Parametric Imaging With PET and SPECT

In molecular imaging modalities such as positron emission tomography (PET) or single photon emission computed tomography (SPECT), parametric imaging is the process of creating fully quantitative 3-D maps of pharmacokinetic parameters from a dynamic series of radiotracer concentration images. An overview of the pharmacokinetic parameters that have been assessed in PET or SPECT studies, and the kinetic models that have been proposed to compute parametric images is presented. Parametric imaging is challenging due to the high level of noise in the raw images obtained from the scanner, and the additional needs to obtain the input function of the kinetic model and to correct for subject motion during the usually long dynamic scans. Methods that have been proposed to assess each of these challenges are been reviewed.