Estimation of Local Cerebral Protein Synthesis Rates with L-[1-11C]Leucine and PET: Methods, Model, and Results in Animals and Humans

Abstract

We have estimated the cerebral protein synthesis rates (CPSR) in a series of normal human volunteers and monkeys using l-[1-¹¹C]leucine and positron emission tomography (PET) using a three-compartment model. The model structure, consisting of a tissue precursor, metabolite, and protein compartment, was validated with biochemical assay data obtained in rat studies. The CPSR values estimated in human hemispheres of about 0.5 nmol/min/g agree well with hemispheric estimates in monkeys. The sampling requirements (input function and scanning sequence) for accurate estimates of model parameters were investigated in a series of computer simulation studies.