Characterization of Improved PASSAG Polymer Gel Dosimeter Using Magnetic Resonance Imaging

Poly 2-acrylamido-2-methy-1-propanesulfonic acid sodium salt and gelatin (PASSAG) gel dosimeter has a negligible toxicity and also excellent dosimetric characteristics. Nonetheless, the main drawback of this gel dosimeter is its relatively low response–dose sensitivity. In this study, we investigated whether adding glucose into the conventional PASSAG gel dosimeter could increase the response–dose sensitivity. For this purpose, new gel dosimeters of G-PASSAG (glucose and PASSAG) were first fabricated, and then irradiated using 6 MV X-rays. The responses ( R 2 ) of gel dosimeters after irradiation were read out by a 1.5 T MRI scanner. In this regard, the R 2 –dose responses and the R 2 –dose sensitivities of conventional PASSAG and G-PASSAG gel dosimeters with 3 and 5 wt% glucose were investigated at a 0–10 Gy dose range, 15–24 °C scanning temperatures, and 1–30 days post-irradiation. The findings showed that the R 2 –dose sensitivities of G-PASSAG gel dosimeters with 3 and 5 wt% glucose (compared to conventional PASSAG gel dosimeter) improved by 6.70 and 27.13%, respectively. Furthermore, there were excellent linear R 2 –dose responses for these new gel dosimeters in a 0–10 Gy dose range. A relative stability in the R 2 –dose sensitivity of the gel dosimeters during 20–24 °C scanning room temperatures was also observed. Moreover, G-PASSAG gel dosimeters represented temporal stability at the R 2 values during 15–30 days post-irradiation. Additionally, the improved R 2 –dose sensitivity over post-irradiation time varied 6.06–10.05% and 16.65–27.13% for G-PASSAG gel dosimeters with 3 and 5 wt% glucose, respectively.