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EPID CALIBRATION
Correction factors (at this moment to be used for pretreat verifications
and linac QA)
DEPENDING ON THE DETECTOR: DIFFERENT CORRECTION FACTORS CAN BE EXPECTED
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Field size
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Backscatter from the EPID arm (Varian aS500, aS1000).
Not needed for aS1200 (backscatter shielding added)
❑
EPID SAG if used at different gantry angles
THE INTENSITY AT EACH POINT IN THE IMAGE MUST BE CALIBRATED IN A
QUANTITATIVE SENSE
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The dose response of each pixel point must be known
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The effects of scattered radiation in the detector must be understood
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The temporal stability of the detector must be known.