GE MEDICAL SYSTEMS CT 9800 QUICK SYSTEM
Rev. 6 Direction 18000
6-11-2
11-1 Vertical Plane Of Table Perpendicular To Scan Plane
To verify that the table is perpendicular to the scan plane, scan the Laser Light Alignment Tool as follows:
1. Install the alignment tool on the phantom holder.
2. Level the tool until the bubble on top of the tool is centered using the adjustment screws
(section 10, Ill. 6-10-2).
3. Turn on the alignment lights.
4. Advance the table into the gantry until the internal axial beam falls into the notched portion of the teflon end
on the tool.
5. Raise the table until the teflon end is roughly at ISO (i.e., coronal lights can be used to mark the location).
6. Use the centering program in Cal Check and center the teflon end of the tool to within ± 0.12 mm. Use the
following technique:
Water Cal
1.5 mm. aperture
120 kV
100 mA
7. At M-level, enter the Scan Program and perform a scout scan at the following technique:
Azimuth : 0°
Table Speed : Fast
Starting Location : -350 mm.(minus 350)
Ending Location : 50 mm.
kV : 120
mA : 100
Tilt : 0°
8. As shown in Ill. 6-10-3 (section 10), verify that the tool is perpendicular to the scan plane using the Line
Cursor Function on the console keyboard. Place the Line Cursor along one side of the tool as shown in
Ill. 6-10-3. If the tool is perpendicular, then the Line Cursor should align perfectly with the side of the tool
along the full length (e.g., Ill. 6-10-3 shows perfect alignment with the side of the tool).
9. If the tool is perpendicular to the scan plane per step 8, then go to the next section. If the tool is not
perpendicular to the scan plane, loosen the table base mounting bolts and move the table for proper
alignment. Rescan the tool per steps 4 through 7 and verify that the tool is perpendicular to the scan plane.
Keep repeating sequence until proper perpendicular alignment is achieved.
10. If table base mounting bolts were loosened in step 9, do not retighten. Instead, go to next section (11-2).
11-2 Centering the Table In the Scan Plane
1. Before performing the procedure in this section, the table must be perpendicular to the scan plane as
determined in the previous section 11-1.
2. At this point, if the table base mounting bolts were loosened in step 9, do not retighten. Go to next step.
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