T807 a novel tau positron emission tomography (PET) tracer. In Vitro Aggregated tau protein is a major neuropathological substrate central to the pathophysiology of neurodegenerative diseases such as Alzheimer's disease (AD). In vitro autoradiography results show that [ 18 F]T807 exhibits strong binding to PHF-tau positive human brain sections (K d =14.6 nM). A comparison of autoradiography and double immunohistochemical staining of PHF-tau and Ab on adjacent sections demonstrates that [ 18 F]T807 binding colocalizes with immunoreactive PHF-tau pathology, but does not highlight Ab plaques. [ 18 F]T807 strongly binds to tau lesions primarily made of paired helical filaments in Alzheimer’s brains e.g. intra and extraneuronal tangles and dystrophic neurites. [ 18 F]T807 off-target binding to neuromelanin- and melanin-containing cells and, to a lesser extent, to brain hemorrhagic lesions is identified. MCE has not independently confirmed the accuracy of these methods. They are for reference only. In Vivo [ 18 F]T807 is able to cross the blood–brain barrier and ished out quickly in mice model. [ 18 F]T807 clears rapidly from the brain, with activity values decreasing from 4.43% ID/g at 5 minutes to 0.62% ID/g at 30 minutes. Kidney elimination is a significant clearance pathway, resulting in a maximum tracer concentration of 14.99% ID/g in the kidneys at 5 minutes, which decreases to 5.52% ID/g at 30 minutes. The accumulation of activity in muscle and bone remain relatively low throughout the PET scan . MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid