Dynamic PET & structural MRI images with accompanying blood sample data for repeatability study investigating human cerebral ammonia metabolism with 15O-H2O and 13N-NH3 PET tracers. Data from eight healthy subjects. Each subject had a 15O-H2O PET-CT brain scan followed by a 13N-NH3 scan; both scans repeated same day. Continuous and manual arterial blood sampling was acquired on all scans, with metabolite analysis on the NH3 scan blood manual samples. This data was used in the paper: “Evaluation of [13N]ammonia positron emission tomography as a potential method for quantifying glutamine synthetase activity in the human brain” by Egerton A and Dunn JT et al in EJNMMI Research.