Peeking into healthy brains to see if Alzheimer's is brewing

In this photo taken May 19, 2015, Judith Chase Gilbert, of Arlington, Va., is loaded into a PET scanner by Nuclear Medicine Technologist J.R. Aguilar at Georgetown University Hospital in Washington. Gilbert shows no signs of memory problems but volunteered for a new kind of scan as part of a study peeking into healthy brains to check for clues about Alzheimer’s disease.