A study of non-invasive Patlak quantification for experimental whole-body dynamic FDG-PET studies of mice

Plasma time-activity curve (PTAC) is usually required in tracer kinetic modeling as the input function of an underlying kinetic model for quantifying in-vivo pathological/physiological changes. The procedure of invasive arterial blood sampling poses more challenges especially for small animal studies due to limited blood volume and small-size blood vessel. In this study, a recently proposed non-invasive quantification method based on Patlak graphic analysis (PGA) was systematically investigated by using five whole-body dynamic FDG-PET studies of mice. The nonlinear least square (NLS) method and invasive PGA were also used for the comparison. The results demonstrated that the high linearity of relative influx rates was observed between the non-invasive PGA and invasive PGA. Brain is suggested to be reference ROI for non-invasive PGA with slight overestimation of relative influx rate for tumor. The non-invasive PGA approach could be an effective solution in small-animal FDG-PET dynamic studies when the contribution of k4 can be ignored.