Speaker
Description
The mysterious differential effectiveness of ultra-high dose rate (UHDR) irradiations, returning a protective effect on normal tissues for same antitumor efficacy as compared to conventional dose rates, the so-called FLASH effect, observed in numerous preclinical experiments, triggered in the last 3-4 years an exponentially growing number of biophysical modeling works attempting to investigate and explain it from the mechanistic point of view.
Since it was appearing that such a phenomenon should imply several physical, chemical and biological stages of the radiation action, different spatio-temporal scales were considered and analyzed in these modeling approaches.
An overview of these investigations will be concisely reported, with a focus on the ongoing joint efforts of GSI and TIFPA in this context, especially in the attempt of combining different scales.
In particular, radiation chemical based approaches, employing TRAXCHEM [1-2], the GSI radiation chemical track structure code and its specific extensions, allowing to go from the physical stage to the homogeneous chemical stage will be mentioned and a novel dedicated extension of the Generalized Stochastic Microdosimetric model (GSM2)[3-4] for UHDR regime, aiming at combining the DNA damage and repair kinetics with the chemical stages on several levels.
Impact of LET [3] and dose delivery features will be discussed as well.
REFERENCES
[1] Boscolo et al. Int J Mol Sci, 21, 24 (2020);
[2] Boscolo et al.RadiotherOncol 162, 68 (2021);and 163, 237 (2021)
[3] Cordoni et al. Phys Rev E103, 012412 (2021)
[4] Cordoni et al. Rad Res 197, 218 (2022)
[5] Weber, Scifoni, Durante MedPhys 49, 1974 (2022)