Dynamic micro-PET studies were conducted using the 18F-labeled heterodimeric tracers [18F]AlF-PSMA-FAPI-01 and [18F]AlF-PSMA-FAPI-02 and the corresponding monomeric tracers [18F]FAPI-42 and [18F]AlF-PSMA-BCH in nude mice bearing A549-FAP or 22Rv1 tumor xenografts. The gene discussed is FAP; the disease is neoplasm.