Basic radiological characteristics of a non-scattering gel dosimeter for 3D dosimetry

Abstract

We used a spectrophotometer to compare the dosimetric properties of two non-scattering (radiochromic) gel dosimeters: a non-scattering gel dosimeter developed in-house and a PRESAGE (TM) gel dosimeter. We evaluated the dosimetric characteristics, including spectral absorption, dose linearity, reproducibility, and dose rate dependency of the two gel dosimeters. The non-scattering gel and the PRESAGE (TM) gel dosimeters showed peak sensitivity at wavelengths of 600 nm and 630 nm, respectively. Over a range of doses the best dose linearities of the non-scattering and the PRESAGE (TM) gel dosimeters resulted in R-2 values of 0.99 at wavelengths of 600 nm and 630 nm, respectively. The reproducibility and dose-rate dependence of each of the two gel dosimeters were within the range of +/- 3 %. Our results revealed that the peak sensitivities of the two radiochromic gel dosimeters were significantly different; the in-house non-scattering gel dosimeter demonstrated peak sensitivity at a wavelength of 600 nm while the PRESAGE (TM) gel dosimeter had peak sensitivity at a wavelength of 630 nm. We confirmed that for 3D gel dosimetry, the in-house non-scattering gel dosimeter had a more stable dose response compared with a commercial non-scattering gel dosimeter.