Autoradiography of boron-porphyrin derivatives and other boron compounds for neutron capture therapy

1)在过去的24年中，已证明巯基十一氢十二硼酸盐作为中子捕获核素用于脑肿瘤的硼中子捕获治疗是有效的。对更有效的化合物或适用于除脑肿瘤以外的癌症的化合物的研究一直在继续。由加州大学的Stephen Kahl开发的硼四苯基卟啉（BTPP）被认为是有希望的肿瘤治疗药物。作为研究该物质效能的第一步，建议对包括BTPP在内的几种硼化合物进行中子诱导α-放射自显影研究。尽管Kahl的承诺，BTPP实际上是在1989年下半年才交付。BTPP通过全身途径（皮下注射）给药于移植犬骨肉瘤的裸鼠。在6、24、48和72小时后，处死动物，将整个身体冷冻并切片。这些切片被硝酸纤维素薄膜覆盖，并暴露在中子中，中子被硼捕获并产生锂和α粒子。通过对胶片上记录的这些轨迹的分析，可以得出结论，这种BTPP逐渐在肿瘤中积聚，与其他化合物不同。肿瘤周围的正常组织似乎没有任何显著量的硼。因此，BTPP被认为是适合于BNCT。毒理学和动力学研究将需要实际的治疗目的。2）动力学研究的巯基十一氢十二硼酸酯已被用于人类患者继续。

1) Mercaptoundecahydrododecaborate has proved over the past 24 years to be effective as a neutron capturing nuclide for boron-neutron capture therapy of brain tumors. The search for more efficient compounds or compounds applicable to cancers other than brain tumors has been continuing. Boronotetraphenylporphyrin (BTPP) developed by Stephen Kahl of California University (Barkeley) is suggested to be promising for tumor treatments. As the first step to study the efficacy of this substance, neutron-induced alpha-autoradiographic study of a few boron compounds including BTPP was proposed. In spite of Kahl's pledge, BTPP was actually delivered only in the latter half of 1989.BTPP was administered by a systemic route (hypodermal injection) into the nude mice carrying transplanted canine osteosarcoma. After 6, 24, 48 and 72 hours the animals were sacrificed, and the whole body was frozen and was sliced. The slices were covered with cellulose nitrate film and they were exposed to neutrons which were captured by boron and produced lithium and alpha particles. By the analyses of these tracks registered on the film, it was concluded that this BTPP gradually builds up in the tumor, different from other compounds. The normal tissue surrounding the tumor did not appear to have any significant amount of boron. Consequently BTPP was considered to be suited to BNCT.Toxicological and kinectic studies will be required for actual therapeutic purpose.2) Kinectic studies on mercaptoundecahydrododecaborate which has been used are continued with human patients.