MCNP计算含肿瘤Snyder修正头部模型的硼中子俘获治疗剂量

为得出硼中子俘获治疗(BNCT)中不同能量中子在含肿瘤Snyder修正头部模型内的深度-剂量曲线,籍以进一步理解BNCT原理,优化BNCT治疗中子源的能谱分布,本文利用MCNP模拟计算0.025 3 eV、1 eV、1 keV、10 keV、100 keV、1 MeV和混合能量的超热中子源在含肿瘤Snyder修正头部模型内的硼剂量、热中子剂量、超热和快中子剂量以及次级光子剂量组分的深度-剂量分布,并在此基础上得到总的相对生物学剂量的深度-剂量分布,以判断不同能量组中子源在BNCT中的优劣。结果表明,热中子头皮浅表处硼剂量高于肿瘤区硼剂量;快中子源硼剂量小,但其剂量组分中超热和快中子剂量过大;超热中子具有一定的穿透性,在脑深部肿瘤区形成了较高的硼剂量和总的相对生物学剂量。说明超热中子具有良好的BNCT治疗效果,热中子和快中子不适宜用于脑部BNCT治疗。

Boron Neutron Capture Therapy Dose Calculation for Tumor Modified Snyder Head Phantom Using MCNP

For obtaining the depth-dose curves in tumor modified Snyder head phantom for series energy neutrons for boron neutron capture therapy （BNCT）, and optimizing the energy distribution of source neutron, ultimately, getting a better understanding of the principle of BNCT, MCNP was used for calculating the boron dose, thermal neutron dose, epithermal and fast neutron dose, induced photon dose and the total relative biologic effectiveness (RBE) dose in tumor modified Snyder head phantom for series energy neutrons, including 0.025 3 eV, 1 eV, 1 keV, 10 keV, 100 keV and 1 MeV. The results show that boron dose in superficial tissue of neutron is higher than in the tumor area; fast neutron has a small boron dose deposition in all depths, nevertheless, its epithermal and fast neutron dose is too high; epithermal neutron has a suitable penetrating ability, deposits a relatively high boron dose and total RBE dose in the target tumor area. It can conclude that epithermal neutron has a good BNCT curative effectiveness; thermal and fast neutrons are not good enough for BNCT use.