A radiotracer containing a synthetic amino acid analogue of L-leucine radiolabeled with fluorine F 18 with potential diagnostic imaging use. Similar to most amino acids, fluciclovine F18 appears to enter cells through the energy-independent L-type amino acid transporter (LAT) system. As an amino acid analogue, this agent is preferentially accumulated by tumor cells due to their increased metabolic needs; however, unlike naturally occurring amino acids, this non-natural amino acid-analogue radiotracer is not metabolized. Accordingly, fluciclovine F18 accumulates in tumor cells and can potentially be used to image tumors using positron emission tomography (PET).