Biological characteristics of [^18F]-THK523 for tau imaging

Reliable and non-invasive diagnostic tools are highly valuable for successful therapeutic strategies for the treatment of Alzheimer＇s disease （AD）. The existence of neurofibrillary tangles （NFTs） consisting of tau pro- tein are one kind of the pathological features of AD, and its level of severity is correlated with the stage of AD. However, no clinically approved positron emission tomography （PET） probe is currently available for selective imaging of neurofibrillary tangles on patients. In this paper, we report our studies on biological characteristics of [^18F]-THK523 as a novel tau imaging probe. With low molecular weight, [^18F]-THK523 is stable, electri- cally neutral, lipophilic and non-mass concentration-dependent. Preliminary biological studies have shown the excellent properties of [^18F]-THK523 as brain imaging tracer for further research.