Dose-Rate Variations for Patient Treatments in Flash and conventional radiation therapy

几十年来，放射治疗一直是癌症治疗的重要组成部分。而当 对肿瘤控制参数已有较好的认识，正常组织并发症的可能性较大。 在设计治疗方案时，通常只将容量(NTCP)视为限制因素。 然而，随着对原发病变的治疗不断改进，NTCP及其对 生活质量已成为研究的焦点。 据报道，节省健康组织的最突出的方法之一是闪光放射治疗，即超辐射治疗。 TRAFAST(&GT；40GY/S)照射，据报道，这会产生令人难以置信的组织保存效果，而不会出现... 治疗肿瘤有很好的疗效。相反，也有极低剂量率辐射的报道。 以提供保护功能。总之，这些实验表明，目前的临床常规，治疗 事实上，中等剂量率为~2GY/分钟的患者在考虑 健康的组织副作用。 在临床实践中，患者接受各种放射治疗方式的治疗。而结果是- 不同方式的ING目标剂量是相似的，给药到正常组织的剂量和时间结构- 分娩的真实情况可能会有很大的差异。尽管治疗计划的剂量率范围不同，但 生物效应仅根据接收到的总剂量进行估计。 我们假设剂量率在放射治疗的结果中起着重要的作用 被用于特定的治疗方案。对于闪光疗法等极端情况，平均剂量- 利率没有充分反映相关的时间结构。我们将把蒙特卡罗模拟应用于 确定从临床分钟尺度(点扫描/机架旋转时间)到NA的时间结构 并评估对健康组织保留的潜在影响，这将促进- 证明放射治疗患者的生活质量。

Radiation therapy has been an important component in the treatment of cancer for many decades. While the parameters of tumor control have been relatively well understood, normal tissue complication proba- bilities (NTCPs) are often only thought of as constraining factors in the design of a treatment regimen. However, with continuously improving treatments of primary lesions, NTCP and their impact on the quality of life have moved into the focus of research. One of the most prominent methods reported to spare healthy tissue is FLASH radiation therapy, i.e. ul- trafast (>40 Gy/s) irradiations, which reportedly results in incredible tissue sparing effects without com- promising efficacy for tumor cure. Conversely, very low dose-rate irradiations have also been reported to offer protective features. Together, these experiments suggest that the current clinical routine, treating patients with a medium dose-rate of ~2 Gy/min, could in fact be the least favorable when considering healthy tissue side effects. In clinical practice, patients are treated with a variety of radiation treatment modalities. While the result- ing target doses are similar across modalities, the dose delivered to the normal tissue and the time struc- ture of the delivery can vary significantly. Despite the range of dose-rates across treatment plans, the biological effect is estimated only based on the total dose received. We hypothesize that dose-rate plays an important role in the outcome of radiation therapy that can be exploited for specific treatment scenarios. For extreme cases such as FLASH therapy, averaged dose- rates do not capture the relevant time structures adequately. We will apply Monte Carlo simulations to determine time structures from the clinical scale of minutes (spot scanning / gantry rotation time) to na- noseconds (intra-spot delivery time) and assess potential effects on healthy tissue sparing that would im- prove the quality of life for radiation therapy patients.