[E-18/19]-4, an anionic GCPII/PSMA inhibitor for image-guided intervention in prostate cancer, is described. [19F]4 is radiolabeled with a radiochemical yield that is >27% and a molar activity of 190 +/- 50 mCi/ptmol in a <1 h, one-step, aqueous isotopic exchange reaction. [F-19]-4 allows PSMA expression to be imaged by fluorescence (FL) and [18F]-PET. PC3-PIP (PSMA-positive, EC50 = 6.74 +/- 1.33 nM) cancers are specifically delineated in mice that bear 3 million (18 mg) PC3-PIP and PC3 (control, PSMA-negative) cells. Colocalization of [F-18/19]-4 PET, fluorescence, scintillated biodistribution, and PSMA expression are observed.