PET (positron emission tomography) imaging with BAY85-8102 F-18, DPA-714 for investigation of neuroinflammation pattern in probable Alzheimers patients versus healthy volunteers and radiation dosimetry in healthy volunteer.

Inclusion Criteria:

• Able to give fully informed consent in writing
• Males or females aged >/= 50 years
• No significant disease or drug use
• Absence of any sign of dementia/cognitive impairment in neuropsychological examinationsPatients for brain imaging:
• Patient and designee capable of giving fully informed consent in writing
• Patient fulfils DSM-IV and NINCDS-ADRA criteria for probable Alzheimers disease
• Patient has undergone physical and neurological examination, ECG and test of routine hematological and biochemical parameters prior to radiotracer administration Exclusion Criteria:- Pregnancy or lactation
• Current unstable medical condition (e.g. unstable angina, myocardial infarction or coronary revascularization in the preceding 12 months, cardiac failure, chronic renal failure, chronic hepatic disease, severe pulmonary disease, blood disorders, poorly controlled diabetes, chronic infection)