iaea human health series publications - SEDIM

(6) The target, filter, kV, grid, density control position and operation mode for imaging the 45 mm test objectshould be entered into Chart 3 in Annex II.(7) If patient images are interpreted in soft copy, view the ‘for presentation’ image of the flat field phantom takenas per the steps above on the radiologist display workstation. Window width choice should be based on whatis appropriate for or typical of breast images or a phantom with breast-like features. The level should be set sothat the background of the phantom is dark grey and the 1 mm thick contrast disc is light grey, but not purewhite. There should be noise visible in both areas (indicating that those regions are not saturated or clipped).Record the window width and window level on the radiographer baselines and summary chart (Chart 3 inAnnex II).(8) With the same window width and window level as used above, evaluate the entire image for overallappearance and for artefacts. Examine the entire image for broad area artefacts such as non-uniformities,blotches and streaks, and for detailed artefacts such as black or white pixels, clusters of pixels, lines or specks.Broad area artefacts are typically best seen while observing the phantom image as a whole, not piecewise.Detailed artefacts are typically best seen while observing the phantom image at full spatial resolution, whereone pixel on the display matches one pixel in the image, or even in magnified form (with a magnificationgreater than 1.0).Note: It is not necessary to view the image on all available soft copy monitors. This is a test of imageacquisition, not display. Monitor performance is assessed separately.(9) If patient images are interpreted on hard copy, print the image using the window width and window level thatwould be used for a patient image. Record the window width and window level used on the radiographerbaselines and summary chart (Chart 3 in Annex II). Record whether the phantom image was evaluated onhard copy (H), soft copy (S) or both (B).(10) View the image on a mammographic quality viewbox, preferably the one used by the radiologist. Evaluate theentire phantom image for artefacts, using the method described in step 8. (For CR systems, see alsoSection 7.1.4.3.)8.4.1.4. Interpretation of results(1) There should be no blotches or regions of altered texture appearance.(2) There should be no observable lines or structural artefacts.(3) There should be no ‘bright’ or ‘dark’ pixels evident.8.4.1.5. Recommendations and corrective actionIf any artefacts are visible that might mimic or obscure anatomic information, or if any patterns are seen, arecalibration or flat fielding of the digital detector may be needed for DX systems. The compression plate and allaccessible surfaces that are in the imaging field should be cleaned to remove any debris or extraneous material.After this has been done, repeat the test. If artefacts persist, contact the authorized service representative.8.4.1.6. Time frame for corrective actionImmediately: If this test fails, do not image patients until corrective action has been taken.87