Hologic DISCOVERY A, Technical Manual

Page: 107 / 274

Discovery QDR Series Technical Manual
3-55
3. Start the QDR/APEX software in Service mode.
4. On the QDR/APEX main screen, select
Utilities|Service Utilities|X-Ray
Survey
.
5. Set Pulse to 1, press <ALT><P>.
6. Set
a. Hi Gains to 2.
b. Lo Gains to 1.
c. X-ray Mode to 3.
d. Aperture to 7.
5. Press <Enter>.
6. Display the X-Ray Survey bar graph, press <Ctrl><Page Down>.
7. Observe Hi Air, press <Alt><S>.
8. Turn on X-rays, press <F1>.
9. Verify that the average X-ray signal level is 6.25V and that all detectors are
within the 4.5V to 8.5V range. If these conditions are met, the procedure is com-
plete. Do not adjust the A/D gain.
If these conditions are not met, continue to “Adjust the A/D Gain” on page 3-55.
3.5.2 Adjust the A/D Gain
Caution:Do not adjust the A/D gain unless absolutely necessary as defined by “Check
and Verify the A/D Gain” on page 3-54.
1. Adjust the A/D gain potentiometer to achieve an average X-ray signal of 6.25V.
2. Check that all detectors are within a range of 4.5V to 8.5V.
3. Perform the Detector Flattening procedure described in “Perform Detector Flat-
tening ” on page 3-55.
3.5.3 Perform Detector Flattening
This procedure flattens the X-ray beam for each scan mode and finds the metal edge of the
table.
Note: All covers, table mat, etc., normally in the X-ray path, MUST be on the Scanner
before running Beam Flattening.
1. Restart the Discovery software in service mode (if not already). Press the
Center
Table
button and turn on the laser.
2. If you are using an Anthropomorphic Spine Phantom (resembles vertebral bod-
ies, Part Number 030-1967), place the phantom on end (vertical) with the spinal
WARNING: X-rays are generated during this procedure. Keep hands, head and other body parts out
of beam.