Radiosynthesis of [18F]flumazenil for imaging benzodiazepine receptors and its evaluation in human volunteers using simultaneous PET-MRI

Fluorine-18 (18F) flumazenil (FMZ) was synthesized and purified using a single solid-phase cartridge and the formulation was tested in animals for biodistribution at various time points. A 90 min dynamic scan was acquired in human volunteers on simultaneous PET-MRI. The radiochemical purity was amounted to 94 ± 2%. The animal biodistribution showed high uptake in the brain specifically in the cortex region. The human images showed binding in benzodiazepines (BZ) receptor-rich regions, such as the neocortex, and the lowest uptake in the pons. [18F]FMZ was synthesized and purified using a sep-pak cartridge. This method allowed to apply this tracer in human studies showing the typical accumulation pattern in regions with high benzodiazepine receptors.