Florbetapir F-18

Florbetapir F-18 (Amyvid, Eli Lilly) was the first amyloid PET tracer approved by the FDA, in April 2012, for imaging beta-amyloid neuritic plaque density in adults with cognitive impairment being evaluated for Alzheimer's disease (AD) and other causes of cognitive decline. In June 2025 the FDA approved a label update adding a second indication: selection of patients who are candidates for amyloid-beta-directed therapy, reflecting the arrival of approved anti-amyloid antibodies. A negative scan indicates sparse to no neuritic plaques and reduces the likelihood that AD explains the impairment; a positive scan indicates moderate to frequent plaques, a pattern also seen in some cognitively normal older adults, so it does not by itself establish an AD diagnosis and is meant to be used alongside full clinical evaluation.

The recommended dose is 370 MBq (10 mCi) as a single intravenous bolus in up to 10 mL, followed by a saline flush, with 10-minute PET images acquired approximately 30 to 50 minutes after injection. The maximum mass dose is 50 micrograms. Effective dose from a 370 MBq administration is about 7 mSv in an adult. Reading is by visual assessment of cortical grey-white contrast loss by a trained reader; quantification against the Centiloid scale can be used alongside the visual read, per the 2025 label update, and is the metric used to track amyloid clearance during anti-amyloid antibody therapy.

In the clinical pathway defined by the 2025 SNMMI/Alzheimer's Association appropriate use criteria, amyloid PET is rated 'appropriate' both for diagnostic clarification in patients with an uncertain aetiology after specialist assessment and, with the highest confidence rating, for determining eligibility for an approved amyloid-targeting therapy such as lecanemab or donanemab. In the United States, Medicare coverage of amyloid PET is no longer restricted: CMS retired the national coverage determination at 42 CFR 220.6.20 effective 13 October 2023, ending the prior coverage-with-evidence-development framework and the one-scan-per-lifetime limit, and coverage decisions (including for repeat scans to document plaque clearance) now sit with local Medicare Administrative Contractors rather than a single national rule.