Mathematical Modeling of PAG‐ and NIPAM‐Based Polymer Gel Dosimeters Contaminated by Oxygen and Inhibitor

Abstract A mathematical model for crosslinking copolymerization of acrylamide (or NIPAM) and N,N'‐methylenebisacrylamide is extended to account for contamination by oxygen and the inhibitor MEHQ. This model improves basic understanding of interactions among oxygen, MEHQ and polymerization reactions in gel dosimeters that are used to verify radiation doses delivered by cancer treatment equipment. Improved parameter estimates result in a good match between model predictions and data. The model predicts that a larger absorbed dose will be required to overcome the oxygen inhibition with increasing oxygen contamination, in agreement with experimental data. The model also predicts that MEHQ, in the absence of oxygen, has almost no influence on dosimeter response. magnified image