Test-retest Study With [18F]PI-2620 in PSP-RS and NDC

\[18F\]PI-2620 is a radioactive diagnostic agent being developed for the indication of PET imaging of the brain to detect tau pathology in adult patients who are being evaluated for neurodegenerative decline. All patients will receive two administrations of \[18F\]PI-2620 at a radioactive dose of 185 megabecquerel (MBq).