The accumulation of amyloid (Abeta) in the brains of patients suffering from Alzheimer's disease is widely accepted to be related to both the pathogenesis and the devastating symptoms of the disease and is a key target for many of the efforts to develop a treatment. Prana scientists discovered that abnormal, aging-related interactions between key biologically important metals and Aâ can explain many of the neuropathological and cognitive symptoms characteristic of AD. Prana scientists are developing a novel drug for the treatment of AD, PBT2, that can attenuate the interaction between bioavailable metal ions and Aâ to reduce many of the downstream toxic events resulting from this interaction and also the ongoing aggregation and accumulation of Aâ. In a clinical trial of 78 patients with mild AD, after a 12 week treatment period PBT2 has been shown to reduce Aâ in the cerebrospinal fluid of patients who received the drug as well as to improve cognitive outcomes. The proposed study will employ Pittsburgh Compound-B (PiB), 2-(4'methylaminophenyl benzothiazole for positron emission tomography (PET) imaging of the brain in patients with amnestic MCI and mild AD to assess the effect of PBT2 on Aâ deposition.