Ultralow Dose PET Imaging of 18F-Florbetapir, 18F-Flutemetamol

This study is testing ultralow-dose versions of two PET scan tracers — 18F-florbetapir and 18F-flutemetamol — used to detect amyloid plaques in the brain (a hallmark of Alzheimer's disease), to see if much smaller doses can produce equally useful images with less radiation exposure. **You may be eligible if...** - You are 18 or older - You are able to provide informed consent and follow study procedures - Women of childbearing potential must not be pregnant and must have a negative pregnancy test **You may NOT be eligible if...** - You have already received radiation doses close to the annual research limit from prior studies - You have enrolled in this specific study more than four times before - You are claustrophobic in ways that prevent lying in a scanner - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.