Brain amyloid imaging has become an essential tool in the study and diagnosis of Alzheimer's disease (AD) and related neurodegenerative disorders.1,2 The ability to detect amyloid-β (Aβ) deposition in vivo has significantly enhanced our understanding of disease pathology, allowing for more accurate diagnosis, better differentiation between dementias, and improved patient selection for clinical trials.3,4 Since the first successful use of amyloid positron emission tomography (PET) with [¹¹C]Pittsburgh Compound-B ([¹¹C]PiB) in the early 2000s, the field has expanded with the development of several ¹⁸F-labeled tracers.5 These radiopharmaceuticals have made amyloid imaging more accessible by extending the imaging window and simplifying logistics compared to the short half-life of [¹¹C]PiB.

The global experience with amyloid imaging, however, is highly variable. In regions with well-established nuclear medicine infrastructure, amyloid PET has been increasingly incorporated into clinical workflows, providing crucial support for the diagnosis of AD, particularly in cases of atypical dementia and mild cognitive impairment (MCI). In North America and parts of Europe, regulatory approvals and reimbursement policies have played a key role in shaping clinical use, with the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) issuing guidelines for its appropriate application.6 Conversely, in many low- and middle-income countries, the high cost of tracers, limited PET scanner availability, and a lack of trained personnel have restricted the widespread adoption of this technology. These disparities raise important questions about the equity of access to advanced diagnostic tools and the potential consequences for patient care and research efforts worldwide.

Beyond accessibility, the clinical utility of amyloid imaging remains a topic of discussion. While amyloid PET has demonstrated high sensitivity and specificity for detecting fibrillar amyloid deposits, its role in routine clinical practice is still debated. One of the main challenges is the interpretation of amyloid positivity in individuals without cognitive impairment, as a significant proportion of cognitively normal elderly individuals exhibit amyloid accumulation without developing dementia.6 Furthermore, the relationship between amyloid deposition and cognitive decline is complex, with other pathological processes, such as tau aggregation, neuroinflammation, and vascular dysfunction, playing crucial roles in disease progression.7,8 As a result, current research is focused on integrating amyloid imaging with other biomarkers, including cerebrospinal fluid (CSF) analysis, tau PET, and emerging plasma biomarkers, to improve diagnostic accuracy and predictive value.9,10

From a research perspective, amyloid imaging has been instrumental in advancing clinical trials for disease-modifying therapies targeting Aβ. However, these advances also bring new challenges, including the need to refine imaging-based biomarkers for assessing therapeutic efficacy and understanding the long-term implications of amyloid removal.11 This review aims to provide a comprehensive analysis of the global experience with brain amyloid imaging, exploring its clinical applications, technological advancements, and regional differences in implementation.