Assessing tumor metabolic heterogeneity of non-small cell lung cancer with total body PET-CT imaging on the uExplorer: Analysis of dynamic changes of 18F-FDG uptake.

e20549 Background: Total body positron emission tomography (PET) of uExplorer enables imaging of highly quantitative parameters beyond the standardized uptake value (SUV). The aim of this prospective study is to assess the dynamic changes of 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake in characterizing tumor heterogeneity of non-small cell lung cancer (NSCLC). Methods: Sixteen NSCLC patients were prospectively enrolled in a prospective study (NCT04654234, GASTO-1067) between September 2020 and December 2020. All patients underwent a dynamic total-body 18F-FDG PET/CT scan before any treatment. The primary lung tumor, metastatic regional lymph node and inflammatory lymph node were manually delineated by a nuclear medicine physician and a radiation oncologist. Total Body PET was acquired between 0 – 60 mins after the injection of FDG from the subject’s feet. We compared lesion heterogeneity and different image-derived PET metrics including the SUV-mean, Patlak-derived influx rate constant (Ki) and distribution volume (DV). Results: The SUV-mean and Ki-mean of primary lung tumor and metastatic lymph node were significantly higher than inflammatory lymph node (p < 0.001), while there was no significantly different of DV(p > 0.05). By the scatter plot of SUV-mean and Ki-mean of primary lung tumor, 9 patients had been separated into high dynamic FDG metabolic (H-DFM) group and 7 in low DFM(L-DFM) group. The SUV-mean(p = 0.0002) and Ki-mean(p = 0.0002) of primary lung tumor were significantly higher in H-DFM group, whereas there is no difference in metastatic lymph node of both group. Interestingly, the SUV-mean and Ki-mean of primary lung tumor were higher than that of metastatic lymph node(p = 0.0002) in H-DFM group. On the contrast, the SUV-mean and Ki-mean of primary lung tumor were lower than that of metastatic lymph node(p = 0.05) in L-DFM group. There is no significant difference of DV-mean among primary lung tumor, metastatic lymph node and inflammatory lymph node in both arms. Conclusions: The results demonstrated that dynamic parameters from total body PET scan has the potential of providing complementary information of tumor heterogeneity in NSCLC than conventional static SUV imaging. The characteristics of H-DFM and L-DFM group could be taken into account for evaluation of further treatment response.