Improved staging of patients with carcinoid and islet cell tumors with 18F-dihydroxy-phenyl-alanine and 11C-5-hydroxy-tryptophan positron emission tomography

J Clin Oncol. 2008 Mar 20;26(9):1489-95. doi: 10.1200/JCO.2007.15.1126.


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 (11)C-5-hydroxytryptophan ((11)C-5-HTP) PET and 6-[F-18]fluoro-L-dihydroxy-phenylalanine ((18)F-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 (11)C-5-HTP PET, (18)F-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 (11)C-5-HTP PET, (11)C-5-HTP PET/CT, (18)F-DOPA PET, (18)F-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 (18)F-DOPA PET and (11)C-5-HTP PET detected more lesions than SRS (P < .001). (11)C-5-HTP PET was superior to (18)F-DOPA PET in islet cell tumors (P < .0001). In all cases, CT improved the sensitivity of the nuclear scans.

Conclusion: (18)F-DOPA PET/CT is the optimal imaging modality for staging in carcinoid patients and (11)C-5-HTP PET/CT in islet cell tumor patients.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5-Hydroxytryptophan*
  • Adenoma, Islet Cell / diagnostic imaging*
  • Adult
  • Aged
  • Carbon Radioisotopes
  • Carcinoid Tumor / diagnostic imaging*
  • Dihydroxyphenylalanine*
  • Female
  • Fluorodeoxyglucose F18
  • Humans
  • Male
  • Middle Aged
  • Pancreatic Neoplasms / diagnostic imaging*
  • Positron-Emission Tomography* / methods
  • Radiopharmaceuticals
  • Receptors, Somatostatin / metabolism
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed* / methods


  • Carbon Radioisotopes
  • Radiopharmaceuticals
  • Receptors, Somatostatin
  • Fluorodeoxyglucose F18
  • Dihydroxyphenylalanine
  • 5-Hydroxytryptophan