ESTRO 2025 - Abstract Book

S2152

Interdisciplinary – Education in radiation oncology

ESTRO 2025

Results:

Our findings revealed negligible temperature variations (< 0.05 K) in both the target and surrounding tissues, suggesting that the exposure time/deposited energy of the beam is insufficient to induce a noticeable temperature increase and therefore negligible thermal damages. Conclusion: The results obtained in this work show that the heat diffused to the tissues during UHDR irradiation doesn’t result in a noticeable temperature increase. It could rather drive high activation energy reactions by overcoming kinetic barriers that were otherwise not possible, thanks to the localized kinetic energy increase of atoms. Additionally, owing to this localized nature of hot-atom chemistry, it is worth considering it when understanding the difference between FLASH and CONV RT, even though it doesn’t result in thermal damage. References: [1] Lin, B. et al., FLASH Radiotherapy: History and Future. Front. Oncol. 2021, 11. [2] Farr, J. et al., Ultra-High Dose Rate Radiation Production and Delivery Systems Intended for FLASH. Med. Phys. 2022, 49 (7), 4875–4911. [3] Wolfgang, R. Hot Atom Chemistry. Annu. Rev. Phys. Chem. 1965, 16 (1), 15–42. [4] Wang, Y. et al., Bio-Thermal Response and Thermal Damage in Biological Tissues with Non-Equilibrium Effect and Temperature-Dependent Properties Induced by Pulse-Laser Irradiation. J. Therm. Biol. 2023, 113, 103541. [5] Nour, M. et al., Framework of the Bio-Heat Transfer for Laser/Cancer Treatment. Int. J. Pharma Med. Biol. Sci. 2016, 5, 194–200. Keywords: Thermal modelling, FLASH-RT, Tumor