Advanced Physics for Brachytherapy 2018

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:

a bD +

a b +

n

OD

OD

D a b OD c OD = +  + 



= −

log

/



=

/

c D +

D c −

• Separate calibration recommended for each lot • Calibration quality criterion is (of course) uncertainty

Figures from: Devic, Physica Medica 27(3) 122 (2011)