GE CT-9800

GE MEDICAL SYSTEMS CT 9800 QUICK SYSTEM
Rev. 19 Direction 18000
6-9A-14
15) Turn the mounting studs the specified amount to bring the detector into alignment. One turn of the
mounting adjustment moves the detector 0.071” (1.81mm)
Note: The detector adjustment hardware works such that CW adjustment moves the detector
toward the gantry. This is the opposite of Xenon.
16) While holding the adjustment stud with a 7/16” wrench, re-tighten the adjustment locking nut.
17) Torque the inside detector mounting nuts to 25 ft-lbs. When the inside nuts have been torqued, torque
the outside nuts to 25 ft-lbs while holding the inside nut from turning. If a torque wrench is not available
the nuts should be tightened finger tight and then tightened 1/2 flat with a wrench. Tighten the large
detector mounting nuts to 25 ft-lbs.
18) Repeat steps 4) thru 11) until the detector is within tolerance.
9A-7 REFERENCE & DATA CHANNEL OUTPUT check
and Tube X-RAY OUTPUT (DOSE MEASUREMENT) check
Perform a reference and Data channel output check at the following times:
a) New installation: Perform anytime after KV/mA calibration, but before Q-Cal intensity check.
b) Tube replacement: Perform anytime after KV/mA calibration, but before Q-Cal intensity check.
c) Preliminary check when System Dose measurements are questioned.
d) Check for bad channels
In addition: Perform a Tube X-Ray output (Dose Measurement) check at the following times:
e) When the System Dose measurements are questioned.
f) To check X-ray Intensity when the High Voltage subsystem output is suspect.
These procedures assume that the following items have been verified:
a) There must be nothing obstructing the X-ray beam
b) There is nothing blocking any detector channels (except for the Q-CAL channel).
c) Check the tube housing for the correct filter:
1 dot = titanium - the correct filter for XENON detector
2 dots = molybdenum - the correct filter for HILIGHT detector
d) Check the tube
Generator calibration at 80 KVP/40 ma is accurate to within 1KV and 1ma
Generator 40ma station is within spec.
Bleeder output is 80KV
e) Check alignments:
POR - Plane of Rotation alignment
BOW - Beam on Window alignment
Aperture (collimator) spacing is exact ( or on the wide side of the specification)
X-ray calibration
f) Check that the detector has no electrical shorts or opens.
and for XENON:
- The bias supply is 350VDC loaded with less than 10 mV P=P ripple
- The pressure is within specification