Production and Labeling of Rhenium-186 and 188 via HEDP Using Natural Rhenium and it’s Biodistribution in Rats

In this project, production of radioactive rhenium for medical application by the Tehran Research Reactor, using natural rhenium along with labeling Rhenium by hydroxy ethiliden diphosphonate(HEDP) was investigated. After the production of Re-HEDP, its biodistribution in rats was also evaluated. To obtain the radioactive isotopes, natural rhenium with %99.9 purity, manufactured by Merck, was irradiated by the Tehran Research Reactor. Natural rhenium consists of two isotopes, Re-185 and Re-187, so irradiation the target with neutron in the reactor eventuates in two radioisotopes,186Re and 188Re. This research was performed in three phases. At the first phase, rhenium was irradiated in various irradiation boxes. The best result was 470mCi/mg after 5 days of irradiation. The chemical process includes oxidation of Re which in the presence of water results in formation of perhenic acid. Afterward, labeling of HEDP by means of Re is performed. All the process was performed in Lead Cell. Gamma spectroscopy and Thin Layer Chromatography were used for radionuclide and radiochemical purity, respectively. Re-HEDP was injected in rats and the biodistribution in different organs were studied by means of gamma spectroscopy. The results of the gamma spectroscopy approved the radionuclide purity. Labeling via HEDP resulted in %97.57 radiochemical purity. Biodistribution in rats showed (1.007 %ID/g 4h P.I), (0.89%ID/g 24h P.I) and (0.58 %ID/g 48h P.I) for bone and was the maximum percent of the absorbed dose rate.