Neuroendocrine tumours (NETs) represent a heterogenous group with a broad variability of clinical outcome and a need for personalised therapy. Molecular imaging plays an important role in guiding the most appropriate choice of treatment for NETs, including surgery, chemotherapy, somatostatin analogues, radionuclide therapy, liver-directed therapy or observation. This presentation will demonstrate the utility of molecular imaging (especially positron emission tomography) in the management of NETs through use of instructive case examples and reference to published literature. Goals of molecular imaging such as localisation of functional NETs (eg insulinoma or ectopic ACTH secreting tumours), accurate tumour staging, therapeutic response assessment and in vivo disease characterisation (especially paraganglioma / endocrine neoplasia syndromes) will be discussed.
68Ga-DOTA-octreotate (GaTate) PET/CT is a far superior imaging modality to 111In-Octreotide SPECT/CT due to higher binding affinity of octreotate vs octreotide for SSTR2 receptor, higher spatial resolution with PET vs planar/SPECT imaging, less expensive radionuclide, shorter image acquisition time and lower radiation dose. Alongside it’s theranostic partner 177Lu-DOTA-octreotate (LuTate), GaTate PET/CT plays an important role in guiding treatment with peptide receptor radionuclide therapy.
18F-FDG PET/CT retains an important role in the imaging of gastroenteropancreatic NETs as the dominant predictor of survival and for assessment of sites of discordant FDG-avid disease not targeted by octreotide-based therapies. The imaging phenotypes of the various paraganglioma syndromes will be discussed (including the FDG-avid pseudo-hypoxic signature of the SDHx or VHL tumours) and the role of other tracers for the imaging of paragangliomas (123I MIBG, 18F-DOPA and GaTate) will be reviewed. Recent developments including the use of GLP-1 receptor imaging for localisation of insulinoma will also be discussed.