PET imaging using 64Cu-labeled sulfophthalocyanines: Synthesis and biodistribution

Sulfonated metallo phthalocyanines (MPcS n ) are second generation photosensitizers advanced for photodynamic therapy of various medical applications. A series of ZnPcS n was demetallated and subsequently converted to the corresponding [ 64Cu]CuPcS n in 40–50% isolated yields and >98% radiochemical purities. Tumor-bearing mice were injected with the 64Cu-labeled products and subjected to 3-h dynamic PET imaging studies. Biodistribution patterns showed characteristic differences between the various derivatives. Tumor uptake was detected only for the amphiphilic derivatives [ 64Cu]CuPcS 2 and [ 64Cu]CuPcS 3C 6 (1–1.5%ID/g). The biological data suggest that PET imaging with [ 64Cu]CuPc can be used to establish structure–PDT efficacy relationships for Pc-based photosensitizers.