GE MEDICAL SYSTEMS CT 9800 QUICK SYSTEM
Rev. 16 Direction 18000
6-9-18
3. The average value of the 5 reference channels (i.e., channels 2, 3, 734, 735 and 736) must be greater than
or equal to 115,000 and the other signal channels (i.e., channels 4 through 733) must be 40%-60% of the
average of the 5 reference channels. Channel 1 will have an output approximately 55% to 60% of the
average of the five reference channels. These values indicate that the tube is good.
4. If the average of the 5 reference channels is less than 115,000, then the tube should be replaced because
system performance will be compromised. If the average of the 5 reference channels is greater than
158,000, tube output is excessive relative to CT Dose Measurements. Check the X-ray Calibration and the
collimator aperture width. Refer to the list of system checks at the introduction of this sub-section.
B: Channel Output Check
To test the outputs of the data channels, proceed starting with the last step of the previous section (i.e., we just
finished displaying the means for the reference channels). Proceed as follows:
1. • [CANCEL] Display the means of the non-reference channels.
• (CANCEL) Press Cancel Key 2 times to get back to the main Analysis menu.
2. The system passes the channel output test if the mean values are between 40% to 60% of the average
output of the reference channels (subsection 1A, Tube Output, step 3) for channels 4 through 730. If the
mean values are less than 55% and /or greater than 60%, troubleshoot the faulty channel(s). See RDCS
Manual, Direction 18008.
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