Dosimetry in leakage of (188)Re-DTPA during intracoronary balloon brachytherapy.

Rhenium-188 is reported to be one of the best radionuclides for intracoronary balloon brachytherapy. Among several preparations of (188)Re available for brachytherapy, (188)Re-diethylene triamine penta-acetic acid (DTPA) and (188)Re-mercaptoacetyltriglycine (MAG3) are recommended owing to their rapid excretion via the renal system and the absence of accumulation in the thyroid. The aim of this study was to calculate the dose of radiation exposure in a real human accident. During a 4-year clinical trial of (188)Re-DTPA balloon brachytherapy in 242 patients, there was one accident involving balloon leakage. Dosimetry was performed by both image-based and biological analysis. The radiation exposure to the whole body was calculated as 113 mGy by image-based analysis and 83 or 88 mGy by biological analysis, which was approximately half the reported dose in the case of (188)Re-perrhenate. The radiation exposures to other vital organs were also within the tolerated ranges. We conclude that (188)Re-DTPA has better clinical feasibility and safety for intracoronary balloon brachytherapy than (188)Re-perrhenate.