Preclinical studies of [⁶¹Cu]ATSM as a PET radiopharmaceutical for fibrosarcoma imaging

[⁶¹Cu]diacetyl-bis(N⁴-methylthiosemicarbazone) ([⁶¹Cu] ATSM) was prepared using in house-made diacetyl-bis(N⁴-methylthiosemicarbazone) (ATSM) ligand and [⁶¹Cu]CuCl₂ produced via the ^natZn(p, x)⁶¹Cu (180 μA proton irradiation, 22 MeV, 3.2 h) and purified by a ion chromatography method. [⁶¹Cu]ATSM radiochemical purity was >98 %, as shown by HPLC and RTLC methods. [⁶¹Cu]ATSM was administered into normal and tumor bearing rodents for up to 210 minutes, followed by biodistribution and co-incidence imaging studies. Significant tumor/non-tumor accumulation was observed either by animal sacrification or imaging. [⁶¹Cu]ATSM is a positron emission tomography (PET) radiotracer for tumor hypoxia imaging.