Institute of Radiation Physics (IRA), Lausanne University Hospital and University of Lausanne, CH-1007 Lausanne, Switzerland.
Univ. Bordeaux, CNRS, LP2I Bordeaux, UMR 5797, F-33170 Gradignan, France.
Phys Med. 2023 Jun;110:102601. doi: 10.1016/j.ejmp.2023.102601. Epub 2023 May 16.
FLASH radiotherapy is a promising approach to cancer treatment that offers several advantages over conventional radiotherapy. With this novel technique, high doses of radiation are delivered in a short period of time, inducing the so-called FLASH effect - a phenomenon characterized by healthy tissue sparing without alteration of tumor control. The mechanisms behind the FLASH effect remain unknown. One way to approach this problem is to gain insight into the initial parameters that can distinguish FLASH from conventional irradiation by simulating particle transport in aqueous media using the general-purpose Geant4 Monte Carlo toolkit and its Geant4-DNA extension. This review article discusses the current status of Geant4 and Geant4-DNA simulations to investigate mechanisms underlying the FLASH effect, as well as the challenges faced in this research field. One of the primary challenges is to accurately simulate the experimental irradiation parameters. Another challenge is the temporal extension of the simulations. This review also focuses on two hypotheses to explain the FLASH effect - namely the oxygen depletion hypothesis and the inter-track interactions hypothesis - and discusses how the Geant4 toolkit can be used to investigate them. The aim of this review is to provide an overview of Geant4 and Geant4-DNA simulations for FLASH radiotherapy and to highlight the challenges that need to be overcome in order to better study the FLASH effect.
FLASH 放射治疗是一种有前途的癌症治疗方法，与传统放射治疗相比具有多个优势。利用这项新的技术，可以在短时间内提供高剂量的辐射，从而产生所谓的 FLASH 效应——一种以不改变肿瘤控制为特征的健康组织保护现象。FLASH 效应背后的机制尚不清楚。一种解决此问题的方法是通过使用通用的 Geant4 蒙特卡罗工具包及其 Geant4-DNA 扩展来模拟水介质中的粒子传输，从而深入了解可以区分 FLASH 和常规照射的初始参数。本文综述了 Geant4 和 Geant4-DNA 模拟在研究 FLASH 效应机制以及在该研究领域中面临的挑战方面的现状。主要挑战之一是准确模拟实验照射参数。另一个挑战是模拟的时间扩展。本文综述还重点介绍了两种解释 FLASH 效应的假说，即氧气耗竭假说和轨道间相互作用假说，并讨论了如何使用 Geant4 工具包来研究它们。本文综述的目的是提供关于 FLASH 放射治疗的 Geant4 和 Geant4-DNA 模拟的概述，并强调需要克服的挑战，以便更好地研究 FLASH 效应。
