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Session: Joint AAPM-ESTRO Symposium: FLASH-From Experimental Beam Lines to the Clinic [Return to Session]

Joint AAPM-ESTRO Symposium: FLASH-From Experimental Beam Lines to the Clinic

B Singer1*, E Diffenderfer2*, A Lomax3*, C Simone4*, (1) Aarhus University Hospital, Aarhus, DK, (2) University of Pennsylvania, Philadelphia, PA, (3) Paul Scherrer Institute, Villigen, SE, (4) New York Proton Center, New York, NY


MO-AB-BRB-0 (Monday, 7/11/2022) 7:30 AM - 9:30 AM [Eastern Time (GMT-4)]

Ballroom B

FLASH radiotherapy is the delivery of ultra-high dose rate radiation several orders of magnitude higher than what is currently used in conventional clinical radiotherapy, and it looks to be as a promising technique that can revolutionize the future of cancer treatment. However, the mechanisms under the flash effect and also the best modality to be chosen are topics under discussion. In this symposium, we will unveil what we know and what is still to be known of flash therapy.
The delivery of ultra-high dose rate has been shown in pre-clinical models to reduce the risk of toxicity without compromising tumor control. Specifically, in small and medium-sized animals, irradiation at >40 Gy/second has allowed for less skin toxicity, less lung fibrosis, less loss of neural stem cells, better gastrointestinal crypt regeneration, and better hematopoietic stem cell recovery. As such, FLASH has the potential to improve normal tissue complication probability and widen the therapeutic window for radiotherapy delivery. In this symposium, we Brita Singers Sorensen will discuss the radiobiological background of the flash effect. The current data is pointing towards different factors which could potentially influence the level of tissue sparing effect such as: dose rate, time structure, tissue type, total dose and fractionation. Eric Diffenderfer will focus on the importance of high quality pre-clinical experiments that are key factors to generating the data needed to build mechanistic and phenomenological models of the proton FLASH effect. The physics and dosimetry of developing ultra-high dose rate treatment techniques for in vivo studies must consider the reproducibility of delivering accurate doses and dose rates to relatively small target volumes in small animals.
Charles Simone and Tony Lomax will update us on the clinical trials on flash. The first prospective clinical trial was recently completed, and additional trials are undergoing or in planning. Additional understanding of the mechanism of action of the FLASH effect will help inform future trials. In particular, these talks will discuss the existing data and proposed mechanisms of action of the FLASH effect, describe different modalities that can be used to deliver ultra-high dose rate radiotherapy, detail the existing clinical literature, and discuss the current landscape and future clinical trials investigating the FLASH effect.

1.Describe the current radiobiological data of FLASH
2.Identify the gaps in the current knowledge of the effects of FLASH
3.Discuss how to develop and validate ultra-high dose rate proton beam delivery on an experimental beam line.
4.Examine techniques for reproducible, accurate, and efficient proton beam targeting for in vivo experiments
5.Discuss differences in delivery between proton and photon FLASH and current challenges in implementing ultra-high dose rate radiotherapy in clinic
6.Examine the rationale for disease site selection of future clinical trials investigating the FLASH effect



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