Evaluation of [11C]RO6924963, [11C]RO6931643, and [18F]RO6958948 as Tracers for Positron Emission Tomography (PET) Imaging of Tau in Healthy and Alzheimer's Disease (AD) Participants

Radiolabeled low molecular weight compound, administered as single intravenous injection. The mass dose of \[11C\]RO6924963 injected will be \</=10 micrograms (mcg), injection volume \</=20 milliliters (mL). Target injected activity for \[11C\]RO6924963 will be 370-740 megabecquerel (MBq) \[10-20 millicurie (mCi)\].

Radiolabeled low molecular weight compound, administered as single intravenous injection. The mass dose of \[11C\]RO6931643 injected will be \</=10 mcg, injection volume \</=20 mL. Target injected activity for \[11C\]RO6931643 will be 370-740 MBq (10-20 mCi).

Radiolabeled low molecular weight compound, administered as single intravenous injection. The mass dose of \[18F\]RO6958948 injected will be \</=10 mcg, injection volume \</=20 mL. Target injected activity for \[18F\]RO6958948 will be 185-370 MBq (5-10 mCi). The final activity of \[18F\] RO6958948 will be adjusted up to 10 mCi per scan to allow sufficient counts by end of 200 minutes post radiotracer injection.