Neuroendocrine tumours can be visualized by several nuclear medicine modalities based on different mechanisms of cellular uptake. The most widely used radiopharmaceutical are the metaiodobenzylguanidine (123I/131I MIBG) and pentetreotide (111In pentetreotide). The first tracer follows the metabolic pathway of norephinephrine while the second one binds to somatostatin receptors which are expressed with high intensity on the neuroendocrine tissue. Some radiopharmaceuticals (Anti-CEA, Anti-CgA, Anti-GD2 monoclonal antibodies) have today only an experimental value, others such as 99mTc(V)DMSA had in the past very limited indications (medullary thyroid cancer) but at present their production is going to be stopped. An interesting series of new peptides showing a great affinity for the receptors/structures expressed by the neuroendocrine tissue is under evaluation in order to obtain a better tumour specificity. Among the positron-emitting radiopharmaceuticals, the 18F-fluorodeoxyglucose (FDG), in spite it is considered the most widely used tracer for clinical PET in oncology, did not show a satisfactory uptake in the well differentiated neuroendocrine tissues. On the contrary 18F-FDG is the best radiopharmaceutical to visualize those rare poorly differentiated neurondocrine tumours with a high proliferative index. For this reason also in this area, new radiopharmaceuticals have been studies and developed. A serotonin precursor 5-hydroxytryptophan (5-HTP) labelled with 11C has shown an increased uptake in carcinoids. Another radiopharmaceutical in development for PET is 11C L-DOPA which seems to be useful in visualizing endocrine pancreatic tumours. 18F-DOPA whole body PET may be a more promising imaging approach. Aim of this review is to summarize the potential of nuclear medicine techniques in the diagnosis of neuroendocrine tumours and to stresses the renewed role of nuclear medicine in the management of this disease.
|Number of pages||17|
|Publication status||Published - 2001|