QUALITY CONTROL PROGRAM FTH GOMBE, GOMBE STATE NIGERIA.pptx

Quality Control Program of Digital Imaging system (CT and DR)

1. QUALITY CONTROL PROGRAMME OF DIGITAL X-RAY EQUIPMENT BY Buhari Rabiu ABUBAKAR DEPARTMENT OF RADIOLOGY, FEDERAL TEACHING HOSPITAL, GOMBE . 2 ND JUNE, 2025 1

2. CONTENT INTRODUCTION LIST OF ABBREVIATIONS AIM AND OBJECTIVES BENEFITS OF QC COMPONENTS OF QC RESPOSIBILITIES METHODS PERFOMANCE CRETERIA INTERPRETATION OF RESULTS Conclusion 06/02/25 2

3. List of Abbreviations AAPM : The American Association of Physicists in Medicine AAPM A-Se : amorphous selenium A-Si: amorphous silicon CCD : charged couple devices CR : computed Radiography DDR : Direct digital radiography IAEA : international atomic energy agency IR: image receptor MOSFET : metal oxide semiconductor-field effect transistor PACS : picture archiving and communication in medicine PSP : photo stimulable phosphors QA : quality assurance QC : quality control WHO : world health organization 06/02/25 3

4. Introduction The optimization of radiographic acquisition parameters is of great importance, as too high or too low exposures for the diagnostic purpose are unacceptable, ( Steffensen , C., et al 2020). Today film-screen radiography is now obsolete and has been replaced by digital radiography ( Euclid, S. et al , 2019). AAPM has offered a definition of digital radiography as “radiographic imaging technology producing digital projection images such as those using PSP, a-Se, a-Si, CCD, or MOSFET technology ( Fauber , T. L., 2017 ). 06/02/25 4

5. Introduction QA means the 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 the personnel (W. M. Ngoye et al ., 2019 ) . An equipment QC program establishes baseline performance levels, tracks system performance over time, and reveals performance trends ( IAEA, 2023) . Thus, QC in medical imaging is an ongoing process ( Ijabor et al ., 2021 ). 06/02/25 5

6. Aim and Objectives This document outlines the tests that are typically part of a QC program for digital radiography equipment, including portables with a dedicated detector. The main objectives are to briefly describe: The basic QC tests for a digital x-ray unit . The basic QC tests for electronic image display monitors. 06/02/25 6

7. Benefits of Quality Control Performance degradation can be identified leading to preventative action. Patients benefit when equipment performance is maintained at acceptable levels. This is important as it can lead to more accurate and safer diagnostic imaging. Consequently, improving the overall quality of healthcare. A QC program is an important element in achieving accreditation. ( Elbakri & Ingleby , 2019) 06/02/25 7

8. Test Priorities The tests are carried out based on test priorities: essential and desirable, with respect to their importance in influencing image quality and dose . Essential : refers to tests that must be done in a facility . Desirable : describes the test procedures that should be performed if feasible. ( IAEA, 2011 & 2023 ) 06/02/25 8

9. Components of QC The program consists of: A cceptance testing O n-going quality control, and P eriodic review of QC data and outcomes . ( Elbakri & Ingleby , 2019) 06/02/25 9

10. Acceptance Testing It is performed on new equipment to demonstrate that it is performing within the manufacturer’s specifications and criteria . T o confirm that the equipment meets the purchaser’s specifications. (Said et al ., 2021 ). Ideally, performed by or under the oversight of a medical physicist when a system is installed, relocated (where relevant) or undergoes significant upgrades or maintenance . ( Elbakri & Ingleby , 2019 ) 06/02/25 10

11. Ongoing Quality Control ( QC) Routine performance tests, such as status tests and constancy tests for conventional x-ray equipment, including their accessories, (IAEA, 2023 ) . Involves designing and implementing a QC program, collecting and analyzing data, investigating results that are outside the acceptance levels for the QC program, and taking corrective action to bring these results back to an acceptable level ( Ijabor et al ., 2021). The tests require only the use of instruments, reproducible and known objects (phantoms) and test objects, which do not cost much (Said et al ., 2021). 06/02/25 11

12. Interpretation of Results and Corrective A ctions Performance Standards Each test in the QC programme has a specified tolerance level for achievable and acceptable results as applicable. Achievable: indicates the level at which a facility should work if it is feasible. Acceptable: indicates that performance must be within these tolerances, beyond which the equipment should not be used. Should the results of a test fall outside the specified tolerance , the test should usually be repeated to confirm the result before action is take. (IAEA , 2011 & 2023) 06/02/25 12

13. Requirements It has been well established that to achieve high quality radiography, the following elements are essential: Well trained and experienced personnel (radiologist, radiographer, medical physicist ). Modern , well designed equipment. Equipment in good working order. Proper positioning and technical factors for exposure. Appropriate image viewing conditions. ( Elbakri & Ingleby , 2019 ) 06/02/25 13

14. QC Tools for Digital Radiography Examples of these tools include: Screen-contact wire mesh pattern Anti-scatter grid, calibrated ion chamber, Densitometer for hard copy film evaluation. Manufacturer-approved cleaning solutions and cloths. Two metric-calibrated 30-cm steel rulers Low-contrast phantom. Aluminum step wedge. ( AAPM, 2006) 06/02/25 14

15. Basic Test Factors I nspection of the IP Image Plate Erasure/ erasure thoroughness ( CR Only). Alignment: X-ray to light field / X-ray to detector. Image Uniformity and Artefact Evaluation Image Quality/ spatial accuracy . E xposure indicator calibration L aser beam function Monitor and Printer Detector Calibration / Flat Field / Dark Noise Test (DR Only). 06/02/25 15

16. Record Sheet – Mechanical Inspection DATE: INITIALS: ITEM DESCRIPTION Pass ( ) Fail ( x ) 1 Check that all cables are free from breaks, kinks or knots. Cables should not be under other heavy equipment 2 Verify that the interlocks and brakes are working correctly. 3 Ensure that the table, tube and bucky move smoothly. 4 Ensure that control panel switches, indicator lights and meters are functioning 5 Ensure that the field light is functioning, has adequate intensity and collimator is free from dust. 6 Ensure that the current technique charts are displayed near the control panel 06/02/25 16 (General QA and QC guidelines, 2013) Fig. 1.0: Example of Record Sheet for Mechanical Inspection

17. Roles and Responsibilities Typically, the routine QC activities are carried out by a Radiographer or technologist while in-depth checks are performed by, or under the guidance of a medical physicist . Some of the personnel involve may include the following: QA manager Licensee or Registrants Qualified medical physicist Radiographer Radiologist ( IAEA, 2011 ) 06/02/25 17

18. QA manager The designated quality manager should: R eview non-compliance issues. P rovide strategies for corrective and preventative action in a timely manner and, F ormulate quality improvement strategies within the department. (“ General X-Ray QA and QC Guideline,” 2013 ) 06/02/25 18

19. Licensee or Registrant E nsure that all regulatory and/or licensing requirements are met. He must ensure that all personnel who work at the facility are appropriately qualified and trained, and meet all continuing education and experience requirements . (General X-Ray QA and QC Guideline , 2013) 06/02/25 19

20. Radiologist Motivating , supervising and managing all aspects related to the QC programme in the area of all systems of conventional radiography. Selecting a single radiographer to be the primary QC radiographer to perform the prescribed QC tests and to oversee those tests that have been delegated to other individuals. Ensuring the availability of the equipment and necessary materials for implementation of the QC tests. Arranging staffing and scheduling so that adequate time is available to carry out the QC tests and to record and interpret the results. ( General X-Ray QA and QC Guideline, 2013 ) 06/02/25 20

21. Radiologist.. Reviewing the test results at least every three months, or more frequently if consistency has not yet been achieved. Ensuring that records are properly maintained and updated in the conventional radiography QC procedures manual. Continually providing feedback, to the technical personnel and/or radiographers on the image quality and the QC procedures. Verifying the percentage of rejected images and ensuring that appropriate corrective action is implemented. ( General X-Ray QA and QC Guideline, 2013 ) 06/02/25 21

22. Medical Physicist Advising the facility on the safe and effective use of X-rays for conventional radiography. This includes image quality and radiation protection of the patient and personnel. Advising the facility on equipment for digital radiography including the PACS. In some circumstances, the physicist may work as a liaison between the facility and a specialist in PACS. Conducting tests to ensure the safety and proper performance of equipment used in radiography. Providing oversight and advice to the radiographer who carries out the radiographer’s component of the QC programme . ( IAEA, 2011) 06/02/25 22

23. Radiographer Ensuring that the QC tests are performed, interpreted and recorded appropriately. The radiographer is responsible for the day‐to‐day operation of the QC program. Recording imaging problems. Undertaking additional continuous education courses in conventional radiography, including digital aspect . ( General X-Ray QA and QC Guideline, 2013 ) 06/02/25 23

24. Daily Inspect system operation and verify operational status. Follow manufacturer’s recommendations for equipment warm-up. Check meters and audible and visual indicators for proper function. Inspect equipment for mechanical soundness and smooth motion (including collimator). For the image acquisition system, inspect operation and verify operational status. Detector Calibration / Flat Field / Dark Noise Test ( DDR Only ). ( Elbakri & Ingleby , 2019) 06/02/25 24

25. Monthly For CR systems, erase all plates in the inventory. Scan a randomly selected unexposed cassette of each size , and check for obvious non-uniformities and artefacts. Perform an image quality test with a phantom. Perform retake and reject analysis. A reasonable target reject rate for general radiography is 8%, with thresholds for investigation set at 10% and 5% . Verify performance of modality displays qualitatively by displaying and evaluating an image of the SMPTE pattern or equivalent. Monitor QC for DDR only. Printer QC (if applicable ). (“ General X-Ray QA and QC Guideline,” 2013 ) 06/02/25 25

26. Quarterly Clean all imaging plates (CR systems) if recommended by the manufacturer or deemed necessary in consultation with the physicist . M echanical inspection of the digital x-ray system and associated components. Alignment of X-ray to light field (CR and wireless DR detectors) / X-ray to detector (integrated DR detectors ). Consistency of Exposure Index. Image Uniformity and Artefact Evaluation. (“ General X-Ray QA and QC Guideline,” 2013 ) 06/02/25 26

27. Semi-annually Image Quality: T o ensure adequate image quality from each x-ray unit . (General X-Ray QA and QC Guideline , 2013 ) 06/02/25 27

28. Annually Annual testing by or under the oversight of a medical physicist to evaluate performance against vendor. S pecifications and baseline levels established at acceptance. Annual equipment QC review by a medical physicist. ( General X-Ray QA and QC Guideline, 2013 ) 06/02/25 28

29. Erasure Thoroughness and “Ghosting ” (Causes) Causes: Too short erasure time. Too old light bulbs, or burn out. IP exposed to external radiation sources. Any of these problems would result in insufficient erasure of the plate. Note that even with proper erasure, when a CR phosphor plate is subjected to an extreme x-ray exposure, a residual image may persist . In a DR detector, ghosting is caused from residual electrical charge that has been trapped in a-Se or a-Si detection layer, and is released only slowly over time. Indirect conversion DR systems usually have shorter image lag than direct-conversion systems . (Carroll, Q. B., 2023) 06/02/25 29

30. Erasure Thoroughness and “Ghosting ” (QC Procedure) To check for inadequate erasure; F irst expose an aluminum step wedge or other object made of homogeneous material and process the PSP plate. I mmediately make a second exposure on the same plate without the object in the beam and with about 2 cm of collimation on all sides of the field. T he image can then be visually examined for any appearance of the object as a “ ghost image ” or “ image lag .” P erform a primary erasure on all CR cassettes, weekly. C omplete Record Sheet. ( CARROLL, Q. B., 2023 ) 06/02/25 30

31. 06/02/25 31 Wikipedia, 2025 Fig. 2.0. Diagram of CR cycle

32. Alignment: X-ray to light field / X-ray to detector To ensure accurate collimation and full coverage of image receptor without unnecessary exposure of patient. This test should be performed on all x-ray units. Ensure x-ray tube and table are level. Place CR cassette / wireless DR detector on table top. Set a source to detector distance of 100cm Dim the room lights so that you can clearly see the edges of the light field Collimate to an area greater than 10 x 10cm – the exact area is not important as long as it is within the CR cassette / wireless DR detector. Use coins to mark the edges of the light field. It is good practice to place a coin within and outside the light field. Use an additional coin to mark the anode side . ( General X-Ray QA and QC Guideline, 2013 ) 06/02/25 32

33. Set‑up for X ray–light beam alignment using coins. 06/02/25 33 IAEA, 2023 Fig. 3. 0: light field alignments, A = Fist method, B = 2 nd Method A B

34. 06/02/25 34 IAEA, 2023 Fig. 3. 1: images of light field alignments

35. Alignment: X-ray to light field / X-ray to detector.. Make an exposure using 60kV and 5mAs Open up the collimators fully and make an exposure using 60kV and 1mAs. Readout the CR / DR image. Measure the difference between the x-ray field and the edge of the coin (light field ). Repeat for broad and fine focus (if available). Note that if the x-ray field is greater than the light field, this is a + ve difference. Complete Record Sheet. ( General X-Ray QA and QC Guideline, 2013 ) 06/02/25 35

36. Record Sheet – Alignment: X-ray to light field (CR and wireless DR detectors) Date test was performed Deviation of x-ray from light field / detector. X-ray equipment identification. Person performing test. Limits X-ray to light-field must be within ±1% of SID. X-ray to detector must agree to within 2% of SID. X-ray field should extend to all edges of the detector. DATE INITIALS 06/02/25 36 Broad Focus Deviation between X-ray and light field (mm) (positive indicates x-rays extend beyond light field) Anode edge Cathode edge Top edge Bottom edge Fine Focus (General X-Ray QA and QC Guideline, 2013) Fig. 3. 2: E xample of Record S heet for Light Field Alignments

37. Field Uniformity Field uniformity from IR can be tested by making a “ flat field ” exposure with no object in the x-ray beam, using moderate technique settings. The plate should be thoroughly erased prior to any test exposure. (DR systems automatically erase the detector after each exposure). A long SID of 180 cm ( 72”) should be used to minimize the anode heel effect. The resulting image may be visually scanned for del or pixel defects. Uniform field intensity is measured at five locations across the large (35 x 42 cm ) field—the center, and four corner areas. (Carroll, Q. B., 2023 ) 06/02/25 37

38. Image Uniformity and Artefact Evaluation To ensure that image is uniform and artefact-free. Additionally for DR, to ensure that flat field correction is working . Use the image acquired for Consistency of Exposure Index. Visually inspect the image for non-uniformity and artefacts, accepting that CR images will suffer from the anode-heel effect. ( General X-Ray QA and QC Guideline, 2013 ) 06/02/25 38

39. Image Uniformity and Artefact Evaluation.. Action If artefacts are seen it is important to determine whether they are due to the monitor, the detector , x-ray beam non-uniformity or the copper. Take the following steps: To eliminate the possibility of display artefacts, rotate or pan the image. If the artefact moves with the image it is due to the imaging system; if it stays in the same place, it is due to the display system (monitor). To eliminate the possibility of artefacts (dust, scratches or thickness non-uniformity) on the copper, rotate the copper and repeat the test. ( General X-Ray QA and QC Guideline, 2013 ) 06/02/25 39

40. Image Uniformity and Artefact Evaluation.. If the artefact stays in the same place, it is most likely to be due to the detector. if it moves, it may be attributable to non uniformity on the copper. Clean the equipment (if possible and following vendor guidelines) and repeat the test. 06/02/25 40 Fig. 4.0: set up for image uniformity using PMMA

41. Record Sheet – Image Uniformity and Artefact Evaluation Use Record Sheet Date test was performed Comments on uniformity and artefacts X-ray equipment identification Person performing test Limits Uniform image No evidence of artefacts Date: Initials: Image appears uniform? (Y/N) Comments (heel effect etc ?) Artefacts present? (Y/N) Describe Action taken (if applicable) 06/02/25 41 (General X-Ray QA and QC Guideline, 2013) Fig. 4.1: Example record sheet for image uniformity Test

42. Image Quality To ensure adequate image quality from each x-ray unit. Procedure Select 5 patients (mix of male and female) who have had a chest PA / AP x-ray for each x-ray unit. Perform an assessment of image quality using the checklist on Record Sheet . 06/02/25 42

43. Image Quality Record Date of assessment X-ray equipment ID Radiologist performing test Complete checklist Limits Images must be deemed clinically acceptable. If not, the reasons must be investigated. 06/02/25 43 Fig. 5 .0: Aluminium wedge step for image quality test ( Elbakri & Ingleby , 2019 )

44. The images below give an example of how the images are to be scored Examine rows A through E. Starting with row A, record the number of rows in which all 4 discs are clearly visible . A disc is clearly visible if its edges are discernible enough to circumscribe its perimeter. Stop scoring when you first encounter a row where less than 4 discs are clearly visible. The image would be scored as having 3 rows (A, B and C) where all discs are clearly visible. It would have a score of 4 for the number of large discs clearly visible. 06/02/25 44 ( Elbakri & Ingleby , 2019 ) Fig. 5.1: Exposed Image of Image Quality Test

45. QC of Display Monitor and Printer In the digital age, the electronic display monitor is typically the weakest link in the entire imaging chain. Poor spatial resolution or contrast resolution can lead to misdiagnosis, so QC of the display monitor has become extremely important. Every display monitor in an imaging department should be quality-checked at least once each year. Monitors should be cleaned each month with very mild detergent and a soft, non-abrasive cloth. Consistency between all display monitors within a department is essential (Carroll, Q. B., 2023 ) 06/02/25 45 ( Courtesy: FTH, Gombe , 2025) Fig. 6.0: Monitor and Printer set-up

46. QC of Display Monitor and Printer.. AAPM ) has developed a series of test patterns known as the Task Group 18 (TG18) series1. These are not physical test objects , but exist as files which can be loaded on to systems and displayed on the monitor or printed. It is important to know how to access them . (AAPM, 2021) 06/02/25 46

47. Line Pair Gauges Good Resolution Poor Resolution 06/02/25 47 (IAEA, 2023) Fig. 7.0: Line Pair Gauges

48. kVp Accuracy 06/02/25 48 (IAEA , 2023) F ig. 8.0; St-up for kVp Accuracy

49. Measurement of Leakage Radiation 06/02/25 49 (IAEA , 2023) Fig. 9.0: Set-up for Leakage Radiation. A = Static, B = c-arm A B

50. AEC Sensitivity 06/02/25 50 (Wikipedia, 2025 Fig. 10.0: AEC Sensitivity Activation

51. Digital radiography image receptor covered with a lead apron to test dark noise 06/02/25 51 IAEA, 2023 Fig. 11.0: Set-up for Dark Noise in DDR

52. CONCLUSION QC is meant to help you take good radiographs . The best radiographer in the world will still take bad x-rays if the equipment is not working properly. More importantly, the patient will get higher and unnecessary radiation doses , as will the staff. Adequate training for staff and proper documentation of QC procedures are essential for maintaining a robust QC program. 06/02/25 52

53. RECOMMENDATIONS Since QC is a team effort, is recommended that at least one staff member at each facility is identified with responsibility for ensuring quality checks are undertaken at specified times. Federal and state governments should, as a matter of fact through ministries of health multiply efforts to enact laws and principles guiding the full implementation of QA and QC at all levels, including private hospitals and diagnostic centres Hospitals at all levels should be organizing the classes, seminars, continuous medical education programme, Conferences about the quality assurance and quality control tests in regular interval bases. 06/02/25 53

54. Future Directions Recent advancements in software for certain CR , and soon to include DR systems, now allow a single consolidated view of key management metrics from across the department. The ability to drill down allows users to quickly see what needs to be addressed for productivity improvements , from the managers’ office desktop. As such a QC management system can be viewed as the department administrator’s “digital X-ray dashboard” for this intrinsically distributed modality, the opportunity for more precise and frequent key parameter monitoring and intervention now exists . ( Minnigh , T. R. & Gallet , J ., 2009) 06/02/25 54

55. Future Directions 06/02/25 55 Equipment being used and interrogated by the digital dashboard software . Fig 2. Administrative reporting conceptual diagram . ( Minnigh , T. R. & Gallet , J., 2009)

56. TAKE HOME Effect of exposure on image quality 06/02/25 56 High noise Optimum HighExposure (Very Good) S - 1000 S - 100 S - 50 Low Exposure Optimum Exposure High Exposure Sprawls 4096 2048 FIG:9 Receptor exposure

57. 06/02/25 57 THANK YOU

58. References American Association of Physicists in Medicine (AAPM ). Acceptance testing and quality control of photostimulable storage phosphor imaging systems. Report No 93. 2006. College Park, MD. Elbakri , I., & Ingleby , H. (2019). Equipment Quality Control for Digital Radiography . Imaging Physics Cancer Care Manitoba. [email protected] General X-ray QA and QC Guideline. (2013). In Faculty of Clinical Radiology (pp. 1–33). THE ROYAL AUSTRALIAN AND NEW ZEALAND COLLEGE OF RADIOLOGISTS. Website: www.ranzcr.edu.au. IAEA. (2023). Handbook of Basic Quality Control Tests for Diagnostic Radiology (Vol. 47). IAEA HUMAN HEALTH SERIES PUBLICATIONS. http:// www.iaea.org/Publications/index.html . ( Minnigh , T. R. & Gallet , J., 2009) . Maintaining Quality Control Using a Radiological Digital X-ray Dashboard. Journal of Digital Imaging, Correspondence to: Jacqueline Gallet , Carestream Health , Inc , 150 Verona St, Rochester, NY 14608, USA. 06/02/25 58

59. References Ngoye , W. M., Motto, J. A., & W. E. Muhogora , W. E. (2019). Challenges facing the implementation of quality control programme by radiographers in Tanzania. BRAZILIAN JOURNAL OF RADIATION SCIENCES , 07 (2019) 01-14 (01–14), 1–14 . Ongoing quality control in digital radiography: Report of AAPM Imaging Physics Committee Task Group 151. American Association of Physicists in Medicine Report No. 151. 2015, [email protected] o. SAID , S., GOSHU, B. S., TAJU, E., & TOLAWAK, B. T. (2021). QUALITY ASSURANCE AND CONTROL OF CONVENTIONAL X-RAY MACHINES AT DIFFERENT HOSPITALS AND CLINICS IN EASTERN ETHIOPIA. Romanian Journal of Biophysics , 31, No. 2, P. 79–87, 2021 (2), 79–87. ( Steffensen , C., et al 2020). Optimisation of radiographic acquisition parameters for direct digital radiography: A systematic review. Corresponding author. Philips Australia and New Zealand, North Ryde , Australia. www.elsevier.com/locate/radi. © 2020 The College of Radiographers. Published by Elsevier Ltd. All rights reserved. WORLD HEALTH ORGANIZATION. (1982). Quality Assurance in Diagnostic Radiology, . WHO, Geneva . 06/02/25 59