Incidence of Increased ⁶⁸Ga-DOTANOC Uptake in the Pancreatic Head in a Large Series of Extrapancreatic NET Patients Studied with Sequential PET/CT

Abstract

The aim of our retrospective study was to assess the incidence of increased uptake of 68 Ga-DOTANOC in the head of the pancreas among a large population of patients with extrapancreatic neuroendocrine tumors studied with serial 68 Ga-DOTANOC PET/CT. Methods: Patients who had undergone at least two 68 Ga-DOTANOC PET/CT studies over time were included. Uptake in the head of the pancreas was measured and compared with uptake in normal liver parenchyma (target-to-liver ratio). Patients were followed up for 6-24 mo. Results: We reviewed 245 studies performed on 100 patients and classified the pancreatic uptake as either diffuse or focal. Twenty-three patients (66 scans) showed diffuse uptake; 8 patients (16 scans) showed focal uptake. None of these 31 patients had negative findings on their subsequent scans, and vice versa. During follow-up, localization of neuroendocrine tumors in the pancreas was not suspected in any patient. Conclusion: Focal and diffuse uptake of 68 Ga-DOTANOC in the head of the pancreas occurred, respectively, in 23% and 8% of the patients. The main finding of our study was that increased pancreatic uptake was stable over time.

Comparison of 68Ga-DOTANOC and 68Ga-DOTATATE PET/CT Within Patients with Gastroenteropancreatic Neuroendocrine Tumors

“…Both tracers showed false-positive results in the pancreas (uncinate process) of 2 patients. This falsepositive finding has been described before (35). There was 1 further false-positive result with 68 Ga-DOTATATE in the prostate.…”

Comparison of 18F-DOPA, 18F-FDG and 68Ga-somatostatin analogue PET/CT in patients with recurrent medullary thyroid carcinoma

“…The CT attenuation correction acquisition parameters were 120 kV voltage, 30 mA tube current and 5 mm slice thickness. In centre B images were acquired according to a previously described protocol [17]. In particular, PET/CT was performed on a dedicated hybrid scanner (Discovery STE or Discovery LS; GE Healthcare, Chalfont St. Giles, UK).…”

“…Prior to PET/ CT acquisition the patients were hydrated with 500 ml of water. 18 DOTANOC was labelled with 68 Ga according to a previously described protocol [17]. The administered dose of 68 Ga-DOTANOC was 1.5-2 MBq/kg, and the uptake time was 50-70 min after tracer injection.…”

Is 68Ga-DOTA-NOC PET/CT indicated in patients with clinical, biochemical or radiological suspicion of neuroendocrine tumour?

“…However, considering the physiological uptake of 68 Ga-DOTA-peptides at the head of the pancreas [34,35], positive findings in this area should be interpreted carefully. In our population, the suspicion of pancreatic nodules raised by CT was confirmed in almost half of the cases both at the head and the body/tail level.…”