Laramore G E, Risler R, Griffin T W, Wootton P, Wilbur D S
Department of Radiation Oncology, University of Washington Medical Center, Seattle 98195-6043, USA.
Bull Cancer Radiother. 1996;83 Suppl:191s-7s. doi: 10.1016/0924-4212(96)84911-5.
Fast neutron radiotherapy has proven to be an effective form of treatment in a selected subset of tumors (salivary gland tumors, sarcomas, and locally-advanced prostate cancer), but has not proven to be more beneficial than conventional photon irradiation for the majority of tumor types upon which it has been tested. Normal tissue tolerance limits preclude simply further escalating the neutron dose. Boron neutron capture (BNC) provides a way of selectively augmenting the radiation dose to the tumor. This process is described, and cell culture and animal model data reviewed. An irradiation configuration was developed where an enhancement of 2.10(-3) for 1 microgram of 10B per gram of tissue was achieved. This is similar to the enhancement achievable in the center of a 20 x 20 cm field envisioned for future applications such as metastases in the brain. A boron concentration of 50 micrograms per gram of tumor tissue leads to a 10% increase in the delivered physical dose in this scenario. The first human test of BNC enhancement of a fast neutron radiotherapy beam using pharmacologically-acceptable doses of orally-administered, 10B-enriched, L-paraboronophenylalanine is reported. An enhancement of tumor response was demonstrated for a melanoma skin nodule test system. Boron levels achieved in blood, skin, and tumors are presented. Future research plans are discussed.
快中子放射治疗已被证明在某些特定类型的肿瘤（唾液腺肿瘤、肉瘤和局部晚期前列腺癌）中是一种有效的治疗方式，但对于大多数已对其进行测试的肿瘤类型而言，尚未证明它比传统光子照射更具优势。正常组织的耐受极限使得无法简单地进一步提高中子剂量。硼中子俘获（BNC）提供了一种选择性增加肿瘤辐射剂量的方法。本文描述了这一过程，并对细胞培养和动物模型数据进行了综述。开发了一种照射配置，每克组织中1微克10B可实现2.10（-3）的增强效果。这与设想用于未来诸如脑转移等应用的20×20厘米野中心可实现的增强效果相似。在这种情况下，每克肿瘤组织中50微克的硼浓度会使 delivered physical dose增加10%。报道了首次使用药理学上可接受剂量的口服10B富集的L-硼苯丙氨酸对快中子放射治疗束进行BNC增强的人体试验。在黑色素瘤皮肤结节测试系统中证明了肿瘤反应增强。给出了血液、皮肤和肿瘤中达到的硼水平。讨论了未来的研究计划。
