OPTIMAL EXPERIMENT DESIGN FOR PET QUANTIFICATION OF RECEPTOR CONCENTRATION

The mathematical models used to analyze positron emission tomography ( PET) data obtained for receptor quantitation have many unknown paramet ers which must be estimated from the data, Obtaining unique and precis e estimates of the model parameters from PET data is difficult as a re sult of the complex interdependence of the parameters, In this work we address the task of estimating the concentration of myocardial beta-a drenergic receptors using unlabeled and F-18-labeled S(-)-fluorocarazo lol as the receptor ligand, For a three-injection study we have optimi zed the ligand injection times and dosages using the D-optimal criteri on for estimating receptor concentration. We found that in optimizing a three-injection experimental design, the dose of ligand in the third injection approaches zero so that the optimal three-injection design is actually a two-injection experiment. Using this optimal experiment, we demonstrate estimates of receptor concentration that are almost fi ve times as precise as compared to an empirically designed three-injec tion experiment.