Spectrophotometric determination of the optimal wavelength for a polymer-gel dosimeter

Abstract

The purpose of this study was to determine the optimal wavelength for a polymer-gel dosimeter previously developed by our research groups; this was done through a spectrophotometric characterization of its dosimetric properties. A gel sample was irradiated with a 6-MV photon beam from a linear accelerator, and its response was spectrophotometrically analyzed. The absorbance, dose linearity, reproducibility, and dose-rate dependence of the dosimeter were evaluated at various wavelengths and doses. The absorbance of the polymer-gel dosimeter did not show any peak sensitivity within the studied range of wavelengths. For the range of doses studied, the best dose linearity was recorded, with an R-2 of 0.9701 at a wavelength of 400 nm. The reproducibility of the results was excellent, and the error in the dose-rate dependence was within the range of +/- 3%. The gel dosimeter displayed a very stable response, thus confirming the efficiency of this 3D dosimeter.