An easy method to account for light scattering dose dependence in radiochromic films.
OBJECTIVE
To date no detector can offer the unbeatable characteristics of film dosimetry in terms of spatial resolution and this is why it has been chosen by many institutions for treatment verification and, in that respect, radiochromic films are becoming increasingly popular due to their advantageous properties. It is the aim of this work to suggest an easy method to overcome one of the drawbacks in radiochromic film dosimetry associated with the scanning device, namely, the nonuniform dose dependent response, mainly due to the light scattering effect.


METHODS
The suggested procedure consists of building four correction matrices by sequentially scanning one, two, three, and four unexposed blank films. The color level of these four matrices is compatible with four points in the calibration curve dose range. Therefore, the dose dependent correction to the scanned irradiated film will be obtained by interpolating between the four correction matrices.


RESULTS
The validity of the suggested method is checked against an ion chamber 2D array. The use of the proposed flattening correction improves considerably the dose agreement when compared with the cases in which no correction is applied.


CONCLUSIONS
The method showed to be fast and easy and practically overcomes the dependence on the dose of light scattering of flatbed scanners.
Miras
Hector
H
Department of Medical Physics, Virgen Macarena Hospital, Seville E-41009, Spain. hector.miras@gmail.com
Arrans
Rafael
R
D000465:Algorithms; D002138:Calibration; D003116:Color; D005373:Film Dosimetry / Q000379:methods*; D008027:Light; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D014962:X-Ray Film