Whole-body F-18 dopa PET for detection of gastrointestinal carcinoid tumors

PURPOSE: To evaluate fluorine 18 (F-18) dopa positron emission tomography ( PET) in comparison with established imaging procedures in gastrointestinal carcinoid tumors. MATERIALS AND METHODS: After evaluation of the normal distribution of F-18 dopa, 17 patients with histologically confirmed tumors were examined with F -18 dopa PET. Results of 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) PET, somatostatin-receptor scintigraphy, and morphologic imaging (computed tomo graphy and/or magnetic resonance imaging) were available for all patients. Results of the procedures were evaluated by two radiologists and two nuclea r medicine specialists, whose consensus based on all available histologic, imaging, and follow-up findings was used as the reference standard. RESULTS: Ninety-two tumors were diagnosed: eight primary tumors, 47 lymph n ode metastases, and 37 organ metastases. F-18 dopa PET led to 60 true-posit ive findings (seven primary tumors, 41 lymph node metastases, 12 organ meta stases); FDG PET, 27 (two primary tumors, 14 lymph node metastases, 11 orga n metastases); somatostatin-receptor scintigraphy, 52 (four primary tumors, 27 lymph node metastases, 21 organ metastases); and morphologic imaging, 6 7 (two primary tumors, 29 lymph node metastases, 36 organ metastases). This resulted in the following overall sensitivities:F-18 dopa PET, 65% (60 of 92); FDG PET, 29% (27 of 92); somatostatin-receptor scintigraphy, 57% (52 o f 92); morphologic procedures, 73% (67 of 92). Although the morphologic pro cedures were most sensitive for organ metastases, 18F dopa PET enabled best localization of primary tumors and lymph node staging. CONCLUSION:F-18 dopa PET is a promising procedure and useful supplement to morphologic methods in diagnostic imaging of gastrointestinal carcinoid tum ors.