Sudan Academy of Science (SAS)

Atomic Energy Council

Evaluation of Quality Control in X-ray

departments in Al Neelain University

Hospitals

A proposal submitted for partial fulfillment requirements of

master (M. Sc) degree in Radiation Protection and environment

By:

Hafsa Idrees MerghaniB. Sc in Radiotherapy (SUST)

Supervisor:

Dr. ABD ELRHMAN A. EL BADAWIY

Dedication

This study is dedicated to my father, my great

mother, my loved family and to my friends.

Acknowledgements

I would like to thank my supervisor

Dr. ABD ELRHMAN A. EL BADAWIY

Al Mogran University Hospital

Al Neelain University Dental Clinics

Department of Medical Physics(AL Neelain University)

List of contents

Title pages

Dedication.......................................................................................................... i

Acknowledgment.............................................................................................. ii

List of content..................................................................................................... iii

List of tables........................................................................................................iv

List of abbreviation............................................................................................ v

Abstract................................................................................................................vi

Chapter one: Introduction

V Introduction......................................................................................................

Definition of Quality Control (QC)................................................................ Y

Quality Assurance (QA)..................................................................................

M Quality Control Program.................................................................................. *

Quality Assurance Program............................................................................. °

Optimization.......................................................................................................

Criteria of quality...............................................................................................V

conventional x-ray............................................................................A

Dental radiology................................................................................................

W Intraoral Radiographic Examination............................................................

Periapical examination................................................................................

W Paralleling Technique......................................................................................

W Bisected Angle Technique...............................................................................

Bite-wing Radiography..............................................................................

Occlusal radiograph.............................................................................

V* Justification.............................................................................................

Problem of the study.............................................................................

Objectives................................................................................................

W General objective..................................................................................

Specific objectives................................................................................

Thesis outlines..........................................................................................

Chapter two: Literature review

^A Theoretical background...........................................................................

^AA Quality Control....................................................................................

^AA Quality Administration Procedure....................................................

^AA Quality control tests.............................................................................

^AA Equipment.............................................................................................

^A.° Dental x-ray machine.............................................................................

X-ray machine test..................................................................................

fJ.V X-ray film..........................................................................................................

Screens and cassettes..........................................................................................

Viewing equipment......................................................................................

Film processing............................................................................................

Darkroom lighting......................................................................................

Processing equipment..................................................................................

Processing solution......................................................................................

V.V® Developer strength..................................................................................

Fixer strength...............................................................................................

Manual and automatic film processing...................................................

Reject analysis............................................................................................

Radiation protection..................................................................................

ALARA concept........................................................................................

previous studies................................................................................................

Chapter three

Materials

materials........................................................................................................

Conventional x-ray machine....................................................................

Dental x-ray machine..................................................................................

f.\f Digital meter...................................................................................................

f.M Fresh films.........................................................................................................

f.\° View box............................................................................................................

Methods................................................................................................................

f.V Sample size........................................................................................................

f.^A Data collection.................................................................................................

f.^.f Study area........................................................................................................

f.f.* Data analysis......................................................................................................

f.f.® Ethical clearance...............................................................................................

f.'O Study period.........................................................................................................

Chapter four

Results

M Results for quality control tests..........................................................................

*.f Observed result for other tests......................................................................

*.V Results of testing darkroom integrety..........................................................

Chapter five

Discussion,...

Discussion.........................................................................................

°.f Conclusion......................................................................................................

®.f Recommendation...................................................................................

References..............................................................................................................

Title

List of tables

page

Table *. Kvp &time accuracy in dental clinic......................................

Table Kvp &time reproducibility in dental clinic.............................

Table patient dose evaluation in dental clinic....................................

Table *. * Kvp &time accuracy in ALmogran Hospital...........................

Table Relative mA & mAs Linearity .............................................

Table O mAs Consistency

Table *.V KVp & Time reproducibility and linearity test

(output)............................................................................................................

Table Half value layer (HVL) test......................................

Table Developing and fixing time in dental clinic..............................

Table Reject films analysis in dental clinic..........................................

Table Reject films analysis in AL Mogran Hospital.............................

List of abbreviations

ALARA: As low as reasonable achievable

KV: Kilovoltage

KVp: Kilovoltage power

mA: milliamper Q.C: Quality Control

Q.A: Quality Assurance

SAEC: Sudanese Atomic Energy Committee

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Abstract

The aim of radiographic quality control (QC) program is to ensure that the

diagnostic images produced by this machine are of a sufficiently high quality so

that they provide adequate diagnostic information at the lowest possible cost

and with the least possible exposure of the patient to radiation. Quality control

measures are therefore as essential in a medical practice, as they are in a

specialized radiography department. This importance of quality is

acknowledged in the ionizing radiation regulations which make quality

assurance\control in radiography department a mandatory requirement.

This study aims to assess the quality control in x-ray department in AL Neelain

University Hospitals. The study was experimental, done by testing the

operational status of the x-ray machines and assessing the radiation protection

system.

The experiments results showed that there was a noted drop in the kVp

accuracy, and there was no regular reject analysis system.

Chapter One

M Introduction:

The principle goal of quality assurance of X-ray machine is minimization of

radiation exposure and obtains high image quality. This can be assess by

performance the X-ray machine by optimum operating parameters such as

reproducibility of tube voltage, dose output, time, X-ray tube efficiency,

Accuracy of kVp , mA , time , focal spot size and half value layer (T.M. Taha

AAPM report —describes quality assurance protocol for diagnostic x-ray

equipment at the radiologic technologist level. also The World Health

Organization (WHO) defines a quality assurance (QA) program in diagnostic

radiology as an organized effort by the staff operating a facility to ensure that

the diagnostic images produced are of sufficiently high quality so that they

consistently provide adequate diagnostic information at the lowest possible cost

and with the least possible exposure of the patient to radiation (Stephen Inkoom

et al Y«U).

Quality control in diagnostic radiology is essential to ensuring accurate

diagnostic information at optimal radiation doses, thereby making it possible to

reduce unnecessary radiation hazard to patients, workers and the public. Quality

assurance actions include both quality control (QC) techniques and quality

administration procedures. QC is normally part of the QA programme and

quality control techniques are those techniques used in the monitoring (or

testing) and maintenance of the technical elements or components of an X-ray

system. Certain essential quality control tests have greater effect on the final

diagnostic image quality.

The quality control techniques thus are concerned directly with the equipment

that can affect the quality of the image i.e. the part of the QA programme that

deals with instrumentation and equipment. (Stephen Inkoom et al Y*U) In

diagnostic radiology, the half-value layer (HVL) of the x-ray beam is needed in

order to judge the beam quality of the X-rays spectra.

M Definition of Quality Control (QC):These are specific actions designed to keep measurable aspects of the process

involved in manufacturing a product or providing a service within specified

limits. These actions typically involve measurement of a process variable,

checking the measured value against a limit, and performing corrective action if

the limit is exceeded. . (Stephen Inkoom et al Y*U)

Y.f Quality Assurance (QA):These are planned and systematic actions that provide adequate confidence that

a diagnostic x-ray facility will produce consistently high quality images with

minimum exposure of the patients and healing arts personnel. The

determination of what constitutes high quality will be made by the facility

producing the images. Quality assurance actions include both quality control

techniques and quality administration procedures. . (Stephen Inkoom et al Y«)1)

M Quality Control Program:Is allows a facility with limited resources and personnel to monitor the basic

components of the imaging process at a low cost through the usage of simple in

expensive tools and minimal staff time. . (Stephen Inkoom et al Y*U)

Y.® Quality Assurance Program:It is an organized entity designed to provide quality assurance for a diagnostic

radiology facility. The nature and extent of this program will vary with the size

and type of the facility, the type of examinations conducted, and other factors. .

(Stephen Inkoom et al Y«U)

Optimization:Optimization in the field of diagnostic radiology simply means any process or

procedure which ensures that doses due to appropriate medical exposure for

radiological purposes are kept as low as reasonably achievable (ALARA)

consistent with obtaining the required diagnostic information, taking into

account economic and social factors.

There are two types of x-ray machines in AL Neelain University Hospitals one

is dental machine in college of dentistry, the other is plain x-ray machine in AL

mogran Hospital. . (Stephen Inkoom et al Y.U)

'.V Criteria of quality:Every radiographic examination should produce radiographs of optimal

diagnostic quality, having the following features:

i. The radiographs should show the complete area of interest on the image.

ii. The radiographs should have the least possible amount of distortion.

iii. The radiographs should have the least optimal density and contrast (Eric

Whaites, Y««Y).

'.A Conventional x-ray:Radiography is the imaging of body structures, or parts of the body, using X-

rays. X-rays are a form of radiation (X-radiation) similar to visible light, radio

waves and microwaves. X-radiation is special because it has a very high energy

level that allows the X-ray beam to penetrate through the body and create an

image or picture. (Hakan Ilaslan,Y« ^°)

Plain film X-rays remain an important tool for the diagnosis of many disorders.

In radiography, a beam of X-rays, produced by an X-ray generator, is

transmitted through an object, e.g. the part of the body to be scanned. (Hakan

Ilaslan,Y« °)

The X-rays are absorbed by the material they pass through in differing amounts

depending on the density and composition of the material. X-rays that are not

absorbed pass through the object and are recorded on X-ray sensitive film.

While bone absorbs X-rays particularly well, soft tissue such as muscle fiber,

which has a lower density than bone, absorbs fewer X-rays. This results in the

familiar contrast seen in X-ray images, with bones shown as clearly defined

white areas and darker areas of tissue (Figure Y) Y. This makes conventional X-

rays very suitable for scans of bones and tissue dense in calcium such as in

dental images and detection of bone fractures. Other uses of radiography

include the study of the organs in the abdomen, such as the liver and bladder;

chest radiography for diseases of the lung, such as pneumonia or lung cancer

and mammography to screen for breast cancer. X-ray fluoroscopy is used to

detect a number of diseases associated with the stomach and intestine, genitals

and urinary tract. (Hakan Ilaslan,Y* °)

Traditionally, medical X-ray images were exposed onto photographic film,

which require processing before they can be viewed and take up a lot of space

in hospitals and doctors' offices. Digital X-rays, which overcome these

problems, have therefore become increasingly popular in radiography. Similar

to a digital camera, an electronic detector is used instead of film. This

“electronic image” is processed by a computer, enabling it to be stored digitally

and viewed on screen immediately without processing. (Hakan Ilaslan,Y* °)

X-ray imaging provides fast, high-resolution images and is relatively

inexpensive. The average examination for most plain film examinations takes

no more than minutes and requires no special preparation of the patient.

The operator, usually the radiographer (also known as a radiologic

technologist), selects the amount and type of X-rays to be used according to the

patient's size, the tissue or part of the body being imaged and the amount of

image contrast required. Because movement, e.g. of the lungs and diaphragm,

blurs the image, patients are usually asked to hold their breath during the

exposure. The X-ray picture is stored on a piece of film called a radiograph.

These are interpreted by a physician specially trained to interpret them, known

as a radiologist. (Hakan Ilaslan,Y °)

'.^ Dental radiology

'A' Intraoral Radiographic Examination

The intraoral radiographic examination is a radiographic inspection of teeth &

intraoral adjacent structures. It requires the use of intraoral film, which placed

inside the mouth.

There are three common types of radiographic examination that use intraoral

film:

Periapical examination.

Interproximal examination.

Occlusal examination.

'A* Periapical examination:

Main Indications:

Detection of apical infection/inflammation.

Assessment of the periodontal status.

After trauma to the teeth and associated alveolar bone.

Assessment of the presence and position of unerupted teeth.

Assessment of root morphology before extractions.

During endodontics.

Preoperative assessment and postoperative appraisal of apical surgery.

Detailed evaluation of apical cysts and other lesions within the alveolar bone.

Evaluation of implants postoperatively.

There are two methodes for obtaining periapical radiograph:

A. Paralleling technique

B. The bisecting angle technique

Y.^.f Paralleling Technique

The film packet is placed in a holder and positioned in the mouth parallel to the

long axis of the tooth under investigation (magnification, loss of definition

target-film distance long PID).

Y. The X-ray tube head is then aimed at right angles (vertically and

horizontally) to both the tooth and the film packet.

f. A film holder must be used to hold the film parallel with the long axis of the

tooth. The patient cannot hold the film. The technique is reproducible.

This positioning has the potential to satisfy four of the five ideal requirements

of shadow cast principles.

Y.M Bisected Angle TechniqueThe film packet is placed as close to the tooth under investigation as possible

without bending the packet.

Y. The angle formed between the long axis of the tooth and the long axis of the

film packet is assessed and mentally bisected.

f. The X-ray tube head is positioned at right angles to this bisecting line with

the central ray of the X-ray beam aimed through the tooth apex.

Using the geometrical principle of similar triangles, the actual length of the

tooth in the mouth will be equal to the length of the image of the tooth on the

film.

'A® Bite-wing Radiography:

Interproximal caries.

Over-hang filling.

Level of crestal bone between the teeth.

Interproximal calculus.

Principles:

The film is placed in the mouth parallel to the crown of both upper & lower

teeth.

The film stabilized when the patient bites on the bite-wing tab or bite-wing film

holder.

The central ray of the x-ray beam is directed through the contacts of the teeth,

using a + *̂ degree vertical angulation.

'A^ Occlusal radiograph:

The maxillary anterior occlusal radiograph can be made on both adults and

children. For an adult, it is made using a size t film/phosphor plate with the

long axis anterior-posteriorly or horizontally. It is important to have a

minimum of cm of film/phosphor plate anterior to the maxillary central

incisors. (T.M. Taha Y^T).

'.'» Justification:

Radiation is a major risk in diagnostic medical imaging and therapy. The

problem is caused by incorrect use of radiography equipment and from

unnecessary radiation exposure to patients.

Y.YY Problem of the study:

In Sudan, there is lack of knowledge of the importance quality control of X-ray

machine, in the most hospitals there is no regular quality control of X-ray

machine, also majority of them no radiation protection officer (RPO) employed

to monitors the radiation protection and supervise the quality control process.

Y.YY Objectives:

Y.YY.Y General objective:

The main objective of this study is to evaluate the quality control in X-ray

departments.

Y.YY'.Y Specific objectives:

- To evaluate the quality control program in Al Neelain University

hospitals.

- To evaluate radiation protection program at X-ray departments under

study in order to reduce unnecessary radiation to the patients and

occupational.

- to identify the effect of quality control tests in reducing the radiation dose

to the patients and operators.

- to get image with high quality with minimum radiation (ALARA).

Y.Yf Thesis outlines:

This study consists of five chapters; chapter one includes introduction, problem

of the study, and objectives, chapter two highlights the literature review, chapter

three shows the methodology of the study, chapter four deals with results and

data analysis, and chapter five discusses the results, conclusion, and

recommendations. At last there are references and appendices.

Chapter Two

Literature review

Y.' Theoretical background:

Y.'.' Quality Control:

Quality control uses a plan of action to ensure radiographs of consistently high

quality and high protection from radiation and infection. This plan includes

several routine assessments of image, and protective measures. The assessment

includes the image quality; this is affected by the performance of the x-ray

machine, manual processing procedure, viewing condition, system of infection

control and radiation protection. Optimization of these conditions results in the

most accurate diagnostic images and lowest possible exposure for patient and

radiographer. The study aimed to assess the quality control system in the x-ray

departments in AL Neelain University Hospitals, and suggests a corrective

action when necessary, in order to solve the problems which may lead to errors

in the application of quality control. The study will be carried out through the

data collection and assessment of radiation protection in this department. In

previous studies a comparison done between different types of dental

radiographic techniques, said that the bisecting technique is the best in

visualizing the entire tooth and its supporting structures (Rehab et al, Y««V).

Another study said the orthopan tomography is the best in demonstrating the

surrounding bone of the teeth (Fekry et al Y««Y).

Y.'.Y Quality Administration Procedure

It is refers to the management of the quality assurance plane in x-ray office. The

basic elements of a quality administration program include the following:

i. Description of the plan

ii. Assignment of duties

iii. A monitoring schedule

iv. A maintenance schedule

v. A record-keeping log

vi. A plan for evaluation and revision

vii. In-service training

A written description of the quality assurance plan used x-ray radiography

should be on file and made available to all staff members. The staff members

must understand the standards of quality as well as the purpose of maintaining

quality control of radiographic procedures. A written monitoring schedule

detailing all quality control tests and the frequency of testing for all x-ray

equipment should be posted in the department. A record-keeping log of all

quality tests, including the specific test performed, the data performed, and the

test results, should be carefully maintained and kept on a file in the department

(Bachman et al *̂ ).

^.Y.f Quality control tests:

Are specific test that are used to maintain and monitor x-ray equipment. To

avoid excess exposure of patient and personnel to x-radiation, the radiographer

must have clear understanding of the quality control procedure used to test

specific equipment, supplies, and film processing in x-ray office. (Quality

assurance for dental facilities et al, *̂ ).

^.Y.i EquipmentQuality control test are necessary to monitor x-ray machine, x-ray film screen,

and cassettes and viewing equipment to consistently produced diagnostic high

quality radiographs, dental x-ray equipment must be functioning properly

(Quality assurance for dental facilities et al *̂)

^.Y.® Dental x-ray machine

The dental x-ray machine most be inspected and monitoring periodically and

most also be calibrated at regular interval and. Calibration of dental x-ray

equipment most be performed by qualified technique to ensure consistent x-ray

machine performance and production of diagnostic radiographs. There are many

annual tests recommended for dental x-ray machine. These tests are designed to

identify minor manufactions, including machine output variation, tube head

drift, timing errors, inaccurate Kilo voltage and mill amperage reading. Most of

the tests require some basic testing material, film and test logs to record results

(Quality assurance for dental facilities et al *̂).

X-ray machine test:

Generally, x-ray machines are quite stable and rarely need to be tested; the

following parameters should be measured:

. X-ray output A radiation dosimeter is used to measure the intensity of

radiation output, usually is measured in milliroentgens.

Y. Beam alignment.

T. Beam energy. The KVp or HVL of the beam should be measure to ensure

that the beam has sufficient energy to produce good quality radiograph

without excessive soft tissue dosage.

Timer. The timer should be accurate. The test can be done by using a

spinning top with notch on the edge.

mA the linearity of the mA control should be done with a dosimeter or

with step wedge.

V. Focal spot size. It may become enlarged with excessive heat generated

within the x-ray machine. (Quality assurance for dental facilities et al

m.).

X-ray film:

The x-ray film must be properly stored, protected and used before its expiration

date. For quality control purposes, each box of film should be tested for

freshness as it is opened. The following fresh film test is recommended to check

newly opened box of film:

. Prepare film. Unwrap one unexposed film from newly opened box.

Y. Process film. Use fresh chemicals to process the unexposed film.

The result of fresh film can be interpreted as follows:

a. Fresh film, if processed film appears clear with as height blue tint, the

film is fresh and has been properly stored and protected.

b. Fogged film, film that has expired, has been improperly stored, or has

been exposed to radiation appears fogged. If the film is fogged it must not

be used (Quality assurance for dental facilities et al *̂).

^.Y.A screens and cassettes:

Intensifying screen used within the cassettes holder should be examined

periodically for dirt and scratches. Screen should be cleaned be monthly

commercially available cleaners recommended by the screen manufacture.

The following film screen contact test is recommended:

. Insert one film between screens in the cassette holder.

Y. Place wire mesh test object on the top of the loaded cassette.

f. Position the position indicating device (PID) using a f* -inch target -

film distance while directing the central ray perpendicular to the cassette.

f. Expose the film using *̂ mA, V* KVp.

Process the exposed film.

V. View the film on a view box. The result of the film-screen contact test

can be interpreted as follows:

a. Adequate contact:

If the wire of mesh image seen on the film exhibits a uniform density, good

film-screen contact has taken place. Proceed with cassette and screen use.

b. Inadequate contact:

If the wire of mesh image seen on the film exhibits varying densities; poor film­

screen contact has taken place. Areas of poor film-screen contact appear darker

than good contact areas.

^.'.^ Viewing equipment:

a. The view box is a light source that is used to view radiographs. A

working view box is necessary equipment for the interpretation of the

radiographs. The view box contains fluorescent light bulbs that emit light

through an opaque plastic or plexiglass front. The view box should emit a

uniform light when it is functioning properly. A photographic light meter

can be used to determine proper viewing brightness (Quality assurance

for dental facilities et al *̂).

*.'.' * Film processing:

Film processing is on the most critical areas in quality control and

requires daily monitoring, processing problem have the potential to result

in a large number of non-diagnostic radiographs. Quality control tests

must be performed routinely to determine whether or not the condition

for film processing is acceptable (Quality assurance for dental facilities et

al ^V).

^.'.'' Darkroom lighting

The darkroom must be checked for light tightness and proper safe

lighting every V months. The following light leak test is recommended for the

darkroom:

. Prepare darkroom, close the darkroom door and turn off all lights

including the safelights.

Y. Examine darkroom, once your eyes are accustomed to the darkness;

observe the areas around the door, the seams of the walls and ceiling, the

vent areas, and keyhole for light leaks.

The following safe lighting test, often referred to as the coin test is

recommended:

i. Prepare darkroom. Turn off all the lights in the darkroom including

the safelight (Quality assurance for dental facilities et al *̂).

ii. Prepare film. Unwrap one unexposed film. Place on a flat surface

at least f feet from the safelight. Place a coin on top of the film.

iii. Turn on the safelight. Allow the film and coin to be exposed to the

safelight for f to f minutes.

iv. Remove the coin and process the film.

If on visible image is seen on the processed radiograph, the safe

lighting is correct. If the image of the coin and a fogged background

appear on the processed radiograph, the safelight is not safe to use

with that type of film, to avoid safe lighting problem, the radiograph

must use the film manufactures recommended safelight filers and bulb

wattages. In addition, the film must be unwrapped at last f feet away

from the safelight. A coin test is used for safe lighting. Coin placed on

unexposed film under safelight. Developed film showing outline of

coin indicating that safelight intensity is too great and is not safe.

Safelight problem must be corrected before processing with film

processing (American Academy of Dental Radiology Quality

Assurance Committee, ^AT).

The film with seven coin on it, has been gradually uncovered every f*

second. The coin-covered part of the film remains white while the

surrounding film is blackened or fogged. The longer the film is

exposed to the safelight the darker it becomes (American Academy of

Dental Radiology Quality Assurance Committee, ^AT).

^.'.'^ processing equipment:

Processing equipment must be maintained and monitored on a daily basis.

The thermometer and timer must be checked for accuracy with manual

processing techniques. The processing time and temperature recommendations

of the film manufacturer must be followed. If automatic processing equipment

is used, the water circulation system must be checked, and the solution levels,

replenishment system, and temperatures must all be monitored. The

manufacturer's procedure and maintenance direction must be carefully

followed. Each day, two test films should be processed in the automatic

processor. Test films are recommended:

i. Prepare film. Unwrap two unexposed films, expose one to light.

ii. Process both films in the automatic processor.

The result of the automatic processor test films can be interpreted as

follows:

a. Functioning processor:

If the unexposed film appears clear and dry and if the film exposed to light

appears black and dry, the automatic processor is functioning properly.

b. Non-functioning processor:

If the unexposed film does not appear clear and dry and if the exposed

film does not completely appear black and dry, and then the

processing solution and temperature must be checked. Correction must

be made before processing with processing (American Academy of

Dental Radiology Quality Assurance Committee, ^Af).

^.Y.Yf Processing solution:

The most important component of the film processing quality control

is the monitoring of the processing solution. The processing solution

must be replenished daily and changed every f to f weeks as

recommended by manufacturer. As alternative using the calendar to

determine the freshness of solution, quality control tests can be used to

monitor the strength of the developer and fixer solution. Processing

solution must be evaluated each day before any patient films are

processed (American Academy of Dental Radiology Quality

Assurance Committee, ^AT).

^.Y.Yt developer strength

When the developer solution loses strength, the time­

temperature recommendation of the manufacturer is no longer

accurate.an easy way to check the strength of the developer

solution is to compare film densities to a standard. One of the

following tests can be used:

i. Reference radiograph

ii. Step wedge radiograph

iii. Normalization device

Reference radiograph:

It is one that processed under idea condition and then used to

compare the film densities of radiograph that are processed

daily.

The following step can be taken to create reference radiograph:

i. Prepare film. Use fresh film to make a reference

radiograph.

ii. Expose the film using the correct exposure factor.

iii. Process the film using fresh chemicals at recommended

time and temperature.

View the references radiograph and the daily radiographs side

by side on a view box. Compare the densities on the reference

radiograph with the densities on the daily radiographs.

Comparison of daily radiographs with the reference radiograph

can be interpreted as follows:

a. Matched densities: if the densities on the reference

radiograph match the densities on the daily radiograph, the

developer solution strength is adequate. Process with

processing.

b. Unmatched densities: if the densities on the daily

radiographs appear lighter than those seen on the reference

radiographs, the developer solution either weak or cold. If

the densities seen on the daily radiographs appear darker

than those seen on the reference radiograph, the developer

solution is either too concentrated or too worm.

Weakened or concentrated developer solution must be

replaced. If the developer solution is too cold or too worm, the

temperature must be adjusted.

Step wedge radiograph:

A step wedge is advice constructed of layered aluminum steps.

When a step wedge is placed on the top of a film and then

exposed to x-rays, the different steps absorb varying amount of

x-rays. When processed, different film densities are seen on the

dental radiograph as result of the step wedge. The following

steps can be taken to create step wedge radiographs.

i. Prepare the film: Use a total of Y. fresh films to create a

supply of films for daily testing. Place an aluminum step

wedge on top of one film.

ii. Expose the film: Repeat with remaining films using the

same step wedge and exposure factor.

iii. Using fresh chemical: Process only one of the exposed film.

This processed radiograph will exhibit different densities as the

result of step wedge and is known as standard step wedge

radiograph.

iv. Storage of the film: store of the remaining exposed films

in a cool, dry area protected from radiation.

v. films processing: each day, after the chemicals have been

replenished, process one of the exposed step wedge film.

vi. Viewing the radiographs: view the standard radiograph and

the daily radiograph side by side on a view box . Compare the

densities seen on the daily radiograph with the densities seen

on the standard radiograph. Comparison of the daily step

wedge radiograph with the standard step wedge radiograph can

be interpreted as follows.

a. Matched densities:

Use the middle densities seen on the standard step wedge

radiograph for comparison. If the density seen on the

standard radiograph matches the density seen on the

daily radiograph, the developer solution strength is

adequate. Proceed with processing.

b. Unmatched densities:

If the density on the daily radiograph differs from that on the standard

radiograph by more than two steps on the step wedge, the developer

solution is depleted. The developer solution must be changed before

proceeding with processing (American Academy of Dental Radiology

Quality Assurance Committee, ^AT).

^.Y.Y® Fixer strength:

The fixer removes the unexposed silver halide crystals on the film that result in”

clear” area on the film, when the fixer becomes weak, the film takes a longer

time to clear, and when the fixer is at full strength, a film takes minutes, to

clear without agitation(American Academy of Dental Radiology Quality

Assurance Committee, ^AT).

^.Y.Y^ Manual and automatic film processing:

Quality control of manual and automatic film processing is important because

deficiencies in this process are the most common cause of faulty radiographs.

Several steps, followed carefully, greatly increase the probability of producing

radiographs of consistently high quality. Replenish solution daily at the

beginning of the workday, check the level of processing solutions and replenish

if necessary. The developer should be Replenish with fresh developer or

preferably with developer Replenished.

The fixer should be replenished with fixer. At the beginning of the workday,

check the temperature of the processing solution. The solution must reach the

optimal temperature before use “YA F (Y*C) for manual processing and AY F (YA

C) for heated automatic processing. Regular clearing for processing equipment

is necessary for optimal operation. The replacement frequency of processing

solution depends on the rate of use of the solution and on the size of the tank

(Council dental material et al., ^Aa).

YJJV Reject analysis:

To achieve high standard level of images quality, there should be continuous

assessment for the rejected films so as to reduce the number of the retakes

radiographs. Every x-ray department must have a reject-analysis system. The

system must determine what information required, how the data can be

collected, and how correct problems arise in the department using the collected

data (Bachman et al, Yaa«).

Y.Y.YA Radiation protection:

Many of early pioneers in x-ray radiography suffered from adverse effects of

ionizing radiation. The role of the radiographer is to achieve a high protection to

the patient before, during, and after exposure to x-ray (International

Commission on Radiation Protection).

With the use of proper patient protection techniques, the amount of radiation

received by the patient can be minimized.

Y.Y.Y^ ALARA concept:

All exposure to radiation must be kept to a minimum, or as reasonably

achievable to provide both protections to the patient and operators, every

possible method should be employed to minimize risk (Alcox, ^VA).

M previous studies:

Evaluation of Diagnostic Radiology Department in Term of Quality

Control (QC) of X-Ray Units at Khartoum State Hospitals

H.A.IsmaiP, O.A.Ali\ M.A.OmerT, M.E.Garelnabii, N.S.Mustafa0

, ^Radiation & Isotopes Center -Khartoum (RICK) - Sudan

T, i, °Sudan University of Science and Technology - College of Medical,

Radiologic Science, Khartoum, Sudan

The mean objective in diagnostic radiology is to in provide high

qualitydiagnostic image while keeping the patients and workers dose in the

lower limit according toALARA principle, (Maria Lucia Nana et al ^).

To optimize the practice of diagnostic radiology, adequatequality assurance

(QA) program should be in place. A hospitals with ^A x-ray units

distributed in Khartoum state were evaluated inthis study.Each x-ray unit

was tested for Kvp andtimeReproducibility , accuracy of Kvp and time ,

mAs linearity, and coincidence between light beam and radiation beam.

The dark rooms were alsoevaluated to assess the fog level.CONNY II QC

Dosimeter made by PTW company were use to for this study. The analysis

of the results showed that two out of eighteenunit had a problem in mAs

linearity, also two out of eighteen unit had a problem in kVp accuracy and

one had a problem inkVp reproducibility. three devices have defects

concerning adaptation with optical fieldand radiation field. More than ° * %

of the darkrooms had a problem in fog level; time accuracy and time

reproducibility were in the acceptable limit.The quality control of the

radiologicaldevices should be performed periodically and regularly and the

defects of the devices should be removed in order to beassured of the

appropriate function of the devices. many of these machines need service

because of lack ofimplementing the quality control program regularly,

which indicates that the quality control programs should be

extendedregularly.because the dark rooms is very important place specially

in conventional radiology departmentlike in Sudan so it need to periodic

review to monitor the fog.

- Ibrahim Idris Suliman B.Sc. (Physics), M.Sc. (Nuclear Physics)August

(Y**V* Patient Dosimetry and Quality Control in Diagnostic Radiology

X-ray tube voltage and generator requirements are generally fulfilled,

except for x-ray tube output at low mAs values. The use of an AEC

unit for different phantom thicknesses for various types of

examinations does not yield constant image receptor entrance dose.

The requirements for the correspondence of the x-ray filed and the

light field, as well as those for the display station and the hard copy

device are fulfilled. However, the image on the monitor is smaller than

the corresponding x-ray field. The x-ray field is completely visualised

on the hard copy. • The image quality assessed by the various methods

indicates that the results for the paediatric unit are worse than for the

chest x-ray unit. For the chest x-ray unit image quality is similar to the

results obtained in a recent survey of PA chest radiography

- RadyAzzoz, Khalid M. ElShahat , Rezk Abdel MonemRezk(Sep.-Oct.

Y*̂ ^Evaluation of Quality control systems for X-Ray machines at

different Hospitals using patient's radiological dose assessment

technology

The study showed variations in technique, exposure factors, film-screen

combinations, and radiation dose for the same type of examination, both

within and between rooms, which strongly supports the idea that further

optimization is possible. Eighty hospitals recorded lower ESD values

below EC/IAEA recommended diagnostic reference levels * mGy), and

of the hospitals exceeded the UK national reference value (* mGy).

Radiographic practices in Ghana are not fully optimized and this,

therefore, calls for robust implementation of an appropriate and realistic

QAprogram, which currently is not in existence in all the facilities

surveyed. The variations in the data obtained also demonstrate the

importance of creating awareness for the radiographic staff about regular

quality control testing of the equipment and standardization of protocols

Chapter three

Materials and methods

?.' Materials:

?.'.' X-ray machine:

Model x-ray tube assembly *.V/\^P^ADE-A o. MAX/FOCUS KV/*.V/1.V

mm. Production class . Manufactured V«^T august made in Japan

V^ABBZX**^V....

Dental x-ray machine:

Tube housing assembly model: A£V£.V< ^.manufactured: July Italy.

Output max: V.KVp -AmA-T.Vs VT.v...A IEC TTV.total filtrationVmmAL.

Preheating time: ms.

x-ray tube model

The x-ray machine was tested by the quality control team of the department of

radiation protection.

?.'.? Digital meter:

All tests of this machine were done by using:

digital meter (RAD-CHECK Plus model «V-°YV)-(KV meter RMI V£°); RMI

.SN ° *A made in USA gammex RMI.

Vi*A Multi-function meterserial no A««T^-YVVA.made in USA.gammex RMI.

which can give a reading for different tests of the x-ray machine by applying a

single exposure.

V.M Fresh films:

The x-ray films were tested by using fresh film test to check newly opened box

of films.

PRIMAX RDX-®AE soft.exp V*Y*.1.

^.Y.® View box:

The view box was examined weekly for dirt and discoloration of the plexiglass

surface.

Methods:

Sample size:

-f® periapical film

- '® A size film

- YYB size film

- YV C size film

Data collection:

V.V.V Study area:

AL Neelain university hospitals (Al Mogran Hospital and dental clinics).

Method:

The research based on performing all control test of X-ray machine and

evaluating radiation program in these departments.

Data analysis:

By using Excel program to analyze the data.

?J.® Study period:

f months

Chapter four

Result

M results for quality control tests in dental clinic showed by tables below was

performed using a digital meters .The result showed a noted variation in

Kvp&time accuracy,Kvp&time reproducibility ,HVL,patient dose evaluation .

Table *?: Kvp & time accuracy

KVp & TIME ACCURACY (Put dosemeter in beam at cm from focus)

No KVp

KVpMeasure

d Difference

CorrectedKVp

KVp Error%

Accepte d*

Time (ms)

TimeMeasured

TimeError

(%)Accepted*

*

5 V. V\o .J.A V1VA -Y.5 £ Yes v . o£o -V No

Y V. vvv .,YH VHH -Y.tr Yes ..o ..tYo .^o No

r V. VV VY.YYt -Y.V5 Yes ..o ..tYo -^o No

£ V. VY.f *.®f VY.U -r.tr Yes *.ty *.yv® -1V.Y No

®

* *>° • kV and error <±®% S > • % error for I/O units

< % error for all other units

Table f.Y Kvp &time reproducibility

< KVp & TIME REPRODUCIBILITY

KVp V. t ms

No KVp Time

V\^ *.fYf

Y V^.A *.fYf

T VY.* *.fYf

Average yyn ..nt

Coefficient of variation coefficient of variation < ®% = •.••YYH

f. Patient Dose Evaluation

■ place cone tip * mm from dosemeter

■ set maxillary molar/ bitewing setting

Standard I/O units kVp Dose

(V-V. kVp): < V.o mGy for molar view or < i mGy for 0* - kV unit

Should be kVp):

—mGy for molar view

< 0mGy for any view

0> kV: <0.* mGyV. kV: <V.° mGy

(E speed film)

Slit dose from OPG units Dose

Should be < mGycmV

Dose-width product for panoramic film: <V° mGy mm

Table i.T patient dose evaluation

D' ‘.M mAsV (V* mAs^ ) DY ..V

D,( mR ) DV (mR )

VTT

^Y Yff

YfY

...XT

Resultsfor quality control tests in conventional x-ray unit showed by tables

below was performed using a digital meters .The result showed a noted

variation Kvp&time accuracy,relative mA&mAs linearity,mAs consistency,Kvp

and linearity test and HVL test.

Table t.t Kvp&time accuracy

KVp & TIME ACCURACY (Using the KV meter)

First Exposure Factors KVp (a.-^. • ) A. mA (Y..-i. •) x.. t (v.-y..) ms .. mAs x.

FDD vo cm Wave Form CP

No KVp

KVpMeasure

dCorrected

KVp KVp Error% Accepted*Tim

eTime

Measured

TimeError

(%)Accepted*

*

0. 0. o.J.A .... Yes o. iV.V ..TV Yes

V V. oA.A 0V..U v. .. Yes oV oV.T ^T.Yi Yes

T V. VA.V VV.YYi W Yes VT VT.i ..oV Yes

i A. VA.A VV.Ti \o. Yes V^ V\T ..i Yes

0 V. AV . AV.. iA \VA Yes A. A..T i.o Yes

* *± ^.% **

Table f.® RELATIVE mA & mAs LINEARITY

Y RELATIVE mA & mAs LINEARITY (Using the KV meter)

KVp V* t Y**

i mA R Acceptable* mAs R Acceptable**

Y ^T Y** v Y*

Y YY® Yn* NO YY.® Yn. * NO

T Y* * T*T NO Y* T*.T NO

f Y®* TVY NO Y® TV.Y NO

* |Ri - (mAsi *R ! / mAs!) |/ (mAs *R! / mAs^ ) < !«% ** |Ri - (mAi *r! / mA!) |/ (mAi *R ! / mA! ) < !«%

Table O mAs CONSISTENCY

r mAs CONSISTENCY (Using the KV meter)

mAs (Using the KV meter) YY.o

No KVp Y. KVp V. KVp A.

Y mA t Ry mA t RY mA t Rr

Y Yr Y.. Yt. ‘ Yr Y.. Yt.o Yr Y.. Y..Y

r YYo Y.. YA.A YYo Y.. Yt.Y YYo Y.. YA.A

t Yo. o. YA.Y Yo. o. Yt.Y Yo. o. Yt.r

Average t.trr Average o.r. Average o.trr

Acceptable YES Acceptable YES Acceptable YES

* {Sqrt(S(R- Ra v)*/(n->))/ Ra v ) < *.*° } =

Table t.V KVp AND TIME REPRODUCIBILITY AND LINEARITY TEST (output)

i KVp AND TIME REPRODUCIBILITY AND LINEARITY TEST (output), Radcheck

KVp V. t msec Y.. mAsY Y. mAsY (Y* mAsY ) Y.

No KVp Time Dy( mR ) Dy (mR )

Y Yt.. Y...t ot Y Y Y

Y YA.t Y...o oA Y Y Y

T ^A.n Y* *.f ®n Y Y Y

Average nv.Y ! . •.V vi.mnv UV.mV

Coefficient of variation{sqrt(E(D- Dav)7(n-!))/ dav = •.••* Acceptable YES

KVp Reproducibility {sqrt(E(KVp- KVpav)Y/(n-!))/ KVpav <•.•» = •.••xovv Acceptable YES

Time Reproducibility {sqrt(E(t-tav)7(n-!))/ tav <.,.°} = •.• Acceptable YES

X!= D!a v / mAs! XY= DYa v / mAsY

|xy- xy 1 = xY+ xY = *.Y*(xy+ xy) = Acceptable*:

* 1 X!_ Xy l< ..!*(X !+ Xy)

Table f.A HALF VALUE LAYER (HVL) TEST

0 HALF VALUE LAYER (HVL) TEST

KVp Field Size X cm'

No Added filter(t)(mm) Iy (mR) Iy (R) lav (R)

Y ... Y Y Y

Y Y.. AV

r Y.. V.

t Y.o Yr

HVL XmmAL

RECOMMENDED MINIMUM HVLS AT VARIOUS KVPS

Measured KVp Minimum HVL(mmAl)

MeasuredKVp

Minimum HVL(mmAl)

Measured KVp Minimum HVL(mmAl)

r. ..r V. Y.o YY. r

t. ..t VY Y.Y YY. r.Y

tt ..o A. Y.r Yr. r.o

o. Y.Y t. Y.o Yt. r.A

Y. Y.r Y. . Y.V Yo. t.Y

1 RADIATION FIELD

A COLLIMATOR

Working □ YES V □ NO

Light working □ YES V □ NO

Light edge clear □ YES V □ NO

Cross indication □ YES V □ NO

Cross centered □ YES V □ NO

B BEAM ALIGNMENT TEST

I PERPENDICULARITY TEST

F-table top Y** cm

KVp ®* mA Y** t Y* msec mAs ®

Balls Images overlap

(perpendicularity within ..°o)

Ball Image in the Ystcircle

(misalignment is o)

Ball Image in the Ynd circle

(misalignment is r.. o)

Ball Image out of circles

Acceptable

Yes

V

II COINCIDING TEST

FFD mAs Measured Variance

Long Axis Short Axis

% Variance

Long Axis Short Axis

Acceptable*

Y** cm Y*

* < Y% of FFD (Ycm)

Table t.t film developing and fixing time (Dental Clinic)

Date Developing time

In sec

Fixing time

In sec

o\YY\Y.YV Yo A.

V\YY\Y.YV Yo Ao

t\YY\Y.YV r. to

YY\YY\Y.YV rr to

Yt\YY\Y.YV to tt

Table t.Y. rejects film analysis (Dental Clinic)

Investigation a b c D e f G h i J

Upper anterior

Y . . . Y . . Y . r

Upper premolar

Y . . . Y . Y . Y o

Upper molar . Y . . t Y Y r . YY

Loweranterior

Y . . . Y Y . . . t

Lower premolar

. Y . . . Y Y r Y A

Lower molar Y Y . . t Y Y r Y Yt

*key points:

Films total r r ♦ ♦ Y 1 1 A r £o

(a) Overdeveloped, (b) underdeveloped, (c) overexposed, (d) underexposed, (e)

film position error, (f) horizontal angulation error, (g) vertical angulation error,

(h) con-cut, (i) machine failure, (j) films total.

Table £.A rejects film analysis (Al Mogran Hospital)

Investigation a b C d E F

Chest x-ray £ 1 ♦ ^Y

Shoulder r ♦ 1

Cervical 0 r Y ♦ ♦ A

Hand forearm

♦ Y ♦ r 1

Arm-wrist Y Y ♦ 1

Pelvis-hip 0 ♦ Y ♦ A

Femur-knee £ ♦ ♦ ♦ Y 1

Leg-ankle ♦ ♦ r

Films total V V 0 V oV

*key points:

(a) Patient position, (b) angulation, (c) overexposed, (d) underexposed, (e) light

beam diaphragm, (f) films total.

M observed results for other tests:

M.Y Results of testing darkroom integrity:

The result of this test in dental clinic showed a light leakage in the area near to

the roof and the darkroom door but it did not cause film fog, but there is no

darkroom in AL Mogan Hospital because they use CR processing system.

Chapter five

Discussion, conclusion and recommendations

®.Y Discussion

In dental clinic the test showed by tables f.Y,f.Y,f.Twere performed using a

digital meter. The result shows a noted variation in kVp,TIME ACCURACY,mA &

mAs and output. The kVp of this machine was fixed at V* kv, there was

increasing in the kv(Y*%) and decreasing in time measured(Y*%),Kvp &time

reproducipility were acceptable(*.*®),also patient dose evaluation was

acceptable .

In ALMogran Hospital in tables f.f,f.®,f.\f.V,f.A, the results show variance

reading of digital meter but were acceptable (Kvp&time accuracy

Y *%),( RELATIVE mA & mAs LINEARITY !.%),(mAs CONSISTENCY—0)

),(KVp AND TIME REPRODUCIBILITY AND LINEARITY TEST (output) — 0). HVL is

Ymm.

Table f.n showed results regarding the assessment of the developing fixing

time, a timer was used to evaluate the activity of the processing solution. There

was no thermometer to check the solution temperature, and there was a mild

difference in developing and fixing time, because the processing solutions were

change continuously every two weeks.

The table f.Y* and f.YY showed that there was no regular reject analysis in the

departments under study. A number of f® films in dental department and ®V

films in conventional department were collected over the period of three

months.

Figure f.Y showed the distribution of the reject films in dental department

according to their causes and the investigation region. The highest number of

reject films (t) was in the lower and upper molar region due to patient

movement.

The study within the departments showed that there was a good radiation

protection system, therefore there was no radiation detected behind the

protective shield.

The co-patients did are not usually allowed to stay in the departments during the

exposure.

Moreover, the radiographer keeps attention to the application of the ten-day rule

to protect the pregnant ladies and their fetuses. Regarding a viability of the

protective devices, there was a lead apron beside the protective shield, but there

was no thyroid collar.

The study also showed that there was no quality control officer, and no quality

control tests programmed at all.

In AL Mogran Hospital the reject of films due to processing was very rare that

because they are use CR (computerize radiography processing system).

Conclusion

From the results in chapter four, and from discussion in chapter five, the tests

were done for the x-ray machines by using a digital meter and showed a noted

variation in kV, which degrades the image quality. The evaluation of the quality

control system revealed that the absence of regular reject analysis resulted in the

repetition of the same errors. The study also showed that the mentioned

departments should have a quality control officer to observe the quality control

program, and the departments should also provide quality control test tools.

®.V Recommendation

. The x-ray machines of AL Neelain Hospital need to be calibrated in such a

way as to be close to the standard.

Y. The dental department should be provided by thyroid collar.

r. Establishment of a written quality control programme with quality control

officer.

£. Correction of high rate of the retakes cardiographs by establishing regular

o. Providing the department staff with personnel radiation dose monitoring

devices.

1. The x-ray machines should undergo regular routine tests to ensure that

radiation protection, for both staff and patients, has not significantly

deteriorated.

V. All those involved in radiography should have received adequate theoretical

and practical training for the purpose of radiological practices and relevant

competence in radiation protection.

References

T.M. Taha.Study the Quality Assurance of Conventional X-Ray Machine using

Non-Invasive KV Meter.International Journal of Science and Research (IJSR)

ISSN (Online): YrYt-V.Yt Y.Yr).

Stephen Inkoom. Radiation Protection Institute, Ghana Atomic Energy

Commission, Wide Spectra of Quality Control Legon, Accra, Ghana.Y.YY

American academy of Dental Radiology Quality Assurance Committee:

Recommendation for quality assurance in dental radiology Oral Surg Oral Med

Oral Pathol oo:tYY, YtAr.

International commission on radiation protection: radiation protection, ICRP Publ. Y., Oxford, Ytt., Author. Blackwell Scientific, Oxford.

Armstrong P, Wastie ML, YtAr: Diagnostic Imaging. tth edn.

Glass BJ, Yttt: Infection Control in Dental Radiology, NY state Dent j Y.:tY.

H.A.IsmailY, O.A.AliY, M.A.Omerr, M.E.Garelnabit, N.S.Mustafao

MSD MANUAL professional version January Y.Yo Hakan Ilaslan,MD.