JRR-4における中性子捕捉療法の線量評価
2007 年 42 巻 1 号 p. 23-37
詳細
2007 年 42 巻 1 号 p. 23-37
In this paper, an outline of dose estimations for boron neutron capture therapy (BNCT) is presented from standpoint medical physics and biological field. BNCT is a sort of the radiation therapy for an obstinate cancer like malignant brain tumor. To perform clinical trials of the BNCT, characteristics of doses given to a patient by neutron irradiation have to be comprehended accurately. To investigate RBE for several organs with neutron, in-vitro biological experiments involving neutron irradiations were carried out. The dose estimation method for the BNCT and the dose characteristics by neutron irradiations are introduced. First doses were analyzed based on experimental measurement. Distributions of thermal neutron flux and gamma-ray dose rate that are fundamental values of the dosimetry were determined by experiments with a water phantom, then dose distributions and the characteristics in the phantom were analyzed based on the measurements and the RBE values. Based on the dosimetry techniques, a treatment planning system which can determine accurately the doses and its distributions in a patient using Monte-Carlo transport code was developed in JAEA. To verify the accuracy of the dose calculation, the phantom experiments was reprinted using the system, then the calculation values were compared with the measurement values obtained from the phantom experiments. This report describes the dosimetry method for BNCT based on experimental measurements and outline of the computational dosimetry system for BNCT.
