A brief history of Aβ imaging.

β-Amyloid (Αβ) imaging revolutionized the in vivo assessment of Alzheimer's disease (AD) Αβ pathology and its changes over time, increasing our insights into Aβ deposition in the brain by providing highly accurate, reliable, and reproducible quantitative statements of regional and global Aβ burden in the brain, proving essential for the differential diagnosis, staging, and evaluation of disease-specific anti-Αβ therapeutic approaches. Longitudinal observations, coupled with different disease-specific biomarkers to assess potential downstream effects of Aβ, have confirmed that Αβ deposition in the brain starts decades before the onset of symptoms. Aβ imaging studies continue to refine our understanding of the role of Αβ deposition in AD, and its relation to other imaging and fluid biomarkers. HIGHLIGHTS: Αβ imaging revolutionized the in vivo assessment of Alzheimer's disease Αβ pathology. Αβ imaging has increased our insights into Aβ deposition in the brain by providing highly accurate, reliable, and reproducible quantitative statements of regional and global Αβ burden in the brain. Αβ imaging is essential for the differential diagnosis, staging, and evaluation of disease-specific anti-Αβ therapeutic approaches. Αβ imaging studies continue to refine our understanding of the role of Αβ deposition in Alzheimer's disease, and its relation to other imaging and fluid biomarkers.