GRPR and neoplasm: Their results showed that the GRPR/integrin αvβ3 bispecific tracer ([18F]FB-BBN-RGD) achieved higher tumor uptake and tumor-to-background contrast ratios than both of its corresponding monospecific tracers ([18F]FB-BBN for GRPR and [18F]FB-RGD for integrin αvβ3).