HF Series Generators
Maintenance
MA-1004R4
19
4. Select ABC mode.
5. Place 2 mm of Copper (or equivalent homogeneous phantom) in the
Collimator Filter Holder.
6. Make a Fluoro exposure and check that Fluoro kVp displayed on the
Console is between 80 kVp and 60 kVp. If it is more than 80 kV or less
than 60 kV modify the Copper thickness in steps of 0.1 mm (or 0.2 mm)
and make Fluoro exposures until the kVp is within the range.
7. Calculate the value of the optimum dose rate (that will give optimum
brightness) to obtain 2 μR/frame at 9” FOV.
Examples:
For 25 frame/second optimum dose rate 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 dose rate 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 dose r ate (dose rate) 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 the value specified as
Grid Absorption Factor.
8. Make a Fluoro exposure and measure the dose rate. The dose rate read
on the Dosimeter must be the same as the previously calculated with the
tolerance specified by the Dosimeter accuracy. If the dose rate does not
comply, perform the respective Calibration procedures.
9. Stop the Fluoro exposure and select 40 kV. Make a Fluoro exposure and
check that the kV value goes to 70 kV (or the kV obtained in step-6.)
±2 kV w ithout System problems.
10. Stop the Fluoro exposure and select 100 kV. Make a Fluoro exposure
and check that the kV value goes to 70 kV (or the kV obtained in step-6.)
±2 kV w ithout System problems.
To Next Page
Loading...