Simple EPR/Alanine Dosimeter for Medical Application

Abstract

Linac x-ray and direct gamma irradiation sources were used in this study to irradiate simple polycrystalline alanine- in-glass (AiG) dosimeters with low-doses, typical for medical therapy, and high-doses, typical for syringes’ sterilization processe, respectively. The generated “stable” alanine radicals were quantitatively investigated by electron paramagnetic resonance (EPR) spectroscopy in the presence of an external standard reference (Mn2+/MgO) to correct for spec- trometer sensitivity variation. The results indicated that the de-amination of L-alanine is the main reaction to form the “stable” radical and the AiG-dosimeter gives comparable sensitivity for both low and high radiation doses. Moreover, a linear EPR-radiation dose response is observed over a very wide range, from 0 to 50 kGy, which is contrary to what has been reported by Bruker BioSpin using alanine’s pellet. This linear response and the well-known doses’ cumulative characteristics of alanine are in favor of the use of this simple dosimeter in ample medical applications, particularly the conventional radiotherapy treatment per patient.