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Virtual clinical trials evaluating the impact of uptake time in 18F-FDG-PET/CT oncology imaging

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Date: September 16, 2022 12-1 PM Eastern time

Speakers: Paul Kinahan, Ph.D.

Positron emission tomography (PET) is primarily used to determine the presence of cancer as well as staging. Changes in tumor uptake of 18F-fluorodeoxyglucose (FDG) in PET images is used in clinical trials of potential cancer therapies and has been suggested as a clinical marker for response to therapy. FDG-PET image values are typically normalized to standardized uptake values (SUVs), which have established estimates of test-retest variability. One source of variability is the change in SUV over the time between FDG injection and the PET scan (typically 60 min) due the biodistribution dynamics. We evaluated the impact of uptake time in for two different tasks by using Virtual Clinical Trials (VCTs). In the first VCT we evaluated the effect of non-ideal variability of uptake time for clinical trials of new cancer therapies, where the metric was the needed number of patients for a pre-determined study power. In the second study, we estimate the uptake time that maximizes the probability of lesion detectability. Both of these studies are enabled by knowledge of the pathophysiology and biochemistry of FDG uptake in cancer, the imaging physics, and models of outcomes. These are embedded in a VCT framework and enable studies that are not clinically feasible.