Assessment of dose rate scaling factors used in NCTPlan treatment planning code for the BNCT beam of THOR
Assessment of dose rate scaling factors used in NCTPlan treatment planning code for the BNCT beam of THOR
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DOI：
10.1016/j.apradiso.2009.03.033
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发表时间：
2009-07-01
影响因子：
1.6
通讯作者：
Chou, F. I.
中科院分区：
文献类型：
--
作者：
Hsu, F. Y.;Liu, M. T.;Chou, F. I.
清华大学开放池式反应堆（THOR）多年来一直用于硼中子俘获治疗（BNCT）的可行性研究和技术改进。2004年夏天，在美国THOR完成了BNCT的超热射束端口的重建，并进行了研究和实验，以加速台湾第一例BNCT的临床治疗。NCTPlan是一种基于蒙特卡罗的临床治疗计划代码，在这项工作中用于计算BNCT的剂量率分布。在THOR BNCT出束口前照射自制的带有伺服电机控制系统的Snyder头体模。体模由安装在丙烯酸基底上的丙烯酸树脂浇铸树脂浸渍的3 mm石英棉外壳制成，并充满水。将金箔（裸露和镉覆盖）和成对的离子室（一个具有石墨壁并填充有CO2气体，另一个具有A-150塑料组织等效壁并填充有组织等效气体）放置在Snyder体模内，以测量和估计射束中心轴上的深度-剂量分布。剂量组分包括热中子、快中子、光子和B-10（n，α）Li-7反应发射的α粒子的贡献。对深度剂量分布的计算结果与实测结果进行了比较和分析。剂量率比例因子（DRSFs）定义为BNCT体模内辐射场中每个剂量分量单独导出的归一化因子，其提供测量数据和计算数据之间的最佳一致性。本文报道了THOR的BNCT射束的体模内剂量学计算和实验结果，以及NCTPlan程序中所确定的DRSF。(C)2009爱思唯尔有限公司版权所有。
Tsing Hua open-pool reactor (THOR) at Tsing Hua University in Taiwan has been used to investigate the feasibility and to enhance the technology of boron neutron capture therapy (BNCT) for years. A rebuilt epithermal beam port for BNCT at THOR was finished in the summer of 2004, and then researches and experiments were performed to hasten the first clinical treatment case of BNCT in Taiwan in the near future. NCTPlan, a Monte Carlo-based clinical treatment planning code, was used to calculate the dose-rate distributions of BNCT in this work. A self-made Snyder head phantom with a servo-motor control system was irradiated in front of the THOR BNCT beam exit. The phantom was made from a 3 mm shell of quartz wool impregnated with acrylic casting resin mounted on an acrylic base, and was filled with water. Gold foils (bare and cadmium-covered) and paired ion chambers (one with graphite wall and filled with CO2 gas, another with A-150 plastic tissue equivalent wall and filled with tissue equivalent gas) were placed inside the Snyder phantom to measure and estimate the depth-dose distributions in the central axis of the beam. Dose components include the contribution of thermal neutrons, fast neutrons, photons and emitted a particles from B-10(n,alpha)Li-7 reaction. Comparison and analysis between computed and measured results of depth-dose distributions were made in this work. Dose rate scaling factors (DRSFs) were defined as normalization factors derived individually for each dose component in the BNCT in-phantom radiation field that provide the best agreement between measured and computed data. This paper reports the in-phantom calculated and experimental dosimetry and the determined DRSFs used in NCTPlan code for the BNCT beam of THOR. (C) 2009 Elsevier Ltd. All rights reserved.