Distinction of neutron dose generated from equipment and patient in proton radiation therapy

为评价双散射型质子放射治疗机的中子剂量，研制了高灵敏度热中子探测器。此外，通过蒙特卡罗计算，在假定患者的水模体中评估中子分布和能谱。作为评价的结果，在从射束轴中心到12 cm的距离中的等中心处的中子剂量与质子剂量的比率为3。6 mSv/戈伊。质子放射治疗中的中子照射量不仅取决于来自设备的中子，而且还取决于质子与患者的碰撞。

To evaluate of the neutron dose generated from the proton radiation therapy equipment of the double scattered type, the high sensitivity thermal neutron detector was developed. In addition, the neutron distribution and the energy spectrum were evaluated in the water phantom that assumed the patient by Monte Carlo calculation. As a result of the evaluation, the ratio of the neutron dose to the proton dose at isocenter in the distance from a beam axis center to 12 cm was 3. 6 mSv/Gy. The neutron exposure in the proton radiation therapy depended on not only the neutron from the equipment but also the proton's colliding with the patent was confirmed.