Ultra-high dose rate proton radiobiology at the “Dresden platform for high dose-rate radiobiology”

The recent rediscovery of the “Flash-effect” revived the interest in high dose-rate radiation effects throughout the radiobiology community, promising protection of normal tissue, while simultaneously not altering tumour control. Several preclinical and clinical studies are presently dedicated to electron FLASH with Linacs. However, the mechanisms of Flash is still unresolved albeit its clear impact in tissue sparing to radiation toxicity. For protons, the Flash effect was confirmed in a few animal experiments using the beam parameters available at clinical cyclotrons.
Laser-driven proton accelerators offer the possibility to extend the range of proton beam parameters to higher dose rates enabling the investigation in vivo of high dose-rate effects for up to 10^9 Gy/s. The general applicability of these beams for radiobiological studies was proven with simple cellular models and zebrafish embryos. One-step further, systematic in vivo experiments were prepared with a proof-of-principle mouse irradiation campaign at the Draco laser accelerator and, for comparison, at the University Proton Therapy Dresden (UPTD). Moreover, to investigate the interplay of oxygen tension, oxygen consumption and proton dose rate in more detail, an experiment with zebrafish embryos was performed at both proton sources.
At the conference, we will give an overview of our radiobiological experiments performed at both DRACO and Oncoray/UPTD, for different dose rates and varying oxygen pressures.