Clinical Evaluation of Florbetapir F 18 (18F-AV-45)

Subjects who meet all of the following criteria are eligible to enroll in this study: 1. Male or female subjects at least 18 years of age; 2. Subjects who sign an IRB approved informed consent prior to any study procedures. Where subjects are deemed incapable of informed consent, a legally authorized representative may provide consent, with the subject's documented assent; and 3. Subjects who in the opinion of the investigator can tolerate the PET scan procedures. Subjects will be excluded from enrollment if they: 1. Have clinically significant hepatic, renal, pulmonary, metabolic, or endocrine disturbances as indicated by history, which in the opinion of the investigator might pose a potential safety risk to the subject; 2. Have current clinically significant cardiovascular disease. Clinically significant cardiovascular disease usually includes one or more of the following: * cardiac surgery or myocardial infarction within the last 4 weeks; * unstable angina; * acute decompensated congestive heart failure or class IV heart failure; * current significant cardiac arrhythmia or conduction disturbance, particularly those resulting in ventricular fibrillation, or causing syncope, or near syncope; * uncontrolled high blood pressure; or * QTc \> 450 msec (by history or for patients with cardiac disease by screening evaluation in companion study) Before enrolling a patient with any of the above conditions, the investigator must have performed a cardiac evaluation and obtain permission from the sponsor. 3. Have a history of drug or alcohol abuse within the last year, or prior prolonged history of abuse; 4. Women of childbearing potential who are not surgically sterile, not refraining from sexual activity or not using reliable methods of contraception. Women of childbearing potential must not be pregnant (negative urine beta-hCG at the time of screening and negative urine beta-hCG on the day of imaging) or breastfeeding at screening. Women must avoid becoming pregnant, and must agree to refrain from sexual activity or to use reliable contraceptive methods for 24 hours following administration of Florbetapir F 18 Injection ( such as oral contraceptives for at least three months or an IUD for at least two months prior to the start of the screening visit, or various barrier methods, e.g., diaphragm or combination condom and spermicide); 5. Have a history of relevant severe drug allergy or hypersensitivity (Relevant severe drug allergies should be determined by the PI, and any questions about a subject's eligibility can be directed to Avid. If a subject has a history of severe drug allergies, it may be dangerous for them to participate in a study); 6. Are patients who have received an investigational medication under an FDA IND protocol within the last 30 days. Additionally, the time between the last dose of the previous experimental medication and enrollment (completion of screening assessments) must be at least equal to 5 times the terminal half-life of the previous experimental medication. Patients who have ever participated in an experimental study with an amyloid targeting therapy (e.g., immunotherapy, secretase inhibitor) may not be enrolled without prior sponsor approval unless it can be demonstrated that the patient received only placebo in the course of the trial; 7. Are patients with current clinically significant unstable medical comorbidities, as indicated by history or physical exam, that pose a potential safety risk to the subject. 8. Are patients who have received a radiopharmaceutical for imaging or therapy within the past 24 hours prior to the imaging session for this study. If another radiotracer is required in the companion protocol, patients may be able to receive a radiopharmaceutical for imaging or therapy within the 24 hours prior to the imaging session with prior sponsor approval and at the discretion of the investigator.; and 9. Are patients who, in the opinion of the investigator, are otherwise unsuitable for a study of this type. If at the time of enrollment subjects do not meet all eligibility criteria, the subjects may still be enrolled if documentation is provided demonstrating that the subject will meet all criteria at the time of the first imaging procedure.