Tracer uptake will be expressed in Standardized Uptake Value Ratio (SUVR). Regions used for tracer uptake quantitation will include cortical regions (frontal cortex, posterior cingulate, lateral temporal cortex, parietal cortex, occipital cortex, mesial temporal cortex, inferior temporal cortex, hippocampus, and anterior cingulate). Subcortical regions (basal ganglia, substantia nigra, choroid plexus) will be used for detection of possible off-target binding. Regions predicted to be free of tau pathology will be used as reference (cerebellum and pons). SUVR will be calculated as SUV target/SUV reference region (e.g., cerebellar gray).

Pharmacokinetics of \[18F\]MNI-1020 will be assessed by using plasma concentration data and compared in participants with probable Alzheimer's disease (AD) and age matched healthy participants.

An adverse event is any untoward medical event that occurs in a participant administered an investigational product, and it does not necessarily indicate only events with clear causal relationship with the relevant investigational product.

Within the AD participants, the distribution and binding of \[18F\]florbetapir will be compared to the \[18F\]MNI-1020 binding across multiple regions. This will be done by visual reading of scans, with amyloid signal predicted to be high in frontal cortical regions in participants with probable AD and absent from cortex in healthy participants, while tau signal is predicted to be present in hippocampus and entorhinal cortex in healthy elderly participants, and in medial and lateral temporal cortex in participants with probable AD. Semi-quantitative analysis will also be conducted comparing SUVR of the tracers in these same regions, using cerebellum as reference.