GE CT-9800

GE MEDICAL SYSTEMS CT 9800 QUICK SYSTEM
Rev. 12 Direction 18000
6-9A-21
4. Calculate ISO center using CTDS alignment program.
Enter CTDS
• (AL) Alignment
• (1) Isocenter
• (xx) Input Exam # recorded in step 3.
• (ISOCAL) Enter Air calibration filename from step 1.
System ISOCENTER will be calculated and recommendation for tube movement displayed if ISO is outside
its limits. Record displayed data, then exit alignment program.
5. Review ISO projection
• If ISO is more than ± 0.10 from 373.75, adjust tube position, generate new ISOCAL, and retest ISO
without wait. Step 6, then repeat Steps 1, 2, and 3.
• If ISO is between ± 0.02 and ± 0.10 from 373.75, adjust tube position, then wait before retesting. Step 6,
and Step 7, then repeat Step 3.
• If ISO is within specification of ± 0.02 from 373.75, make no tube adjustment, but wait before retesting.
Step 7, then repeat Step 3.
6. At gantry
• Remove side covers
• Turn off scan drive switch
• Rotate for AZ = 270° (Tube at 3:00 O’clock)
• Install dial indicator and shift tube position the amount indicated in Step 5. Refer to Section 9-2-1 for tube
positioning.
• Arm scan drive switch
7. Call Data Collection (DC) program
• DC (automatic download
• Option 3, tube position = 0°.
• Rescan pin in space per Step 3.
8. • ISO is complete on two successive ISO scans within 373.75 ± 0.02.
• Record ISO from Step 4 for system and HHS records.
• Remove pin from phantom holder and phantom holder from table.
• Verify that the Tube Z position has not shifted. Repeat Section 9A-4, Steps 1 through 6.