Mathematical modelling of depth-dose response of polymer gel dosimeters

A dynamic partial differential equation (PDE) model is used to simulate the effects of radiation depth-doses on polymer formation in Polyacrylamide Gel (PAG) dosimeters. Depth-doses are simulated using different types of radiation including Co60 gamma and 6 and 15 MV X-ray photon beams, along with 6, 9, 12, 16 and 20 MeV electron beams. Effects of monomer diffusion (edge enhancement) and temperature are studied. Diffusion results in excess polymer formation at the position of maximum dose (4% for Co60 γ-radiation and less for other types of radiation studied). Temperature increases on the order of 2 0C increase the mass of polymer formed by approximately 2-3%. These results provide insight for calibrating dosimeters using depth-dose information.