Impact of dose rate and its definition on the production of hydrogen peroxide in pure water
Introduction
The clinical interest in particle therapy continues to grow due to its precise dose dis tribution and increased biological effectiveness. Recent attention has focused on ultra high dose rate (UHDR) irradiation, which has been associated with reduced normal tissue toxicity, an effect that is partially attributed to altered radiolysis chemistry. However, most existing experimental studies only compare UHDR irradiation at a fixed dose rate with conventional dose rates, provid ing limited insights into the continuous dose rate dependence of radiolysis processes.
Methods
This study aims to systematically investigate the dose rate dependence of hydrogen peroxide H2O2 formation, a long-lived product of water radiolysis, across a wide range of dose rates and under varying pulse structures and irradiation conditions using protons and carbon-ions.
Results
The results demonstrate a non-linear relationship, with H2O2 yields increasing up to 20–30Gys−1 before declining at higher dose rates. These findings help to reconcile discrepancies between current experimental observations and simulation predictions, emphasizing the critical role of instantaneous dose rate distribution and pulse characteristics. The data provide essential input for advancing radiolysis modeling and for understanding UHDR effects in particle therapy.
