Positron emission tomography compartmental models

The current article presents theory for compartmental models used in positr on emission tomography (PET). Both plasma input models and reference tissue input models are considered. General theory is derived and the systems are characterized in terms of their impulse response functions. The theory sho ws that the macro parameters of the system may be determined simply from th e coefficients of the impulse response functions. These results are discuss ed in the context of radioligand binding studies. It is shown that binding potential is simply related to the integral of the impulse response functio ns for all plasma and reference tissue input models currently used in PET. This article also introduces a general compartmental description for the be havior of the tracer in blood, which then allows for the blood volume-induc ed bias in reference tissue input models to be assessed.