Study to Evaluate the Feasibility of [18F]Florbetapir PET for Assessment in MS Patients

Eligibility criteria (for all subjects): * Ability to understand the purpose and risks of the study and provide signed and dated informed consent and authorization to use protected health information in accordance with national and local subject privacy regulations * Willingness to comply with study procedures * Willingness to provide written informed consent * Age greater than or equal to 18 and less than or equal to 60 years old at the time of the informed consent * Subjects of childbearing potential must practice effective contraception during the study and be willing and able to continue contraception until PET testing is completed * For females, must be of non-childbearing potential or have a negative urine and blood pregnancy test on the day of \[18F\]Florbetapir PET injection Inclusion Criteria (Healthy Volunteers): * No history of or signs of acute or chronic neurological or psychiatric illness based on evaluation by a research physician. Inclusion Criteria (MS Subjects): * Have a diagnosis of relapsing remitting MS according to the 2010 MacDonald Criteria * Have at least 10 demyelinating lesion on brain MRI with the following characteristics: * Hypointense on T2 weighted images with FLAIR Exclusion Criteria (for all subjects): * The subject has clinically significant abnormal laboratory value and/or clinically significant unstable medical or psychiatric illness * The subject has evidence of clinically significant gastrointestinal, cardiovascular, hepatic, renal, hematological, neoplastic, endocrine, alternative neurological (other than RRMS), immunodeficiency, pulmonary, or other disorder or disease. * Women who are pregnant or actively breastfeeding * The subject has any disorder that may interfere with drug absorption, distribution, metabolism, or excretion (including gastrointestinal surgery) * The subject has participated in another clinical study within the previous 30 days * Renal impairment with a creatine clearance \<80mL/minute at screening (creatine clearance estimated by Cockcroft-Gault equation) * The subject is scheduled to have a major surgery or procedure during the time of the study.