Comparison of 68Ga-DOTANOC and 18F-DOPA PET/CT for the detection of carcinoid tumors

124 Objectives Few recent studies have highlighted the utility of 18F-DOPA imaging in carcinoid tumors. 68Ga-DOTANOC PET/CT, however, has already been established in many countries for the evaluation of carcinoid tumors. Thus, a prospective trial was designed for a head-to-head comparison of 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT. Methods Twenty eight patients with biopsy proven carcinoid tumors were prospectively enrolled and scheduled for 68Ga-DOTANOC and 18F-DOPA PET/CT. These patients were scanned for staging/restaging, detection of recurrence and for evaluation of response to therapy. Both the studies were conducted, in random orders, within three weeks time interval. The scans were reported independently by two experienced nuclear medicine physicians. The readers were blinded to the clinical and biochemical details. PET/CT results were correlated with conventional imaging, and when possible with histopathology. Results The most common primary tumor site was the pancreas followed by the ileum. One primary site was localized to lung and one in lateral ventricle. The most common metastatic site was liver. Either on patient-basis (sensitivity- 96% vs 71%) or on lesion-basis (92 vs 63), 68Ga-DOTANOC scans picked up more disease compared to 18F-DOPA imaging. Conclusions Overall, 68Ga-DOTANOC showed superior sensitivity in evaluation of primary carcinoid tumors as well as metastatic involvement of liver, lymph node and bone. Moreover, 68Ga-DOTANOC PET positivity indicates somatostatin receptor expression, thus guiding further management with octreotide and/or radiopeptide therapy