Translational Research in FLASH Radiotherapy-From Radiobiological Mechanisms to In Vivo Results.

Loredana G Marcu,Puthenparampil Wilson,Dylan D Peukert,Eva Bezak

doi:10.3390/biomedicines9020181

Loredana G Marcu, Puthenparampil Wilson + Show 2 more

Open Access

https://doi.org/10.3390/biomedicines9020181

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Abstract

FLASH radiotherapy, or the administration of ultra-high dose rate radiotherapy, is a new radiation delivery method that aims to widen the therapeutic window in radiotherapy. Thus far, most in vitro and in vivo results show a real potential of FLASH to offer superior normal tissue sparing compared to conventionally delivered radiation. While there are several postulations behind the differential behaviour among normal and cancer cells under FLASH, the full spectra of radiobiological mechanisms are yet to be clarified. Currently the number of devices delivering FLASH dose rate is few and is mainly limited to experimental and modified linear accelerators. Nevertheless, FLASH research is increasing with new developments in all the main areas: radiobiology, technology and clinical research. This paper presents the current status of FLASH radiotherapy with the aforementioned aspects in mind, but also to highlight the existing challenges and future prospects to overcome them.

Highlights

The aim of radiotherapy is to deliver a tumoricidal dose to the neoplasm while keeping normal tissue toxicity to a minimum
Over the last few decades, radiotherapy has improved via novel technologies, such as image-guided radiation therapy (IGRT) and intensity-modulated radiation therapy (IMRT) and through the clinical implementation of particulate radiation with superior physical and radiobiological properties, as compared to the more-established photons and electrons [1,2]
Looking at cell viability and DNA damage repair in vitro, Beddok et al studied three lung cell lines after FLASH or conventional irradiation delivered with the same linear accelerators (LINACs) (4.5 MeV electrons) [41]

Summary

Introduction

The aim of radiotherapy is to deliver a tumoricidal dose to the neoplasm while keeping normal tissue toxicity to a minimum. Over the last few decades, radiotherapy has improved via novel technologies, such as image-guided radiation therapy (IGRT) and intensity-modulated radiation therapy (IMRT) and through the clinical implementation of particulate radiation with superior physical and radiobiological properties, as compared to the more-established photons and electrons [1,2]. Regardless of these advances, the research community continuously strives to improve the existing treatments by trialling new ways of increasing the therapeutic ratio. While the biological mechanisms behind FLASH are not fully elucidated, the scientific rationale behind the administration of ultra-high dose rates is the enhancement of the therapeutic window in radiation therapy through a better normal tissue sparing and similar, or an increased, tumour control, as compared to conventional therapies [4]

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