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, fluorine F 18 fluciclovine ([18]FACBC) 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 occuring amino acids, this non-natural amino acid-analogue radiotracer is not metabolized. Accordingly, [18]FACBC accumulates in tumor cells and can potentially be used to image tumors using positron emission tomography (PET). Check foractive clinical trials using this agent.