On the quantitation of PET data

Positron Tomographs (PT) measure the concentration of a radioisotope in a tissue element of a given organ in vivo [1]. They produce a set of images where each voxel value represents the mean value, over a given time period, of the movement of the radioisotope in that volume element. If the process is repeated over several serial time periods, the kinetics of the radioisotope can be examined and the time activity curve (TAC) can be described with simple or complex model from which physiological parameters (such as blood flow, glucose metabolic rate, receptor concentrations or others) can be identified and estimated [2].