Parametric imaging used in nuclear medicine

Parametric imaging is utilized in a diverse range of nuclear medicine procedures and can be applied to provide additional information of the radiopharmaceutical distribution of the examined tissues and organs that are of physiological and biochemical interest. These findings cannot usually be observed directly in the original (static) scintigraphic images. Parametric imaging can be applied both to Positron Emission tomography (PET) or PET-Computed Tomography (CT) as well as Single-photon emission computed tomography (SPECT) imaging. There are several approaches available for parametric imaging. The simplest parametric image is a difference image obtained by subtraction of two images. Furthermore, there are various image post-processing and analysis methods to facilitate improved delineation of body organs. The current publication describes in detail, the practical applications of image subtraction, time of maximum (Tixel) image, Rutland-Patlak and Logan plots as well as Factor Analysis in the NM field. Current literature results show that parametric imaging is helpful to visualize parameters of tracer kinetics and adds a new information in images. The development of new-generation imaging devices as well as advances in computer hardware and advanced software tools will facilitate the wider use of parametric imaging also in the everyday clinical routine.