Quality Assurance & Quality Control in Medical Radiography PDF

QUALITY ASSURANCE & QUALITY CONTROL IN MEDICAL RADIOGRAPHY Prepared and lectured by: ALLYSON Q. FLORENDO, RRT  QUALITY ASSURANCE & QUALITY CONTROL IN MEDICAL RADIOGRAPHY Prepared and lectured by: ALLYSON Q. FLORENDO, RRT QUALITY ASSURANCE QUALITY CONTROL Deals...

QUALITY ASSURANCE & QUALITY CONTROL IN MEDICAL RADIOGRAPHY Prepared and lectured by: ALLYSON Q. FLORENDO, RRT  QUALITY ASSURANCE & QUALITY CONTROL IN MEDICAL RADIOGRAPHY Prepared and lectured by: ALLYSON Q. FLORENDO, RRT QUALITY ASSURANCE QUALITY CONTROL Deals primarily Deals with with personnel and instrumentation their interactions and equipment. with the patient and other staff.  Quality Assurance in Medical Radiography  Quality assurance as Cardinal Principle of Radiation applied to medical Protection radiography is the organized effort of the staff to ensure production of high quality diagnostic images.  Its purpose is to provide adequate diagnostic information with minimum cost and least radiation exposure to the patient and staff.  QUALITY ASSURANCE CONSISTS OF: Quality Administration Quality Control  Quality  Quality control refers to administration the sets of controls on the procedures are the physical aspects of providing radiology managerial functions services. initiated to ensure  It monitors the factors that that quality control control the production of a measures are radiograph to detect any performed according changes that may to predetermined adversely affect radiographic quality. criteria.  REQUIREMENTS OF A QA/QC PROGRAM  The QA/QC program requires the combined efforts of the whole radiology staff.  Every staff member must therefore be motivated and interested in the establishment and maintenance of an effective QA / QC program.  A hospital QA / QC committee and a QA/QC team must be created to institutionalize the program.  The roles and responsibilities of each person in the committee must be clearly defined.  Composition of QA/QC Team & QA/QC Committee Hospital QA/QC Hospital QA/QC Team Committee 1. Chief Radiologist- head 1. Chief of hospital of x-ray department 2. Administrative officer 2. Chief X-rays/Radiologic Technologist 3. Chief Radiologist 3. Hospital Physicist 4. Chief X-ray/Radiologic 4. Other radiologists and Technologist other radiology 5. Chief Physicist resident physicians 6. Hospital Maintenance 5. Other X-ray/Radiologic Engineer/Technician Technologists 7. Others  Responsibilities of QA/QC Team 1. Do periodic film analysis and prepare monthly film analysis report for presentation to the QA/QC Committee. 2. Establish additional radiographic technique charts when needed, or. revise existing technique charts when appropriate 3. Establish additional darkroom processing charts or revise existing ones when necessary. 4. Do periodic quality control tests of x-ray equipment, accessories, and darkroom equipment and accessories. 5. Keep a room logbook of all test data on equipment, accessories and all c h a n g e s / r e p a i r s done to all equipment / accessories in the room. 6. Keep all brochures and technical manuals of related equipment and accessories.  RESPONSIBILITIES OF QA /QC COMMITTEE 1. M e e t r e g u l a r l y to discuss film analysis report, QC test results, other reports and problems observed in the x-ray section/department. 2. D e c i d e o n c o r r e c t i v e a c t i o n / s to be implemented and on other matters related to the program. 3. Keep a r e c o r d o f m i n u t e s of meetings. ❑ The creation of these groups within the hospital should be formalized with the issuance of a hospital order signed by the hospital chief.  PLANNING & ESTABLISHING QA/QC program in Medical Radiography requires: 1. Commitment and support of radiology personnel to sustain the program. 2. Establishment of standards of image quality to categorize radiographs as g o o d , p o o r , or r e j e c t. 3. Conduct of film analysis every month to identify causes or problems of radiographic quality. 4. Establishment of standard darkroom techniques and conduct of darkroom quality control checks to standardize film processing technique and maintain proper darkroom conditions. 5. Conduct of preventive maintenance and QC checks/tests. 6. Establishment of standard protocols in performing different examinations to standardize radiographic techniques. 7. Establishment of a radiation safety program for personnel and patients. 8. Conduct of continuous education and training.  PREVENTIVE MAINTENACE Preventive maintenance involves a systematic approach to maintaining an X-ray machine in order to prevent unexpected breakdowns and ensure its consistent performance. Instead of waiting for a component to fail, preventive maintenance focuses on regular checks and tasks to identify and address potential issues before they escalate. This approach contributes to the overall longevity and reliability of the machine.  DIAGNOSTIC PROCEDURE IN AN X-RAY FACILITY X-ray tube → Collimator →X-ray beam → Patient → Grid → Film / Screen → Processor → Image → Diagnostic Finding  Processor Patient Image Receptor Time Anatomy Film Temperature Physiology Screen/Film Chemistry Pathology Contact Geometric Exposure Variable Image Factors TFD/OFD/Distortion Quality kVp/mA/Time MOTION View Patient Conditions Tube Interpreter Room light Image Receptor Viewbox light  RADIOGRAPHIC IMAGE QUALITY STANDARDS ▪ Evidence of p r o p e r c o l l i m a t i o n on all sides of the radiograph. ▪ Evidence of the use of g o n a d a l s h i e l d , where appropriate. ▪ Image d e n s i t y and c o n t r a s t appropriate for the visualization of the anatomy of interest. ▪ A b s e n c e o f i m a g e d e g r a d a t i o n due to patient motion or artifacts due to poor film processing , old screens , etc. ▪ A d e q u a t e d i s p l a y o f a n a t o m y of interest for the examination. ▪ Evidence of m a r k e r s to properly identify the patient’s left and right anatomy, hospital name, patient number, date , initials of the x-ray technologist who performed the examination and the cassette number appearing in the radiograph produced. Guidelines for the use of protective shielding state that gonadal shielding should be used; 1. if the patient has reasonable reproductive potential. 2. when the gonads are within 5 cm of the collimated field. 3. when tight collimation is not possible. (A) 1 only (B) 1 and 2 only (C) 1 and 3 only (D) 2 and 3 only Answer: B It is our professional responsibility to minimize exposure dose to both patients and ourselves, and one of the most important ways is with a closely collimated radiation field. Gonadal shielding should be used when the patient is of reproductive age or younger, when the gonads are in or near the collimated field, and when the clinical objectives will not be compromised.  FILM ANALYSIS ❖ Is the subjective evaluation of image quality based on the standards for good and rejected radiographs set by the hospital QA/QC team for the purpose of : ❖ Evaluating the problems leading to poor image quality and film rejects; ❖ Serving as self-improvement tool for the x- ray facility staff and; ❖ Establishing a management data base.  OVERALL REJECT RATE FORMULA ▪ Reject Rate (%) = Total Number of Rejects / Total Number of Films Used ▪ Poor Film (%) = Total Number of Poor Films / Total Number of Films Used ▪ Good Quality Film (%) = Total Number of Good Quality Films / Total Number of Films Used ▪ A reject rate of 1 0 % o r m o r e should be considered unacceptable. ▪ A reject rate of 5 % t o 1 0 % justifies continued monitoring. REJECT FILM ANALYSIS  From a radiologic technologist’s point of view, a reject analysis may be seen as a threat.  It is important to fully explain to all concerned: Why the analysis is being carried out. How it will be carried out. When it will be carried out. The benefit.  BENEFITS 1. Able to identify the main errors and put measures in place to reduce them. 2. Save money by reducing wastage. 3. Reduce radiation dose to the patient by minimizing the number of repeat films. 4. Save time and effort by reducing the number of repeat films 5. Provide ongoing data for comparison. 6. Provide possible source of statistics to support claims for more funding to replace, modify, or repair faulty equipment. POTENTIAL PROBLEMS 1. Staff members do not cooperate fully. 2. Radiologist and clinicians tend to retain substandard films on the grounds that they provide some information. 3. Reject film records are not always kept up to date.  SETTING UP A REJECT FILM ANALYSIS PROGRAM ▪ Design the program. ▪ Determine the period over which the program will run. ▪ Nominate a starting and finishing date and time. ▪ Inform staff : ▪ Why the program is necessary. ▪ How it will operate. ▪ When it will take place. ▪ Who is responsible for the program. ▪ Decide what data is needed. ▪ Design data recording sheets. ▪ Place reject film boxes in appropriate areas. BEFORE PROGRAM STARTS Count all films in store by sizes. Include in the count all unexposed films in cassettes and partially empty boxes. Record this information. Dispose of all current reject films.  ANALYSIS OF THE DATA Overall number of reject films. Number of reject films by size and faults per room (or radiographers). Overall cost of rejected films. Identification of common faults. Reject films as a percentage of films used. FILM SIZE ROOM A ROOM B Number of Number of films Number of Number of films films used per rejected per size films used per rejected per size size size 8 x 10 10 0 8 0 10 x 12 11 0 12 0 11 x 14 9 1 6 0 14 x 17 5 0 4 1 Total films Reject film: 1 Total films Reject film: 1 used: 35 used: 30 Total Films used: 65 Total Cost of Films Rejected: Php 83.00 Total Films Rejected: 2 14 x 17 = Php 45.00 11 x 14 = Php 38.00 Cause of Reject Film: Patient Motion Rad Tech on duty: W. DELA CRUZ, RRT Rejected Film: 3.1% Shift: 7:00 a.m. to 3:00 p.m.  DARKROOM PROCESSING QUALITY CONTROL MANUAL FILM AUTOMATIC FIM PROCESSING TESTS PROCESSING TEST ▪ White light leak/fog Automatic test processor ▪ Safelight efficiency test acceptance test ▪ Radiation fog test Temperature check ▪ Optimum development Replenishment rate time check test ▪ Developer/fixer activity Sensitometric test test  DARKROOM  A light tight room where manual processing of radiographs are carried out.  The darkroom is a vital link in the chain leading to a standard high quality radiographs.  A well positioned and properly exposed radiographs can easily be ruined by poor processing.  WHITE LIGHT LEAK TEST Frequency of test Method Every 6 months 1. Turn on all lights in areas adjacent to the darkroom. After darkroom Switch off all darkroom lights, repair 2. including safelight. As necessary 3. Ensure that all doors in the Equipment required darkroom are closed. Insulation tapes to 4. Remain in the darkroom for 10 minutes for eyes to get temporarily cover used to the dark. holes 5. Look for white light leaks. Chalk to mark Pay particular attention to holes 6. doors, windows, exhaust fan, air vent and pipelines.  ACTIONS TO BE TAKEN Identify location and seal any white light leaks. Repeat the test. Carry out white light fog test whenever necessary. File a report.  WHITE LIGHT FOG TEST Method of test Frequency of test 1. Turn on all lights in areas Every 6 months adjacent to the darkroom. Switch off all darkroom As necessary 2. lights, including safelight. Equipment required 3. Ensure that all doors in the darkroom are closed. 1 sheet of new 4. Place the sheet of film on 18x24cm film. the workbench. Cover half of the film with 1 sheet of 18x24cm 5. the sheet of card. card. 6. Leave for 3 minutes. 7. Process the film. EVALUATION AND ACTION Evaluation of Action to be Results taken If the density of the uncovered Seal any area part of the film of light is greater than leakage. the covered part, then some Repeat the fogging has light leak test. occurred. File a report.  DARKROOM SAFELIGHT CHECK Each safelight should have the correct filters to suit the light sensitivity of the film used. It should have the correct light bulb wattage (15 watts when facing down). It should be installed no less than 130 cm above the workbench. It should have no white light leaks.  SAFELIGHT EFFICIENCY TEST Frequency of test Biannual or annual. Equipment required One 24x30cm cassette loaded with new film. Two sheets of 24x30cm card. One timing clock or watch with second hand. One 24x30cm cm sheet of lead or lead rubber.  CASSETTE PASS BOX RADIATION PROOF TEST Frequency of test Evaluation Yearly. If fogging has occurred to the As necessary. extent that the markers can be Equipment required seen , repeat the test over a 3 coins or lead markers. shorter period. Adhesive tapes. Establish a period of time when 1 loaded 35x43cm cassette fogging does not occur. Method Action to be taken Stick the 3 markers at intervals , down the long edge of the front of the cassette Do not store cassette in the pass with the tape. box. Place the cassette in the pass box , with Remove cassettes in the pass box the markers nearest to the x-ray room. within the no fog period. Leave the cassette in the pass box for a week. Increase lead shielding to pass box. Process the film. File a report.  DEVELOPER TEMPERATURE & DEVELOPMENT TIME  Development time and temperature directly affect the density, contrast and amount of base fog of a radiograph.  It is advisable to follow manufacturer’s time/temperature recommendations.  If these information is not available, it is necessary to carry out a test to determine correct development time and temperature.  DETERMINING THE BEST DEVELOPMENT TIME Frequency Method As required. Before starting the test, stir the developer and record the temperature Equipment required In safelight condition number the test Six sensitometry strips in pencil, 1 to 6. test strips. Attach test strips to the film clips and suspend in the developer. All strips must Thermometer (not be fully immersed in the developer at the mercury). same time. Record start time and start time clock Six film clips or immediately. safety pin. After 30 seconds remove test strips 1, Developer stirring rinse and place in fixer. rod. After a further 30 sec remove test strip 2 , rinse and place in fixer. Stopwatch Repeat this process every 30 seconds Densitometer until all test strips are in the fixer. Fix, wash and dry test strips EVALUATION AND ACTION Evaluation Arrange strips on a viewing box, SENSITOMETRY STRIP side by side in numerical order with all unexposed steps at the same end. Identify the strips that do not show any base plus fog level increase. Study the middle density steps and identify the strips which do not show a density level increase. The most suitable development time, at the temperature used , is the time that gives maximum density but shows no increase in base fog.  SENSITOMETRY STRIPS ARRANGED FOR COMPARISON 0.5 min 1 min 1.5 min 2 min 2.5min 3 min  24 23 22 21 20 TEMPERATURE ⁰C 19 18 17 16.5 1 1.5 2 2.5 3 3.5 4 4.5 5 DEVELOPMENT TIME (minutes) TIME TEMPERATURE DEVELOPMENT GRAPH  SENSITOMETER AND DENSITOMETER Sensitometer- an instrument Densitometer-measures that exposes a test film to light OD of each step in the through a series of filters. sensitometric strips.  DEVELOPER ACTIVITY USING A HYDROMETER TEST  Hydrometer - measures specific gravity of developer.  Specific gravity - measures the relative weight of a solution when compared to water at 23 ⁰C.  Specific gravity measurement is used to show if correct dilution is present.  The specific gravity of water is 1.000.  Specific gravity of developer ranges between 1.070 to 1.100. ◼ Specific gravity decreases with increasing temperature. DEVELOPER ACTIVITY TEST Frequency Evaluation Daily The SG reading should be within +/- 0.004 of the Equipment required manufacturer’s recommendation. Hydrometer If the reading is lower than that Manufacturer’s recommended ,the developer is recommended SG for the over diluted. developer being tested. If the reading is higher than that Method recommended, the developer is too concentrated. Place hydrometer in the developer. Allow it to float. Action If too concentrated add water Note the reading on the scale at the level of If too dilute add replenisher or developer surface. replace developer. FIXER ACTIVITY TEST FIXER Dissolves off all unwanted film emulsion. Makes image permanent. Fixing temperature and fixing time, although important, are not as critical as those of the developer. CLEARING TIME The time it takes to clear the film (dissolving off unwanted film emulsion). Can take from 30 seconds but should not be more than 2 min. The film may be viewed in white light once it has fully cleared.  PERMANENT FIXING This is usually twice the length of the clearing time. Recommended fixing time is at least 4 min to avoid image deterioration at a later time. Films must be removed from the fixer as soon as adequately fixed. Excessive fixing time will remove the image.  FIXER ACTIVITY USING A HYDROMETER TEST  Specific activity of the fixer indicates its level of activity.  The SG of the fixer should be in the region of 0.004 (refer to manufacturer’s recommendation).  FIXER ACTIVITY USING A HYDROMETER TEST Frequency Evaluation Daily SG reading should Equipment Required be within +/- 0.004 Hydrometer of manufacturer’s recommendation. Method SG should be in the Place the region of 1.110 hydrometer in the fixer. High SG means not enough Note the reading dilution. at the surface of the fixer. Low SG means too much dilution. SILVER ESTIMATION TEST  I n d i c at es l e ve l of s i lv e r c o ncen t r a t i o n in fixer solution.  This test helps us to evaluate if replenishment is adequate. SILVER ESTIMATION TEST Frequency Evaluation Daily < 2 g/l is over Equipment required replenished. Silver estimation >6 g/l is under paper. replenished. Note: Freshly mixed Method: fixer will have a Place paper in z e r o reading. fixer. Action Compare with 6 g/l add undiluted Take reading. fixer.  WASHING  Films from the fixer should be washed for 20 min in running water, at a rate of exchanges an hour, in order to ensure satisfactory long term storage of radiograph. HYPO RETENTION TEST  This test indicates adequate/ inadequate washing.  Excessive amount of residual thiosulfate in film emulsion may cause a b r ow n s t a i n to appear on the film. HYPO RETENTION TEST Frequency Method Put a drop of test fluid on the Weekly surface of the film well clear of the image. As necessary Wait for one or two minutes. Equipment required Evaluation Inspect the moistened area. Hypo (thiosulfate) Compare color with test strip. retention test fluid. Action Test strip. Check wash water flow and washing time if color indicates Radiographs to be high level of thiosulfate. tested. Adjust and retest.  DRYING  Removes all moisture , harden the image and make the radiograph durable.  CORRECT HANDLING OF UNPROCESSED FILMS Handle only under Do not allow film to slide over correct safelight any surface to avoid creating static marks. conditions to avoid fogging. Do not allow film to come into contact with any moisture, Handling time should before entering the developer be less than 3 min to to avoid premature avoid fogging. development Water or developer will Keep hands dry when create dark areas; while handling films, to avoid fixer will stop the marking the film. development process and create clear areas. Do not allow film to Clip or hang films firmly on bend because this will hangers. affect the film emulsion producing artifacts. IMAGE ARTIFACTS  An artifact is an unwanted density or image on the radiographs.  The major sources of artifacts are: Exposure Artifacts Handling and Storage Artifacts Processing Artifacts EXPOSURE ARTIFACTS  Occurs during the exposure of the patient not after the exposure has been made.  Exposure artifacts are caused by any of the following: Improper positioning Incorrect combination of exposure factors Patient motion Grid cut off Improper film/screen combination Poor film/screen contact Warped cassettes Lack of patient preparation such as failure to remove jewelries and other body accessories.  HANDLING AND STORAGE ARTIFACT  Occurs because of improper handling and storage of films.  Handling artifacts include light leaks, static, crease marks and fingerprints.  FACTORS AFFECTING FILM HANDLING AND STORAGE Handling – bends, creases, lotion marks Heat – less than 68°F (20°C) Humidity – 40-60% Light – only complete darkness or safety light Radiation – less than 0.2 mR produces fog. Shelf life – check expiration date on box. Storage time – 4 5 d a y s , rotate stock. Pressure – store film boxes u p r i g h t.  PROCESSING ARTIFACTS  Occur as a result of improper processor QC of the transport system.  Processing artifacts include pi marks, guide-shoe marks and chemical stain.  PI MARK ARTIFACT Occurs when a deposit of dirt or chemicals on a portion of a roller which will make a dark or positive mark on the film on each revolution. These pi marks are perpendicular to the direction of film travel through the processor and are spaced at pi or 3.1416 inch intervals.  GUIDE-SHOE MARKS Are caused by the guide shoes which are used to r e v e r s e t h e d i r e c t i o n of the film at the cross over assembly. These marks appear as negative lines parallel to the direction of film travel. Guide-shoe marks indicate a misaligned guide shoe and are scratching the film emulsion.  CHEMICAL FOG Occur when there is improper chemistry in the solution. The chemical fog has a dull gray appearance looking much like a light or radiation fog. The chemical fog is a d i c h r o i c s t a i n comprising of 2 colors. The stain can appear as yellow, green, blue, or purple on the film. Cause : slow processor does not remove chemicals from the film. AUTOMATIC PROCESSOR  Automatic film processing follows the same basic principles as those of manual processing but under automated and controlled conditions.  Regular quality control monitoring and maintenance is essential to ensure the high quality images can be produced consistently.  ACCEPTANCE TESTING OF NEW PROCESSOR  The following must be checked prior to acceptance of a new processor: Specifications of the processor installed are the same as that ordered. Installation has been carried out as stated in the contract. Installation is complete and equipment is working efficiently. All QC tests have been carried out and are satisfactory. All accessory equipment has been supplied and is in good order. Operating manual has been supplied and is the correct one. AUTOMATIC PROCESSOR  POTENTIAL PROBLEMS OF AUTOMATIC PROCESSORS MECHANICAL ELECTRICAL Broken cog teeth. Power failure Roller wear or Drive motor failure splitting. Heating filament Drying section failure Transport system Replenishment pump breakdown failure Film jam Recirculation pump Film damage failure  POTENTIAL PROBLEMS (Continued) CHEMICAL SOLUTIONS WATER Wrongly mixed Inadequate Contaminated supply Inadequate or incorrect replenishment Blocked or Blocked or partially restricted flow blocked replenishment hoses Contaminated Incorrect temperature Algae growth  SENSITOMETRY  It is the study and measurement of the relationship between exposures, films, screens and processing.  Itis a more comprehensive and accurate form of monitoring and evaluating processing performance. IMPORTANT TERMINOLOGIES Sensitometer – a consistent light source Toe Gradient - a line drawn that produces a s t a n d a r d r a n g e between 0.25 and 1.00 density o f d e n s i t i e s , when exposed to levels on the characteristic curve. film. Densitometer- a consistent light source, Mid Gradient – a line drawn combined with a light measuring between 1.0 and 2.0 density levels. sensor, used f o r accurately Upper Gradient - a line drawn measuring film density. between 2.0 and 3.0 density levels. Film Density - the degree of film blackening. Base Plus Fog – the density of a processed film without the effects Contrast- the difference between two or of light or radiation. more densities on a film. Speed- is indicated by the location Gradient- the contrast of a film at a of the curve along the exposure given density. axis. The line drawn tangent to the characteristic curve at a particular density Exposure Latitude - the range of which forms the slope. exposure factors within which the Average Gradient- a line drawn resultant radiograph is considered between the 0.25 and 2.00 density to be acceptable. levels on the characteristic curve.  FILM CHARACTERISTICS Contrast – number of grey levels between white and black High = more black and white image, less levels of gray Low = more grey levels, useful for chest x-rays Latitude – range of exposure techniques High contrast film has narrow latitude Low contrast film has wide latitude Speed – sensitivity Spectral Matching – must be sensitive to specific light spectrum emitted by screen.  QUALITY CONTROL PROGRAM 1. Acceptance Testing 2. Routine Performance Monitoring 3. Maintenance QUALITY CONTROL PERFORMANCE TESTS Focal Spot Measurement or Spatial Resolution Test Collimation (X-ray/Light Field Congruency) kVp Accuracy or kVp Calibration Filtration Exposure Time Accuracy Exposure Reproducibility Exposure Linearity AEC FOCAL SPOT OR SPATIAL RESOLUTION TEST  Focal Spot Blur – blurred structures on the radiograph caused by degradation of the focal spot.  As the tube ages , the anode surface becomes rough resulting in a larger effective focal spot which leads to an increase in off focus radiation.  FOCAL SPOT Target, focus, focal point or focal track A region of the anode target in which electrons interact to produce x-rays. The actual x-ray source. Sizes: small /large Shapes: circular/double banana  TEST TOOLS TO MEASURE F O C A L SPOT SIZE / SPATIAL RESOLUTION. Pinhole Camera - produces an image of the focal spot ; this is m o s t a c c u r a t e method but also e x t r e m e l y d i f f i c u l t and t i m e c o n s u m i n g to set up. Star Pattern – e a s y t o u s e but has significant limitations for focal-spot sizes l e s s t h a n 0. 3 mm. Slit Camera - alternate or m o d i f i e d p i n h o l e c a m e r a. S t a n d a r d for measurement of effective focal-spot size Line Pair Resolution Tool- an alternating series of metal strips with different separations which measures the spatial resolution of the system directly.  TEST LIMIT For focal spot < 0.8 mm : size should be within +/- 50% of the stated focal spot size. For focal spot between 0.8mm and 1.5 mm : size maybe 40% larger than stated focal spot size. For focal spot > 1.5 mm : 30% larger stated focal spot size. The resolution of a film screen system should be >8 line pairs per millimeter (lp/mm).  X-RAY / LIGHT FIELD CONGRUENCY (COLLIMATION ACCURACY TEST)  L i g h t / x - r a y f i e l d c o n g r u e n c y is the condition in which the light field and x-ray field coincide to ensure accurate placement of x-ray field on the film.  The sum of the differences between the light and radiation field edges must be