PREPARATION AND BIODISTRIBUTION OF ~(188)Re-DTPA

The radiolabeling of diethylenetriaminopentaacetate (DTPA) with 188Re is investigated. Under the optimum conditions, the labeling efficiency of 188ReDTPA is more than 95% and the in vitro stability of 188ReDTPA is satisfied. The radiochemical purity of 188ReDTPA decreases with the increase of dilution ratio of saline solution. The biodistribution of 188ReDTPA and Na188ReO4 in normal mice is studied. The data reveals that radioactivity levels in the thyroid gland and the stomach are lower in the 188ReDTPA group than in the Na188ReO4 perrhenate group. The concentration levels in other tissues including lung, liver, testis, muscle, and blood are low throughout this study for both agents. The 188ReDTPA is excreted primarily via kidney to urine. The result indicates that 188ReDTPA should be considered as a potential radiopharmaceutical for endovascular irradiation.