Production and tumour uptake of [⁶⁴Cu]pyruvaldehyde-bis (N ⁴-methylthiosemicarbazone) for PET and/or therapeutic purposes

BACKGROUND: Copper-64 (T_1/2 = 12.7°h) is an important radionuclide used both in PET imaging and therapy. [⁶⁴Cu]- pyruvaldehyde-bis(N⁴-methylthiosemicarbazone) ([⁶⁴Cu]- PTSM) has already been used in the detection of cerebral and myocardial blood flow. In this study, a simple production method and tumour accumulation of [⁶⁴Cu]-PTSM in fibrosarcoma-bearing mice were reported. MATERIAL AND METHODS: Cu-64 was produced via the ⁶⁸Zn(p, αn)⁶⁴Cu nuclear reaction. [⁶⁴Cu]-PTSM was prepared using in-house made PTSM ligand and [⁶⁴Cu]cuprous acetate and injected to fibrosarcoma-bearing mice. RESULTS: Copper-64 was prepared in chloride form (≈200 mCi, > 95% chemical yield at 180° μA for 1.1 h irradiation, radionuclidic purity μ 96%, copper-67 as impurity). The solution of ⁶⁴Cu-PTSM was prepared in μ 80% radiochemical yield and more than 98% radiochemical purity. A significant tumour uptake was observed 2 hours post injection in tumour-bearing mice (tumour/muscle: 9, tumour/blood: 6). CONCLUSION: [ ⁶⁴Cu]-PTSM was prepared on a radiopharmaceutical scale using readily available zinc-68, with high quality and was shown to possess application in the therapy and/or imaging of fibrosarcoma.