The Effect of N, Nʹ-Methylene-bis-acrylamide Removal from a Polymer Gel Dosimeter Formulation: Spin–Spin Relaxation Rate Investigation and Post-irradiation Time Instability

The extreme toxicity of the monomers used in polymer gel dosimeters (PGDs) has caused some limitations in producing, applying, and storing these valuable tools. This study aimed to investigate the response of a new PGD produced by a less toxic monomer of 2-acrylamido-2-methyl-propane-sulfonic-acid potassium salt. Furthermore, in this new formulation, the highly toxic cross-linker, N, Nʹ-methylene-bis-acrylamide, was not used. The new formulation was named PAGPOT. A clinical linac system was used to irradiate the gel dosimeters. The response of irradiated PGDs was read-out using magnetic resonance imaging (MRI). Additionally, the response of the produced PGD was evaluated for different post-irradiation times and read-out temperatures. Results showed a maximum sensitivity of 0.08 s−1 Gy−1 for the PAGPOT PGD. The change in sensitivity as a function of temperature is negligible compared to the uncertainty of the measurement. Results showed that the sensitivity and dose resolution of the PAGPOT PGD are functions of time elapsed post-irradiation. Furthermore, results showed a significant dependence of the R2 response of the PAGPOT PGD on the post-irradiation time. However, it was noticeably less toxic compared with other PGDs.