Positron Emission Tomography (PET) Study With [18F]AZD4694 and [11C]AZD2184, Candidate PET Ligands for Aβ Amyloid

Inclusion Criteria: * Alzheimer's Disease patients - 50-85 years, mild to moderate AD: MMSE ≥16 and ≤ 26, clinical progression of AD over 12 months. * Healthy volunteers: - 50-75 years * BMI 18 and 30 m2/kg * Clinically normal physical findings including supine blood pressure and pulse rate. Exclusion Criteria: * Alzheimer's Disease patients - Clinically significant illness the 2 weeks prior to the administration of the PET ligand * Significant cerebrovascular disease or depression, central nervous system infarct or infection or lesions * Administration of any investigational product within 3 months prior to study and/or PET measurements for scientific purposes within the last 12 months. * Healthy volunteers - clinically significant illness within 2 weeks before administration of PET ligand, history of psychiatric or somatic disease/condition that may interfere, first degree relative with dementia. Obvious deterioration of memory functions.