User Manual

164
2900H EN 20071108Advanced operation (Key-operator mode)
DRYSTAR 5500/5503 REFERENCE MANUAL
Performing the Annual QC tests for mammography application
(DT 2 Mammo) (optional)
Geometric Consistency Test
To be able to notice fluctuations in image size and aspect ratio, you must
perform this procedure once a year.
1 First, perform the daily test.
2 Measure the distances A and B of the geometric square on the QC
mammography test image. Refer to ‘Establishing the image geometry reference
values for mammography application (DT 2 Mammo) (optional)’ on page 158.
3 Record these values as measured distances A and B on Chart 4 (‘Drystar 5500/
5503 Geometric Consistency Control Chart’). Refer to ‘Charts for
mammography QC (optional)’ on page 247.
4 Compare the measured A and B dimensions with the reference dimension
values, A
ref
and B
ref
on Chart 4 (‘Drystar 5500/5503 Geometric Consistency
Control Chart’). Refer to ‘Charts for mammography QC (optional)’ on page 247.
The differences between the measured dimensions of A and B and the reference
values A
ref and B ref should be less than or equal to 1.0%.
5 Check for image distortion.
6 Calculate the aspect ratio by dividing A by B.
The result must be 1 +/- 0.01
Make sure to measure distance A from the left edge of the left line to the
right edge of the right line and distance B from the upper edge of the
upper line to the lower edge of the lower line.
We strongly recommend using a 30 cm (12-inch) machinist scale with 0.5
mm divisions (1/64 inch).
If the image size or distortion values are outside of limits, contact Agfa
service to resolve the problem.