Kinetic Modeling in Positron Emission Tomography

This chapter focuses on kinetic modeling, which uses mathematical techniques to explain the behavior of tracer compounds in the body and which is capable of summarizing important information about the body's physiology. It examines mathematical kinetic models used to analyze time sequences of positron emission tomography (PET) images to gather quantitative information about the body. This includes methods used in the two most ubiquitous applications of PET namely, imaging of blood flow and glucose metabolism. Furthermore, this chapter also examines the use of PET to image specific receptor molecules, which capitalizes on the unique specificity of PET. Kinetic models for PET typically derive from the one-, two-, or three-compartment model in which a directly measured blood curve serves as the model's input function. The coefficients of the differential equations in the model are taken to be constants that are reflective of inherent kinetic properties of the particular tracer molecule in the system. By formally comparing the output of the model to the experimentally obtained PET data, estimating values for these kinetic parameters is possible and thus extracts information about binding, delivery, or any hypothesized process, as distinct from all other processes contributing to the PET signal.