9600 Service Manual - gmecorp-usa.com

36 Image System Calibration
CAMERA IRIS CALIBRATION (SHORT METHOD)
NOTE: This method may be used instead of the "Long Method" as long as the
confidence tests are successful.
Confidence Tests
The confidence tests confirms the radiation output of the system (and therefore the
accuracy of the generator's kV and mA circuits) and also the functionality of the ABS
loop. Perform the confidence tests as described on this page.
VERIFY ENTRANCE EXPOSURE
1. Place a lead apron over the II.
2. Place an Ion Chamber 12" (30 cm) above and centered in the II.
3. In the MANUAL FLUORO mode, select 120 kVp & maximum available mA.
4. Verify the radiation output is ≅ 4.6 R/min using a 5R ABS table for system serial
numbers 69-0001 to 69-1160, or verify the radiation output is less than 9.26 R/min
using a 10R ABS table for system serial numbers 69-1161 or higher.
NOTE: If this radiation level is not met, refer to the Entrance Exposure procedure.
This may be out of adjustment and/or may indicate the generator is out of
calibration.
VERIFY AUTO GAIN
1. Selecting the AUTO FLUORO mode with Auto Histo OFF. Make an exposure and
allow the image to stabilize.
2. Select MANUAL FLUORO and select TECH LOCK to turn it ON.
3. Make an exposure and verify that the image stays the same.
4. Reduce the mA by one-half the current value and make an exposure. Observe the
image becomes darker.
5. Select TECH LOCK to turn it OFF.
6. Make an exposure and confirm the image returns to normal brightness.
NOTE: If not, verify the ABS loop is functioning by examining camera adjustments
(VLI & Camera Gain) to and from the generator.
This concludes the confidence tests. Proceed to the next page to begin
the short method.