Name: Martin Šámal
Affiliation: Charles University and the General University Hospital in Prague
Primary research interest: image processing in nuclear medicine and its clinical applications
Title of the lecture: Parametric Imaging
Keywords: nuclear medicine, dynamic image sequences, physiological models, whole-body PET/CT
Summary: In nuclear medicine, parametric imaging is used to visualize individual pixel values of the “parameters” of mathematical and physiological models applied to the recorded scintigraphic data with the aim to emphasize specific diagnostic information. The simple parameters are, for example, the ratio or the difference of the two separate images, maximum pixel value of image sequence, or time from the sequence beginning to the maximum of individual pixel values. More complicated and useful parameters are represented by the slope and the intercept of Patlak plot, kinetic parameters of compartmental models, score values of principal components or standard uptake values used to quantify the tracer uptake in a tumour. The parameters can provide diagnostic information directly by themselves or to support user-dependent steps in scintigraphic image processing as the definition of the regions of interest and extraction of time-activity curves from specific segments of dynamic scintigraphic data. Recently, parametric imaging is probably expecting a new wave of research and clinical interest related to introduction of the new instrumentation as the whole-body PET/CT. Besides its ability to provide dynamic data that can be converted into the whole-body parametric images, it will also benefit from data reduction ability of parametric imaging because the raw data produced by every examination will be extremely large. The presentation will focus on simple mathematical background of the most frequently used parametric images and on illustrative clinical examples with the aim to motivate a further research in the field.