Imaging of Neuroendocrine Tumors With PET and Fluoro-18-DOPA (F-DOPA)

Imaging of Neuroendocrine Tumors With PET and Fluoro-18-DOPA (F-DOPA)

Imaging of neuroendocrine (NETs), such as carcinoids and pheochromocytomas (PHEOs), is suboptimal, limiting curative treatment. The investigators wanted to explore the use of PET and F-DOPA i.v. for the localization of these types of neoplasms. The investigators used a similar protocol as they had used for PET (Positron emission tomography) or FDG (Fludeoxyglucose) imaging in oncologic patients. F-DOPA, prepared according to United States Pharmacopeia (USP) guidelines, was approved by the North Shore University Hospital Radiation Safety Committee in 1989 and 1994 for the study of neurological diseases and used uneventfully.

Background: Pre surgical conventional imaging of neuroendocrine tumors (NETs) with CT, MRI, In-111 octreotide or 1-123-MIBG (metaiodobenzylguanidine) scintigraphy has limitations. This pilot study tried to improve the localization of these tumors with F-18-F-DOPA PET scanning.

Methods: The investigators studied 22 patients, the majority referred with clinical diagnosis of carcinoid (9) or NETs (9) and a few with pheochromocytoma/paraganglioma (3). Carbidopa was administered prior to the F-DOPA injection in 12 patients. Comparison was made with prior conventional imaging. The F-DOPA findings, read blindly to the findings of other modalities, were compared with results of subsequent surgery (2), endoscopy (1), or a long-term follow up of mean duration of 49 months (for 20 patients). Two subjects were lost to follow-up.

• Inclusion Criteria:

  • 23 years of age and older
  • Appropriate diagnosis by referring physician

• Exclusion Criteria:

  • Less than 23 years of age
  • Greater than 81 years of age
  • Pregnancy
  • Lactation
  • Prior history of radiation treatment
  • Chemotherapy or anti-tuberculosis medications.