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7.2. WEEKLY TESTS7.2.1. Monitor quality control7.2.1.1. ScopeThe accuracy of the diagnosis and the efficiency of the radiologist are influenced by the conditions underwhich the mammograms are viewed. Viewing conditions can affect the diagnostic potential of even the best qualitymammograms. These conditions are determined by: the luminance and calibration of the monitors used for softcopy interpretation; the luminance of the viewboxes used for hard copy interpretation; the ambient roomillumination or the amount of light falling on the monitor and/or viewbox surface; and the quality of the masking offilms on the viewbox.Contrast is extremely important in the mammography image and is degraded by extraneous light.Consequently, monitors and viewboxes should be positioned to avoid incident light from windows, other monitorsor viewboxes, and other sources of bright light, either direct or reflected. General lighting in the room should bediffuse and at a low level.The monitor QC test should be performed on all primary medical display devices used to interpret digitalmammograms (radiologist workstations), and on all secondary display devices. Secondary display devices includethe monitor(s) attached to the acquisition workstation used to verify patient image quality and/or the monitor usedto manipulate and print the images (radiographer workstations). If the interpreting physicians provide finalinterpretations from hard copy only, the tests will only apply to the secondary display devices.A set of tests for evaluating the monitors is provided here. It should be noted that test procedures have alsobeen developed by manufacturers or as part of regional or national QC programmes [46], and these may provide asuitable (and possibly simpler) alternative to these tests.— Objective: To ensure that images on the acquisition workstation monitor and on the monitor used forinterpretation are displayed at adequate contrast and resolution.— Frequency: Weekly and after any service or maintenance of the workstations.7.2.1.2. Instrumentation(1) Modified TG18-QC (or SMPTE) test pattern with DICOM header to match processed images produced by eachacquisition system used at the site. This test pattern may be obtained from the manufacturer of the digitalmammography unit or the workstation. The images can be loaded as patient images in the same manner that priorpatient images are loaded for reviewing on the system. This could be from the PACS or from a CD provided bythe medical physicist, for example. These images should be stored on the system and should not be deleted.(2) Patient images.7.2.1.3. Methodology(a)Evaluating the monitors using test patterns(1) Before conducting this test, review the acceptable viewing conditions worksheet (see Chart 15 in Annex II)posted by the medical physicist in the room where the radiologist workstation is located.(2) Ensure that the lighting conditions and room configuration match those described on the worksheet. Ensurethat no sources of bright light are present in the room or are being reflected from viewboxes and/or monitorsurfaces.(3) If differences exist between the acceptable configuration and the current configuration, adjust the roomappropriately to ensure that viewing conditions are acceptable (i.e. turn off lights that should be off, closecurtains, etc.).(4) For each primary and secondary display device, view the modified TG18-QC pattern on each monitor used todisplay digital mammograms. For primary display devices, typically two monitors are used to display digitalmammograms (see note below).50
FIG. 19. Modified TG18-QC pattern with vertical greyscale bars (A), luminance patches (B) and lettering (C) indicated.(5) Display the test pattern image in the normal manner (as would be done for a clinical image). Ensure that thewindow width is set to maximum and that the window level is set to half the maximum. Use the same windowwidth and window level settings each time.(6) Evaluate subjectively the following aspects of the image (Fig. 19):— General image quality;— Evidence of smearing;— Evidence of other artefacts.(7) Confirm that the vertical greyscale ramps that go from black to white along the sides of the pattern (regionsmarked ‘A’ in Fig. 19) demonstrate a smooth and continuous variation in brightness.(8) Geometric distortion:— Check that the lines on the pattern are straight.— Check that the image is centred on the screen.— Check that the boxes appear square.(9) Luminance:— The luminance squares frame the central portion of the pattern (regions marked ‘B’ in Fig. 19). Check thateach is a distinct shade of grey, different from all other patches.— Examine the 0–5% and the 95–100% contrast squares (Fig. 20) located at the ends of the luminance squareframe. Record if the patches are visible on the relevant monitor QC charts for radiologist (primary) andacquisition (secondary) display devices (Charts 5 and 6 in Annex I, respectively), as applicable.51
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X raysdel matrixCs scintillatorLine
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QUALITY ASSURANCE PROGRAMMEFOR DIGI
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IAEA HUMAN HEALTH SERIES No. 17QUAL
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FOREWORDThe application of radiatio
Page 14: An effective QA programme is necess
Page 17 and 18: The Integrating the Healthcare Ente
Page 21 and 22: technology. Systems containing othe
Page 23 and 24: X raysTop electrodea-Se layerCharge
Page 25 and 26: dose received by inhomogeneous real
Page 27 and 28: 2.3.8.1. Soft copy displayFlat pane
Page 29 and 30: 3. ELEMENTS OF HIGH QUALITY MAMMOGR
Page 31: — The ability to mask edges of ma
Page 34 and 35: Disposal orsaleNew facility(start h
Page 36 and 37: 4.2.3. Radiographer (mammography te
Page 38 and 39: 5.2.2. Electronic versus geometric
Page 40 and 41: To allow full utilization of the di
Page 42 and 43: 5.7. ARTEFACTSWhile the incidence o
Page 44 and 45: FIG. 10. Detector crystallization.
Page 46 and 47: FIG. 13. A more subtle example of a
Page 48 and 49: FIG. 16. An example of poor collima
Page 51 and 52: 7. RADIOGRAPHER’S QUALITY CONTROL
Page 53 and 54: 7.1. DAILY TESTS7.1.1. Monitor insp
Page 55 and 56: 7.1.3. Daily flat field phantom ima
Page 57 and 58: 7.1.4. Visual inspection for artefa
Page 59 and 60: 7.1.5. Laser printer sensitometry7.
Page 61: 7.1.6. Image plate erasure (CR syst
Page 65 and 66: FIG. 21. Radiologist workstation wi
Page 67 and 68: 7.2.1.6. Time frame for corrective
Page 69 and 70: 7.2.3. Weekly quality control test
Page 71 and 72: Note: It is not necessary to view t
Page 73 and 74: TABLE 7. TOLERANCES FOR IMAGING WEE
Page 75 and 76: 7.2.4.4. Interpretation of results
Page 77 and 78: 7.3.1.5. Recommendations and correc
Page 79 and 80: artefacts are typically best seen w
Page 81 and 82: 7.3.3.5. Recommendations and correc
Page 83 and 84: 7.4.1.3. Methodology(1) Annotate th
Page 85 and 86: RECORD OF DIGITAL MAMMOGRAPHY REPEA
Page 87 and 88: (3) Including examinations of at le
Page 89 and 90: 7.5. SEMI-ANNUAL TESTS7.5.1. Comput
Page 91 and 92: 8. MEDICAL PHYSICIST’S QUALITY CO
Page 93 and 94: 8.1. NOTE ON IMAGE NAMING CONVENTIO
Page 95 and 96: (16) On any randomly selected patie
Page 97 and 98: FIG. 30. Positioning of bathroom sc
Page 99 and 100: (6) The target, filter, kV, grid, d
Page 101 and 102: (2) Stack the 20 and 25 mm PMMA sla
Page 103 and 104: TABLE 13. ACCEPTABLE AND ACHIEVABLE
Page 105 and 106: 8.5. DETECTOR PERFORMANCE8.5.1. Bas
Page 107 and 108: 8.5.2. Detector response and noise8
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Breast supportPMMA slabBreast suppo
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(10) Place the thinner test object
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8.6. EVALUATION OF SYSTEM RESOLUTIO
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TABLE 17. ACCEPTABLE FREQUENCIES AT
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8.7. X RAY EQUIPMENT CHARACTERISTIC
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8.7.2. Incident air kerma at the en
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8.8. DOSIMETRY8.8.1. Mean glandular
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TABLE 21. ACCEPTABLE AND ACHIEVABLE
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FIG. 34. Suggested layout for ruler
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8.10. IMAGE DISPLAY QUALITYThe accu
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FIG. 35. Modified TG18-QC test patt
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8.10.1.5. Interpretation of results
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8.10.2. Monitor luminance response
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TABLE 22. MONITOR PERFORMANCE TOLER
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FIG. 38. Measurement of illuminatio
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8.11. LASER PRINTER8.11.1. Laser pr
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8.11.1.5. Recommendations and corre
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8.12.1.4. Interpretation of results
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iopsies are performed, a sink is of
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Appendix IISPECIFICATIONS OF TEST E
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TABLE 24. SPECIFICATIONS OF TEST EQ
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FIG. 40. Image acquired with a unif
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FIG. 43. The left hand image is par
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FIG. 45. A TG18-QC test pattern dis
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[29] ALSAGER, A., YOUNG, K.C., ODUK
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Annex IRADIOGRAPHER DATA COLLECTION
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Chart 2 — DIGITAL MAMMOGRAPHY (DM
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Chart 4 LASER PRINTER SENSITOMETRY
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Chart 6 — WEEKLY DISPLAY MONITOR
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Chart 7(b) WEEKLY QC TEST OBJECT:
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Chart 9 — SAFETY AND FUNCTION CHE
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Chart 11 — LASER PRINTER ARTEFACT
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Chart 13(a) — RECORD OF DIGITAL M
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Chart 14 — CR PLATE SENSITIVITY M
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Annex IIITHE MAMMOGRAPHY EXTRACTThe
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GLOSSARYair kerma. The energy depos
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image quality. The overall merit of
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CONTRIBUTORS TO DRAFTING AND REVIEW
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