

Version 1, 10 March 2016 Appendix to: Method book for the use of MRI in radiotherapy Version 3, 10 March 2016

Safety manual

MRI activities

in

radiotherapy

CONTENTS

Introduction ............................................................................................................................................................. 3

Objectives ............................................................................................................................................................ 3

Overview ...................................................................................................................................................................... 3

MRI scanner policy ................................................................................................................................................. 4

Background .................................................................................................................................................................. 4

Accident risks .............................................................................................................................................................. 4

Signage at the MRI scanner ............................................................................................................................... 5

Signage on equipment ........................................................................................................................................ 6

Floor markings .................................................................................................................................................... 7

Admission to the MRI scanner examination room ........................................................................................ 7

Rules for metal objects and equipment .......................................................................................................... 7

Helium and emergency stop ............................................................................................................................. 11

Fire ................................................................................................................................................................................ 12

Biological effects of the MRI scanner fields ........................................................................................................ 13

The static magnetic field .................................................................................................................................... 13

The time-varying magnetic field ....................................................................................................................... 13

The radio frequency field .................................................................................................................................. 14

Patient examination policy ..................................................................................................................................... 16

Limit values for patients .................................................................................................................................... 16

Limit values for research subjects .................................................................................................................... 17

Limit values for the public and accompanying persons ................................................................................ 18

Screening form for patients............................................................................................................................... 18

Patient positioning procedures ........................................................................................................................ 18

Procedures for accompanying support person .............................................................................................. 19

Implants and foreign metal materials ............................................................................................................... 20

Contrast medium ........................................................................................................................................................ 27

Pregnant patients ................................................................................................................................................ 29

Research in vivo .................................................................................................................................................... 30

Policy for staff ......................................................................................................................................................... 31

Limit values for staff .......................................................................................................................................... 31

Pregnant staff members ..................................................................................................................................... 31

Screening form for staff..................................................................................................................................... 32

Safety training .............................................................................................................................................................. 32

References and links............................................................................................................................................... 33

References ........................................................................................................................................................... 33

Links .............................................................................................................................................................................. 34

2

Appendix I – Screening forms .............................................................................................................................. 35

Appendix II – Limit values with comments ........................................................................................................ 41

The static magnetic field .................................................................................................................................... 42

The time-varying magnetic field: eddy currents ............................................................................................. 43

The time-varying magnetic field: noise levels ................................................................................................. 44

The radio frequency field .................................................................................................................................. 45

Appendix III – Shellock's implant terminology .................................................................................................. 47

MR Safe ................................................................................................................................................................ 47

Conditional .......................................................................................................................................................... 47

MR Unsafe ........................................................................................................................................................... 48

Appendix IV – Glossary ........................................................................................................................................ 50

3

INTRODUCTION

Objectives This safety manual is based on Sahlgrenska University Hospital's safety manual for MR activities at SU,

version 4/2015-01-28, a document developed by MFT/Diagnostic Radiology Physics in consultation

with the MRI departments of Sahlgrenska University Hospital, Mölndal Hospital, Östra Hospital, and

Queen Silvia Children's Hospital.

This safety manual is intended for everyone in radiotherapy who works with MRI scanners (MRI), works

in an MR environment, or has patient contact with MR patients.

The purpose of the manual is:

To ensure that all staff members working with MRI, in an MR environment, with MR patients, or in a ward with an MRI scanner have basic knowledge of MRI safety. The information must be first-hand information.

To provide clear and shared local policies and safety rules.

To ensure that all staff members in contact with patients are able to answer patient questions about MRI safety.

To ensure that all staff members are able to refer to the equipment with correct terminology, i.e.

scanner, MRI scanner, MRI camera, magnetic resonance or magnetic resonance tomography.

Overview Physicians, nurses, physicists and researchers who work with MR or are responsible for MR patients must

be knowledgeable of the content in the following chapters:

Introduction

MRI scanner policy

Biological effects of the MRI scanner fields

Policy for staff

Patient examination policy All staff members who are not included in the above list but who work in an MR environment (e.g.

accompanying physicians, assistant nurses, anaesthesia staff members, technicians), who have contact

with MR patients (e.g. booking and reception staff), are stationed in the department (all staff categories),

or for some other reasons are in the MRI department (e.g. cleaning staff) must as a minimum be

acquainted with the following chapters:

Introduction

MRI scanner policy

Some terms in the document are explained in more detail in Appendix IV – Glossary.

4

MRI SCANNER POLICY

Background An MRI scanner contains a strong magnet that generates a static magnetic field with field strengths that

are measured in Tesla (T). The clinical MRI scanners in Sweden have field strengths up to 3 T, with 1.5

T being the most common. To generate images, magnetic field gradients (a gradient field or time-varying

magnetic field) and radio waves (a radio frequency field) are required. In this document, the term “field”

is used in reference to the static magnetic field, the time-varying magnetic field, and the radio

frequency field (RF field). The time-varying magnetic field and the radio frequency field are only

switched on during image capture. The static magnetic field is on at all times.

Note that MR DOES NOT use any X-rays. MR therefore does not provide any radiation dose and

has completely different safety aspects.

MR is an abbreviation for Magnetic Resonance. So as not to confuse MR with computed tomography (CT), which is an X-ray-based technique, it is important to refer to the equipment with the proper terminology1. Use one of the following designations:

MRI scanner

MRI camera

Magnetic Resonance (MR)

Magnetic Resonance Tomography (MRT)

Scanner

The terms MRI (Magnetic Resonance Imaging) and MRT (Magnetic Resonance Tomography) are often used in articles and literature.

The terms MRI scanner, MRI and MR are used in this document.

Accident risks One of the biggest hazards of MRI scanners is the risk of accidents. Metal objects may be attracted by the

magnetic field and fly towards the scanner, potentially striking the patient, staff or accompanying persons. For

this reason, only objects that are guaranteed to be non-magnetic or that are adapted for an MR environment may

be taken into the examination room. Serious accidents have been caused by objects such as gas cylinders and

scissors flying towards the MRI scanner. A death occurred in the USA when an oxygen cylinder struck a 6-year-

old boy.

Note that even objects that are adapted for use in the examination room, such as IV poles and

anaesthesia equipment, may be drawn towards the scanner. For this reason, they are only permitted in

specially predefined areas.

Large metal objects hitting the scanner can not only cause personal injury, but also expensive scanner

repairs. Small metal objects that fly into the scanner could cause homogeneity projects in the machine,

resulting in image errors. A small paper clip or bobby pin could greatly reduce the scanner's homogeneity.

Some medical implants and metal objects in the body could be turned or otherwise affected by the

magnetic field and cause injury.

1 Some people confuse magnetic resonance and computed tomography. This is unfortunate since they are two very

different techniques with completely different safety aspects. Computed tomography uses X-rays. Thus, a CT scan

applies a dose of radiation to the patient.

5

b.

a. c.

Figure 1. Accident risks with MRI: a) bed, wheelchair, scissors and hammer (arranged image) b. stray magnetic field around

an MRI scanner (Philips Achieva 1,5 T) c. Attractive force of the scanner at different distances from the scanner is a

measure of the spatial gradient strength of the static magnetic field (Starck G. et.al.) ISMRM 11th Scientific Meeting 2003,

Abstract book #2474).

The magnetic field extends far beyond the MRI scanner. Today's MRI scanners are actively shielded to

reduce the magnetic field distribution, BUT the attractive force increases very rapidly as one approaches

the scanner. The attractive force also increases as the field strength increases.

Note that the magnetic field of the MRI scanners is ALWAYS ON. The same restrictions therefore

apply around the clock.

Signage at the MRI scanner The examination room and/or MRI department must be monitored and/or have limited access (e.g.

require use of an access card) to prevent unauthorized persons from entering the examination room. The

purpose is to prevent anyone with loose metal objects or implants from being injured, injuring another

person, or damaging equipment. Signs must also be posted in the areas.

All rooms with a field strength over 0.5 mT must have the following warning signs posted:

− “Warning! Strong magnetic field”

and should also have

− “Do not enter if you have a pacemaker or an electrical/battery-operated implant”

The entrance to the MRI examination room must have the following signs posted:

− “Warning! Strong magnetic field”

and should also have

− “Warning! Magnetic field is always on”

− “Do not enter if you have a pacemaker or an electrical/battery-operated implant” .

− “Do not enter if you have an implanted metal object”

− “No loose metal objects”

6

MR

MR

The signs must be positioned so they are clearly visible even when the door is open, for example on the doors or on the door frame.

WARNING!

MAGNETIC FIELD IS ALWAYS ON

WARNING!

NO PACEMAKERS

NO NEUROSTIMULATORS NO

METALLIC IMPLANTS

Risk of life-threatening injury.

Contact the MR staff

STOP!

No admission unless granted

permission by the MR staff

Risk of serious injury

NO LOOSE METAL OBJECTS

Risk of serious injury!

Figure 2. Examples of suitable signs for the MRI examination room. The appearance of the signs varies depending on the

equipment, but the information must be present in some form or another.

Signage on equipment The equipment situated in and around the MR environment should also be marked. This applies in

particular to equipment and other objects (racks, tables, etc.) used for monitoring or objects that might be

taken into the examination room during an emergency. There are three signs at the MRI scanner

MR Safe

Equipment that does not pose any risks in the MR environment. MR

(e.g. special-order non-magnetic wheelchairs designed for use with the scanner, MR-compatible fire extinguishers)

MR Conditional

Equipment that does not pose any risks in the MR environment under certain specific

conditions. This sign is usually supplemented with the maximum permitted field strength.

This can apply to equipment that may only be positioned outside of certain limits or within MR specifically marked areas; see “Floor markings” below.

(e.g. monitoring equipment, pumps, IV poles permitted within special areas of the examination room)

MR Unsafe

Equipment that poses a risk in all MR environments.

(e.g. regular fire extinguishers, crash carts, defibrillators, steel racks)

7

Floor markings It may be a good idea to mark e.g. 10 mT on the floor of the MRI scanner room. This boundary marks

the maximum field strength for monitoring devices.

Note that different field strengths can be marked in the different MRI scanner rooms. You should

therefore always check what the boundary indicates if conditional equipment is being brought in.

10 mT

20 mT 10 mT

Figure 3. Marking of a) 10 mT boundary for 1.5 T MRI scanner at Sahlgrenska University Hospital b) 20 mT boundary for the 1.5 T MRI scanner at Mölndal Hospital c) 10 mT boundary for the 3 T MRI scanner at Queen Silvia Children's Hospital.

Admission to the MRI scanner examination room

All persons must be checked in accordance with the relevant screening form before they enter the examination room(example screening forms can be found in Appendix I – Screening forms). Some medical implants and metal objects in the body could be turned or otherwise affected by the magnetic field and cause injury. They can also be affected by the time-varying and radio frequency fields and cause severe local heat rise. A large number of medical implants are MR-safe, but they must be assessed on a case by case basis. Many implants are only approved under certain conditions, and adaptation of the setup and examination is required.

− Staff members must be checked in accordance with the relevant screening form before they enter the MRI examination room for the first time. If the individual has an implant, a medical assessment must be carried out to determine whether the individual can enter/work in the examination room.

− All patients must be checked in accordance with the relevant screening form and have undergone a medical assessment before they enter the MRI examination room.

− Other individuals (who are not MR staff or patients) who wish to enter the room (e.g. accompanying persons, building contractors, or students) must be checked in accordance with the relevant screening form before they enter the MRI examination room. If the individual has any type of implant, they must either be medically assessed or refrain from entering the examination room.

− Note that the restrictions also apply to accompanying staff from other departments (e.g. anaesthesia).

All persons must remove all magnetic metal objects (projectiles), wallets, access cards (the data on

the card could be deleted)and watches (could break) before entering the examination room.

All persons who will be in the examination room during the image capturing process must wear at least one type of hearing protection (ear plugs and/or ear defenders).

The MR staff is authorized to decide whether a person is allowed to enter the examination room.

Rules for metal objects and equipment

Private wheelchairs must never be taken into the examination room. Only the special-ordered

wheelchairs designed for use with the scanner may be taken in. These are marked “MR Safe”

8

Patient beds and wheeled walkers must never be taken into the examination room.

Gas cylinders must never be taken into the examination room.

General firefighting equipment must never be taken into the MRI room if the magnetic field is on.There should be non-magnetic fire extinguishers in the MRI department; refer to “Fire” on page

12. These are marked “MR Safe”

Emergency medical bags and defibrillators must never be taken into the examination room; refer to “CPR equipment and emergency equipment” on page 9.

Only MR-approved cleaning equipment may be taken into the examination room (see “Cleaning equipment and cleaning procedures” on page 10).

The only tools that may be taken into the examination room are tools made of titanium (see “Equipment for building contractors” on page 10).

Metal objects like forceps, scissors, pens, paper clips, nail clippers, keys, bobby pins, etc. must never be taken into the examination room.

Magnetic stripe cards, disks, watches, electronic diaries, etc. may be ruined by the magnetic field.

a. b.

c. d.

Figure 4. a, b. Examples of objects that must NEVER be taken into the examination room. Danger to life!

Examples of objects that should NEVER be taken into the examination room. Small objects that fly into the scanner could

cause image errors. d. Examples of objects that should not be taken in because they could be ruined by the magnetic field.

9

Equipment used in the examination room This refers to syringe pumps and equipment for monitoring, anaesthesia, etc. There are many types of

such equipment, but only some of it can be used in an MR environment. The equipment can be drawn

towards the scanner and possibly strike the patient or staff. It could also stop working, malfunction (e.g.

provide the wrong amount of contrast medium) or display incorrect values due to the magnetic field.

All equipment to be used in the MRI examination room must have undergone documented testing from the supplier certifying that it works in an MR environment, or must have been approved by a qualified staff member at the hospital, e.g. a medical physicist.

Equipment without this information may not be used in an MR environment until a qualified staff member at the hospital, e.g. a medical physicist, has evaluated the equipment and declared it safe for use in an MR environment.

Signs must be posted on the equipment; see “Signage on equipment” on page 6.

The equipment may only be placed in predefined permitted areas in the examination room that are marked with e.g. floor markings (see “Floor markings” on page 7). The equipment must never be moved closer to the scanner than it has been declared safe for.

10 mT

Figure 5. Anaesthesia equipment at Queen Silvia Children's Hospital. Note that the equipment is outside of the 10 mT

boundary.

CPR equipment and emergency equipment

Emergency medical bags must never be taken into the examination room.

Defibrillators must never be taken into the examination room.

Oxygen cylinders must never be taken into the examination room.

In an emergency situation where such equipment is required, the person must be taken out of the

examination room. If there is danger of death, a last resort could be to “quench” the magnet (switch off

the magnetic field). However, this causes downtime that lasts several days/weeks and is very costly; see

“Helium and emergency stop” on page 11.

10

Defibrillator Oxygen cylinder

Emergency mask

Figure 6. Defibrillators and oxygen cylinders must never be taken into the examination room.

Cleaning equipment and cleaning procedures

Only cleaning equipment specially designed for use with an MRI scanner may be taken into the examination room.

If other equipment is required, such as a floor polisher, the magnetic field must first be taken down. The following rules apply:

− Contact the MRI department to book a time, if necessary.

− MR staff must be present when the equipment is taken in. Verify with the staff that the magnetic field is really switched off before taking the equipment in.

Anaesthesia equipment, IV poles and measuring devices found in the examination room must not be moved closer to the scanner than they are approved for (see “Signage on equipment” on page 6 and “Floor markings” on page 7). They may be attracted by the magnetic field and fly in towards the scanner, stop working, malfunction, or show incorrect values (even if they are moved back to their original position).

Figure 7. Examples of accidents with cleaning equipment (Obtained from http://www.simplyphysics.com/flying_objects.html)

Equipment for building contractors

No building contractor may enter the examination room without first being checked by the MR staff.

Only tools intended for use in an MR environment may be taken into the examination room when the magnetic field is on. If repairs being performed in the examination room require use of other tools, the magnetic field can be taken down if necessary.

The following instructions apply to all repairs in the examination room:

− Contact the MRI department for assessment and to book a time, if necessary.

− MR staff must be present when the equipment is taken in. The MR staff is authorized to decide who may enter the examination room, what may be taken in, and when this may occur.

11

Helium and emergency stop There is an emergency stop for the magnetic field in both the examination room and the control room.

The emergency stop is marked “Emergency run down”, “Run down” or “Emergency stop”. The

emergency stop causes a quench, which causes the magnetic field to quickly disappear2. In rare cases, a

spontaneous quench may occur 3.

The scanner is designed in such a way that the helium gas released during a quench is directed out of the

building via a quench pipe. No helium gas should therefore come out into the room. The examination

room should nonetheless be evacuated in case of a quench4.

Take the following steps if you need to press the quench button or a spontaneous quench occurs:

Inform everyone in the room that the quench button will be activated.

Also press the emergency stop for the electrical supply.

Take the patient out and make sure that everyone leaves the examination room.

Close the door.

Immediately contact a physicist or engineer, as well as the supplier.

NOTE! It is a very expensive and time-consuming process to restore the magnetic field after an

emergency stop. The emergency stop for the magnetic field should only be used in cases of

serious personal danger

extensive fire

If the magnetic field must be taken down for other reasons, such as something stuck in the scanner, there

are procedures to do this in a controlled manner without causing a quench. In such cases, contact the

supplier, physicist, or engineer.

a. b. c.

Figure 8. Emergency stop/quench button for the magnetic field for three different equipment suppliers a) Philips, b. GE and c) Siemens.

2 The scanners are made with superconducting windings so that current can flow in the magnet windings without energy

loss. In order for the magnet windings to be superconducting, they must be cooled to -270ºC. The windings are therefore

surrounded by liquid helium. The emergency stop causes a quench, which means the conductors in the scanner are quickly

warmed up so the superconductivity is lost. The magnetic field decreases quickly and the helium boils away. The helium gas

is led out of the building via a quench pipe.

3 The risk of helium emission into the room is greatest when a quench occurs in connection with helium filling and service

of the interior components of the scanner.

4 IF helium gas comes out into the room, it displaces the air, thereby creating a risk of suffocation. The examination room

must therefore be evacuated in case of a quench.

12

Figure 9. Quench. Helium gas flows out of the quench pipe on the roof.

Fire For general procedures in case of fire, refer to local fire protection regulations. Because of the strong

magnetic field, special restrictions apply in case of fire in the MRI examination room.

At the MRI department, there should be a powder extinguisher made of non-magnetic material that can be taken into the examination room even if the magnetic field is on. It must be marked

as MR Safe. No other fire extinguishers may be taken into the examination room! Regular fire

extinguishers are usually MR Unsafe. Check the signs on the fire extinguisher before taking it in!

Other firefighting equipment must never be taken into the MRI room if the magnetic field is on. This is highly dangerous and could even result in DEATH!

If a fire in the MRI examination room is so severe that the fire brigade must be called and/or other firefighting equipment is required, take the following steps:

− Evacuate the examination room.

− Close the door of the examination room.

− Activate a quench, i.e. press the emergency stop for the magnetic field. The emergency stop for the magnetic field (quench) is located just inside the door of the examination room and (at most MR departments) in the control room (Figure 8).

− Press the emergency stop for the electrical supply.

− Warn those in the surrounding area and activate the alarm.

− Wait at least 3 minutes for the magnetic field to disappear.

− When the emergency services crew arrives, let them now that the magnetic field is down and let them into the examination room.

13

BIOLOGICAL EFFECTS OF THE MRI SCANNER FIELDS

The static magnetic field The literature does not indicate any serious health effects from whole-body exposure of healthy individuals

to field strength below 8 T (ICNIRP 2009). Temporary sensory effects, such as dizziness, nausea and a

metallic taste in the mouth, may occur when moving in the magnetic field at field strengths > 2T. The

most obvious effect of the static field is the magnetic field's effect on ECG, which can be seen as a slightly

enhanced T-peak, but is harmless to the patient. The effect disappears as soon as the patient leaves the

magnetic field.

No negative effects have been seen from prolonged exposure to the static magnetic field. There is also no

evidence to suggest the static magnetic field would be harmful to a foetus.

Spatial gradients

The attractive force of the magnetic field increases the closer one comes to the scanner. It is not only the

magnetic field itself that determines what force will be acted on any metallic object, but also how much

the magnetic field strength increases with distance. Such spatial gradients, dB/dr, are measured in the unit

T/m. The distribution of the spatial gradients is different for different types of scanners, and different

types of scanners can thereby have different attractive forces even if the field strength is the same. The

spatial gradients play a key role when assessing the safety of different implants.

The attraction of an object depends on the field strength and the spatial gradient B*dB/dr. The torque,

i.e. the twisting force of an object, increases quadratically with the field strength B.

The time-varying magnetic field A time-varying magnetic field arises when the magnetic field gradients (usually called gradients),

which are very small extra magnetic fields (mT), are activated and deactivated for short periods of time

during image capture.

Eddy currents The time-varying field causes electrical eddy currents in the body. The strength of the currents that are

generated depend on the gradient fields' maximum strength, how quickly they increase in strength, and

how frequently they are activated and deactivated. The patient's size and how they are positioned in the

scanner also affect the size of the currents.

High electrical eddy currents can cause nerve and muscle stimulation (and fibrillation at very high levels).

Peripheral nerve and muscle stimulation can be painful at high levels. Eddy current limit values are set to

avoid painful nerve and muscle stimulation. Lower levels can feel like muscle twitching in the body and

may be uncomfortable, even if considered harmless.

The clinical MRI scanners used in Sweden cannot cause fibrillation or painful nerve and muscle

stimulation. Low levels of peripheral nerve and muscle stimulation may be caused depending on the

choice of sequences and sequence parameters.

There is nothing to suggest that eddy currents are harmful to foetuses, but studies of the long-term

biological effects of eddy currents on foetuses are limited (De Wilde 2005). Following the precautionary

principle, the gradient fields should be limited for pregnant women (see “Pregnant patients” on page 29).

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Noise levels A loud pounding noise can be heard when the gradients are activated and deactivated. Because of this,

there is a potential risk of hearing loss (ICNIRP 2004). Typical noise levels for a 1.5 T system are 80-110

dB(A) (Appendix IV – Glossary). Even higher noise levels can occur with a 3T system. Ear plugs dampen

by 10-30 dB(A) if properly inserted, and ear defenders dampen by about 40 dB. Everyone who remains in

the examination room during image capture must use at least one type of hearing protection.

Foetuses are sensitive to noise, and it is hard to protect their hearing since traditional hearing protection

cannot be used (De Wilde 2005). High noise levels during pregnancy have been shown to potentially result

in, among other things, hearing loss in the high-frequency range. The examination time should therefore

be limited for pregnant women. Pregnant staff members or support persons must not remain in the

examination room during image capture (see “Pregnant patients” on page 29 and “Pregnant staff

members” on page 31).

Figure 10. Ear defenders and ear plugs.

The radio frequency field The radio frequency field (RF field) is used to obtain a signal for the image. A large RF coil, the body coil,

is located inside the scanner and the gradient coils and is hidden by the hood. There are also a number of

different RF coils for imaging of various body parts. The body coil is normally transmitting and is

combined with smaller coils that are receiving. There are also other coils (aside from the body coil) that

can be both transmitting and receiving, usually a head coil, head & neck coil or knee coil. The RF field

decreases rapidly as the distance from the transmitting coil increases.

The radio frequency field sends energy into the body, causing an increase in temperature (ICNIRP 2004).

No harmful effects are expected from temperature increases of the whole body that are less than 1˚C.

Limited areas of the body can withstand higher temperature increases through the body's own

temperature regulation, which is significant through normal blood circulation.

15

Figure 11. Examples of RF coils.

16

PATIENT EXAMINATION PPOLICY

Exposure of patients to the fields present in MRI are divided into three levels (ICNIRP 2004):

Normal level:Routine MRI scan for all patients.

Level 1 (controlled level):MRI scan performed outside of the normal level, where discomfort or undesirable effects could occur.

Level 2 (experimental level):Level outside of the controlled level for which ethical vetting to highlight the potential risks.

The content of this document is limited to safety aspects relevant for clinical practice, i.e. normal level and level 1.

Limit values for patients It is advisable to follow the limit values for patients set by ICNIRP (ICNIRP 2004, 2009, 2010). A

summary of how these limit values should be applied to MRI scans is found below. More detailed

information is available in Appendix II – Limit values with comments.

The static magnetic field The following limit values for patients were set for the static magnetic field by ICNIRP in 2009.

Normal level applies up to 4 T. The limit is set due to uncertainty of the effects on the body at higher field strengths, especially on foetuses and young children.Level 1 applies up to 8 T.

Patients should move slowly in the magnetic field to avoid dizziness and nausea.

Patients with implants may only be examined at no more than the field strength and no more than the static gradients for which the implant has been tested and declared safe.

The time-varying magnetic field: eddy currents The specified limit values (ICNIRP 2010) for patients may be difficult to understand, but can be

translated to the following:

At the normal level, the patient does not experience any muscle twitching. If the patient experiences muscle twitching, they are in level 1 or higher. Moderate muscle twitching is not harmful, but may be uncomfortable. Generally speaking, the louder a sequence, the higher the eddy currents the form.

Pregnant women should always be examined at normal level, i.e. no sequences that give rise to muscle twitching should be used. This also results in lower noise levels.

The time-varying magnetic field: noise levels All patients, whether awake or anaesthetized, should use hearing protection if the noise levels exceed 80 dB (A), and must use hearing protection at noise levels of 85 dB (A) (ICNIRP 2004). In practice, this means the following:

All patients must use hearing protection at field strengths of 1.0 T or higher. At 3 T, both ear plugs and ear defenders should be used during the examination.

All children, whether awake or anaesthetized, must always use hearing protection regardless of field strength.

Pregnant patients: Methods for minimizing the foetus' exposure to acoustic sound are to limitthe

scan time and to choose “silent” sequences.

17

The radio frequency field The limit values for the radio frequency field are set to limit heat rise in the body. No harmful effects are

expected from temperature increases of the whole body that are less than 1˚C. For infants, pregnant women, and

people with circulatory disorders, it is desirable to limit the temperature increase to max. 0.5˚C (ICNIRP 2004).

The temperature cannot be measured directly. Limitations in specific absorption rate (SAR) are used

instead5. The estimated SAR is indicated by the scanner for each sequence during the scan. Note that the

scanner does not take into account the total number of sequences being run on the patient and how close

together the sequences are run. The temperature increase in the body is higher if the sequences are run

directly after each other compared to taking a break between the sequences. The latter gives the body the

chance to cool down.

A summary of the limit values for clinical practice are provided below. More detailed information is

available in Appendix II – Limit values with comments.

SAR with whole body exposure:

Normal level: 2 W/kg

Level 1 (controlled) 4 W/kg

Level 2 (research): not permitted SAR body parts:

Head: 3 W/kg

Trunk: 2 to 10 W/kg depending on how much of the trunk is being exposed. The larger the area of the trunk being exposed, the lower the SAR permitted6.

Trunk of pregnant women: 2 W/kg since the foetus receives whole body exposure7.

Legs and arms 2 to 10 W/kg depending on how much is being exposed. The larger the area being exposed, the lower the SAR permitted.

The limit values for SAR are based on an ambient temperature of maximum 24˚C and humidity of maximum 60%. At higher temperatures and humidity levels, or if the patient is wrapped in blankets, heat dissipation is limited and the patient's temperature can get higher.

Limit values for research subjects The limit values for research subjects follows the limit values for patients, but is also limited by the

conditions set during ethical vetting.

5 SAR is a measure of how much energy the patient absorbs per kg of body mass. With whole-body exposure, a SAR of 2 W/kg corresponds to a 0.5ºC temperature increase in the body, and 4 W/kg corresponds to a temperature increase of about 1ºC.

6 For limited areas of the body, a higher SAR can be permitted since the body itself has the ability to regulate the temperature.

What SAR is permitted for different parts of the body depends on the size of the area being exposed and what perfusion the

body part has. The head is more sensitive to temperature increase than the trunk. Arms and legs can more easily give off

increased heat than other parts of the body.

7 Foetuses are particularly sensitive to heat rise and can be subject to whole-body exposure if the mother's abdomen is

18

examined. When scanning the trunk of a pregnant woman, the limit value is therefore 0.5˚C or a SAR of maximum 2 W/kg (normal level).

19

Limit values for the public and accompanying persons In practice, the limit value 0.5 mT is used for all persons not checked using the screening form (controlled area). The limit has been set to prevent people with e.g. implants from being injured.

Higher fields may be permitted under controlled forms (e.g. as support person). In such cases the

limitations are the same as for staff.

Screening form for patients Some medical implants and metal objects in the body could be turned or otherwise affected by the

magnetic field and cause injury. They can also be affected by the time-varying and radio frequency fields

and cause severe local heat rise. A large number of medical implants are MR-safe, but they must be

assessed on a case by case basis. Many implants are only approved under certain conditions, and

adaptation of the setup and examination is required (more information can be found under “Implants

and foreign metal materials” on page 20).

A screening form must be filled in for all persons undergoing an MRI scan (Appendix I – Screening forms). The screening form must be completed in writing by the patient

him/herself or by the patientwith the assistance of a relative, interpreter or physician.

The screening form must be checked by the MR staff at the time of the scan before the patient enters the examination room.

The attending physician is responsible for the medical assessment of patients with implants and pregnant patients. It is best to consult with a medical physicist or another qualified staff member in the event of uncertainty.

Patient positioning procedures

Review the screening form and contact the attending physician if anything is unclear. Never take a patient with an implant into the examination room if the patient has not undergone a medical assessment of the implant that has deemed the implant safe for an MRI scan.

Ask the patient if

− she is pregnant (> 15 years)

− he/she has any piercings. Remove the piercings if possible.

− he/she has any tattoos or permanent cosmetics, e.g. permanent eyeliner8.

Prior to the scan, the patient should change into a robe and preferably also trousers (flannel/cotton).Alternatively, the patient can remove all clothing containing magnetic material, e.g. underwire bra, belt, trousers with heavy zippers and rivets. If the patient is wearing their own clothes, the staff must ensure there are no metal objects in the pockets, for example.

The patient must remove all loose metal objects, e.g. bobby pins, jewellery, watch and dentures.

Heavy make-up should be washed off 9.

Position the patient so that the hands, arms or legs are not crossed or lying skin-to-skin. Skin-to-skin contact could cause burns! A thick layer of fabric (e.g. pillowcase,

8 Black ink sometimes contains iron, which may produce a strong heat rise locally.

9 Some cosmetics contain magnetic material that could cause image distortion and increased heat rise.

19

towel, foam rubber) should be placed between the legs. Trousers or a thin layer of material alone is not always sufficient10. Naked skin should not be allowed to lie against the sides of the tunnel.

Adjustment of positioning may be required for patients with an implant with conditional approval;see “Setup method for patient with ferromagnetic implant” below.

To protect the patient from increased heat rise and burns, the cables required for the scan (e.g. coil cables, ECG, pulse oximeter) must be positioned so they do not cross themselves or each other11. The easiest way is to route the cable straight out from the scanner.

− Never let a cable pass over an implant.

− Avoid contact between the cable and the patient's skin.

− Never use a cable you suspect could be damaged. A break in a cable could cause a strong local heat rise!

Avoid tucking blankets around the patient if it is warm in the room (over 24˚C), since thisaffects

heat dissipation during the scan. (No problems at field strength of 0.5 T or lower.)

If the patient has a tattoo (mainly black tattoos), permanent cosmetics, or piercings, a cold, wet compress or an ice pack can be applied to the area to mitigate any local heat rise.Tell the patient to alert you if it feels uncomfortable.

Give the patient hearing protection. Use ear defenders if possible. If ear plugs are used, make sure they are properly inserted. At 3 T, it is preferable to use both ear plugs and ear defenders.

Give the patient an alarm clock. Setup method for patient with ferromagnetic implant The spatial gradients exert a pulling force on ferromagnetic objects. The safety information for medical implants often provides information on the highest spatial gradient field for which the implant has been tested and is thereby permitted to be exposed to in order to guarantee patient safety. Implants are tested many times following a special procedure. As a result, the spatial gradients of the actual MRI system are usually higher than the values for which the implant has been tested. This does not necessarily mean that the implant is not safe even at higher spatial gradients. Testing and/or investigation must have been performed by the local MR Safety Council.

Some clinics have devised special setup methods that minimize the spatial gradient to which the patient is

exposed. The setup methods aim to avoid exposing the implant to spatial gradients that are higher than

they are approved for12. The ability to use setup procedures must be decided for each individual

implant and for each individual device. Local setup procedures should be defined if the intention is

to use setup procedures. The distribution of the spatial gradients is different for different equipment,

including for MRI scanners with the same magnetic field strength.

Procedures for accompanying support person

An accompanying support person who wants to enter the examination room must be checked using the screening form (Appendix I – Screening forms). Only individuals without implants may enter the examination room. If the individual has an implant, a medical assessment is required.

10 There have been cases of burns on the thighs of patients with poor circulation, even with fabric between the legs. At the

time of the scan, there is often no knowledge as to whether the patient has poor circulation or not.

11 Local heat rise and burns could occur if the cables are crossed. The most common type of incident report for MRI in Great Britain is for burns from cables!

12 The spatial gradients are strongest near the gantry sides of the MRI scanner opening.

20

If the support person is female, ask whether she is pregnant. A pregnant support person is not permitted to remain in the examination room during image capture.

The staff must ensure that the support person has removed all loose metal objects, e.g. bobby pins, jewellery, watch and dentures, and does not have any metal objects in their pockets or the like. No purses or bags may be taken in.

A support person remaining in the examination room during the scan must use the following hearing protection:At 1.5 T, ear plugs or ear defenders. At 3 T, ear defenders.

A relative or accompanying support person (screened) can sit in the examination room during the entire scan process13.

Implants and foreign metal materials Demand for MRI scans of patients with implants is on the rise. More and more implants are being defined as MR

Conditional, which has increased the demand for MRI scans among patients who previously could not be

examined.

Shellock www.MRIsafety.com compiles data on the safety of implants and other metallic objects in an MR

environment. This is updated continually. MR Safe, MR Conditional, and MR Unsafe implants can be found within

the same implant group14. Different restrictions and conditions can also apply to models from the same

manufacturer. It is therefore necessary to know both the make and model of the implant in order to make an

assessment.

The conditions set for the implant may mean that it is not possible to perform a scan with all types of MRI scanners.

The fact that an implant is “approved” at one hospital does not automatically mean that the patient can be scanned

at a different hospital. There may also be requirements that require adaptation of preparations, positioning and the

scan.

Implant assessment Assessment of an implant's safety must be performed by a qualified staff member at the hospital, such as a medical physicist.

An implant is affected by the MRI scanner fields, regardless of whether it is inside or outside of the scan

area. An assessment is therefore required regardless of where in the body the implant is located.

Exact information about the implant must be known (type, model).

The implant's conditions are most suitably assessed by an MR nurse or MR physicist, depending on the condition level of the implant. The eligibility assessment is done by a physician.

An MR nurse can make an initial assessment of the implant based on:

− The conditions described below under the respective implant group.

− An earlier assessment by a qualified staff member at the hospital, such as a medical physicist.

− Shellock's website (www.MRIsafety.com); see “conditions based on Shellock's criteria” below.

When assessing an implant not previously evaluated, a qualified staff member at the hospital, e.g. a medical physicist, must be contacted with as much advance notice as possible. It can sometimes take a long time to find and assess the information, making it difficult to make an emergency assessment.

A qualified staff member at the hospital, e.g. a medical physicist, will write a general assessment of the

implant's safety in an MR environment. The eligibility assessment is done by a physician.

21

13 Relatives are only exposed to the gradient field if they stand right at the scanner opening during image capture. The

RF field is negligible outside of the coil. The time they are in the room is relatively short.

14 Shellock's terminology is explained in Appendix III.

21

Suggested conditions based on Shellock's criteria

Safe, Conditional 1

− Scan OK at the maximum field strength indicated by Shellock.

− SAR: Normal level or level 1.

Conditional 2

− Scan OK at the maximum field strength indicated by Shellock.

− SAR: Normal level or level 1.

− The implant must be firmly embedded (at least 6 weeks after surgery). An implant made of non-magnetic material (e.g. Phynox, Elgiloy, titanium, titanium alloy, MP35N, Nitinol) may be scanned earlier than this.

Conditional 3

− Regards patches. Must NOT be scanned; must instead be removed15. The patch must be removed before the MRI scan and a new patch applied immediately after the scan.

Conditional 4

− Regards halo vests. If the scan is deemed justified, the matter is sent on to a qualified staff member at the hospital, such as a medical physicist, for assessment.

Conditional 5

− If the scan is deemed justified, the matter is sent on to a qualified staff member at the hospital, such as a medical physicist, for assessment.

− The scan is performed based on an earlier assessment of the implant by a qualified staff member at the hospital, such as a medical physicist.

Conditional 6

− If the scan is deemed justified, the matter is sent on to a qualified staff member at the hospital, such as a medical physicist, for assessment.

− The scan is performed

as specified below for the implant group or

as specified in an earlier assessment of the implant by a qualified staff member at the hospital, such as a medical physicist.

− The setup method for a patient with ferromagnetic implant may have to be used, particularly for 3 T, unless otherwise specified in the assessment of a qualified staff member at the hospital, such as a medical physicist.

− SAR: Max 3 W/kg for no more than 15 min. per scan16. A concentration of heat may occur around the implant.

Multiple sequences can be run, but a break between the sequences is recommended for temperature balancing.

Be particularly careful with implants that sit in areas with limited perfusion.

− The implant can cause severe artefacts.

Conditional 7

− Must NOT be scanned, regardless of field strength.

15 The patches contain metal foil that could cause severe heating and burn the patient.

16 Non-clinical tests have shown a temperature increase of < 3°C at 3W/kg for 15 min.

22

Conditional 8

− If the scan is deemed justified, the matter is sent on to a qualified staff member at the hospital, such as a medical physicist, for assessment.

− The scan is performed based on an earlier assessment of the implant by a qualified staff member at the hospital, such as a medical physicist.

− The setup method for a patient with ferromagnetic implant may have to be used, particularly for 3 T, unless otherwise specified in the assessment of a qualified staff member at the hospital, such as a medical physicist.

− SAR: As low as possible, but max. 3 W/kg for maximum 15 min. per scan17. A strong concentration of heat may occur around the implant.

There must be 30-second breaks between scans for temperature balancing purposes.

Be particularly careful with implants that sit in areas with limited perfusion.

Be particularly careful with backs in cases where previous experience has shown that they usually become hot.

− The implant can cause severe artefacts.

Unsafe 1, Unsafe 2

− Must NOT be scanned, regardless of field strength.

Implant not included on www.MRIsafety.com:

− If the scan is deemed justified, the matter is sent on to a qualified staff member at the hospital, such as a medical physicist, for assessment.

− The scan is performed based on conditions and restrictions set by a qualified staff member at the hospital, such as a medical physicist.

Suggested policies for some groups of implants:

Pacemakers (PMs) and internal defibrillators (ICDs)

Most PMs and ICDs are defined as “MR Unsafe”. Performing an MRI scan with such implants would

expose the patient to very large risks18.

However, development is under way to adapt PMs and ICDs to the MR environment. As of September

2014, a small number of PMs and ICDs were defined as “MR Conditional” at 1.5 T, but there are none

for 3T (www.MRIsafety.com). Many patients now receive PMs defined as “MR Conditional” and demand

for MRI scans of such patients is on the rise.

If scanning patients with an MR Conditional PM or ICD, you should define a local procedure that

describes all aspects from receipt of a referral for assessment and booking, to the patient leaving the MRI

department after the scan. The same procedure applies regardless of which body part is being scanned.

The procedure should be defined in collaboration with Cardiology and the Pacemaker unit.

Only patients who satisfy all requirements in this procedure may be scheduled for a scan. This

procedure must be strictly followed when performing the preparations, booking and scan.

17 Non-clinical tests have shown a temperature increase of < 4°C at 3W/kg for 15 min.

18 There have been a number of deaths worldwide linked to pacemakers in the MR environment. The risks consist of i)

displacement or rotation of the implant or leads, ii) temporary or permanent change in the functionality of the implant, iii)

incorrect sensitivity or triggering of the implant, iv) severe heating around the leads and v) induced currents in the leads. The

leads could act as an antenna and cause a severe local heat rise, even if the implant is off.

23

Cochlear implants

Some models of cochlear implants are defined as “Conditional 5” at 1.5 T, but most are defined as

“Unsafe”. Conditions for scanning patients with cochlear implants include:

The clinical indication is strong.

The model designation of the implant is documented in writing.

The implant is defined as “MR Conditional” in www.MRIsafety.com.

The patient does not have any leads left in their body from a previous implant.

The safety of the implant has been investigated by a qualified staff member at the hospital, such as a medical physicist.

− When assessing a “new” implant, a qualified staff member at the hospital, such as a medical physicist, must be contacted several weeks before the scan for investigation of the implant's safety and conditions for the MRI system in question. An implant that has not been assessed previously requires lengthy investigation.

Maximum field strength: 1.5 T.

A scan can only be carried out if the conditions defined by a qualified staff member at the hospital, such as a medical physicist, can be fully met.

The scan must be performed as specified by the qualified staff member at the hospital, such as a medical physicist, for the specific implant.

Other electronic implants

It is advisable to be extremely restrictive in scanning patients with an electronically-activated implant

(magnetically, passively, or actively controlled), e.g. ocular prostheses and dental implants19. More and

more MR Conditional electronic implants are being made available on the market, but most electronic

implants are still rated as “MR Unsafe”.

In order for a patient with an electronic implant to undergo an MRI scan, all of the following

requirements must be met:

The clinical indication is strong.

The model designation of the implant is documented in writing.

The implant is defined as “MR Conditional” in www.MRIsafety.com.

The department has ensured that:

− The patient does not have any leads left in their body from a previous electronic implant20.

− There is no suspicion of a break in the implant leads or implant malfunction.

The safety of the implant has been investigated by a qualified staff member at the hospital, such as a medical physicist.

− When assessing a “new” implant, a qualified staff member at the hospital, such as a medical physicist, must be contacted as soon as the referral is received for investigation of the implant's safety and conditions for the MRI system in question. An implant that has not been assessed previously requires lengthy investigation.

19 The restrictions are based on the risk of serious consequences, including displacement of the implant, severely increased

MR-related heating of the implant and leads, and malfunctioning of the implant (www.MRIsafety.com).

20 These can cause severe local heat rise.

24

A scan can only be carried out if the conditions defined by a qualified staff member at the hospital, such as a medical physicist, can be fully met.

The scan must be performed as specified by the qualified staff member at the hospital, such as a medical physicist, for the specific implant.

The implant must be checked before/after the scan, preparations and adaptation following the instructions given in the technical manual of the implant (see also the statement from a qualified

staff member at the hospital, e.g.medical physicist). Aneurysm clips

Aneurysm clips are made of materials with different magnetic properties. In the early days of MR

technology, there were a couple of deaths caused by clips in the MR environment. Nowadays (January

2016), most aneurysm clips on the market are MR Compatible at 3 T, but approximately 6% of the

models are still “MR Unsafe”. The patient is scanned with the following conditions:

The operation report must be studied.

− The exact information about the clip implanted in the patient must be known (manufacturer, model).

− The clip must be defined as “MR Safe” or “MR Conditional” according to www.MRIsafety.com.

If the above conditions are satisfied, the patient can be scanned at maximum 3T following the conditions for “Conditional 6”:

− SAR: normal level, max. 15 min per scan.

− The setup method for a patient with ferromagnetic implant may have to be used, particularly for 3 T, unless otherwise specified in the assessment of a qualified staff member at the hospital, such as a medical physicist.

Coils, filters, stents and grafts

There are many different types of coils, filters, stents and grafts. Most are made of non-ferromagnetic or

weakly ferromagnetic material. No objects in this group are defined as

“MR Unsafe”, but there are many that are only approved at 1.5 T (January 2016).

Approximately 30% of the objects are defined as “Conditional 8”, suggesting that heating is an

important safety aspect for these implants.

The scan is performed at 1.5 T or the maximum permitted field strength according to www.MRIsafety.com.

− All coils, filters, stents and grafts can be scanned at 1.5 T.

The setup method for a patient with a ferromagnetic implant may have to be used, particularly

at3 T, unless otherwise specified by the assessment of a qualified staff member at the hospital,

such as a medical physicist.

The following parameters must be used for the scan:

− Gradient field: normal level,

− SAR: normal level, maximum 15 min. per scan, 30 s break between scans, or as specified in the statement by the medical physicist for the implant in question.

25

Shunts and reservoirs

As of 2016, most shunts and reservoirs are defined as “MR Safe” or “MR Conditional”. Approximately 25% are still only approved at 1.5 T, and some are hazardous/unsuitable in an MR environment21.

Patients with shunts and reservoirs can undergo MRI scanning under the following conditions:

The manufacturer and model of the implant are known.

With few exceptions21 scans can be done at 1.5 T

− SAR: normal level, max. 15 min per scan.

The setup method for a patient with a ferromagnetic implant may have to be used depending on the assessment of a qualified staff member at the hospital, such as a medical physicist.

An implant approved for 3T by a qualified staff member at the hospital, such as a medical

physicist22 can be scanned at 3 T

− The setup method for a patient with ferromagnetic implant will probably have to be used, unless otherwise specified in the assessment of a qualified staff member at the hospital, such as a medical physicist.

− SAR: normal level with maximum 15 min. per scan, and a 30 s break between scans, or as specified by a qualified staff member at the hospital, such as a medical physicist, for the specific implant.

NOTE! The functionality of the implant should be checked before/after the scan as specified in the manufacturer's instructions (see also the statement from the qualified staff member at the hospital, such as a medical physicist).

Medical pumps for Baclofen

The maximum permitted field strength and the procedure for the MRI scan depend on the type of pump.

Ask the department what pump the patient has.

The scan is performed based on the conditions defined in the statement by a qualified staff member at the hospital, such as a medical physicist.

NOTE! The pump should be checked before/after the scan as specified in the pump manual's instructions (see also the statement from the qualified staff member at the hospital, such as a medical physicist).

Insulin pumps

Insulin pumps must not be taken into the examination room under any circumstances. All pumps are defined as “Unsafe 1”.

When scanning patients with an insulin pump, the pump and accessories must be disconnected and left

outside of the examination room, while the needle (which remains in the patient) can be scanned with MRI.

Ask the department what pump and needle the patient has.

The scan is performed based on the conditions defined in the statement by a qualified staff member at the hospital, such as a medical physicist.

21 The following are hazardous/unsuitable

* Cerebral ventricular shunt tube connector (type unknown) misc. - unsafe

* Shunt valve, Holter type misc. The Holter Co. Bridgeport, PA – unsafe

* Sophy adjustable pressure valve has very strict restrictions. Contact a qualified staff member at the hospital,

e.g. a medical physicist, for a new investigation if a scan is to be performed.

22 23 have been investigated and approved at 3T by medical physicists (January 2016).

26

Metal implants in muscle and bone

Patients with metal objects implanted in muscle or bone can undergo MRI scanning under the following

conditions:

If the implant is made of a non-ferromagnetic material (e.g. Elgiloy, Phynox, MP35N, titanium, titanium alloy, Nitinol, tantalum), the patient can undergo an MRI scan (at max.1.5 T) immediately after placement of the object. For a weakly ferromagnetic material, a waiting period of 6-8 weeks is required before an MRI scan to give the implant time to firmly incorporate into the tissue (www.MRIsafety.com).

Patients must not be scanned if there is any suspicion that a weakly ferromagnetic implant is loosely seated (e.g. patient with “approved” heart valve prosthesis with heart problems or suspected endocarditis).

Conditions:

− “Safe”: scanned at the maximum field strength specified by www.MRIsafety.com.

− The following parameters are used for scanning “Conditional 5, 6, 8”:

· At the maximum field strength specified by www.MRIsafety.com.

· The setup method for a patient with ferromagnetic implant may have to be used, particularly for 3 T, unless otherwise specified in the assessment of a qualified staff member at the hospital, such as a medical physicist.

· SAR: normal level with maximum 15 min. per scan and a 30 s break between scans, or as specified in the statement by the medical physicist for the implant in question.

Shrapnel, bullets or pellets

Shrapnel usually contains steel and is therefore strongly ferromagnetic. The fragments can therefore be

displaced or twisted. However, heating of the RF field is limited.

− Scanning a patient with small fragments may be considered depending on where the object is located and how long it has been in place.

− The patient must never undergo MRI scanning if the ferromagnetic fragment sits in or near a vital organ, the nervous system, or major blood vessels.

The majority of bullets and pellets that are used are non-ferromagnetic, but ferromagnetic bullets do exist (“Unsafe”).

If possible, check what type of bullet/pellet the patient has.

Contact a qualified staff member at the hospital, e.g. a medical physicist, for investigation.

The scan is performed based on the conditions defined in the statement by a qualified staff member at the hospital, such as a medical physicist.

Metal objects in the eye

Metal slivers are ferromagnetic. Even small fragments can cause serious damage to the eye if they rotate in

the magnetic field.

The following questions must be asked if the patient has or has ever had metal slivers in their eye:

− Was your eye examined by a doctor at the time of the accident?

− If so, were you informed that the object was completely removed?

The patient must never undergo MRI scanning if there is the slightest suspicion that the patient still

has metal objects in their eye or if the patient was not informed of the results ofthe examination.

27

Ferromagnetic tattoos and permanent cosmetics

Some tattoo ink and permanent cosmetics contain ferromagnetic material. This can cause pain in the

skin when the ferromagnetic particles are drawn towards the scanner, and can also cause increased

heating. However, major reactions are very rare. Permanent eyeliner has also been shown to cause severe

swelling.

If a patient with a ferromagnetic tattoo or permanent cosmetics will be scanned:

Tell the patient to alert the staff they experience any discomfort.

A cold, wet compress or an ice pack can be applied to the area to mitigate any local heat rise. Piercings

Piercings can come in different types of material, such as surgical steel, titanium, gold and silver. These can

cause increased local heat rise.

The patient should remove the piercing, if possible.

− If this is not possible, the piercing should be isolated from the skin as much as possible (with tape or a bandage) to prevent heat rise. Alternatively, a cold, wet compress or an ice pack can be applied to the area to mitigate heat rise. If the piercing is ferromagnetic, it must be stabilized with tape, a bandage or Velcro.

− A tongue piercing can remain in place if it is made of titanium or surgical steel.

− NOTE! There are “fake” versions of piercings (that do not require a hole) that are held in place with a magnet. These must be removed before the scan.

Tell the patient to alert the staff they experience any discomfort.

If the piercing lies within the scan area, the scan must be performed as specified for “normal level”.

Contrast medium Use of gadolinium-based contrast medium is common in MRI scans. Contrast agent examinations are

safe in most cases, but can temporarily or permanently impair renal function.

In recent years, there have been reported cases of Nephrogenic Systemic Fibrosis (NSF) in connection

with use of gadolinium-based contrast medium in patients with severely (GFR <30 ml/min/1.73 m2) or

moderately (GFR<60 ml/min/1.73 m2) impaired renal function, and in patients who have undergone or

will undergo a liver transplant. There is also an increased risk for people with temporary renal

impairment. Most cases of NSF were linked to so-called linear contrast medium. The cumulative dose is

also considered to be important.

Contrast media are divided into three categories.

1. High risk Linear contrast medium: Omniscan, Optimark (non-ionic) and Magnevist (ionic) All patients must be screed for renal impairment with laboratory tests prior to use.

2. Medium risk Linear ionic contrast medium: MultiHance, Primovist All patients should be screed for renal impairment with laboratory tests prior to use. All patients > 65 years of age must be screened.

3. Low risk Non-linear macrocyclic contrast medium: Dotarem, ProHance and Gadovist. In this group, there is no absolute contraindication to a single dose, not even for dialysis patients.

28

No patient should be prevented from getting a clinically-motivated MRI scan that is enhanced with

contrast medium. For all patients, the smallest possible dose of contrast medium required to achieve

satisfactory results for the scan must be used.

The following restrictions are suggested in relation to contrast medium23.

Patients with normal renal function:

− A scan with Gd contrast medium should not be performed within 24 hours of another scan with ion-based or Gd-based contrast medium since in such cases renal function may be temporarily impaired.

Patients with moderately impaired renal function (GFR < 60 ml/min/1.73 m2):

− Gd contrast medium category 1 should be avoided. With strong indication, the smallest dose possible should be given.

− Gd contrast medium category 2, 3 can be given.

− If the patient underwent a scan with ion-based contrast medium, you should wait 2 days and check to ensure renal function has not been impaired (creatinine/GFR) before another scan.

− Use of Gd contrast medium should not be repeated for at least 7 days.

Patients with severely impaired renal function (GFR < 30 ml/min/1.73 m2) and patients in the perioperative liver transplant period:

− Gd contrast medium category 1 must not be used (contraindicated).

− Gd contrast medium category 2 should be avoided.

− Gd contrast medium category 3 can be given if there is a diagnostic need for this contrast medium. The smallest possible dose should be used.

− If the patient underwent a scan with ion-based contrast medium, you should wait 2 days and check to ensure renal function has not been impaired (creatinine/GFR) before another scan.

− Use of Gd contrast medium should not be repeated for at least 7 days.

Children ages 0-1

− should only be scanned with contrast medium if absolutely necessary considering immature renal function of this age group.

− Only Dotarem (category 3) is approved for children age 2 and under. The smallest possible dose of Gd contrast medium should be given.

− Use of Gd contrast medium should not be repeated for at least 7 days.

− In other respects, refer to information on the respective contrast medium in FASS

− Children > age 1

23 Based on recommendations from

ESUR (http://www.esur.org/ESUR-Guidelines) Guidelines 8.1 2014

Swedish Society of Radiology (http://www.sfbfm.se/sidor/mr-kontrastmedel)

Rekommendationer för KM vid MRT [Recommendations for contrast medium in MRT]/ Swedish Society of Radiology working group, version 3, 18 February 2014

FASS (http://www.fass.se/LIF )

Drug group ATC-V08C

29

− The smallest possible dose of Gd contrast medium category 3 can be given. Only Dotarem is approved for children under the age of 2.

− In other respects, refer to information on the respective contrast medium in FASS

− Pregnant women:

− Use of contrast medium during pregnancy is not recommended unless required based on the woman's clinical condition24.

− If there is a strong indication for contrast medium, the smallest possible dose of Gd contrast medium category 3 must be given.

− Breast-feeding

− The general recommendation is to refrain from breast-feeding for a period of 24 hours25 after injection of the contrast medium. There is no value in refraining from breast-feeding for more than 24 hours.

− Since a very small proportion of Gd-based contrast medium is excreted in breast milk and is then taken up in the baby's intestines, the ACR (American College of Radiology)26 considers it safe for the mother and child to continue breast-feeding after a scan with such. This can be communicated to any mother who does not want to refrain from breast-feeding. Greater precautions should be taken for very small or premature babies.

− A break in breast-feeding for at least 24 hours is required for Gd contrast medium with a high risk of NSF (category 1).

Pregnant patients When performing a scan on a pregnant patient, the effects to the patient and the effects to the foetus must

be investigated. No signs of MRI scans causing injury to foetuses have been reported. It is well known that

foetuses are very sensitive to noise. However, the ear canals are filled with water, which suppresses the

noise dramatically (Wieseler 2010).

The central nervous system of the foetus is very sensitive to temperature increases, especially during the

first trimester. An elevated temperature for a prolonged period of time can affect foetal development

(ICNIRP 1998). Inside the mother, the foetus has limited ability to dissipate its increased heat. An

abdominal scan can result in whole-body exposure for the foetus.

Scans of pregnant women should be restrictive in nature (De Wilde 2005, ICNIRP 2004). The gradient

fields, RF fields and scan time must be limited during the examination. The decision for or against an MRI

scan is dependent on the potential diagnosis. When it comes to scanning the abdominal area, an MRI is a

non-ionizing alternative to CT and conventional X-rays.

Scanning a pregnant woman In an MRI examination of a pregnant woman, the foetus (which is not the patient) is also exposed to the static

magnetic field, eddy currents and high noise levels, regardless of which body part is being scanned. The

eddy currents are at their most powerful in body parts near the opening of the scanner. The foetus is thus

exposed to high eddy currents during scans of e.g. the woman's legs or brain. If the foetus is located within the

RF coil, it is also exposed to the radio frequency field. When it comes to examining the abdominal area, an

MRI

24 There is very little knowledge of how contrast medium affects human foetuses. The contrast medium is absorbed by the

foetus' kidneys and is excreted into the amniotic fluid in the foetus' urine. The foetus swallows the amniotic fluid, causing the

contrast medium to pass through the foetus many times www.MRIsafety.com.

25 It is advisable to use a breast pump before the scan to set aside milk for the next day.

30

26 http://www.acr.org/quality-safety/resources/contrast-manual

31

is a non-ionizing alternative to CT and conventional X-rays. General advice for examinations on pregnant

woman can be found in ICNIRP 2004 and Shellock (www.MRIsafety.com).

The attending physician must perform a risk-benefit analysis for any pregnant patient.

When it comes to examining the abdominal area, an MRI may be the gentlest method for the foetus since the alternative is usually ionizing radiation, resulting in a dose of radiation to the foetus.

For areas outside of the abdomen, methods other than MRI may be more suitable. For CT and X-rays, the dose of radiation decreases greatly as the distance from the foetus increases. The radiation dose is very low if the foetus is outside of the radiation field. With MRI, the foetus is still subjected to the static field, noise levels, and high eddy currents.

According to ICNIRP 2009, the scan can be performed at up to 4T. However, lower field strengths generally produce lower noise levels and are easier to adapt to low SAR, making them preferable.

Detection of pregnancy after the examination is not a reason to recommend abortion. MRI scan of pregnant women

If the scan can be performed at either 1.5 T or 3 T, then 1.5 should be the first choice. The maximum field strength used when scanning pregnant women is 4 T (normal level) (ICNIRP 2009). However, lower field strengths generally produce lower noise levels and are easier to adapt to low SAR, making them preferable.

With 3T, the supine position should be used27.

Avoid sequences with frequent gradients and short rise times as they cause high eddy currents and high noise levels.

Sequences with low SAR values should be used when scanning the abdomen (normal level). Take a break between sequences for temperature balancing. Avoid using blankets since these prevent heat dissipation.

The scan time for pregnant women must be kept short. Contrast medium when scanning pregnant women

Use of contrast medium during pregnancy is not recommended unless required based on the woman's clinical condition28.

If there is a strong indication for contrast medium, the smallest possible dose of Gd contrast medium category 3 must be given.

It is advisable to avoid breast-feeding for 24 hours.

For further information, see “Contrast medium”.

Research in vivo The term research patient refers to a patient or healthy volunteer called in for an MRI scan for research

purposes.

Scans of research subjects are subject to the same restrictions and limit values as for patients, but are also

limited by the conditions set during ethical vetting of the project.

27 Examination of multi-transmit (which is used for 3 T) on foetuses is only investigated using the supine position.

Without multi-transmit there is a risk of local hotspots of SAR.

28 There is very little knowledge of how contrast media affect human foetuses. The contrast medium is absorbed by the foetus'

32

kidneys and is excreted into the amniotic fluid in the foetus' urine. The foetus swallows the amniotic fluid, causing the contrast

medium to pass through the foetus many times www.MRIsafety.com.

33

POLICY FOR STAFF

Limit values for staff It is advisable to comply with the limit values for staff that have been set by ICNIRP, where new

guidelines were published in 2009-2010 and 2014. A summary of how these limit values should be

applied to staff in clinical practice is found below. More detailed information is available in Appendix II

– Limit values with comments.

The static magnetic field The staff is mainly exposed to stray magnetic fields from the static magnetic field. According to ICNIRP

2009, exposure of maximum 2 T to the head and trunk is recommended, but up to 8 T can be permitted

under controlled conditions (ICNIRP 2009). For exposure of just the arms and legs, 8 T is acceptable29.

The stray magnetic field where the staff stands when positioning the patient is between 70 and 500 mT for a 3 T MRI scanner. To avoid sensory effects (such as dizziness and nausea) from motion-induced

electric fields in a few Hz, ICNIRP recommends that B (change in magnetic flux density) does not exceed

2 T over a period of 3 s (ICNIRP 2014)30. This is not exceeded during normal work31. The time-varying magnetic field The time-varying magnetic fields are at their strongest at the outer edges of the scanner, either inside or

outside depending on the scanner design. Staff can reach the limit values for eddy currents if they stand

near the scanner opening during the actual scan.

A staff member remaining in the examination room during the scan must use hearing protection. Pregnant

staff must not remain in the examination room during image capture to protect the foetus from the high

noise levels.

The radio frequency field The RF field decreases rapidly as the distance from the transmitting RF coil increases. It is therefore

unlikely that staff will reach the set limit values for the RF field.

Pregnant staff members No known damage to foetuses has been reported for MR staff32. Pregnant staff members can work as

usual during the pregnancy with a few exceptions.

Pregnant staff members should not be allowed in the examination room during the first trimester.This recommendation is not based on on any known hazard, but is instead based on a general precautionary principle since it is well known that the first trimester is critical for foetal development33.

29 The measure “time average” for exposure that was used in the past has been removed in the current recommendations from ICNIRP.

30 There are also limit values to ensure that staff do not reach the limit for electrical stimulation of peripheral nerves. It is

not possible to reach the limit when working with MRI scanners at 1.5 and 3 T.

31 Can be reached if you go in/out of a 3 T scanner.

32 In a survey from 1993 (Kanal 1993), a questionnaire with many questions related to infertility, pregnancy and birth defects was

sent to female MR staff members. 1915 responses were received, including 1421 from pregnant women. 280 of these pregnant

staff members worked with MR during the pregnancy. The study did not find any statistical differences between those who

worked with MR during pregnancy and others when it came to miscarriage, low birth weight, premature birth, and infertility.

33 The recommendations vary. According to Shellock's recommendations, pregnant staff can be allowed in the

34

examination room throughout the entire pregnancy, regardless of the trimester, but not during the actual image

capturing.

35

Pregnant staff must not be allowed in the examination room during the actual image capturing.This limitation has primarily been set so as not to subject the foetus to high noise levels (De Wilde 2005).

Screening form for staff

All staff members must be checked using the screening form before they enter the MRI scanner examination room for the first time (Appendix I – Screening forms).

If the individual has an implant, a medical assessment must be carried out to determine whether the individual can work in the examination room.

Safety training All staff working with MRI, in an MR environment (whether continuously or only occasionally), or are

stationed in a department where there is an MRI scanner must undergo basic safety training. The purpose

of the training is for everyone to

have basic knowledge of MRI safety to prevent accidents that could harm the patient, staff, relatives, or the MRI scanner, and

know what procedures to take in an emergency situation, such as cardiac arrest in the MR environment, quench, and fire.This corresponds to the information in the chapters “Introduction” and “MRI scanner policy”.

be able to answer simple questions about MRI safety asked by patients.

Physicians, nurses, physicists and researchers who work with MR or are responsible for MR patients

should have knowledge of the information found in the chapters “Introduction”, “MRI scanner policy”,

“Biological effects of the MRI scanner fields”, ”Patient examination policy” and “Policy for staff”.

36

REFERENCES AND LINKS

References 1. De Wilde JP, Rivers AW, Price DL. A Review of the Current Use of Magnetic Resonance Imaging in Pregnancy and Safety

Implication for the Fetus. Progress in Biophysiology and Molecular Biology 87, pp 335-353, 2005.

2. European Society of Urogenital Radiology (ESUR): ESUR Guidelines of Contrast Media 7.0. http://www.esur.org/ESUR-Guidelines.6.0.html

3. Faris OP, Shein M. Food and Drug Administration Perspective: Magnetic Resonance Imaging of Pacemaker and Implantable Cardioverter-Defibrillator Patients. Circulation 114(12) pp 1232-1233, 2006.

4. ICNIRP Statement Medical Magnetic Resonance (MR) procedures: Protection of patients. Health Physics 87(2) pp 197-216, 2004.

5. ICNIRP Statement. Amendment to the ICNIRP “ Statement on medical magnetic resonance (MR) procedures: protection of patients” Health Physics 97(3) pp 259-261, 2009.

6. ICNIRP Guidelines. Guidelines on limits of exposure to magnetic fields. Health Physics 96(4) pp 504-514, 2009.

7. ICNIRP Guidelines. Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz). Health Physics 74(4) pp 494-522, 1998.

8. ICNIRP Statement. ICNIRP Statement on the “Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz)”. Health Physics 97(3) pp 257-258, 2009.

9. ICNIRP Guidelines. Guidelines for limiting exposure to time-varying electric and magnetic fields (1 Hz to 100 kHz). Health Physics 99(6) pp 818-836, 2010.

10. ICNIRP Guidelines. ICNIRP guidelines for limiting exposure to electric fields induced by movement of the human body in a static magnetic field and by time-varying magnetic fields below 1Hz. Health Physics 106(3) pp 418-425, 2014.

11. IEC 60601-2-33. Medical electrical equipment - Part 2-33: Particular requirements for the safety of magnetic resonance equipment for medical diagnosis, 2002.

12. Kanal E, Gillen J, Evans JA, Savitz, DA, Shellock, FG. Survey of Reproductive Health among Female MR Workers. Radiology 187 pp 395-399, 1993.

13. Shellock FG. Reference Manual for Magnetic Resonance Safety, Implants and Devices: 2011 Edition. Biomedical Research publishing group. (ISBN-10 0-9746410-7-3, ISBN-13 978-0-9746410-7-2)

14. Dedini RD, Karacozoff AM, Shellock FG, Xu D, Pekmezci M. MRI issues for ballistic objects: information obtained at 1.5-, 3- and 7-Tesla. The Spine Journal 13 pp 815–822, 2013

15. Swedish Society of Radiology: “Rekommendationer for kontrastmedel (KM) vid magnetresonanstomografi (MRT)”. http://www.sfmr.se/sok/download/kontrast/Rekommendationer_MRT_20070912.pdf

16. Swedish Society of Radiology: “Nefrogen Systemisk Fibros (NSF) Ett nytt sällsynt allvarligt sjukdomstillstånd att ta hänsyn till v id MRT”. http://www.sfmr.se/sok/download/NSF-leander.pdf

17. Wieseler KM, Bhargava P, Kanal KM, Vaidya S, Stewart BK, Dighe MK. Imaging in pregnant patients: Examination appropriateness. Radiographics 30(5), pp 1215-1229, 2010.

37

Links Swedish Work Environment Authority:

www.av.se/

European Society of Magnetic Resonance in Medicine and Biology (ESMRMB):

www.esmrmb.org

European Society of Urogenital Radiology:

www.esur.org

FASS: www.fass.se/LIF/home/index.jsp International Society of Magnetic Resonance in Medicine (ISMRM): www.ismrm.org/ Swedish Radiation Safety Authority: www.stralsakerhetsmyndigheten.se Swedish Agency for Health Technology Assessment and Assessment of Social Services: www.sbu.se Swedish Society of Radiology:

www.sfmr.se

U.S. Food and Drug Administration (FDA): www.fda.gov

38

APPENDIX I – SCREENING FORMS

The following pages contain screening forms for:

Patients. The Swedish version followed by the English version.

Accompanying persons. The Swedish version followed by the English version.This is used for individuals accompanying the patient into the examination room. (Relative, support person, interpreter, etc.)

Staff. Either the staff or the accompanying person screening form is used for students and others entering the

examination room temporarily (e.g. building contractors).

1.

Har du eller har du haft något av följande i kroppen?

JA

NEJ

- Pacemaker - Medicinpump (för t ex insulin eller cytostatika) - Implant for neurostimulation (e.g. in your brain or back) - Hearing implant (e.g. cochlear implant) - Other electrical or battery-powered implant

If YES, what?

2.

Har du eller planeras du att få något föremål inopererat

som kan innehålla metall? - Kärlclips (t ex i hjärnan eller hjärtat) - Föremål så som trachealtub, hudexpanderare, skruvar,

- PEG/slang till magsäcken

Om JA, vad eller vilken typ av operation?

När och var?

3.

Har du något främmande metallföremål i kroppen? - Metallsplitter eller svetsloppa i ögat - Granatsplitter, kulor eller hagel - Annat metallföremål

Om JA, vad?

4.

Har du svårt att vistas i trånga utrymmen (klaustrofobi)?

5.

Går du i dialys eller har kraftigt nedsatt njurfunktion?

6.

Kvinnlig patient – Är du gravid?

7.

Kvinnlig patient – Ammar du?

Kontrollista inför undersökning med magnetkamera (MR)

Namn: Vikt:

Personnummer: Längd:

Var god svara på nedanstående frågor och markera det svar som gäller dig

hjärtklaff, shunt, protes, fast tandställning mm.

Kontakta oss snarast om du svarat JA på någon av frågorna ovan.

Underskrift Datum

Magnetic Resonance (MR) screening form for patients

Name: Weight:

Personal identity number: Height:

Please answer the questions stated below and highlight the answer that applies to you

YES NO

1. Do you have a history of any of the following devices in the body? - Cardiac pacemaker or defibrillator - Implantable medicine pump (e.g. for insulin or cytostatic) - Implant for neurostimulation - Cochlear implant - Other electrically/magnetically activated implant or electrodes

If YES, specify what

2. Do you have any implanted metal objects in your body? - Aneurysm clips (in e.g. the heart or brain) - Other items, e.g. tracheal tube, tissue expander, coil, stent, dental implants, prosthesis, screws, cardiac valve

If YES, what and which type of surgery?

When and where?

3. Do you have any foreign metal objects in your body? - Metallic slivers or fragments in the eye - Shrapnel, bullets or pellets - Other foreign metallic objects

If YES, specify what

4. Do you suffer from claustrophobia (fear of narrow, enclosed spaces)?

5. Are you on dialysis or do you have severely impaired renal function?

6. Female patient – Are you pregnant?

7. Female patient – Are you breast-feeding?

Contact us as soon as possible if you have answered YES to any of the questions above.

Signature Date

Kontrollista för anhörig/medföljande till magnetkameraundersökning

Magnetfältet på magnetkameran är ALLTID på!

Om du som anhörig/medföljande vill gå in i undersökningsrummet måste

du av säkerhetsskäl fylla i denna lista.

V

MAGNETFÄ

Namn anhörig/medföljande Personnummer

1.

Har du något elektriskt eller batteristyrt implantat i kroppen?

JA

NEJ

T ex pacemaker, intern defibrilator, medicinpump (för t ex insulin eller cytostatika), neurostimulator, hörselimplantat (t ex cochlearimplantat).

2.

Har du något inopererat metallföremål i kroppen? T ex kärlclips (t ex i hjärnan eller hjärtat), hudexpanderare, skruvar, hjärtklaff, shunt, protes.

3.

Har du något främmande metalliskt föremål i kroppen? T ex metallsplitter eller svetsloppa i ögat, granatsplitter, kulor eller hagel.

4.

Är du gravid?

Följande saker får INTE tas in i undersökningsrummet

Ytterkläder, väskor.

Föremål som innehåller metall (t ex nycklar, mynt, pennor, gem, hårspännen, nagelfil, fickkniv).

Plånböcker, kreditkort och andra kort med magnetremsa.

Elektroniska föremål (t ex mobil, MP3, PALM).

Klockor.

Jag har lämnat alla ovanstående saker utanför undersökningsrummet JA (Smycken av guld och silver kan behållas på.)

Jag har tagit del av informationen ovan och försäkrar att ovanstående uppgifter är riktiga

Underskrift Datum

MR-personalen avgör OM och NÄR du får gå in i undersökningsrummet!

Hörselskydd SKALL användas under bildtagning!

Magnetic Resonance (MR) screening form for accompanying persons

The scanner's magnetic field is ALWAYS on!

Any relative or accompanying person who wants to enter the examination

room must first fill out this form for reasons of safety.

STRONG

MAGNETIC

FIELD

Name relative/accompanying person Personal identity number

YES NO

1. Do you have any electrical or battery-powered implants in your body? For example, cardiac pacemaker or internal defibrillator, implantable medicine pump (e.g. for insulin or cytostatic), implant for neurostimulation, or hearing implant (e.g. cochlear implant)

2. Do you have any implanted metal objects in your body?

For example, aneurysm clips (in e.g. the heart or brain), tissue expander, coil, stent, screws or cardiac valve implant.

3. Do you have any foreign metal objects in your body?

For example, metallic slivers or fragments in your eye, shrapnel, bullets or pellets.

4. Are you pregnant?

The following items are NOT allowed in the examination room

Coats or other outerwear, purses or bags.

Metal-containing objects (e.g. keys, coins, pens, paper clips, hair clips, nail files or pocket knives).

Wallets, credit cards or other cards with a magnetic stripe.

Electronic devices (e.g. mobile phone, MP3, PDA).

Watches.

I have left all of the above-specified items outside of the examination room YES (Jewellery made of gold or silver may be left on.)

I am aware of the information given in this form and I declare that the information I have

given is truthful.

Signature Date

The MR staff will decide IF and WHEN you are allowed to enter the examination

room! Ear protection MUST be worn during the examination!

Screening form, MR safety for staff Name:

Personal identity number:

YES NO

1. Har du eller har du haft något av följande i kroppen? - Pacemaker - Medicinpump (för t ex insulin eller cytostatika) - Implant for neurostimulation (e.g. in your brain or back) - Hearing implant (e.g. cochlear implant) - Other electrical or battery-powered implant

If YES, what?

2. Har du något inopererat metallföremål i kroppen? - Aneurysm clips (in e.g. the heart or brain) - Objects such as a tracheal tube, tissue expander, screws, cardiac valve, shunt, prosthesis, dental

implants, etc. If YES, what?

3. Har du något främmande metallföremål i kroppen? - Metallic slivers or fragments in the eye - Shrapnel, bullets or pellets - Other foreign metallic objects

If YES, what?

4. Female staff member – Are you pregnant?

I declare that the above information is true and that I have become acquainted with

the applicable safety regulations. I will give notice if any of the information changes.

Signature Date

Supervisor/manager remarks:

I give permission for the above individual to

Enter the MRI examination room

Comments:

Signature of supervisor/manager Date

Printed name

41

APPENDIX II – LIMIT VALUES WITH COMMENTS

For patients, the electromagnetic fields are divided into three levels according to ICNIRP 2004:

Normal level:Routine MRI scan for all patients.

Level 1 (controlled level):MRI scan performed outside of the normal level, where discomfort or undesirable effects could occur. A clinical risk-benefit analysis must be carried out to balance the undesirable effects against the expected benefit.

Level 2 (experimental level):Level outside of the controlled level for which ethical vetting to highlight the potential risks.

The following types of limit values have been specified for staff and the public by ICNIRP 201034:

Basic restrictions (ICNIRP, 2010)“Mandatory limitations on the quantities that closely match all known biophysical interaction mechanisms with tissue that may lead to adverse health effects.”

Reference levels (ICNIRP, 2010)“The rms and peak electric and magnetic fields and contact currents to which a person may be exposed without an adverse effect and with acceptable safety factors. The reference levels for electric and magnetic field exposure may be exceeded if it can be demonstrated that the basic restrictions are not exceeded. Thus, it is a practical or �‘surrogate’ parameters that may be used for determining compliance with Basic Restrictions.”

34 The definitions of the terms basic restrictions and reference values were changed slightly in ICNIRP 2010.

The term “time-weighted average” is no longer included.

42

The static magnetic field Limit values for patients Static field limit values for patients, set by ICNIRP 2009.

Table 1. Basic restrictions for static magnetic field exposure for patients (ICNIRP guidelines 2009).

Limit value (T)

Normal level 4

Level 1 a 8

Level 2 b 8

Limit values for staff Static field limit values for staff, set by ICNIRP 2009.

A higher exposure limit value is permitted for limbs compared to the rest of the body because

limbs do not contain any major blood vessels or internal organs.

Table 2. Basic restrictions for static magnetic field exposure for staff (ICNIRP guidelines 2009 and

Fact sheet ICNIRP 2009).

Limit value (T)

Exposure limit value, head and trunk

2 T but 8 T is acceptable under controlled forms if there are implemented procedures for checking motion-induced

effects.

Exposure limit value, rest of the body 8 T

Recommended limit values for movement in the static magnetic field have been in place for staff

since 2014 (ICNIRP 2014). These restrictions are intended to prevent sensory effects (such as

dizziness and nausea) and electrical stimulation of peripheral nerves. Both can be annoying, but

are not considered to cause long-term health effects. The recommendations are based on the staff

having sufficient knowledge to control their movement patterns themselves.

To prevent sensory effects, such as dizziness and nausea, from motion-induced electric fields under

a few Hz, ICNIRP recommends that B (change in the magnetic flux density) does not exceed 2 T

over a period of 3 s (basic restriction). The higher the magnetic field, the slower the movements.

To prevent electrical stimulation of peripheral nerves, max dB/dt has been set to 2.7 T/s (reference level). The limit has been set to ensure that staff do not reach the limit for stimulation.

Limit values for the public Static field limit values for the public, set by ICNIRP 2009.

43

Table 3. Basic restrictions for static magnetic field exposure for the public (ICNIRP guidelines 2009 and

Fact sheet ICNIRP 2009).

Limit value (mT)

Exposure limit value 40035

Exposure limit value with contraindication 0.5

In practice, the limit value 0.5 mT is used for all persons not checked using the screening form (controlled area).

Higher fields may be permitted under controlled forms (e.g. as support person). In such cases the

limitations are the same as for staff.

The time-varying magnetic field: eddy currents Limit values for patients Gradient field recommendations for patients, set by ICNIRP 2004. The thresholds for

electromagnetic fields between 1 Hz and 10 MHz, i.e. the range within the gradient fields fall, are

based on the restriction of eddy current density to prevent intolerable levels of nerve stimulation

(ICNIRP 2004).

The median threshold for nerve stimulation is described by the following empirical equation:

dB / dtmedian 20( 1 0.36 / ) T/s

where dB/dt is the change in the B-field per unit of time. is the effective stimulus duration in

ms, i.e. is dependent on length of the rise and fall time of the gradients. is defined as the ratio

of the peak-to-peak variation in the B-field and the maximum derivative of B during that period.

Table 4. Maximum exposure level for patients (ICNIRP 2004).

Limit value dB/dt Normal level 80% of dB/dtmedian

Level 1 100 % of dB/dtmedian

Studies of the long-term biological effects of eddy currents on foetuses are limited

(De Wilde 2005). The gradient fields must therefore be limited to the normal level for pregnant women.

Limit values for staff Recommendations for staff from ICNIRP 201036: Limit values for the time-varying electric and magnetic fields created by the magnetic field gradients are indicated below. The guidelines have been set to limit electromagnetic field exposure and to safeguard against adverse health effects in relation to transient response of the nervous system, including peripheral (PNS) and central nerve stimulation (CNS), induction of light flashes (photo phosphenes) on the retina, and possible effects on brain function.

35 400 mT is the maximum field strength. The average over 24 h (40 mT) was previously used as the limit value.

36 New limit values apply for these frequency ranges.

44

Table 5. Basic restrictions for staff for time-varying electric and magnetic fields (undisturbed rms values)

(ICNIRP 2010) within the gradient field frequency ranges.

Exposure Frequency Internal electric fields (V/m) CSN in head 1–10 Hz 0.5/f

10 Hz – 25 Hz 0.05

25 Hz – 400 Hz 2·10-3·f

400 Hz – 3 kHz 0.8

3 kHz – 10 MHz 2.7·10-3·f All tissues in the body and head 1 Hz – 4

kHz 0.8

3 kHz – 10 MHz 2.7·10-3·f where f is the frequency in Hz.

Table 6. Reference values for staff for time-varying electric and magnetic fields (undisturbed rms values)

(ICNIRP 2010) within the gradient field frequency ranges. All action values must be fulfilled simultaneously.

Frequency E-field strength E (kV/m)

Magnetic field strength H (A/m)

Magnetic flux density B (T)

1 Hz – 8 Hz 20 163,000·105/f2 0.2/f2

8 Hz – 25 Hz 20 20000/f 0.025/f 25 Hz – 300 Hz 500/f 800 0.001 300 Hz – 3 kHz 500/f 240 000/f 0.3/f 3 kHz – 10 MHz 0.17 80 0.0001

where f is the frequency in Hz.

The time-varying magnetic field: noise levels Limit values for patients All patients, whether awake or anaesthetized, should use hearing protection if the noise levels exceed 80 dB(A), and must use hearing protection at noise levels of 85 dB(A) (ICNIRP 2004).

All children, whether awake or anaesthetized, must always use hearing protection regardless of field strength.

Limit values for staff Limit values for staff are regulated by the Swedish Work Environment Authority provisions (AFS

2005:16). According to AFS, workers must have access to appropriate hearing protection if the

noise exposure is equal to or greater than the lower action values. If the noise exposure is equal to

or greater than the upper action values, hearing protection must be used.

“Daily noise exposure level” is the equivalent A-weighted sound pressure level normalized to an

eight-hour working day. “Maximum sound pressure level” is the maximum A-weighted sound

pressure level to which staff may be exposed. For more details, refer to the Swedish Work

Environment Authority provisions (AFS 2005:16).

Table 7. Lower and upper action values for noise for staff (AFS 2005:16).

Lower action value dB(A)

Upper action value dB(A)

Daily noise exposure level LEX,8h 80 85 Maximal A-weighted sound pressure level LpAFmax 115

Use of hearing protection may be advisable even at daily exposure levels of about 75–80 dB since

particularly sensitive people could experience hearing damage from exposure to levels lower than

the lower action values.

In practice, the limit values mean that staff and other persons remaining in the examination room

during the scan must follow the same hearing protection rules as patients.

45

The radio frequency field Limit values for patients Radio frequency field limit values for patients, set by ICNIRP 2004. The restrictions have been set so that the temperature increase in connection with the scan does not cause any harmful biological effects.

Table 8. Basic restrictions for body temperature increases and partial body temperature increases (ICNIRP 2004).

Level

Temperature increase, whole

body (˚C)

Local temperature Head

(˚C) Trunk (˚C)

Extremities (˚C)

Normal 0.5 38 39 40 Controlled 1 38 39 40 Experimental > 1 > 38 > 39 > 40

The temperature cannot be measured directly. Limitations in specific absorption rate (SAR) are

used instead. SAR is a measure of how much RF energy the patient absorbs per kg of body mass.

MRI system manufacturers follow an international standard (IEC 600601-2-33). The estimated

SAR is indicated by the scanner for each sequence during the scan. The limit values for SAR are

based on an ambient temperature of maximum 24˚C and humidity of less than 60

%.

Table 9. Restrictions in SAR at a room temperature < 24˚C and< humidity 60% (ICNIRP 2004) for patients

without contraindication. The values apply as an average over 6 minutes. .

Level Whole body SAR

(W/kg)

Partial-body SAR

(W/kg)

Local SAR (averaged over 10 g tissue) (W/kg)

Any, except head

Head Head Trunk Extremities

Normal 2 2–10a 3 10b 10 20

Controlled 4 4–10a 3 10b 10 20

Experimental > 4 > 4–10 > 3 10b > 10 > 20

Short term SAR The SAR limit over any 10 s period should not exceed 3 times the corresponding average SAR limit.

a.Partial-body SARs vary depending on patient size. The small the body part, the higher the SAR permitted. The permitted SAR is calculated as follows: - Normal level: SAR=(10-8*r) W/kg - Controlled SAR=(10-6*r) W/kg where r = weight of exposed body part / total body weight. b Care must be taken to ensure that the temperature increase at the eye is <1˚C. This applies in particular when the eye is within the RF field of a small transmitting coil. The eye has a very limited capacity to dissipate increased heat and is therefore extremely sensitive to heat rises.

46

Limit values for staff Recommendation for staff from ICNIRP 1998, where all conditions must be fulfilled simultaneously.

Table 10. Basic restriction for SAR exposure for staff (ICNIRP 1998) for the frequency range 100 kHz – 10 GHz.

SAR limit value (W/kg)

Whole body average 0.4

Localized SAR (head, trunk) 10

Localized SAR (limbs) 20

It is unlikely that staff will reach these limit values, except when working with interventional MRI.

Beyond SAR, there are no restrictions in current density for these frequencies. However, there are

restrictions in electric field strength and magnetic flux density for the gradient fields.

Table 11. Reference values for exposure to time-varying fields37 (ICNIRP 1998) within the RF

field frequency ranges. All action values must be fulfilled simultaneously.

Frequency range Electric field strength, E (V/m)

Magnetic flux density, B (μT)

10 – 400 MHz 61 0.2

where f is the frequency in Hz.

37 Undisturbed root mean square (rms).

38 The web addresses for most of the implants can be found on www.MRIsafety.com

47

APPENDIX III – SHELLOCK'S IMPLANT TERMINOLOGY

This section provides a brief summary of the meanings of Shellock's various implant conditions. More detailed information is available at www.MRIsafety.com

MR Safe The object is considered safe for a patient who is undergoing an MRI scan or who is in an MR environment at the highest static magnetic field strength specified.

MR Conditional The implant may or may not be MR Safe, depending on the specific conditions that exist. MR

Conditional is divided into a number of subgroups:

Conditional 1

− Implants that are acceptable for a patient undergoing an MRI scan although they proved to be slightly ferromagnetic. Eddy currents may be created. The implant can be scanned at field strengths up to the maximum field strength given by Shellock.

Conditional 2

− Implants that are weakly ferromagnetic (e.g. coils, stents, clips) and are firmly embedded in tissue can be scanned at field strengths up to the maximum field strength given by Shellock. If the implant is made from a non-magnetic material (e.g. Phynox, Elgiloy, titanium, titanium alloy, MP35N, Nitinol), it is not necessary to wait at least six weeks if the field strength is 1.5 T or lower.

Conditional 3 − This mainly applies to certain patches with metal foil (e.g. Deponit, nitroglycerine

transdermal delivery system) or other metal components known to cause excessive heating. This overheating can cause discomfort or burn the patient. Removal of the patch is therefore recommended prior to the MRI scan. A new patch should be applied immediately after the scan.

Conditional 4

− This mainly applies to halo vests and other similar immobilization devices. Although there have been no reports of injury, there are questions about how they affect the static magnetic field and MR-related heating. Contact the manufacturer for additional information38.

Conditional 5 − The implant is acceptable for a patient undergoing an MRI scan only if the specific

guidelines or recommendations given by Shellock and the manufacturer. Review the MRI-related criteria on the manufacturer's website or contact the manufacturer for the latest safety information38.

Conditional 6 − These implants are deemed to be “Conditional” according to the terminology given by American

Society for Testing and Materials (ASTM) International.

42 A 4ºC temperature increase (temperature of approximately 41ºC) is a lot!

48

− Non-clinical testing has shown that a patient with these implants can be examined safely immediately after surgery under the following conditions:

Maximum static magnetic field: 3 T.

Maximum spatial gradient: 7.2 T/m39.

Maximum SAR: 3 W/kg for 15 minutes of scanning.This produces a temperature increase of <

3ºC40.

− The image quality may be compromised in the vicinity of the implant. Optimization of the MR parameters may be necessary.

Conditional 7

− These implants are not intended for use in MRI. They must not be inside of the scanner tunnel and subjected to the time-varying magnetic field and RF field during image capture. Contact the manufacturer for additional information. In practice, it means they are Unsafe for whole-body systems.

Conditional 8

− If the implant is marked 1.5, 3 T, it may means there are multiple versions of the same stent with different conditions. Contact the manufacturer for additional information.

− These implants are deemed to be “Conditional” according to the terminology given by

American Society for Testing and Materials (ASTM) International. Non-clinical testing has shown that a patient with these implants can be examined safely immediately after placement under the following conditions:

Maximum static magnetic field: 3 T.If the implant is marked 1.5, 3 T, there may be multiple versions of the implant. Carry out the scan at 1.5 T.

Maximum spatial gradient: 7.2 T/m41.

Maximum SAR: 3 W/kg for 15 minutes of scanning.This produces a temperature increase of < 4ºC 42.

− The image quality may be compromised in the vicinity of the implant. Optimization of the MR parameters may be necessary.

MR Unsafe Implants and other items that are contraindicated for MRI and/or individuals being in the

examination room.

Unsafe 1 − These objects are contraindicated for MRI scans and for individuals entering the

examination room. The object is assessed as posing a potential or real risk or danger

39 Many MRI systems exceed these limits near the gantry. The setup method for a patient with ferromagnetic

implant may have to be used, particularly for 3 T. An assessment must be made by a qualified staff member at

the hospital, such as a medical physicist.

40 3ºC is quite a lot.

41 Many MRI systems exceed these limits near the gantry. The setup method for a patient with ferromagnetic

implant may have to be used, particularly for 3 T. An assessment must be made by a qualified staff member at

the hospital, such as a medical physicist.

49

to the patient or others in the MR environment, mainly due to the risk of displacement or rotation of the object. There may also be other hazards.

Unsafe 2 − These objects are contraindicated for MRI scans. The potential risk of the implant is

related to the formation of strong eddy currents, extensive temperature increase, and other potential hazards. However, the influence of the static magnetic field is small.

50

APPENDIX IV – GLOSSARY Artefact

Image error, e.g. distortion of the geometry, line, shadow, black area. This can be caused by the

patient (e.g. respiratory motion), implants in the body, or the characteristics of the equipment.

Basic Restrictions (ICNIRP 1998): Exposure restrictions are based on known biophysical mechanisms of

interaction with tissue that can lead to adverse health effects”.

dB (A)

The sound pressure level is a measure of the strength of sound and is measured in dB, which is a

logarithmic scale. The ear is not equally sensitive to all frequencies. To mimic the human auditory

perception, the audio meter contains a weighting filter (a-filter) that provides a frequency-

dependent weighting of the measurement signal to the ear's sensitivity. The unit dB (A9 refers to

measurement with an A-filter.

Ferromagnetic material

Ferromagnetic material is greatly magnetized by an external magnetic field. Ferromagnetic material

is drawn towards the magnetic field.

In this document, the term “ferromagnetism” is used for implants since the term “magnetism” also includes other magnetic properties.

Field strength

In this document, the term refers to magnetic field strength, which is a measure of the strength of

the magnetic field inside the tunnel. Field strength is measured in Tesla (T). The unit Gauss is

sometimes used, where 1 Gauss = 0.1 mT. Field strength decreases greatly as the distance from

the magnet increases. Field strength greater than 0.5 mT (5 Gauss) requires safety monitoring.

Gradients

Gradients (i.e. magnetic field gradients) are small additional magnetic fields that are activated and

deactivated during the scan, thereby creating a time-varying magnetic field. The pounding noise

heard during the scan is the gradients being activated and deactivated. The strength of the

gradients is greatest near the openings of the scanner and grows weaker towards the centre of the

scanner. Gradient strength is linear from the isocentre and is indicated in the unit mT/m. The

time-varying field forms electrical eddy currents in the body.

For spatial gradients, refer to “Spatial gradients”.

Interventional MRI

Combination of MRI and surgery. The surgery is either performed in the MRI room or in a directly

connecting room, where the patient is taken into the MRI room and scanned in connection with the

surgery.

Ionizing and non-ionizing radiation

Ionizing radiation is radiation with the ability to knock electrons loose from atoms, which

converts the atoms to ions. Examples of ionizing radiation in healthcare are radiography and

radiotherapy. Non-ionizing radiation has no ability to ionize atoms. Examples of non-ionizing

radiation in healthcare are MRI, ultrasound and laser therapy.

Reference levels (ICNIRP 2010): “The electric magnetic fields and contact currents to which a person may be

exposed without an adverse effect and with acceptable safety factors. The reference levels for electric and magnetic field

exposure may be exceeded if it can be demonstrated that

51

the basic restrictions are not exceeded. Thus, it is a practical or “surrogate” parameters that may be used for determining compliance with Basic Restrictions.”

RF field

A radio frequency magnetic field (RF field) is used in MRI to obtain a signal. The RF field

frequency used depends on the field strength of the MRI scanner and varies between 8.5 MHz

(at 0.2 T) and 170 MHz (at 4 T) for clinical MRI, which sis the same frequency range used for

radio-controlled toys and regular radio stations.

SAR

SAR stands for Specific Absorption Rate and is defined as the energy per unit of time (as the

average over the whole body or parts of the body) that is absorbed per unit of mass of biological

tissue. SAT is measured in W/kg.

Static magnetic field

A magnetic field that does not vary with time. The strength of the magnetic field (field strength) is measured in Tesla (T). The unit Gauss is sometimes used, where 1 Gauss = 0.1 mT.

Spatial gradients

Spatial gradients are a measure of how much the field strength increases as one approaches the

scanner, expressed in the unit T/m. The attractive force that the scanner (magnet) exerts on a

ferromagnetic object is greatest where the field strength is greatest, which is normally near the

gantry opening of the scanner; see Figure 1c. The distribution of the spatial gradients, and thereby

the attractive force of the scanner, differs between different scanner models, even if the field

strength is the same. The spatial gradients play a key role when assessing the safety of different

implants.

Time-varying magnetic field

A magnetic field that varies in time. There are many different types of time-varying magnetic

fields, and these have differing effects on the body depending on their frequency (i.e. how

quickly the magnetic field changes). The time-varying magnetic field primarily referred to in this

safety manual is created when the gradients are activated and deactivated. The RF field is also a

time-varying magnetic field.