Dual tracer functional imaging of gastroenteropancreatic neuroendocrine tumors using 68Ga-DOTA-NOC PET-CT and 18F-FDG PET-CT: competitive or complimentary? Clin Nucl Med. 2014;39:e27-e34. [PMID: 24217539 DOI: 10.1097/rlu.0b013e31827a216b]

GEP-NETS update: functional localisation and scintigraphy in neuroendocrine tumours of the gastrointestinal tract and pancreas (GEP-NETs)

For patients with neuroendocrine tumours (NETs) of the gastrointestinal tract and pancreas (GEP) (GEP-NETs), excellent care should ideally be provided by a multidisciplinary team of skilled health care professionals. In these patients, a combination of nuclear medicine imaging and conventional radiological imaging techniques is usually mandatory for primary tumour visualisation, tumour staging and evaluation of treatment. In specific cases, as in patients with occult insulinomas, sampling procedures can provide a clue as to where to localise the insulin-hypersecreting pancreatic NETs. Recent developments in these fields have led to an increase in the detection rate of primary GEP-NETs and their metastatic deposits. Radiopharmaceuticals targeted at specific tumour cell properties and processes can be used to provide sensitive and specific whole-body imaging. Functional imaging also allows for patient selection for receptor-based therapies and prediction of the efficacy of such therapies. Positron emission tomography/computed tomography (CT) and single-photon emission CT/CT are used to map functional images with anatomical localisations. As a result, tumour imaging and tumour follow-up strategies can be optimised for every individual GEP-NET patient. In some cases, functional imaging might give indications with regard to future tumour behaviour and prognosis.

The role of combined Ga-DOTANOC and (18)FDG PET/CT in the management of patients with pancreatic neuroendocrine tumors

PURPOSE

The aim of this study was to evaluate the effect of combined (68)Ga and (18)F-FDG PET/CT on treatment management for patients with pancreatic neuroendocrine tumor (PNET).

METHODS

Between January 2012 and April 2014, 49 consecutive patients with a cytologically and/or histologically proven diagnosis of PNET underwent combined (68)Ga and (18)FDG PET/CT on the same day.

RESULTS

The study group consisted of 21 males and 28 females with a median age of 59 years. Disease detection was achieved in 48 out of the 49 cases with (68)Ga imaging, and in 36 of the 49 cases with (18)FDG PET/CT. These results corresponded to sensitivities of 98% for (68)Ga versus 73% for (18)FDG PET/CT. Patients with NET-G1/NET-G2 had a positive (68)Ga and negative (18)FDG PET/CT in 13 cases, whereas both (68)Ga and (18)FDG PET/CT were positive in 27 cases. Patients with NEC-G3 were positive by both (68)Ga and (18)FDG PET/CT in 7 cases and positive only by (18)FDG in 1 case. Another NEC-G3 patient was only positive by (68)Ga PET/CT. The median Ki67 was 7% for (68)Ga PET/CT-positive tumors and 10% for tumors with both (68)Ga and (18)FDG PET/CT positivity (p = 0.130). Half of the patients with a prevalent uptake of (18)FDG (n = 7) had an NEC-G3 compared with 12% of patients with a prevalent uptake of (68)Ga (p = 0.012). There were no significant differences between patients with positive (68)Ga and those with positive (18)FDG with regards to treatment choice.

CONCLUSIONS

The association of (18)FDG slightly increases sensitivity of (68)Ga PET/CT alone in the diagnosis of PNET. A combined dual tracer PET/CT does not influence the choice of treatment strategy.