GE MEDICAL SYSTEMS CT 9800 QUICK SYSTEM
Rev. 12 ➤ Indicates Change Direction 18000
4-12-13
12-9 Beam Hardening
➤ This section describes the procedure for measuring beam hardening correction. The following phantom will be
used for these tests:
➤ • 35cm poly
➤ • 20cm water section of the QA phantom
1. Scan the 35cm phantom listed on the Data/Work sheet for that technique. Scan at least 5 slices.
2. Next, scan the 20cm water section of the QA phantom listed on the Data/Work sheet for that technique.
Scan at least 5 slices.
3. Perform ROI’s at the locations specified on the respective Data/Work sheets. Each ROI box size is
described on the work sheet.
NOTE: For the 20cm water section of the QA phantom, 80% (4 out of 5) of the slices must meet
specs.
X
c
- Mean CT number about the Center Image Coordinate.
AVX
c
- Average Mean CT Number about the Center Image Coordinate for a minimum of 5 slices.
X
o
- Mean CT number for the outside of the phantom image.
AVX
o
1,2,3,4,5
- Average Mean CT Number for the outside of the phantom image. Derived by averaging the
Mean CT Number value for all of the specified outside coordinates per slice.
12-10 Data Sheets for Image Performance
Data sheets for means/image noise, high contrast resolution, linearity, and beam hardening are contained in this
section, see table of contents for locations.
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