A Survey of Current Acquisition & Analysis Techniques for

Myocardial Perfusion Imaging Using Philips Gamma Cameras

Joe O’Brien & Bill Thomson, City Hospital, Birmingham

Cariss Bird, Priory Hospital, Birmingham

&

Introduction• Aware of some variation amongst Philips users in

acquiring and analysing Myocardial Perfusion Imaging (MPI) studies.

• Decided to provide a survey for Philips NMUG Meeting.

• The survey would be beneficial:– Forms a basis of discussion at UG Meeting.– Allows users to compare their technique with

others.

Survey & Presentation

Marconi & Picker Systems

Joe O’Brien

ADAC Systems

Cariss Bird

Due to work commitments and time constraints, just

the Marconi & Picker users have been surveyed.

The Survey

• 30 customers on Philips NM customer list

• 12 customers do not perform MPIs

• 1 customer did not participate

• So 17 customers surveyed

• Completed surveys available

• Contacted via telephone for anonymous survey

The Survey• Basic Questions

• Radio-pharmaceutical

e.g. how many patients per year?

e.g. type of RP, activity per test, delay time?

• Gamma Camera e.g. which camera and collimator do you use?

• Acquisition

• Reconstruction

e.g. matrix size & zoom (pixel size), orbit setup, gated or non-gated?

e.g. FBP or iterative reconstruction, Pre-filter or 3D Post filter ?

Basic Questions

MPI Patients per Annum per Camera

0 200 400 600 800 1000 1200 1400 1600

1

3

5

7

9

11

13

15

17

Cu

sto

mer

Number of Patients

Radiopharmaceutical• Most commonly used:

MIBI(5)

Tetrofosmin(12)

Radiopharmaceutical

1 Day1000MBq

(2)

2 Day400MBq

(15)

• Protocol:

Radiopharmaceutical• Imaging Delay Time:

0 20 40 60 80 100 120

1

5

9

13

17

Cus

tom

er

Delay Time in Minutes

MIBI

Tetro

Cameras Included in Survey

• Dual headed AXIS most common

• Exclude others from presentation

Axis

Prism 2000XP

Prism 3000XP

Prism 1000XPIrix

(11)

(4)

(2)

(1)

Acquisition Settings Used By All AXIS Users

• Orbit settings:

– Non-Circular

– Head Orientation at 102°

– 102° of rotation per head

– 34 projections per head

• Acquisition based on TIME per step

• Factory set energy window

Variable Acquisition Settings

• Orbit setting

– Step & Shoot - 3 Continuous - 8

• Gating

– Gated - 5 Non-Gated - 6

• BEACON

– Used - 3 Not Used - 8

Variable Acquisition Settings

• Time per step

010203040506070

1 2 3 4 5 6 7 8 9 10 11

Customer

Tim

e (S

eco

nd

s) STRESS

REST

Variable Acquisition Settings

• Collimator

LEGAP

(6)

LEHR

(5)

Variable Acquisition Settings

• Matrix & Zoom (i.e Pixel Size)

No of Users Matrix Zoom Pixel Size

4 128 by 128 1.000 4.67

5 64 by 64 1.600 5.84

1 64 by 64 1.488 6.28

1 Not sure

Reconstruction Settings Used By All AXIS Users

• Routinely Check for Patient Motion

• No Pre-filtering of data

• All use 3D Post-filter

Variable Reconstruction Settings

• Reconstruction Method

Iterative(3)

Don’t Know(1)

FBP(7)

Variable Reconstruction Settings

• Diameter

• Effectively zooms data and alters pixel size. Left as Default

(8)

Don’t Know(2)

Varied between patients

(1)

Variable Reconstruction Settings

• Filter– All used ‘Low Pass’ but with variable settings:

Variable Reconstruction Settings

• Gated Analysis Programs

QGS(4)

Emory(1)

Conclusions• Survey of Philips NM Users performing MPI.

• Majority using AXIS system.

• Users have some similar methods of acquisition

and analysis.

• But overall there are significant differences e.g.

1/2 use LEHR, the other 1/2 use LEGAP

• Worthy of discussion at UGM!

Effect of Collimator

• Local standard protocol for MPI uses LEGAP collimator.

• We considered the effect on lesion detectability using a

LEHR collimator instead.

• Scanned a torso phantom fitted with a cardiac insert

• Installed a large 100% and small 50% defect.

• Filled with 8MBq Tc-99m

Effect of Collimator• Short Axis Images

• Qualitatively, there is no discernable difference in lesion detectability

HR

GP

Effect of Collimator• HLA Images

• Qualitatively, no discernable difference in lesion detectability.

• But up to 40% more counts.

HR

GP