GE Advantium CT9800, Technical Publications

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GE MEDICAL SYSTEMS CT 9800 QUICK SYSTEM
Rev. 19
Direction 18000
4-13-5
13-11 Center Sloped Phantom
Set the sloped phantom on the phantom holder and center it using the alignment lights and adjusting the dials on
the phantom holder. The flat faced side of the phantoms must be parallel to the plane of rotation /-
0.5mm in both the x and y axis. Scout scans, both 0
°
and 90
°
, must be used to measure phantom position. If
necessary, shim the phantom.
Move the slope phantom into the gantry using the respective table move button. Use the internal alignment lights
to center the phantom in the internal axial plane. Be sure to position the phantom in the Z-axis so that the internal
alignment lights strike the center of the sloped edge. The phantom must be centered axially to +/- 0.5mm. To
center the sloped phantom, enter the Cal Function utility and use the Center Phantom Program:
(a) Refer to CT9800 Phantom Centering Procedure.
(b) After scan, system tells you how much to move the phantom to center it in the scan plane. Continue to
scan and adjust the phantom until it is centered to /- 0.5mm.
The phantom must be centered in all directions to obtain accurate results.
(c) After the phantom is centered to 0.5 mm, press CANCEL button to exit program.
13-12 Perform AutoTest Phantom Scans
For AutoTest, you will prescribe two exams, one for the slope phantom, then one for the flat crosstalk phantom.
Each exam will be composed of 4 scans at 3 different techniques, for a total of 12 slices per exam. The easiest
way to set up these exams is to prescribe the four scans at the first technique, then prescribe more scans in the
same exam. Use the 4-digit detector number as the patient ID for both exams. Scan on small cal.
TO PERFORM AXIAL SCANS, PROCEED AS FOLLOWS:
(a) Press the SCAN button.
(b) When the Parameters Screen appears, fill in the following data:
ID: Use the 4 digit detector number.
NAME: Sloped phantom.
REFERRED BY: Press RETURN.
RADIOLOGIST: Press RETURN.
OPERATOR: Press Return.
REQUISITION NUMBER: Press RETURN.
SELECT SCAN RX FILE NUMBER OR LIST FILES: Press carriage return.
(c) Exam number is displayed. Write down exam number. Press RETURN to continue to the Exam Parameters
Screen.
CAUTION