Rogus R D, Harling O K, Yanch J C
Massachusetts Institute of Technology, Nuclear Reactor Laboratory, Cambridge 02139.
Med Phys. 1994 Oct;21(10):1611-25. doi: 10.1118/1.597267.
During the past several years, there has been growing interest in Boron Neutron Capture Therapy (BNCT) using epithermal neutron beams. The dosimetry of these beams is challenging. The incident beam is comprised mostly of epithermal neutrons, but there is some contamination from photons and fast neutrons. Within the patient, the neutron spectrum changes rapidly as the incident epithermal neutrons scatter and thermalize, and a photon field is generated from neutron capture in hydrogen. In this paper, a method to determine the doses from thermal and fast neutrons, photons, and the B-10(n, alpha)Li-7 reaction is presented. The photon and fast neutron doses are measured with ionization chambers, in realistic phantoms, using the dual chamber technique. The thermal neutron flux is measured with gold foils using the cadmium difference technique, the thermal neutron and B-10 doses are determined by the kerma factor method. Representative results are presented for a unilateral irradiation of the head. Sources of error in the method as applied to BNCT dosimetry, and the uncertainties in the calculated doses are discussed.
在过去几年中，人们对使用超热中子束的硼中子俘获疗法（BNCT）的兴趣与日俱增。这些束流的剂量测定具有挑战性。入射束主要由超热中子组成，但存在一些光子和快中子的污染。在患者体内，随着入射超热中子的散射和热化，中子能谱迅速变化，并且氢中的中子俘获会产生一个光子场。本文提出了一种确定热中子、快中子、光子以及B - 10（n，α）Li - 7反应剂量的方法。使用双电离室技术，在实际人体模型中用电离室测量光子和快中子剂量。用镉差技术通过金箔测量热中子通量，用比释动能因子法确定热中子和B - 10剂量。给出了头部单侧照射的代表性结果。讨论了该方法应用于BNCT剂量测定时的误差来源以及计算剂量的不确定性。
