Particle Accelerators and Beams Conference 2026

Very High Energy Electron FLASH Radiotherapy: Accelerator Development and Emerging Experimental Evidence

1 Jul 2026, 11:40

20m

Oral Submissions Contributed talks

Speaker

Prof. Roger Jones

Description

Here we present a conspectus of very high energy electron (VHEE) developments and the potential for FLASH radiotherapy across multiple accelerator facilities. FLASH radiotherapy (FLASH-RT) delivers radiation at ultra-high dose rates (>40 Gy/s) and has demonstrated the potential to reduce normal tissue toxicity while maintaining tumour control compared with conventional dose-rate irradiation. Very high energy electrons (VHEEs; 50–250 MeV) are a promising modality for FLASH delivery due to their deep penetration, reduced lateral scattering, and compatibility with advanced accelerator technologies.

This work reviews progress in VHEE FLASH radiotherapy, encompassing beam development, dosimetry, and emerging experimental evidence from several high-energy electron platforms. A central focus is the characterisation of beam parameters and dose rates required for FLASH-compatible delivery, alongside early investigations of radiobiological response under ultra-high dose rate conditions.

Selected recent measurements illustrate current capabilities. Beam characterisation in water phantoms has been used to derive percentage depth-dose (PDD) profiles and transverse beam spread over electron energies of 100–250 MeV. By adjusting bunch charge and repetition frequency, both conventional (CONV) and ultra-high dose rate (UHDR) regimes have been achieved, with UHDR conditions exceeding the FLASH threshold (>40 Gy/s).

Complementary radiobiological studies using lung adenocarcinoma cells have assessed survival and DNA damage following CONV and FLASH VHEE irradiation. Initial results show dose-dependent reductions in survival, with differences between dose-rate regimes indicating potential alterations in biological response at ultra-high dose rates.

Overall, there is a growing capability across multiple VHEE platforms to support FLASH radiotherapy research, integrating accelerator physics, beam delivery optimisation, and radiobiological investigation. Continued development of VHEE facilities will be essential to refine delivery strategies and support translation toward potential clinical applications of VHEE-FLASH radiotherapy.