Synthesis and Application of Carborane Containing MR Imaging Agent

为了改善和优化有效的中子俘获疗法（NCT）治疗，有必要真实的跟踪载体在体内的分布。然而，使用现有技术难以估计肿瘤的硼含量。我们成功地合成了含有钆-二亚甲基三胺五乙酸（DTPA）单元的碳硼烷，其以商品名Magnevist市售并用作MR成像造影剂。通过MRI、ICP-AES和α-放射自显影术，使用荷瘤的Donryu大鼠在体内对Gd-碳硼烷络合物作为MR成像剂和硼载体剂进行了评价。MR成像显示，与Gd-DTPA相比，碳硼烷Gd-DTPA在体内代谢较慢。ICP-AES法测定结果表明，化合物进入正常组织并迅速代谢，而在肿瘤和脑组织中不蓄积。α-放射自显影显示在内脏器官和肿瘤组织的坏死中获得高水平的硼。

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.