RecruitingDrug trialImaging Biomarkers in Preclinical and Symptomatic ADThe purpose of this research study is to evaluate adult children of parents with and without Alzheimer's disease which represent an ideal population for investigating the biological changes that precede the clinical onset of AD. The investigators will be imaging the brain to detect the presence of amyloid deposits (plaques in the brain). Amyloid is a protein that may be related to dementia of Alzheimer's disease (DAT).