Hoang Ngoc Tran (France)
Université de Bordeaux, CNRS/IN2P3, UMR5797 Centre d'Études Nucléaires de Bordeaux GradignanAuthor Of 1 Presentation
MODELLING OF WATER RADIOLYSIS FOR ULTRA-HIGH DOSE RATE (FLASH) ELECTRON BEAMS IN GEANT4-DNA
Abstract
Background and Aims
FLASH radiation modalities deliver ultra-high dose rates with high dose per pulse and a low number of pulses. In this work, we investigate the impact of electron beams with different doses per pulse (from 0.01 to 40 Gy) on water radiolysis using the Geant4-DNA code.
Methods
The single-track simulation mode is extended to multiple electron tracks delivered in the same pulse to obtain the desired dose to the target volume. This extension allows us to simulate the chemical stage up to hours after radiation exposure.
Results
The G values of hydroxyl radicals (•OH), hydrated electrons (e−aq) and hydrogen radicals (H•) decrease earlier in time as the dose per pulse increases. In oxygenated water, a shorter lifetime of the reactive oxygen species (ROS) – superoxide radical (O2•-) and hydroperoxyl radical (HO2•) – is obtained for higher doses per pulse, which reduces the level of hydrogen peroxide (H2O2). These observations are compared with the available experimental data.
Conclusions
We found that the significant reduction in ROS yield results from the high concentration of species generated with high doses per pulse.