Vatech A9, User Manual, Page: 134 / 196

12. Maintenance
134 vatech A9 (Model name: PHT-30CSS) User Manual
12.4.1.3 Analyzing CT Number Phantom
1. Double-click the saved PHANTOM image in EzDent-i to run Ez3D-i.
2. In the Axial pane, double click the pane to maximize the Axial view.
4. Make the boxes on the WATER, TEFLON, and AIR area as shown below.
Try to make each box as close to 20.0 mm 2 in the area as
possible.
5. Compare the CT NUMBER average values from the WATER, TEFLON, AIR areas
with the standard.
MATERIAL MEAN LOWER LIMIT UPPER LIMIT Scope
AIR
-990 HU
-1030 HU -900 HU
IEC 61223-2-6:
5.5.4, 5.5.5
WATER 0 HU -50 HU 50 HU
TEFLON
980 HU
900 HU 1100 HU
6. Record the mean CT Number value of each material.
8. Remove User Phantom from the PHANTOM JIG ASS’Y.