Synthesis and Application of Carborane Containing MR Imaging Agent

为了改进和优化有效的中子捕获治疗（NCT），有必要实时跟踪载体在体内的分布。然而，利用现有技术很难估计肿瘤中的硼含量。我们成功地合成了含钆-二亚甲基三胺五乙酸（DTPA）单元的碳硼烷，该单元以Magnevist的商品名上市，用作MR成像造影剂。采用MRI、ICP-AES、α-放射自显像等方法，在体内评价gd -碳硼烷配合物作为载硼剂和磁共振成像载体的作用。MR成像显示碳硼烷Gd-DTPA在体内代谢较Gd-DTPA慢。ICP-AES法测定结果表明，化合物能快速进入正常组织代谢，未在肿瘤组织和脑组织中积累。α-放射自显像显示，在内脏器官和肿瘤坏死组织中获得了高水平的硼。

In order to improve and optimize efficient neutron capture therapy (NCT) treatment, it is necessary to follow the distribution of a carrier in the body in real time. However, it has been difficult to estimate the boron content of the tumor using technologies available. We succeeded to synthesize the carborane containing gadolinium-dimethylenetriamine pentaacetic acid (DTPA) unit which is commercially available under the trade name of Magnevist and is used as an MR imaging contrast medium. The evaluation of the Gd-carborane complex as an MR imaging and boron carrier agent was carried out in vivo using tumor-bearing Donryu rats by means of MRI, ICP-AES, and α-autoradiography. The MR imaging revealed that the carborane Gd-DTPA was metabolized slower in the body in comparison with Gd-DTPA. The results of ICP-AES method indicated that compound was incorporated into normal tissues and metabolized quickly, whereas it was not accumulated into tumor and brain tissue. The α-autoradiography showed that a high level of boron was obtained in the internal organs and in the necrosis of tumor tissue.