 Inclusion Criteria:Patients for brain imaging:- patient and designee capable of giving fully informed consent in writing- patient fulfils DSM-IV and NINCDS-ADRDA criteria for probable Alzheimers disease. Other forms of dementia excluded- males or postmenopausal females aged 50 yearsHealthy volunteers for brain imaging: - able to give fully informed consent in writing- absence of any sign of dementiacognitive impairment in neuropsychological examinations- males or postmenopausal females aged 50 years Healthy volunteers for whole body imaging:- able to give fully informed consent in writing - males or postmenopausal females aged 60 years - no significant disease or drug use Exclusion Criteria:For all healthy volunteers and patients:- Any disease, condition, or concomitant medications that significantly compromises the function of the body systems and could result in excessive accumulation, impaired metabolism, altered excretion of the radiotracer, or might interfere with the conduct of the study or interpretation of the results 