Sodium 131i-mercaptododecaborate biodistribution in B-16 melanoma in mice

The biodistribution of sodium mercaptododecaborate labeled with radioactive iodine (I-131-BSH) in melanoma B-16 and surrounding tissues in mice has been studied for administration by various methods including intraperitoneal, single and double intratumor injection, and introduction under tumor bed. It is shown that a high content of I-131-BSH in the tumor is reached in all cases. The maximum accumulation of the boron compound is observed 1 h after administration. In this case the ratio of radioactivities in melanoma B-16 and surrounding tissues in most animals was greater than 3. A study of I-131-BSH uptake in tumor cells showed that a considerably greater accumulation of the compound is observed 3 and 6 h after intraperitoneal administration in the intercellular space (65.3% and 63.0%, respectively) in comparison to the cellular content (34.7% and 37.0%, respectively). The levels of accumulation become identical in about 12 h after administration. Approximately equal uptake of the boron compound in the intercellular space and tumor cells was observed over the entire period of investigation (0.5-2 h) after a single intratumor administration of I-131-BSH. The results of this study suggest that the intratumor administration of boron compounds is promising for neutron capture therapy, especially in combination with neutron teletherapy.