NET Imaging: Past, Present and Future

Introduction: Molecular imaging has emerged as a significant role player for the Neuroendocrine Tumours (NETs’) diagnosis. Neuroendocrine (NE) cells have the ability to secrete hormones; these are found everywhere in the human body. Therefore, neuroendocrine tumours (NETs) is the umbrella term for a group of unusual, slow-growing cancers of NE cells. NETs are easy to diagnose due to their functional characteristics, explicitly expression of Somatostatin receptors (SSTRs), which allows radioisotope labelled pharmaceuticals for accurate diagnosis, staging, and treatment planning.

Methods: In the early days, 111In labelled with pentetreotide and octreotide was used successfully for the imaging of well-differentiated tumours with the help of SPECT imaging. The introduction of PET-CT with 68Ga-DOTATATE,68Ga-DOTATOC,68Ga-DOTANOC has improved the sensitivity and specificity for NET imaging which was lacking with the 111In labelled radiopharmaceuticals. 64Cu-DOTATATE is a promising radiopharmaceutical for the future due to its long half-life and straightforward in-house labelling.

Results: 18F-FDOPA also emerged as a promising radiopharmaceutical due to its uptake influenced by the tumour's ability to store amine precursors and the amino acid decarboxylase activity. In addition, 18F-FDOPA shows high sensitivity for the diagnosis of ileal NET and seems helpful for the diagnosis of insulinoma.

Conclusions: This presentation is aimed at describing with case examples, how imaging of Neuroendocrine tumours has become more sensitive and specific over time, and demonstrating standard practice previously, currently and new, emerging PET tracers for the future.