Contemporary nuclear medicine diagnostics of neuroendocrine tumors

Abstract

The new positron emission tomography (PET/CT) methods for neuroendocrine tumors detection are presented and compared with classic, conventional methods. Conventional methods use a gamma scintillation camera for patients with neuroendocrine tumor imaging, after intravenous injection of one of the following radiopharmaceuticals: 1) somatostatin analogues labeled with indium-111 (111In-pentetreotide) or technetium-99m (99mTc-EDDA/HYNIC-TOC); 2) noradrenaline analogue labeled with iodine-131 or -123 (131I/123I-MIBG); or 3) 99mTc(V)-DMSA. Contemporary methods use PET/CT equipment for patients with neuroendocrine tumor imaging, after intravenous injection of pharmaceuticals labeled with positron emitters [fluorine-18 (18F), galium-68 (68Ga), or carbon-11 (11C)]: 1) glucose analogue (18FDG); 2) somatostatin analogue (68Ga-DOTATOC/68Ga-DOTATATE/68Ga-DOTANOC); 3) aminoacid precursors of bioamines: [a) dopamine precursor 18F-DOPA (6-18F-dihydroxyphenylalanine), b) serotonin precursor 11C-5HTP (11C-5-hydroxytryptophan)]; or 4) dopamine analogue 18F-DA (6-18F-fluorodopamine). Conventional and contemporary (PET/ CT) somatostatin receptor detection showed identical high specificity (92%), but conventional had very low sensitivity (52%) compared to PET/CT (97%). It means that almost every second neuroendocrine tumor detected by contemporary method cannot be discovered using conventional (classic) method. In metastatic pheochromocytoma detection contemporary (PET/ CT) methods (18F-DOPA and 18F-DA) have higher sensitivity than conventional (131I/123I-MIBG). In medullary thyroid carcinoma diagnostics contemporary method (18F-DOPA) is more sensitive than conventional 99mTc(V)-DMSA method, and is similar to 18FDG, computed tomography and magnetic resonance. In carcinoid detection contemporary method (18F-DOPA) shows similar results with contemporary somatostatin receptor detection, while for gastroenteropancreatic neuroendocrine tumors it is worse. To conclude, contemporary (PET/CT) methods for somatostatin receptor detection (68Ga-DOTATOC/-NOC/-TATE) in neuroendocrine tumors are much more sensitive (almost twice) and more accurate than conventional. Therefore the classical methods should be urgently replaced by contemporary methods.

Recent Development of Nuclear Molecular Imaging in Thyroid Cancer

“…When there are elevated levels of serum calcitonin and the conventional imaging has negative results, nuclear molecular imaging techniques including 201Tl, 99m Tc-(V)-DMSA, 99m Tc-sestamibi, 99m Tc-tetrofosmin, 123/131I-MIBG, Indium-111-octreotide, and 99m Tc-EDDA/HYNIC-TOC scintigraphy can be used [ 46 , 59 ]. Compared to the above methods using a gamma scintillation camera for patients with neuroendocrine tumor imaging, the new positron emission tomography (PET/CT) methods (18F-FDG-PET, 18F-DOPA, 18F-fluorodopamine, 68Ga-DOTATOC/-NOC/-TATE, 11C-5-hydroxytryptophan) are much more chosen, due to higher sensitivity and more accuracy [ 60 ].…”

“…But F-DOPA PET/CT has a limited sensitivity in the detection of residual disease (lesion-based sensitivity: 24%) [ 63 ]. Literature shows that MTC diagnostics contemporary method (18F-DOPA) is more sensitive than conventional 99m Tc-(V)-DMSA method and is similar to 18F-FDG or computed tomography and magnetic resonance [ 60 ]. But some studies suggest that the sensitivities of both 18F-DOPA PET/CT and 18F-FDG-PET/CT to detect MTC are associated with calcitonin and CEA doubling time.…”

Clinical relevance of 18F-FDG PET/CT in the postoperative follow-up of patients with history of medullary thyroid cancer

“…99m Tc-EDDA/HYNIC-Tyr3-octreotide (Tektrotyd). [8][9][10][11][12][13] The radiopharmaceuticals labelled with a positron-emitting radionuclides suitable for positron emission tomography with computed tomography (PET/CT) are 18 F-fluorodeoxyglucose ( 18 F-FDG), 18 F-fluorodihydroxyphenylalanine ( 18 F-DOPA), and 68 Ga-labelled somatostatin analogues ( 68 Ga-DOTATATE or DOTATOC). According to the literature, overall sensitivity of conventional nuclear medicine methods γ emitting radionuclides is lower in comparison to conventional anatomic imaging (i.e.…”

“…The most frequently used radiopharmaceuticals for the diagnosis and follow up of MTC, labelled with γ emitting radionuclides, are metaiodoben-zylguanidine (MIBG) labelled either with 131 I or 123 I, 99m Tc-pentavalent dimercaptosuccinic acid ( 99m Tc(V)-DMSA), 111 In-pentetreotide (Octreoscan) and 99m Tc-EDDA/HYNIC-Tyr3-octreotide (Tektrotyd). 8 , 9 , 10 , 11 , 12 , 13 The radiopharmaceuticals labelled with a positron-emitting radionuclides suitable for positron emission tomography with computed tomography (PET/CT) are 18 F-fluorodeoxyglucose ( 18 F-FDG), 18 F-fluorodihydroxyphenylalanine ( 18 F-DOPA), and 68 Ga-labelled somatostatin analogues ( 68 Ga- DOTATATE or DOTATOC). According to the literature, overall sensitivity of conventional nuclear medicine methods γ emitting radionuclides is lower in comparison to conventional anatomic imaging ( i.e .…”