GE Senographe DS Manual page 1694

GE Healthcare
Revision 1
Job Card CAL A041 - Bad Pixel Calibration
6-2 Procedure
! Notice:
Before starting the calibration, check that the Conditioner temperature has stabilized at 26°C ±2°C.
1. Remove the Bucky and remove the compression paddle.
2. Launch the Service Desktop (see
3. From the Service Desktop, click the Calibration button
Summary display, click again on Detector.
4. Select Bad pixel and Start; follow the on-screen instructions to run the calibration.
5. The IDC automatically acquires 16 offset images (no X-rays) and computes results.
6. When the offset acquisitions and calculations are complete, you are requested to install the Flat Field
phantom (25 mm of acrylic) on the Image Detector.
7. The parameters are automatically set to Rh/Rh; 30kV, 11mAs. Take one acquisition for Image Qual-
ity. The IDC computes a first image quality check. If the result is OK, Bad Pixel Calibration can con-
tinue. Release the Prep and Expose buttons between each exposure.
8. The parameters are automatically set to Rh/Rh; 30 kV; 56 mAs. Take four exposures. Release the
Prep and Expose buttons between each exposure.
9. You are requested to make a low dose exposure. The parameters are set automatically (Rh/Rh; 30
kV; 5.6 mAs).
10. You are requested to make a high dose exposure using the following parameters: (Rh/Rh; 30 kV;
80 mAs).
11. The IDC uses the acquired images to create the bad pixel map which will be used for subsequent
image correction. The bad pixel results are displayed on the screen in the form of a table indicating
Pass or Fail for all tested specifications.
6-3 Errors
WARNING
One Defect category FAIL means that the detector is above the GE Bad Pixel specifica-
tions. The root cause of the failure must be found before the customer can use the system
for clinical use. If the customer uses a detector having more Bad Pixels than allowed there
is a risk to loose information in the clinical images.
• Exposure abort during calibration. If the X-ray exposure is aborted during bad pixel calibration, the
buzzer sounds and the calibration is terminated at the end of the current set of exposures. The cali-
bration must be re-started.
• If any failure is reported, check to see if the collimator blades are within the detector FOV. If so, cor-
rect the problem and try again.
• If an Isolated bad pixels failure is reported, check detector temperature and repeat the calibration
when the temperature is correct.
• If a Cluster or Bad Columns failure is reported, check the Flat Field phantom for imperfections such
as scratches or dust, and repeat the calibration after correction.
When a Bad Columns failure is reported, also check that the floppy diskette or CD-ROM supplied
with the detector was correctly loaded when the Image Receptor was installed, as instructed in the
Job Card D/R A141 - Image Receptor/Digital Detector on page
Chapter 9
Service Information and Procedures Class A 2385072-16-8EN
Launching the Service Desktop on page
Page no. 1694
120).
and select Detector Calibration, after
1099. It contains bad column informa-
Senographe DS
JC-CAL-A-041.fm