A direct head-to-head comparison study between [11C]-L-deprenyl (prototype of [11C]DED) and [18F]THK-5351 in patients with non-AD neurological disorders whose brains are not expected to harbor tau pathology concluded that [18F]THK-5351 was superior to [11C]-L-deprenyl for visualizing lesions undergoing reactive astrogliosis (Ishibashi et al., 2021). This evidence concerns the gene MAPT and Alzheimer disease.