Vatech A9 PHT-30CSS, Technical Manual

Page: 59 / 244

Page 58 of 244
2.3. CT Sensor Calibration
To ensure CT image quality, perform CT sensor calibration according to this section.
To assure image quality, perform sensor calibration in various temperature
and humidty settings.
2.3.1. CT Sensor Calibration Standard
See the tables below for dark and bright calibration standards.
Dark Calibration Median Value Standard
Min Max
Median value 700 2300
Bright Calibration Standard Value
Acquisition conditions
Half Scan
4-point 2-point
Filter
AL filter Al X
Cu filter(Cu 1 mm) O X
※
Using filter by each calibration point
Ensure that the median value for each bright cal point meets the standards in the table below:
Bright Standard Values: 2-point without Cu 1 mm filter
Bright Min Max
Median value
Cal Point 1 4500 5500
Cal Point 2 9500 10500
Bright Standard Values: 4-point with Cu 1 mm filter
Bright Min Max
Median value
Cal Point 1 80 120
Cal Point 2 150 700
Cal Point 3 800 1800
Cal Point 4 2000 2500
After bright calibration, Cal point 1 and 4 must satisfy the standards listed
above. The date from other Cal points can be different from the standards
because of the sensor you use for the calibration.