User Manual Part 2

118
2852 A EN 20070205
DRYSTAR AXYS
Performing the Weekly QC tests for mammography
application (DT 2 Mammo) (optional)
Spatial Resolution, Artifact Test and Low Contrast Visibility
To identify artifacts and verify spatial resolution you must perform the follow-
ing test weekly or as needed for troubleshooting image quality problems.
Procedure
1 First, print out the QC mammography test image. Refer to “Performing the daily
QC test for mammography application (DT 2 Mammo) (optional)” on page 116.
2 Check the QC test image visually for artifacts: no significant disturbing artifacts
should be visible.
3 Check the spatial resolution.
The test film also shows three squares which each contains an oval. These 3 ovals con-
tain 3 groups, each having 5 dots. All five dots of each group must be visible with a
magnifying glass. The smallest cluster of 5 dots is only visible if the viewing conditions
are good.
4 Check the Low Contrast Visibility at both the high (100 / 95%) and low end
(0 / 5%) of the density scale. You should be able to see the circle in the square
(refer to item 1 on the “QC test image for mammography applications
(DT 2 Mammo) (optional)” on page 107) and the upper circle (refer to item 2
on the “QC test image for mammography applications (DT 2 Mammo)
(optional)” on page 107).
WARNING: Good viewing conditions are important for the correct
interpretation of both diagnostic and test images. Make sure that the light
box intensity (luminance) is 3000 and 6000 cd/m² (4500 and 6500 °K)
for mammography. Use a magnifying glass and use shutters to collimate.
Make sure the ambient light is low.