Monte Carlo water-equivalence study of two PRESAGE® formulations for proton beam dosimetry

PRESAGE^® is a radiochromic solid dosimeter which shows promising potential for 3D proton beam dosimetry. Since an idea dosimeter should be water-equivalent, total depth dose distributions in two PRESAGE^® formulations irradiated by a 62 MeV proton beam were compared with that in water using GEANT4 Monte Carlo simulations. The dose delivered by secondary particles was also calculated. Our results show that after water-equivalent depth scaling, PRESAGE^® can be considered water equivalent for dosimetry of a 62 MeV clinical proton beam.