Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Purpose
To evaluate and compare diagnostic sensitivity of positron emission tomography (PET) scanning in carcinoid and islet cell tumor patients with a serotonin and a catecholamine precursor as tracers.
Patients and Methods
Carcinoid (n = 24) or pancreatic islet cell tumor (n = 23) patients with at least one lesion on
conventional imaging including somatostatin receptor scintigraphy (SRS) and computed tomography (CT) scan underwent ¹¹C-5-hydroxytryptophan (11C-5-HTP) PET and 6-[F-18]fluoro-L-dihydroxyphenylalanin (¹⁸F-DOPA) PET. PET findings were compared with a composite reference standard derived from all available imaging along with clinical and cytologic/histologic information.
Results
In carcinoid tumor patients, per-patient analysis showed sensitivities for ¹¹C-5-HTP PET, ¹⁸F-DOPA PET, SRS, and CT of 100%, 96%, 86%, 96%, respectively, and in islet cell tumors of 100%, 89%, 78%, 87%, respectively. In carcinoid patients, per-lesion analysis revealed sensitivities for ¹¹C-5-HTP PET, ¹¹C-5-HTP PET/CT, ¹⁸F-DOPA PET, ¹⁸F-DOPA PET/CT, SRS, SRS/CT, and CT alone of, respectively, 78%, 89%, 87%, 98%, 49%, 73%, and 63% and in islet cell tumors of 67%, 96%, 41%, 80%, 46%, 77%, and 68%, respectively. In all carcinoid patients ¹⁸F-DOPA PET and ¹¹C-5-HTP PET detected more lesions than SRS (P < .001). ¹¹C-5-HTP PET was superior to ¹⁸F-DOPA PET in islet cell tumors (P < .0001). In all cases, CT improved the sensitivity of the nuclear scans.
Conclusion
¹⁸F-DOPA PET/CT is the optimal imaging modality for staging in carcinoid patients and ¹¹C-5-HTP PET/CT in islet cell tumor patients.