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(14) Examine the digital image and measure the distance from the chest wall edge of the compression plate (the ‘0’mark on the ruler or edge of coin) to the active edge of the detector using the ruler taped to the compressionpaddle.(15) Enter the results on Chart 12 in Annex II.(16) Repeat steps 2 through 15 for each image receptor size. If the unit has multiple positions for the small paddlethat result in different collimator blade positions (i.e. left and right, to allow better positioning for MLOviews), these should be evaluated.(17) Ensure that the detector is fully irradiated, that is, that the collimation does not block the edges of the activefield of the detector.(18) Repeat with the magnification table, if applicable.8.9.1.4. Interpretation of results and conclusionsTolerances:(1) Missing tissue at the chest wall:— Achievable: ≤5 mm;— Acceptable: ≤7 mm.(2) Coincidence between active detector edge and radiation field:— Achievable: The beam completely irradiates the active area of the detector but does not extend beyond thebreast support.— Acceptable: The beam completely irradiates the active area of the detector and does not extend beyond thebreast support except at the chest wall, where it can extend beyond the breast support to a maximum of 5mm. 29(3) The patient contact chest wall edge of the compression paddle should not extend beyond the chest wall edgeof the image receptor by more than 5 mm, and the chest wall edge of the paddle must not be visible in theimage.8.9.1.5. Recommendations and corrective action(1) If the missing tissue at the chest wall is greater than 7 mm or the alignment of the compression paddle and theX ray field with the active detector area does not meet the acceptable tolerances noted above, service supportis required.8.9.1.6. Time frame for corrective actionCorrective action should be taken within a period of 30 days.29Ideally, if appropriate collimation were available, the X ray field would only irradiate the entire area of the breast that lies onthe image receptor. At the time of writing such a feature is not available.118
8.10. IMAGE DISPLAY QUALITYThe accuracy of the diagnosis and the efficiency of the radiologist are influenced by the conditions underwhich the mammograms are viewed. Viewing conditions may 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 effective masking of films onthe viewbox.Contrast is extremely important in the mammography image and is degraded by extraneous light.Consequently, monitors and viewboxes should be positioned so as to avoid light from windows, other monitors orviewboxes, and other sources of bright light, either direct or reflected. General lighting in the room should bediffuse and at a low level.Ambient room lighting is as important as monitor and viewbox luminance for the radiographic readingenvironment. Ambient illumination should be low to improve low contrast object detectability. Glare falling uponthe monitor face and being reflected into the eyes of the radiologist should be as low as possible. In the past, it wasrecommended that the ambient room illumination be no greater than 10 lx and ideally less than 5 lx. Currently,levels between 20 and 40 lx are considered to be more reasonable [69]. Furthermore, it recently has been suggestedthat there is a benefit in terms of reduced eyestrain if room lighting levels are somewhat higher and room finishesare chosen such that light the brightness of the reflected from the walls of the room in the radiologist’s line of sightis similar to the average brightness emanating from the monitors when a grey image (~30% of full imagebrightness) is displayed. However, again it must be ensured that as little of this light as possible falls upon, and isreflected from, the monitor face. Under such conditions, ambient room lighting up to 75–100 lx may be acceptable.It should be confirmed that the luminance of light reflected off the monitor screen toward the eyes of the radiologistdue to ambient light (e.g. tested with the monitor turned off) is considerably less than 1/250 of the maximumluminance provided by full image brightness. This ensures that the reflection of ambient light does not have anappreciable effect on the contrast ratio of the display.Radiologists should experiment with the lighting conditions while viewing the TG18-QC test patterns andalso while viewing clinical mammograms. Once the illumination conditions for reading have been established, theyshould be kept constant, and monitors should be set up for those conditions [70].Illuminance is measured by placing the detector–filter–diffuser combination at the viewbox or monitorsurface, pointed away from and parallel to the surface. These measurements can be influenced by the individualtaking the measurement, especially if he or she stands between a source of light and the detector–filter–diffusercombination, or wears reflective clothing.Some vendors provide software packages and procedures for evaluation of monitor performance. Suchpackages may be convenient for carrying out the assessment and tracking of display performance. If such packagesare used, however, it should be ensured that all the functionality discussed below is assessed.119
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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
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An effective QA programme is necess
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The Integrating the Healthcare Ente
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technology. Systems containing othe
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X raysTop electrodea-Se layerCharge
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dose received by inhomogeneous real
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2.3.8.1. Soft copy displayFlat pane
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3. ELEMENTS OF HIGH QUALITY MAMMOGR
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— The ability to mask edges of ma
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Disposal orsaleNew facility(start h
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4.2.3. Radiographer (mammography te
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5.2.2. Electronic versus geometric
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To allow full utilization of the di
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5.7. ARTEFACTSWhile the incidence o
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FIG. 10. Detector crystallization.
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FIG. 13. A more subtle example of a
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FIG. 16. An example of poor collima
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7. RADIOGRAPHER’S QUALITY CONTROL
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7.1. DAILY TESTS7.1.1. Monitor insp
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7.1.3. Daily flat field phantom ima
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7.1.4. Visual inspection for artefa
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7.1.5. Laser printer sensitometry7.
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7.1.6. Image plate erasure (CR syst
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FIG. 19. Modified TG18-QC pattern w
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FIG. 21. Radiologist workstation wi
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7.2.1.6. Time frame for corrective
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7.2.3. Weekly quality control test
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Note: It is not necessary to view t
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TABLE 7. TOLERANCES FOR IMAGING WEE
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7.2.4.4. Interpretation of results
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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
Page 109 and 110: the service engineer responsible fo
Page 111 and 112: (13) Using the annotation tool on t
Page 113 and 114: Breast supportPMMA slabBreast suppo
Page 115 and 116: (10) Place the thinner test object
Page 117 and 118: 8.6. EVALUATION OF SYSTEM RESOLUTIO
Page 119 and 120: TABLE 17. ACCEPTABLE FREQUENCIES AT
Page 121 and 122: 8.7. X RAY EQUIPMENT CHARACTERISTIC
Page 123 and 124: 8.7.2. Incident air kerma at the en
Page 125 and 126: 8.8. DOSIMETRY8.8.1. Mean glandular
Page 127 and 128: TABLE 21. ACCEPTABLE AND ACHIEVABLE
Page 129: FIG. 34. Suggested layout for ruler
Page 133 and 134: FIG. 35. Modified TG18-QC test patt
Page 135 and 136: 8.10.1.5. Interpretation of results
Page 137 and 138: 8.10.2. Monitor luminance response
Page 139 and 140: TABLE 22. MONITOR PERFORMANCE TOLER
Page 141 and 142: FIG. 38. Measurement of illuminatio
Page 143 and 144: 8.11. LASER PRINTER8.11.1. Laser pr
Page 145 and 146: 8.11.1.5. Recommendations and corre
Page 147: 8.12.1.4. Interpretation of results
Page 150 and 151: iopsies are performed, a sink is of
Page 152 and 153: Appendix IISPECIFICATIONS OF TEST E
Page 154 and 155: TABLE 24. SPECIFICATIONS OF TEST EQ
Page 156 and 157: FIG. 40. Image acquired with a unif
Page 158 and 159: FIG. 43. The left hand image is par
Page 160 and 161: FIG. 45. A TG18-QC test pattern dis
Page 162 and 163: [29] ALSAGER, A., YOUNG, K.C., ODUK
Page 165 and 166: Annex IRADIOGRAPHER DATA COLLECTION
Page 167 and 168: Chart 2 — DIGITAL MAMMOGRAPHY (DM
Page 169 and 170: Chart 4 LASER PRINTER SENSITOMETRY
Page 171 and 172: Chart 6 — WEEKLY DISPLAY MONITOR
Page 173 and 174: Chart 7(b) WEEKLY QC TEST OBJECT:
Page 175 and 176: Chart 9 — SAFETY AND FUNCTION CHE
Page 177 and 178: Chart 11 — LASER PRINTER ARTEFACT
Page 179 and 180: 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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