Advances in technology stimulated novel research ideas exploring new means of delivering radiotherapy. Delivery of doses at ultra-high dose-rate has been of particular interest due to remarkable reduction of normal tissue toxicity (known as the FLASH effect) with respect to conventional treatments. These effect have been observed for electrons, protons, and photons, although the specific biological mechanisms remain to be elucidated. The medical physics community has mostly focused on developing methods and technologies to accurately delivery precise radiation doses at very high dose rates, which is quite challenging from a technological and engineering perspective. In this workshop, we will discuss the strategies for the implementation, dosimetry of FLASH radiotherapy and treatment planning, including treatment delivery and biological effect associated with ultra-high dose-rate irradiations.


A working group will be established to write a white paper covering the main streams discussed during the workshop, i.e. treatment planning, dosimetry and clinical implementation of FLASH radiotherapy.

Online workshop, 28th May 2021 (CET)

Invited speakers:

Magdalena Bazalova-Carter (University of Victoria)

Robert Stewart (University of Washington)


10:00 – 10:05 Welcome (by Catharine Clark)

10:05 – 10:15 Introduction (outline and overview of the meeting)

10:15 – 10:30 Round table (quick introductions – name and the affiliation)

10:30 – 11:30 Invited lectures:
        Magdalena Bazalova-Carter - Challenges of clinical implementation of FLASH RT
        Robert Stewart - Monte Carlo Modelling of the Effects of Oxygen on DNA Damage

11:30 – 13:00 Participant pitches (5-7 min each)

13:00 – 14:00 Lunch

14:00 – 15:10 Breakout sessions:
 (3 focus groups; each focus group will select an individual who will be responsible for reporting of the outputs)
- The implementation of FLASH RT in a clinical setting (chaired by Cristina)
- Dosimetry of FLASH RT (chaired by Anna)
- The inclusion of FLASH effects in treatment planning (chaired by Frank)

15:15 – 16:00 Discussions (each focus group presents the outcomes of the breakout sessions)

16:00 – 16:15 Wrap up and deciding on the next steps (tasks to complete before meeting in October: preparation of working documents by each focus group)

16:15 – 16:30 Close


Live workshop, 22-23 October 2021

1) Kristoffer Petersson (University of Oxford)

2) Wilko Verbakel (Amsterdam University Medical Center)

3) Anna Vella (University of Oxford)

4) Pierre Montay-Gruel (University of California)

 R&D vendors:

Timo Koponen (Varian)

Rudi Labarbe (IBA)

Sebastian Adamczyk (IntraOP)

Giuseppe Felici (S.I.T. - Sordina IORT Technologies)

Eric Traneus (Raysearch)