• Males and females aged 50-80 years

• Able to understand, sign and date written informed consent

• Signed and dated written informed consent obtained from the subject

• The subject has an appropriate caregiver capable of accompanying subject, if necessary

• Have an Montreal Cognitive Assessment (MoCa) score ≥ 27

• Female subjects 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 subjects and their partners of childbearing potential must commit to the use of a highly effective method of contraception for a minimum of 90 days following each PET scan

• Male subjects must commit to not donate sperm for a minimum of 90 days after each PET scan

• Willing and able to cooperate with study procedures including lying flat and still on the scanning bed for 60 minutes

• Healthy with no clinically relevant finding on physical examination at screening

• No cognitive impairment from neuropsychological battery as judged by the investigator

• A brain MRI without evidence of significant neurological pathology

• A beta-amyloid Neuraceq® PET demonstrating a negative beta-amyloid status

• No signs of movement disorder as judged by Progressive Supranuclear Palsy Rating Scale (PSPRS), Movement Disorder Society - Unified Parkinson's Disability Rating Scale (MDS-UPDRS) and Progressive Supranuclear Palsy Clinical Deficits Scale (PSP-CDS)

• Patients with a clinical diagnosis of probable PSP-RS based on the Movement Disorder Society criteria (Höglinger et al., 2017)

• Medications taken for symptomatic treatment of PSP must be maintained on a stable dosage regimen for at least 30 days before the [18F]PI-2620 PET imaging visits