Evaluation of a [⁶⁷Ga]-Thiosemicarbazone Complex as Tumor Imaging Agent

[⁶⁷Ga]labeled 2-acetylpyridine 4,4-dimethylthiosemicarbazone ([⁶⁷Ga]- [APTSM₂]₂⁺) was prepared using freshly prepared [⁶⁷Ga]GaCl₃ and 2-acetylpyridine 4,4-dimethylthiosemicarbazone (APTSM₂) for 30 min at 90°C (radiochemical purity: >97% ITLC, >98% HPLC, specific activity: 15–20 Ci/mmol). Stability of the complex was checked in human serum for 37°C. The biodistribution of the labeled compound in vital organs of normal and fibrosarcoma bearing mice were compared with that of free Ga³⁺ cation up to 24h. Initial SPECT images and biodistribution results showed significant tumor uptake in fibrosarcoma-bearing mice after 2 hour post injection.