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EBT films: sensitivity/linearity
•
Sensitivity is film, scanner, protocol, and dose
dependent
•
It is non-linear and different or all RGB
channels can be used
•
A variety of fitting functions has been used in
literature. Popular choices are power fits and
rational functions:
•
Separate calibration recommended for each lot
•
Calibration quality criterion is (of course)
uncertainty
Figures from: Devic, Physica Medica 27(3) 122 (2011)
log
/
/
a bD
a b
n
OD
OD
D a b OD c OD
c D
D c
+
+
= −
=
= + +
+
−