Depth-dose evaluation for gadolinium neutron capture therapy

钆中子俘获疗法的深度剂量评估

基本信息

批准号：
03680197
负责人：
MATSUMOTO Tetsuo
金额：
$ 1.02万
依托单位：
Musashi Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

The isotope gadolinium (^<157>Gd) has been suggested as an alternative neutron capture (NCT) agent to ^<10>B. Possible advantages of Gd-NCT are as follows : (i) thermal neutron cross sections (245,000 barn) for ^<157>Gd is 66 times larger than that of ^<10>B. (ii) gadolinium neutron capture reactions produce prompt gamma-rays with relatively low energy accompanying by emission of low energy conversion and Auger electrons. (iii) gadolinium is used as a contrast medium for magnetic resonance imaging (MRI) and may lead to an effective Gd-NCT compound.In this study the depth-dose distributions were evaluated by phantom experiments and calculations for possible application of Gd-NCT. The experiments were carried out at the irradiation port in the experimental beam hole (7R) of JRR3M. The distributions of thermal neutron flux and gamma-ray dose rate in a tumor-simulated phantom were measured by gold foil activation, TLDs and film methods. A two-dimensional neutron-coupled gamma-ray transport code (DOT3.5) was also employed for the calculations of neutron and capture gamma-ray fluence rates.The calculations and experiments showed that (i) a significant dose can be delivered to a tumor when Gd is accumulated in the tumor. (ii) the dose distribution was a function of storongly interrelated parameters such as gadolinium concentrations, tumor site and collimator aperture (neutron beam size). (iii) the Gd-NCT by thermal neutrons appears to be strong potential for treatment of superficial tumors.

已建议将同位素gadolinium（ ^<157> gd）作为 ^<10> b的替代性中子捕获（NCT）剂。 GD-NCT的可能优势如下：（i） ^<157> GD的热中子横截面（245,000谷仓）大于 ^<10> b的66倍。（ii）中子捕获反应产生迅速的伽马射线，其能量相对较低，伴随着低能转化和螺旋电子的发射。（iii）Gadolinium用作磁共振成像（MRI）的对比介质，并可能导致有效的GD-NCT化合物。在这项研究中，通过Phantom实验评估了深度剂量分布，并计算可能应用GD-NCT 。实验是在JRR3M的实验梁孔（7R）的辐照端口进行的。通过金箔激活，TLD和膜方法测量了肿瘤模拟幻影中热中子通量和伽马射线剂量率的分布。还采用了二维中子耦合伽马射线传输代码（DOT3.5）进行中子的计算和捕获伽马射线的速率。计算和实验表明，（i）可以将显着剂量传递给A当GD积聚在肿瘤中时肿瘤。（ii）剂量分布是稳固相互关联的参数的函数，例如gadolinium浓度，肿瘤部位和准直孔径（中子束大小）。（iii）热中子的GD-NCT似乎是治疗浅表肿瘤的强大潜力。