Introduction to Pharmacokinetic Modeling

Pharmacokinetic modeling has a long history that originates from tracers or indicators that were injected into the bloodstream and needed direct contact with a sensor to be detected. Examples of these approaches are provided by the Fick method [1], requiring blood sampling to assess the oxygen saturation, or thermodilution [2, 3], where a catheter is inserted in the central circulation to measure the blood temperature. Pharmacokinetic modeling has a long history that originates from tracers or indicators that were injected into the bloodstream and needed direct contact with a sensor to be detected. Examples of these approaches are provided by the Fick method [1], requiring blood sampling to assess the oxygen saturation, or thermodilution [2, 3], where a catheter is inserted in the central circulation to measure the blood temperature. Modeling was adopted to deal with noisy data and to provide a physiological interpretation of the measurements. Since the introduction of the first indicators, accuracy and complexity of the adopted models have shown terrific development, supported by increasing computing capabilities. Model fitting computations that only few decades ago could take several days, today can be solved in a split of a second. This chapter introduces the fundamental knowledge on pharmacokinetic modeling, establishing the basis for the modern developments applied to contrast-enhanced imaging.