[18F]F-4

[18F]F-4 is a radiopharmaceutical developed for positron emission tomography (PET) imaging of tau protein aggregates, which are characteristic of Alzheimer's disease (AD) and other non-Alzheimer's disease (non-AD) tauopathies. It is a fluorinated derivative of the carbazole scaffold of [18F]PI-2620, another tau PET tracer. The selection of [18F]F-4 was based on in vitro binding assays in human tissues from AD, progressive supranuclear palsy, and corticobasal degeneration patients, combined with in silico predictions for blood-brain barrier permeability. Preclinical in vivo PET imaging in healthy rats demonstrated suitable brain uptake and kinetics for neuroimaging. A first-in-human PET study in healthy subjects and AD patients confirmed its utility as an alternative radiopharmaceutical for imaging tau protein.