Pöller F, Sauerwein W
Department of Medical Radiation Physics, University of Essen, Germany.
Radiat Res. 1995 Apr;142(1):98-106.
It was shown that radiation effects in tumor cells treated with fast neutrons may be increased by the neutron capture reaction 10B(n, alpha)7Li. The classic approach for macroscopic dosimetry in fast-neutron therapy cannot be applied to the dose in boron neutron capture therapy (BNCT). The effectiveness of BNCT in killing tumor cells depends on the number of 10B atoms delivered to the tumor, the subcellular distribution of 10B and the thermal neutron fluence at the site of the tumor. Monte Carlo calculations of the energy depositions of short-range particles with high LET coming from 10B disintegrations were performed and compared to the observed biological effects. The simulation allows us to study the influence of the localization of intracellular 10B in the nucleus, cytoplasma, plasma membrane or extracellular space. The biological response function which describes the probability of the lethal effect produced by a single particle track through the cell nucleus was found by comparing the calculated microscopic dose distribution spectra for single events with the survival observed experimentally. Calculations for a human melanoma cell population treated as a monolayer in the presence or absence of boron with d(14)+Be neutrons will be demonstrated. Two different boron compounds enriched in 10B were investigated in this study: boric acid (H3 10BO3) and p-dihydroxyboryl phenylalanine (BPA). The study shows that a high fraction of BPA enters the cytoplasm while boric acid was found only in the extracellular space. The computer simulations indicate that BPA yields a higher potential effectiveness for inactivation of melanoma cells than boric acid.
结果表明，快中子辐照的肿瘤细胞中的辐射效应可能会因中子俘获反应10B(n,α)7Li而增强。快中子治疗中宏观剂量学的经典方法不能应用于硼中子俘获治疗（BNCT）中的剂量计算。BNCT杀死肿瘤细胞的有效性取决于递送至肿瘤的10B原子数量、10B的亚细胞分布以及肿瘤部位的热中子注量。对来自10B衰变的高传能线密度短程粒子的能量沉积进行了蒙特卡罗计算，并与观察到的生物学效应进行了比较。该模拟使我们能够研究细胞内10B在细胞核、细胞质、质膜或细胞外空间中的定位影响。通过将单次事件的计算微观剂量分布谱与实验观察到的存活率进行比较，发现了描述单个粒子径迹穿过细胞核产生致死效应概率的生物学响应函数。将展示对作为单层处理的人黑色素瘤细胞群体在有或无硼存在下用d(14)+Be中子进行的计算结果。本研究中研究了两种富含10B的不同硼化合物：硼酸（H310BO3）和对二羟基硼基苯丙氨酸（BPA）。研究表明，很大一部分BPA进入细胞质，而仅在细胞外空间发现硼酸。计算机模拟表明，BPA对黑色素瘤细胞失活的潜在有效性高于硼酸。
