Alzheimer's Disease: Clinical Investigation and Neuroimage Studies Including 18F-PM-PBB3 and 18F-florbetapir (AV-45) PET Examination

Inclusion Criteria: * Patient with probable AD (Appendix I) Inclusion criteria 1. Age ranges from 45\~90 years 2. Patients fulfill the criteria of probable AD (DSM IV and NINCDS-ADRDA) 3. Mild cognitive impairment to moderate dementia (CDR: 0.5 to 2.0 or MMSE: 10-25) 4. Female subjects of childbearing potential must practice effective contraception during the study and be willing and able to continue contraception after the final study Patient with amnestic MCI due to AD criteria (Appendix II: criteria proposed by world ADNI) Inclusion criteria 1. Age ranges from 45\~90 years 2. Patients fulfill the criteria of aMCI (The early aMCI and late aMCI were proposed by world ADNI) 3. Amnestic mild cognitive impairment (CDR: 0.5 or MMSE: 26-30, with logical memory \>=7) 4. Female subjects of childbearing potential must practice effective contraception during the study and be willing and able to continue contraception after the final study Patients with probable FTD (Appendix III) 1, 2, 3 Inclusion criteria 1. Age ranges from 45\~90 years 2. Patients fulfill the criteria of probable FTD 3. Mild cognitive impairment to moderate dementia (CDR: 0.5 to 2.0 or MMSE: 10-25) 4. Female subjects of childbearing potential must practice effective contraception during the study and be willing and able to continue contraception after the final study Healthy control Inclusion criteria 1. Age ranges from 45\~90 years 2. Normal cognitive function (CDR: 0 or MMSE: 26-30) 3. Female subjects of childbearing potential must practice effective contraception during the study and be willing and able to continue contraception after the final study Exclusion Criteria: * 1\) Implantation of metal devices including cardiac pacemaker, intravascular metal devices. 2\) Major systemic diseases including coronary arterial disease, heart failure, uremia, hepatic failure, prominent strokes, acute myocardial infarction, poorly controlled diabetes, previous head injury, intracranial operation, hypoxia, sepsis or severe infectious diseases 3) Major psychiatric disorders, drug or alcohol abuse and major depression 4) Pregnant women or breast- feeding women 5) Subjects in whom MRI was contraindicated 6) History of severe allergic or anaphylactic reactions particularly to the tested drugs 7) History of positive test for human immunodeficiency virus (HIV) 8) Indication of impaired liver function as shown by an abnormal liver function profile at screening (eg. repeated values of aspartate aminotransferase \[AST\] and alanine aminotransferase \[ALT\] ≧ 3X the upper limit of normal values)