Much more elaborated FDG quantification methods and considered as reference methods exist in PET imaging (compartmental analysis, Patlak). Simplified kinetic methods have also been proposed which correlate better with Patlak reference method than the conventional SUV. The investigators proposed a new methodological approach to obtain the parametric information in PET. This approach allows to define new indexes (average percentage of FDG-metabolized or not metabolized; time required to metabolize 80% of FDG). The approach has been clinically evaluated in a pilot study for the differentiation between benign and paraganglioma lesions.