基于PARTER开展肿瘤Flash-RT研究——设计及计算

闪光放疗（Flash-RT）是近年来国际肿瘤放疗研究的前沿科技和研究热点，其使用超大剂量率（通常大于100 Gy/s）在极短时间（1~50 ms）内将全部放疗剂量注入靶区。研究发现其对正常组织体现出更小的损伤，同时可呈量级地降低放疗时间。中国工程物理研究院太赫兹自由电子激光装置上的超导电子加速器可提供最高平均流强5 mA的6~8 MeV电子束流，基于它的先进放疗研究平台（PARTER）具有Flash-RT研究的潜力。本文首次介绍PARTER及详细的Flash-RT专用靶和准直器物理设计方案，并给出关键参数的蒙特卡罗模拟计算结果。根据设计，平台上生物样品内注入的最高剂量率达2 000 Gy/s，剂量注入时间从μs到百ms持续可调，100 Gy/s以上剂量率覆盖深度超过20 cm，符合Flash-RT研究要求。文中给出了详细的计算过程和结果分析，以提供给之后在PARTER上开展Flash-RT实验研究作为基本参考数据。

Design and calculation of Flash-RT based on PARTER

Flash radiotherapy (Flash-RT) which is an international cutting-edge technology and hotspot in the domain oftumor radiotherapy in recent years delivers all the treatment dose into the target area in an ultra-short time (about 1-50 ms)at ultra-high dose rate (usually >100 Gy/s). Various researches revealed that Flash-RT could significantly reduce the time ofradiotherapy and bring less damage to normal tissues. The superconducting electron accelerator of the CTFEL facility inChina Academy of Engineering Physics can produce 6-8 MeV electron beam up to 5 mA in average current, and theplatform for advanced radiotherapy research (PARTER) based on the superconducting electron accelerator should be asuitable platform for Flash-RT research. Herein PARTER and the detailed design schemes of Flash-RT specific targets andcollimators are firstly introduced. According to Monte Carlo simulation, the maximum dose rate for the biological sampleson the platform was up to 2 000 Gy/s, and the exposure time was continuously adjustable from μs to 100 ms, and thecoverage depth for dose rate larger than 100 Gy/s was more than 20 cm, which meet the requirements of Flash-RT research.The detailed calculation process and result analysis are described for providing some basic reference data for the followingFlash-RT experiments which are carried out on PARTER.