The variable clinical outcome of patients with G2 and G3 well differentiated GEP-NETs makes the selection of an optimal treatment strategy challenging.~A subject with 68Ga-DOTATATE uptake on all lesions without FDG uptake is likely to have low-grade, metabolically inactive disease, leading to an indolent disease course and may also be a predictive biomarker in subjects being considered for PRRT.~Conversely, avidity on 18F-FDG PET/CT and non-avidity on 68Ga-DOTATATE may indicate a high-grade NET, and would predict resistance to PRRT, suggesting that a more aggressive approach with systemic chemotherapy might be beneficial.~Therefore, the prospective assessment of PETNET score in patients with G2 or G3 GEP NETs, which may be biologically diverse is the most clinically relevant group for dual-tracer PET imaging.~Primary Objectives:~To determine the distribution of PETNET scores derived from 18F-FDG and 68Ga-DOTATATE PET/CT in patients with G2 and G3 well differentiated GEP-NETs.~To determine the proportion of patients in whom the addition of 18F-FDG PET/CT data results in a change in planned clinical management.~Secondary Objectives:~mTo determine whether there is intra-individual variability in somatostatin receptor expression and glucose metabolism (as seen on DOTATATE PET and FDG PET, respectively) across different tumor sites within the same patient.~To determine whether a correlation exists between tumor texture features on 68Ga-DOTATATE PET and FDG PET to tumor grade and Ki67 index.~To assess if an association exists between tumor texture features on 68Ga-DOTATATE PET and glucose metabolism; and/or an association between tumor texture features on FDG PET and somatostatin receptor expression.
The variable clinical outcome of patients with G2 & G3 well diff GEP-NETs makes the selection of an optimal treatment strategy challenging.~Initial data suggests that high DOTATATE uptake and low FDG uptake are suggestive of low grade disease, with an indolent course.~Conversely, low DT uptake and high FDG uptake are suggestive of high-grade/ aggressive disease.~G2/3 GEP NETs may be biologically diverse; clinically relevant cohort for dual-tracer PET imaging.~Our secondary objectives are~To determine the distribution of PETNET scores derived from 18F-FDG & 68Ga-DT PET in patients with G2 & G3 well diff GEP-NETs.~To determine the proportion of patients in whom the addition of 18F-FDG PET data results in a change in planned clinical management.~To assess intra-individual variability in SSTR expression & glucose metabolism (as seen on DT and FDG PET) across different tumor sites within the same patient.~2) To determine whether a correlation exists between tumor texture features on 68Ga-DT & FDG PET to tumor grade and Ki 67 index.~3) To assess for an association between tumor texture features on 68Ga-DT PET and glucose metabolism; and/or an association between tumor texture features on FDG PET and SSTR expression.