Brain PET in the era of anti-amyloid-β antibody therapy for Alzheimer disease.

Here the current and emerging roles of brain positron emission tomography (PET) in Alzheimer's disease (AD) in the era of anti-amyloid-β antibody therapy, with a focus on clinical applications, methodological considerations, and future perspectives were reviewed. A narrative review of the literature on PET imaging in AD, including FDG-PET, amyloid PET, and tau PET, was conducted with particular emphasis on their clinical utility in diagnosis, and disease monitoring. Relevant guidelines, including appropriate use criteria and Japanese clinical guidelines, were also reviewed. FDG-PET provides valuable information for the differential diagnosis of neurodegenerative dementias based on characteristic hypometabolic patterns, although its role remains supportive due to the lack of direct assessment of molecular pathology. Amyloid PET enables noninvasive visualization of cerebral amyloid-β deposition and has become essential for confirming eligibility for anti-amyloid therapies. Standardized use criteria and interpretation guidelines are critical for appropriate clinical implementation. Quantitative approaches, such as standardized uptake value ratios (SUVRs) and the Centiloid scale, improve comparability across studies and institutions. Tau PET reflects neurofibrillary pathology and correlates with disease severity and progression, with increasing relevance for patient stratification. In addition, recent advances in high-resolution dedicated brain PET systems and artificial intelligence-based image analysis are expected to enhance diagnostic performance and workflow efficiency. In the era of disease-modifying therapy, brain PET imaging has become integral to the clinical management of AD. Amyloid PET is indispensable for treatment eligibility, while tau PET provides complementary information on disease stage and prognosis. Ongoing technological and methodological advancements will further expand the role of PET imaging in precision medicine for dementia.