PET-amyloid / PET-tau imaging

These are PET scans that let doctors see Alzheimer's-related proteins in a living brain. Amyloid PET uses tracers (florbetapir, florbetaben, flutemetamol, all FDA-approved) to light up amyloid-beta plaques. Newer tau PET tracers, like flortaucipir, map the tangles of tau protein and how far they have spread (Braak stages). Since 2023 to 2024, knowing your amyloid and tau status actually changes care. The FDA approved two anti-amyloid antibody drugs, lecanemab (Leqembi) and donanemab, and both require a confirmed positive amyloid scan before you can get them. Tau staging increasingly helps predict the course and likely benefit. A standard scale called Centiloid lets scans be compared across machines and tracers, though insurance coverage is still limited in most systems. The radiation dose is about 5 to 10 mSv per scan (amyloid tracers ~5 to 7, tau up to ~9), so cost and radiation matter for any idea of population screening.

Last reviewed: June 22, 2026

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