KaVo 3D eXam, Operator'S Manual

Page: 103 / 170

k990400 September 19, 2007
Calibration and Quality Assurance
10-13
d. Move the position of the slice to the middle of the phantom
as shown in the figure.
29. Right click the image and select HU Statistics from the menu.
30. Area of ROIs should be at least 40mm
2
but less than 46mm
2
.
Use the Region Tool to define a ROI in the center of each circle
of material implanted within the QA phantom. Note: to achieve
an accurate measurement,
boxes should be as large as possible
without touching the circle diameter.
31. Note and record the Hounsfield value of each material. See table
below.
The Upper and Lower Limits are based on the baseline value of air (-1000)
32. Call Service, if any of the four measured values exceed the Low
or High limit.
Material
Scanned Value
(Hounsfield Units)
Lower
Limit
Upper
Limit
Air (Black) (lower left)
-1000 -800
Acrylic (Light Gray) (lower right)
10 85
LDPE (Dark Gray) (upper right)
-135 -50
Teflon (White) (upper left)
600 900