There has been a recent revival of interest in the FLASH effect, after experiments have shown normal tissue sparing capabilities of ultra-high-dose-rate radiation with no compromise on tumour growth restraint. A model has been developed to investigate the relative importance of a number of fundamental parameters considered to be involved in the oxygen depletion paradigm of induced radioresistance. An example eight-dimensional parameter space demonstrates the conditions under which radiation may induce sufficient depletion of oxygen for a diffusion-limited hypoxic cellular response. Initial results support experimental evidence that FLASH sparing is only achieved for dose rates on the order of tens of Gy s⁻¹ or higher, for a sufficiently high dose, and only for tissue that is slightly hypoxic at the time of radiation. We show that the FLASH effect is the result of a number of biological, radiochemical and delivery parameters. Also, the threshold dose for a FLASH effect occurring would be more prominent when the parameterisation was optimised to produce the maximum effect. The model provides a framework for further FLASH-related investigation and experimental design. An understanding of the mechanistic interactions producing an optimised FLASH effect is essential for its translation into clinical practice.

最近，人们对 FLASH 效应重新产生了兴趣，此前实验表明，超高剂量率辐射的正常组织保留能力不会影响肿瘤的生长抑制。已经开发了一个模型来研究被认为涉及诱导辐射抗性的氧耗竭范式的一些基本参数的相对重要性。一个示例 8 维参数空间演示了辐射可以诱导足够的氧气消耗以实现扩散受限的缺氧细胞反应的条件。^{初步结果支持实验证据表明，仅在几十 Gy s -1}量级的剂量率下才能实现 FLASH 保留或更高，对于足够高的剂量，并且仅适用于在辐射时略微缺氧的组织。我们表明，FLASH 效应是许多生物、放射化学和递送参数的结果。此外，当优化参数化以产生最大效果时，发生 FLASH 效果的阈值剂量将更加突出。该模型为进一步的 FLASH 相关调查和实验设计提供了框架。了解产生优化 FLASH 效果的机制相互作用对于将其转化为临床实践至关重要。