Development of 62Zn bleomycin as a possible PET tracer

Bleomycin (BLM), labeled with radioisotopes, is widely used in therapy and diagnosis. In this study, BLM was labeled with 62Zn for oncologic PET studies. The complex was obtained at pH = 2 in saline at 90oC in 25 min. Radio-TLC showed an overall radiochemical yield of 95-97% (radiochemical purity > 97%). Stability of complex was checked in vitro in mice and human plasma/urine. Preliminary in vivo studies were performed to determine complex stability and distribution of 62Zn BLM in normal and fibrosarcoma-bearing mice. 62Zn BLM accumulated significantly in induced fibrosarcoma tumors in mice according to biodistribution/imaging studies. 62Zn BLM can be used in PET oncology studies due to its suitable physicochemical properties as a diagnostic complex in vitro and in vivo. Further studies should be performed for evaluation of the complex behavior in larger mammals. (author)