HF Series Generators
Calibration
CA-1036R2
56
2.8.2.1 ABC SYSTEM ADJUSTMENT WITH ABC SIGNAL FROM TV CAMERA COMPATIBLE WITH
THE GENERATOR
1. Be sure that the Video System and the Image Intensifier are powered and
operating correctly.
2. Set up a Dosimeter as close as possible to the Image Intensifier
Radiation Input to measure the Entrance Image Intensifier Exposure
Dose Rate. Position the Probe at the center of the primary beam with the
entire active volume w ithin the primary beam.
Place the Tube-Collimator Assembly at the normal SID (1 meter), fully
open the Collimator Blades and align the Image Intensifier with the light
beam.
3. Adjust TV Camera gain for 1 volt peak-to-peak composite video output.
4. Set Jumper JP21 to position B on the RF Adaptation Board.
5. Select the maximum PPS and Non-ABC mode.
6. Place 2 mm of Copper (or equivalent homogeneous phantom) in the
Collimator Filter Holder.
7. Calculate the value of the optimum radiation (that will give optimum
brightness) usually is 2μR/frame at 9” FOV (for more information refer to
Image System documentation).
Examples:
For 25 frame/second optimum radiation is 3 mR/min.
2 μR/frame x 25 frame/s = 50 μR/s.
50 μR/s x 60 s/min = 3000 μR/min = 3 mR/min.
For 30 frame/second optimum radiation is 3.6 mR/min.
2 μR/frame x 30 frame/s = 60 μR/s.
60 μR/s x 60 s/min = 3600 μR/min = 3.6 mR/min.
The optimum radiation value should be measured at Image Intensifier
Radiation Input. Intensifier grid should be removed, if it can not be
removed, this value should be multiplied by two or by the value specified
as Grid Absorption Factor.
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