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Performing the Weekly QC tests
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.
Good viewing conditions are important for the correct interpretation of
both diagnostic and test images. Make sure that the lightbox intensity
(luminance) is between 2000 and 4000 cd/m² (4500 and 6500 °K). Use a
magnifying glass and use shutters to collimate. Make sure the ambient
light is low.
First, print out the QC test image. Refer to
1
page 57.
Check the QC test image visually for artifacts: no significant disturbing artifacts
2
should be visible.
Check the spatial resolution.
3
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.
Check the Low Contrast Visibility at both the high (100 / 95%) and low end
4
(0 / 5%) of the density scale. You should be able to see the circle in the square
(refer to item 1 on the
item 2 on the
'QC test image'
Record these values on the Drystar 4500 Chart 3 (Drystar 4500 Artifacts and
5
Spatial Resolution Control Chart).
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 4500
can be used for any further clinical imaging.
Refer to
page
191
schedule'
assistance.
2801E EN 20050215
'QC test image'
on page 54).
'Maintaining image quality and resolving image quality problems'
of the Drystar 4500 Reference manual and
on page 61, or call your local Agfa service organization for
'Performing the daily QC test'
on page 54) and the upper circle (refer to
Advanced operation (key-operator mode)
D
4500 U
RYSTAR
SER MANUAL
on
on
'Preventive maintenance
59
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