Synthesis and preliminary evaluation of 47Sc-labeled FAPI-46 for cancer theranostics

To evaluate the suitability of 47 Sc for SPECT imaging and therapeutic effect, a fibroblast activation protein (FAP) inhibitor FAPI-46 was used for cancer theranostics in preclinical setting. 47 Sc was successfully produced via thermal neutron irradiation of 46 Ca and then conjugated with FAPI-46, achieving a high radiochemical purity over 98%. In vitro experiments confirmed the FAP mediated specific binding to MG-63 cells for 47 Sc-FAPI-46. Biodistribution and SPECT/CT imaging indicated specific uptake of 47 Sc-FAPI-46 in PANC-2 pancreatic tumors. Therapeutic experiments revealed an effective anti-tumor ability with negligible toxicity of 47 Sc-FAPI-46 in xenografted tumor mice.