Understanding the FLASH effect to unravel the potential of ultra-high dose rate irradiation

Kacem, H.; Almeida, Aymeric; Cherbuin, Nicolas; Vozenin, Marie-Catherine

doi:10.1080/09553002.2021.2004328

Cited by 55 publications

(49 citation statements)

References 64 publications

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“…This differential response to radiation delivered at UHDR between tumor and normal tissue widens the therapeutic window and is dubbed by the FLASH effect 1 . Although the underlying radiobiological mechanism of the FLASH effect remains elusive and is under active investigation, 21,22 these promising preclinical results have inspired translational efforts to realize a wide range of delivery platforms with UHDR capabilities 23–30 …”

Section: Introductionmentioning

confidence: 99%

A 2D strip ionization chamber array with high spatiotemporal resolution for proton pencil beam scanning FLASH radiotherapy

et al. 2022

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Purpose Experimental measurements of two‐dimensional (2D) dose rate distributions in proton pencil beam scanning (PBS) FLASH radiation therapy (RT) are currently lacking. In this study, we characterize a newly designed 2D strip‐segmented ionization chamber array (SICA) with high spatial and temporal resolution and demonstrate its applications in a modern proton PBS delivery system at both conventional and ultrahigh dose rates. Methods A dedicated research beamline of the Varian ProBeam system was employed to deliver a 250‐MeV proton PBS beam with nozzle currents up to 215 nA. In the research and clinical beamlines, the spatial, temporal, and dosimetric performances of the SICA were characterized and compared with measurements using parallel‐plate ion chambers (IBA PPC05 and PTW Advanced Markus chamber), a 2D scintillator camera (IBA Lynx), Gafchromic films (EBT‐XD), and a Faraday cup. A novel reconstruction approach was proposed to enable the measurement of 2D dose and dose rate distributions using such a strip‐type detector. Results The SICA demonstrated a position accuracy of 0.12 ± 0.02 mm at a 20‐kHz sampling rate (50 μs per event) and a linearity of R2 > 0.99 for both dose and dose rate with nozzle beam currents ranging from 1 to 215 nA. The 2D dose comparison to the film measurement resulted in a gamma passing rate of 99.8% (2 mm/2%). A measurement‐based proton PBS 2D FLASH dose rate distribution was compared to simulation results and showed a gamma passing rate of 97.3% (2 mm/2%). Conclusions The newly designed SICA demonstrated excellent spatial, temporal, and dosimetric performances and is well suited for commissioning, quality assurance, and a wide range of clinical applications in proton PBS clinical and FLASH‐RT.

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Section: Introductionmentioning

confidence: 99%

A 2D strip ionization chamber array with high spatiotemporal resolution for proton pencil beam scanning FLASH radiotherapy

et al. 2022

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“…Current experimental evidence for irradiation parameter requirements can be summarised as follows. UHDR irradiations using single broad electrons beams were able to produce a pronounced FLASH effect when delivering a large doses (>4-8 Gy) in a short overall delivery duration (<200 ms) and currently available single fraction data suggest that the FLASH effect is diminished or lost when decreasing the dose per fraction or prolonging the treatment time [3,74,[109][110][111][112]. Instead, for increasing single fraction doses, in vivo data show a trend towards an increased normal tissue protection [3,74,113,114].…”

Section: Accounting For the Flash Effect In Uhdr Electron Treatment P...mentioning

confidence: 99%

FLASH radiotherapy treatment planning and models for electron beams

Rahman

Trigilio

Franciosini

et al. 2022

Radiotherapy and Oncology

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“…Diese ist von besonderem Interesse für die Untersuchung des sogenannten FLASH‐Effekts [4]: Aktuelle präklinische Studien weisen darauf hin, dass sich therapeutisch positive Effekte ergeben können, wenn die Strahlendosis nicht wie nach derzeitigem Stand der Technik innerhalb von Minuten, sondern in weniger als einer Sekunde verabreicht wird. Dabei zeigen sich geringere Nebenwirkungen im gesunden Normalgewebe bei gleichbleibender Wirkung im Tumor.…”

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