A new quantitative method for measuring oxygen extraction fraction by positron emission tomography: theory and simulation studies.

A mathematical method has been developed by which the cerebral extraction fraction of oxygen (OEF) administered in a bolus can be quantitatively measured and compared with a previously established method by Mintun et al. Successive injection of three tracers are required: 15O-labeled O2 as a test tracer, a diffusible tracer as a reference tracer and also as a flow tracer, and a tracer for cerebral blood volume (CBV). No decay correction or calibrations between head and arterial measurements are required. Simulation studies have shown that the calculated OEF values are less sensitive to measurement errors in CBV, cerebral blood flow, partition coefficient, time shift effect and tissue inhomogeneity than in the previous method.