Evaluation of Imaging Characteristics of [18F]PI-2620 PET in AD and PSP Patients Using High and Low Specific Activity

Inclusion Criteria: * Males and females aged 50-80 years * Able to understand, sign and date written informed consent, which is confirmed by the judgment of the referring physician * Written informed consent must be obtained before any assessment is performed * Prior evaluable MRI * Female patients must be documented by medical records or physician's note to be either surgically sterile (by means of hysterectomy, bilateral salpingectomy or bilateral oophorectomy) or post-menopausal for at least 1 year (no menses for 12 months without an alternative medical cause). If they are of child-bearing potential, must commit to use of a highly effective contraceptive measure for the duration of the study * Male patients and their partners of childbearing potential must commit to the use of a highly effective method of contraception for a minimum of one week following each PET scan * Male patients must commit to not donate sperm for a minimum of one week after each PET scan. Inclusion Criteria for mild-moderate AD patients * Patients with mild or moderate AD in accordance with NIA-AA guidelines 2011 * Have a CDR score of ≥ 0.5 at screening * Have an MMSE score of ≤ 24 at screening * Prior evaluable amyloid PET imaging confirming presence of beta-amyloid brain pathology * Medications taken for symptomatic treatment of AD must be maintained on a stable dosage regimen for at least 30 days before the \[18F\]PI-2620 PET imaging visits Inclusion Criteria for patients with probable PSP * …