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(b)Testing of density control (if applicable) and/or dose selection modeSome digital units and all CR systems are used with X ray units that have a variable ‘density control’. Indigital mammography, the purpose of the density control is primarily to allow control of the image noise level.Small changes are not normally perceptible. It is desirable that use of the density control will allow the radiationdose to be increased by 25–100%, and similarly decreased by 25–50%, from the ‘0’ or ‘normal’ position in severalsteps.(1) Place a total thickness of 45 mm of PMMA (plus the spacer) on the breast support as described above.(2) For CR systems, to test the +/– density control, make exposures using the AEC. Use two density settingsbelow the ‘0’ or ‘normal’ position, one at ‘0’ and two above it, with each setting attempting to give about a±25% variation in mAs. A total of five exposures is required for this test.(3) Record the density setting and the resulting mAs used to image the PMMA each time.(4) For DX systems, make exposures in all applicable dose modes and determine their effect on the exposurefactors.(5) Record the dose mode setting and the resulting mAs used to image the PMMA each time.(6) It is not necessary to process the image after each exposure — the digital image itself will not be used. Theobjective is to ensure that the density setting adjusts the mAs in a reasonable manner.(7) Provide a copy of the radiographer baselines and summary chart (Chart 3 in Annex II) to the radiographer atthe facility, to be used as a baseline for the radiographer’s tests.8.4.2.4. Interpretation of results and conclusionsTolerances:(a)Thickness behaviour(1) The SDNR values for images of 20, 45 and 70 mm of PMMA should exceed the acceptable values given inTable 13 for the aluminium contrast object and those given in Table 14 for the PMMA contrast object.(2) SDNR performance must be achieved within the current dose limitations (see Table 21).(3) For contact mode mammography, exposure time should not exceed 2.0 s for 45 mm and 4.0 s for 70 mm ofPMMA. This does not apply to scanning systems where the dwell time at any location is much shorter thanthe time taken to image the entire breast.For each thickness of PMMA, acceptable and achievable SDNR values are provided in Tables 13 and 14.These values must be regarded as provisional at this stage, and updates, as available, will be provided in the futureat http://humanhealth.iaea.org. Regardless of what the ultimate SDNR values are, it is expected that a DX systemshould be able to match the achievable SDNR using a dose that is well within the current dose tolerances (seeTable 21). Some CR systems may not be able to reach the achievable SDNR values without exceeding these dosetolerances. In general, greater importance should be given to achieving adequate image quality than to lowering thedose.Caution should be exercised in interpreting the results of SDNR measurements. For all systems, it is expectedthat a higher SDNR corresponds to better image quality, provided the image sharpness is unchanged. Thus anincrease in radiation exposure will reduce quantum noise, resulting in an increase in SDNR and better image qualityif MTF is unchanged. However, an increase in SDNR may be due to a deteriorating MTF, which would result in anoverall reduction in image quality. Thus SDNR is not on its own a reliable measure of image quality but is an easyto measure parameter that is a sensitive indicator of changes that relate to image quality. Therefore any change inSDNR needs to be investigated to understand its cause.90
TABLE 13. ACCEPTABLE AND ACHIEVABLE VALUES FOR SDNR USED FOR AEC EVALUATION:0.2 mm THICK ALUMINIUM CONTRAST OBJECT a PMMA thickness (mm)20 45 70System Acceptable Achievable Acceptable Achievable Acceptable AchievableAgfa CR (MM3.0) 13.8 20.1 12.4 18.0 10.8 15.8Agfa CR (HM5.0) 10.2 15.0 8.9 13.0 8.0 11.7Fuji CR 9.8 14.2 8.8 12.8 7.7 11.2Fuji Amulet 6.1 8.7 5.5 7.8 4.8 6.8GE 2000D 8.9 12.9 7.9 11.5 6.9 10.0GE DS 8.9 12.9 7.9 11.5 6.9 10.0GE Essential 12.7 18.4 11.3 16.5 9.9 14.4Hologic Selenia 4.8 7.0 4.3 6.3 3.8 5.5IMS Giotto 7.8 11.3 7.0 10.1 6.1 8.8Carestream CR (M2 plate) 9.5 13.9 8.5 12.5 7.5 10.9Carestream CR (M3 plate) 11.7 17.0 10.2 14.8 9.1 13.3Konica CR(RP-6M)(RP-7M)(CP-1M)11.48.76.616.612.89.510.27.85.914.811.48.58.96.85.113.010.07.5Planmed Nuance 6.3 9.1 5.0 7.2 4.3 6.2Sectra D40 3.6 5.3 3.2 4.7 2.8 4.1Sectra L30 3.6 5.3 3.2 4.7 2.8 4.1Siemens Novation DR 5.1 7.4 4.5 6.6 4.0 5.8Siemens Inspiration 4.4 6.3 3.9 5.7 3.4 5.0aSource: NHSBSP technical evaluations published on www.cancer.screening.nhs.ukTABLE 14. ACCEPTABLE AND ACHIEVABLE VALUES FOR SDNR USED FOR AEC EVALUATION:1 mm THICK PMMA CONTRAST OBJECTPMMA thickness (mm)20 45 70System Acceptable Achievable Acceptable Achievable Acceptable AchievableAgfa CR (MM3.0) 5.8 8.7 5.1 7.8 4.3 6.7Agfa CR (HM5.0) aFuji CR 3.9 6.5 3.4 5.8 2.9 4.8Fuji Amulet 2.1 3.4 1.8 2.9 1.5 2.5GE 2000D 3.4 5.61 3.0 5.0 2.5 4.191
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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
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 and 62: 7.1.6. Image plate erasure (CR syst
Page 63 and 64: FIG. 19. Modified TG18-QC pattern w
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: (2) Stack the 20 and 25 mm PMMA sla
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 and 130: FIG. 34. Suggested layout for ruler
Page 131 and 132: 8.10. IMAGE DISPLAY QUALITYThe accu
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
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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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