Shirley Wang, writing in the Wall Street Journal, describes progress in using PET scanning to detect Alzheimer's disease at an earlier stage:
The test uses a chemical called florbetapir, known by the brand name Amyvid, which is a radioactive agent that tags clumps of a sticky substance called an amyloid. Amyloid proteins are hallmarks of Alzheimer's disease. The chemical, which costs $1,600 per dose, then is detected using a brain imaging technique called positron emission tomography, known as PET scans.
For patients who already have some symptoms of cognitive decline, a positive scan suggests that moderate to frequent amyloid plaques are present in the brain, which is consistent with Alzheimer's disease.