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Calibration:
Determination of the sensitometric curve
❑
The film calibration procedure consists in acquiring a set of single measurements of net
optical density NOD with the corresponding absorbed dose and obtaining a function
which relates NOD for a given dose, called the sensitometric curve. The NOD is obtained
by subtracting the average OD of a non-irradiated film to an irradiated film using
regions of interest ROIs of constant sizes and uniform field doses
OD =-log
10
(T) =-log
10
(I
0
/I)