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(6) Measure the luminance at each point. Record the values on the data collection sheet.(7) Repeat the tests for all viewboxes used for interpreting printed mammograms and for the viewboxes used bythe radiographer to check the printed mammograms during the examination.8.10.3.4. Calculation procedureFor a single viewbox or single panel in a viewbox bank, select the central luminance value (L c ) and the mostdiscrepant reading recorded (L disc ). Apply the following expression:Maximum deviation (%) = 100 LdiscL- Lcc(10)For viewboxes consisting of several panels or for viewboxes adjacent to one another, the maximum deviationbetween the central luminance value of any panel, L cx , and the calculated mean of the central luminance of allpanels, L mean , is found by applying the following expression:Maximum deviation (%) = 100 Lcx- LLmeanmean(11)8.10.3.5. Interpretation of results and conclusions(1) Luminance: Acceptable — maximum luminance for each panel: greater than 3000 cd/m 2 (nit). 32(2) Luminance uniformity: Acceptable — less than 30% maximum deviation for different areas of a singleviewbox or single panel in a viewbox bank, and less than 15% maximum deviation between central luminanceof panels in a viewbox bank or between adjacent viewboxes.(3) Room illuminance: Acceptable — 20–40 lx.(4) A convenient and effective method for masking viewboxes to exclude bright light around the edges ofmammograms should be available.8.10.3.6. Recommendations and corrective actions(1) If the ambient illumination conditions are greater than the recommended values, contact the person in chargeof the maintenance service to modify the illumination of the area.(2) If the luminance level of the viewbox is less than 3000 cd/m 2 , or if the luminance or the colour of light of anindividual lamp appears significantly different from those of others in the same viewbox, all lamps in theviewbox should be replaced.Note: Tri phosphor or quad phosphor tubes are recommended because of their increased luminance output. Ifpossible, all tubes in a viewbox or viewbox bank should be replaced at the same time to ensureuniformity. It is advisable to purchase fluorescent tubes in one batch to ensure that the colour matchesbetween the tubes.32If the viewbox is to be used only for viewing laser printed hard copy film, a luminance of less than 3000 cd/m 2 is probablyacceptable.130
8.11. LASER PRINTER8.11.1. Laser printer evaluation and baseline values8.11.1.1. ScopeThis procedure should be performed on all printers used to print digital mammograms. Where possible,printing should be conducted directly from the acquisition workstation or radiologist review station to evaluate theintegrity of the entire printing chain. It should be noted that in some facilities, the same printer is used to print outimages from different types of examination (breast, chest, bones, ultrasound, CT, MRI). Each examination type ormodality has a defined LUT. Therefore, the correct LUT has to be selected before mammograms or the different testpatterns are printed. For this reason, it is important to ensure that the appropriate LUT is automatically selected bythe printer when the images are sent to print from the mammography system.— Objective: To ensure that high quality, uniform, artefact free images are produced; to determine the normaloperating levels to be used by the radiographer for their laser printer sensitometry test.— Minimum frequency: Initially and then annually and after service to the printer or modifications to the imagedisplay and/or printing software.8.11.1.2. Instrumentation(1) Unit specific TG18-QC pattern (see Fig. 35) with DICOM header and image size exactly matching themodality produced by each acquisition system or a greyscale step wedge.(2) Uniform test pattern such as TG18-UNL80.(3) Densitometer.(4) Magnifying lens (4× to 5× magnification).(5) Transparent ruler showing millimetres.(6) Radiologist viewbox.8.11.1.3. Methodology(1) Turn on the radiologist viewbox and allow it to warm up for 20 minutes to allow the light output from thelamps to stabilize.(2) If possible, at the workstation used for printing, using the image annotation tool, place a vertical and ahorizontal line or ruler, each 5 cm in length, on the TG18-QC image near the existing rulers on the pattern.(3) Print the annotated TG18-QC pattern from the workstation, ensuring that the window width is set to 100% offull scale and that the window level is set to 50% of full scale.(4) Place the film on the radiologist viewbox for the visual verification steps.(5) Verify that all density steps are visible. Measure the optical density at each step and record the results on thelaser printer evaluation chart (Chart 17 in Annex II). The luminance response as observed contrast/jnddifference values is plotted and the luminance ratio (dynamic range) is calculated automatically on Chart 17in Annex II.(6) Verify that the low contrast squares are visible in the corners of the density steps, and record compliance onChart 17 in Annex II.(7) Verify that the 0–5% and 95–100% low contrast targets are visible.(8) Using the magnifying lens, verify that the line pair patterns are visible in both directions for half Nyquist andfull Nyquist frequencies at high and low contrast. Record the outcome on Chart 17 in Annex II.(9) Display the uniform image provided (e.g. TG18-UNL80). Set the window width to 100% of full scale and thewindow level to give a printed optical density between 1.5 and 2.0. Print the image. Record the window widthand window level settings, and use the same settings each time the test is performed.(10) Measure the optical density in the middle of the resulting uniform film and record this value on Chart 17 inAnnex II.(11) Examine the uniform film image for artefacts.131
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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
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artefacts are typically best seen w
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7.3.3.5. Recommendations and correc
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7.4.1.3. Methodology(1) Annotate th
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RECORD OF DIGITAL MAMMOGRAPHY REPEA
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(3) Including examinations of at le
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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 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: FIG. 38. Measurement of illuminatio
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
Page 181 and 182: Chart 14 — CR PLATE SENSITIVITY M
Page 183 and 184: Annex IIITHE MAMMOGRAPHY EXTRACTThe
Page 185 and 186: GLOSSARYair kerma. The energy depos
Page 187 and 188: image quality. The overall merit of
Page 189: CONTRIBUTORS TO DRAFTING AND REVIEW
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