Dosimetric properties of sulfosalicylic acid-ferrous-polyvinyl alcohol-glutaraldehyde hydrogel dosimeters using magnetic and optical techniques

Abstract

A chemically cross-linked transparent hydrogel dosimeter is prepared with ferrous ammonium sulfate (FAS), polyvinyl alcohol (PVA), 5-Sulfosalicylic acid (SSA), and cross-linking agent glutaraldehyde (GTA). The SSA-Ferrous-PVA-GTA dosimeter was irradiated to doses up to 40 Gy using a medical linear accelerator, and turned into pink with different intensity of colors. The dosimeter was evaluated using nuclear magnetic resonance relaxometry (NMR) and ultraviolet-visible (UV-Vis) spectrophotometry techniques. It showed a linear dose-response up to 40 Gy in terms of absorbance as well as relaxation rate (R2). Dependence on dose rate and photon beam energy of the gel dosimeter were also investigated and found to be independent using both readout techniques. The dosimeter was stable after 8 h of irradiation. Other important key dosimetric parameters such as scanning temperature, post-irradiation, and overall uncertainty of SSA-Ferrous-PVA-GTA gel dosimeter were also measured and analyzed.