当前位置: X-MOL 学术J. Synchrotron Radiat. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Study of the X‐ray radiation interaction with a multislit collimator for the creation of microbeams in radiation therapy
Journal of Synchrotron Radiation ( IF 2.4 ) Pub Date : 2021-02-09 , DOI: 10.1107/s1600577520016811
P Pellicioli 1 , M Donzelli 1 , J A Davis 2 , F Estève 3 , R Hugtenburg 4 , S Guatelli 2 , M Petasecca 2 , M L F Lerch 2 , E Bräuer-Krisch 1 , M Krisch 1
Affiliation  

Microbeam radiation therapy (MRT) is a developing radiotherapy, based on the use of beams only a few tens of micrometres wide, generated by synchrotron X‐ray sources. The spatial fractionation of the homogeneous beam into an array of microbeams is possible using a multislit collimator (MSC), i.e. a machined metal block with regular apertures. Dosimetry in MRT is challenging and previous works still show differences between calculated and experimental dose profiles of 10–30%, which are not acceptable for a clinical implementation of treatment. The interaction of the X‐rays with the MSC may contribute to the observed discrepancies; the present study therefore investigates the dose contribution due to radiation interaction with the MSC inner walls and radiation leakage of the MSC. Dose distributions inside a water‐equivalent phantom were evaluated for different field sizes and three typical spectra used for MRT studies at the European Synchrotron Biomedical beamline ID17. Film dosimetry was utilized to determine the contribution of radiation interaction with the MSC inner walls; Monte Carlo simulations were implemented to calculate the radiation leakage contribution. Both factors turned out to be relevant for the dose deposition, especially for small fields. Photons interacting with the MSC walls may bring up to 16% more dose in the valley regions, between the microbeams. Depending on the chosen spectrum, the radiation leakage close to the phantom surface can contribute up to 50% of the valley dose for a 5 mm × 5 mm field. The current study underlines that a detailed characterization of the MSC must be performed systematically and accurate MRT dosimetry protocols must include the contribution of radiation leakage and radiation interaction with the MSC in order to avoid significant errors in the dose evaluation at the micrometric scale.

中文翻译:

X射线辐射与多缝准直器相互作用的研究,用于在放射治疗中产生微束

微束放射疗法 (MRT) 是一种发展中的放射疗法,它基于使用由同步加速器 X 射线源产生的只有几十微米宽的光束。使用多缝准直器 (MSC) 可以将均匀光束空间分割成微光束阵列,带有规则孔的机加工金属块。MRT 中的剂量学具有挑战性,以前的工作仍然显示计算和实验剂量分布之间的差异为 10-30%,这对于临床治疗实施是不可接受的。X 射线与 MSC 的相互作用可能导致观察到的差异;因此,本研究调查了由于辐射与 MSC 内壁的相互作用和 MSC 的辐射泄漏引起的剂量贡献。在欧洲同步加速器生物医学光束线 ID17 上,针对不同的场大小和用于 MRT 研究的三个典型光谱,评估了水等效体模内的剂量分布。使用胶片剂量测定法来确定辐射与 MSC 内壁相互作用的贡献;实施蒙特卡罗模拟来计算辐射泄漏贡献。结果证明这两个因素都与剂量沉积相关,尤其是对于小场。与 MSC 壁相互作用的光子可能会在微束之间的山谷区域带来高达 16% 的剂量。根据所选光谱,靠近体模表面的辐射泄漏对 5 mm × 5 mm 场的谷剂量贡献高达 50%。当前的研究强调,必须系统地对 MSC 进行详细的表征,准确的 MRT 剂量学协议必须包括辐射泄漏的贡献和与 MSC 的辐射相互作用,以避免在微米尺度的剂量评估中出现重大错误。结果证明这两个因素都与剂量沉积相关,尤其是对于小场。与 MSC 壁相互作用的光子可能会在微束之间的山谷区域带来高达 16% 的剂量。根据所选光谱,靠近体模表面的辐射泄漏对 5 mm × 5 mm 场的谷剂量贡献高达 50%。当前的研究强调,必须系统地对 MSC 进行详细的表征,准确的 MRT 剂量学协议必须包括辐射泄漏的贡献和与 MSC 的辐射相互作用,以避免在微米尺度的剂量评估中出现重大错误。结果证明这两个因素都与剂量沉积相关,尤其是对于小场。与 MSC 壁相互作用的光子可能会在微束之间的山谷区域带来高达 16% 的剂量。根据所选光谱,靠近体模表面的辐射泄漏对 5 mm × 5 mm 场的谷剂量贡献高达 50%。目前的研究强调,必须系统地对 MSC 进行详细的表征,准确的 MRT 剂量测定协议必须包括辐射泄漏的贡献和与 MSC 的辐射相互作用,以避免在微米尺度的剂量评估中出现重大错误。根据所选光谱,靠近体模表面的辐射泄漏对 5 mm × 5 mm 场的谷剂量贡献高达 50%。目前的研究强调,必须系统地对 MSC 进行详细的表征,准确的 MRT 剂量测定协议必须包括辐射泄漏的贡献和与 MSC 的辐射相互作用,以避免在微米尺度的剂量评估中出现重大错误。根据所选光谱,靠近体模表面的辐射泄漏对 5 mm × 5 mm 场的谷剂量贡献高达 50%。当前的研究强调,必须系统地对 MSC 进行详细的表征,准确的 MRT 剂量学协议必须包括辐射泄漏的贡献和与 MSC 的辐射相互作用,以避免在微米尺度的剂量评估中出现重大错误。
更新日期:2021-03-04
down
wechat
bug