In initial autopsy studies, the UCLA group found that one of these new compounds (called FDDNP - UCLA Patent Ref. No. 1998-507-1) clearly displayed the well-defined amyloid proteins characteristic of the disease. They then injected a radioactive form of the compound into the veins of living Alzheimer's patients, and the PET scan accurately measured the concentration of the compound in the patient's brain. This allowed them to see for the first time, increased signals coming from living human brains in areas that contained dense collections of the abnormal proteins. .