User Manual

Table Of Contents
163
2900H EN 20071108 Advanced operation (Key-operator mode)
DRYSTAR 5500/5503 REFERENCE MANUAL
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
following test weekly or as needed for troubleshooting image quality
problems.
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 161.
2 Check the 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
contain 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 mammography test image’ on page 158) and the
upper circle (refer to item 2 on the ‘QC mammography test image on page 158).
5 Record these values on Chart 3 (‘Drystar 5500/5503 Artifacts and Spatial
Resolution Control Chart’). Refer to ‘Charts for mammography QC (optional)
on page 247.
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.
In case of significant artifacts, insufficient spatial resolution or failure of
any other recommended QC tests, the cause of the problem must be
identified, and corrective action must be taken before the Drystar 5500
can be used for any further clinical imaging.
Refer to ‘Maintaining image quality and resolving Image quality problems’ on
page 220 and ‘Preventive maintenance schedule’ on page 186 or call your local
Agfa service organization for assistance.