[PET in Neurology: Imaging Pathology, Metabolism, and Disease Progression]

Anti-amyloid-β therapies for Alzheimer's disease-lecanemab (Leqembi approved in September 2023) and donanemab (Kisunla®; approved in September 2024)-have been authorized in Japan and are now in clinical use. In parallel, amyloid positron emission tomography (PET) is now reimbursed by the national health insurance for determining treatment eligibility and three amyloid PET radiopharmaceuticals are currently approved. Amyloid PET images interpretation relies primarily on visual reads, which require dedicated training, and clinicians with limited PET imaging experience may find some cases challenging. Although quantitative approaches (e.g., standardized uptake value ratio and Centiloid metrics) are available, their accurate application likewise necessitates appropriate training. Moreover, the availability of tau PET, which images cerebral tau deposition, is also expanding. Additional PET relevant to neurological diseases include those assessing glucose metabolism, oxygen metabolism, amino acid transport, and dopaminergic systems. When used appropriately, these modalities enable a noninvasive, multidimensional assessment of the pathology, metabolism, and disease burden, thereby allowing for a more refined characterization of neurological disorders.