Study on Detectors for On-line Measurement and estimation of absorbed energy using SPECT system in Neutron Capture Therapy

中子俘获治疗中SPECT系统吸收能量在线测量和估算探测器的研究

• 批准号: 07558186
• 负责人: KOBAYASHI Tooru
• 金额: $ 3.52万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07558186/
• 关键词: Neutron Capture Therapy; On-line Measurement; SPECT; Prompt Gamma-ray measuement; CdTe Semiconductor; Heavy Water Facility; Lithium Neutron Shielding; 中性子捕捉療法; 半導体検出器; 生体内照射線量分布; 同時測定法; 検出素子; 即発γ線スペクトル; CdTe(カドミウム-テルル)

The purpose of this research is to clarify the feasibility of single photon emission computed tomography system with prompt gamma analysis (named PG-SPECT system), which is expected as an effective real-time measurement method for dose distribution in a living body. We put emphasis on the optimization of the detector material and its size, and the improvement in the system maintenance, such as disuse of the cooling with liquid nitrogen etc., which is usually indispensable to semiconductor detector.In 1995 (Heisei 7), the applicability of Ge semiconductor detector and CdTe semiconductor detector to the PG-SPECT system were studied. Especially, the CdTe detector is thought to be an adequate detector for this system, because of its possibilities of downsizing and disuse of the cooling by the recent remarkable innovation.In 1996 (Heisei 8), the characteristics of CdTe detector at room temperature was estimated, and the effectiveness of the simple cooling method applying Peltier effect was researched by experiments and simulation calculation. It was confirmed that the CdTe detector with the Peltier cooling had great potentialities. Moreover, shielding sheets for thermal neutrons were made using polyethylene mixed with 6LiF,which purchased in 1995, at 30 weight percent, and its effectiveness was confirmed from experiments.In 1997 (Heisei 9), the characteristics evaluation of Ge detector and CdTe detector was continued by experiments and simulation calculations. Furthermore, (1) the reduction of statistical error at low-counts and (2) the collimation system for small-size detector at mixed field of neutrons and gamma-rays were examined. From those results, some research subjects are newly extracted for the next steps.

这项研究的目的是阐明具有及时的伽马分析（命名为PG-spect System）的单光子发射计算机断层扫描系统的可行性，这是一种有效的实时测量方法，可用于活体中的剂量分布。我们强调了探测器材料及其大小的优化以及系统维护的改进，例如用液氮来取消冷却，通常对于半导体检测器是必不可少的。1995（Heisei 7）（Heisei 7）（Heisei 7），GE半导体检测器的适用性和CDTE半多数探测器对PG-SPECT进行了调整。尤其是，CDTE检测器被认为是该系统的足够检测器，因为它最近出色的创新可能会缩减和废除冷却。在1996年（Heisei 8）（Heisei 8），估计了CDTE检测器在室温下的特征，并且通过实验和模拟计算了简单冷却方法应用Peltier效应的有效性。有人证实，带有Peltier冷却的CDTE检测器具有很大的潜力。此外，使用与6LIF混合的聚乙烯制成了热中子的屏蔽板，该片段于1995年以30％的重量购买，并通过实验确认了其有效性。在1997年（Heisei 9），通过实验和模拟计算继续进行GE检测器和CDTE检测器的特征评估。此外，（1）检查了低计数和（2）在中子和γ射线混合场上小型检测器的准直探测器的统计误差的减少。从这些结果中，一些研究对象是新提取的。