面向HIRFL-CSR主动式点扫描技术的剂量标定方法研究(英文)

Calibration Procedure for Beam Monitors in Scanned Carbon Beam Therapy at HIRFL

基于HIRFL-CSR肿瘤重离子治疗终端主动式束流配送系统发展了面向三维点扫描适形调强治疗技术的在线监测器点扫描剂量标定方法。为了验证点扫描剂量标定方法的稳定性和可靠性,利用HIRFL-CSR提供的C离子束考察了在线监测器剂量标定因子的能量依赖以及不同扫描步长的影响。结果表明:在线监测器剂量标定因子存在能量依赖;不同扫描步长对剂量标定因子影响较小(偏差小于1.8%)。证明了点扫描剂量标定方法的稳定性和可靠性。鉴于在三维点扫描适形调强治疗技术中影响在线监测器点扫描剂量标定因子的因素较多,建议今后续继续研究点扫描剂量标定因子影响因素,修正和完善点扫描剂量标定方法。

As an important step of the application of spot scanning technique to heavy ion therapy,an experimental calibration procedure of online beam monitors based on standard of absorbed dose to water has recently been developed for scanned pencil-like carbon ion beam in the deep-seated tumor therapy terminal at the Heavy Ion Research Facility in Lanzhou(HIRFL).In this work,creating homogeneous irradiation field with steerable spot beam was tested using a 207 MeV / u pencil-like carbon ion beam.Then the verification of energy dependence of the calibration factors(CFs) and the influence of scanning step on the CF were also shown,as a part of the heavy ion clinic dosimetry researches.The results showd that the monitor CF presented energy dependence and performed stable response with deviation of 1.8%for the variation of scan steps.In this paper,the suitability and effectiveness of beam monitor calibration procedure for dynamic particle beam delivery were verified and the further research points to improve the calibration procedure were suggested.