The U.S. Food and Drug Administration (FDA) gave the O.K. last Friday to a new radioactive dye that helps doctors scan the brain for Alzheimer’s disease.

The dye, called Amyvid (florbetapir), made by Eli Lilly & Co., binds to the sticky amyloid proteins that build up in the brains of patients with Alzheimer’s. The dye can be detected by using positron emission tomography, or PET scans.

The test could allow doctors to diagnose Alzheimer’s much earlier and more accurately. In patients with symptoms of cognitive decline, the presence of amyloid would support an Alzheimer’s diagnosis. The dye cannot be used alone to diagnose Alzheimer’s, however, especially not in people without symptoms because people with normal brain function may accumulate amyloid plaques as they age, and because the plaques can be associated with neurological conditions other than Alzheimer’s.

via Alzheimer’s Brain Scan Test Gets FDA Approval | Healthland | TIME.com.