The Role of Beam Monitoring in FLASH-RT clinical translation: state-of-the-art and future directions

Thursday 19 Mar 2026, 09:00 → 11:00 Europe/Lisbon

LIP-Lisboa/3-311 - Sala de Seminários (LIP Lisboa)

FLASH Radiotherapy (FLASH-RT) has emerged as a promising paradigm in radiation oncology, defined by the delivery of therapeutic doses at ultra-high dose rates (UHDR, typically ≥40 Gy/s). Since the seminal work of Favaudon et al. in 2014, which first reported a significant reduction in normal tissue toxicity while maintaining tumour control, the so-called FLASH effect has been the subject of intense investigation. Subsequent preclinical studies have successfully reproduced these findings across a wide range of radiation modalities, including photon, electron, proton, carbon and helium beams, highlighting the broad potential of FLASH-RT.

In 2019, the first patient was treated with FLASH-RT using an electron beam in Lausanne, followed in 2020 by the initiation of the FAST-01 clinical trial in Cincinnati, which explored proton FLASH for the treatment of symptomatic bone metastases. These studies demonstrated the feasibility and safety of FLASH delivery in humans. Currently, several clinical trials are ongoing, primarily using electron beams, reflecting both their technological maturity and availability.
Despite this progress, a major barrier to clinical implementation persists: the lack of reliable, real-time beam monitoring and dosimetry under UHDR conditions. Conventional ionization chambers, the current clinical standard, suffer from saturation, recombination effects and limited temporal resolution when exposed to FLASH beams. These limitations pose significant challenges for accurate dose delivery, beam control and patient safety, underscoring the need for new monitoring concepts specifically tailored to FLASH-RT.

This seminar will provide an overview of the current state-of-the-art in beam monitoring for FLASH-RT, highlighting the fundamental limitations of existing technologies and the key performance requirements for next-generation solutions. Ongoing research and development efforts, including those undertaken by Particles4Health, will be discussed in a general context as part of the broader international effort to overcome these challenges. Finally, future directions will be outlined, emphasising the central role of advanced beam monitoring in enabling the safe, reproducible and routine clinical translation of FLASH-RT.