FDG PET is not all that sensitive in neuroendocrine cancers(NET). One study revealed that for neuroendocrine tumors, 18F-FDOPA was more accurate (sensitivity, 100%; specificity, 91%) in the detection of skeletal lesions than octreotide scintigraphy or CT but was insensitive (sensitivity, 20%; specificity, 94%) in the lung, ostensibly because of respiratory motion during image acquisition. Octreotide scintigraphy yielded its best results in the liver (sensitivity, 75%; specificity, 100%); however, it was less accurate than PET in all organs. However, 18F-FDOPA PET is less sensitive than FDG PET and standard imaging procedures for the staging of small cell lung cancer. Popperl et al recommends that 18F-FDG should be preserved for less differentiated tumors, while amine precursors and somatostatin analogs should be implemented in the diagnostic process of well-differentiated NET. NCCN on p. MS-12 does not recommend FDG PET.
NETSPOT, after radiolabeling with Ga 68, is a radioactive diagnostic agent recently indicated by the FDA for use with positron emission tomography (PET) for localization of somatostatin receptor positive neuroendocrine tumors (NETs) in adult and pediatric patients. For followup and restaging, its use is off-label.
Imaging of Advanced Neuroendocrine Tumors with 18F-FDOPA PET
Alexander Becherer, Monica Szabó, Georgios Karanikas, Patrick Wunderbaldinger, Peter Angelberger, Markus Raderer, Amir Kurtaran, Robert Dudczak, and Kurt Kletter J Nucl Med 45: 1161-1167
D. J. A. Margolis, J. M. Hoffman, R. J. Herfkens, R. B. Jeffrey, A. Quon, and S. S. Gambhir
Molecular Imaging Techniques in Body Imaging
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Becherer A, Szabo M, Karanikas G, et al. Imaging of advanced neuroendocrine tumors with (18)F-FDOPA PET. J Nucl Med 2004;45:1161–1167.
Jacob T, Grahek D, Younsi N, et al. Positron emission tomography with [(18)F]FDOPA and [(18)F]FDG in the imaging of small cell lung carcinoma: preliminary results. Eur J Nucl Med Mol Imaging 2003;30:1266–1269.
Gabriele Pöpperl PET and PET–CT in Neuroendocrine Tumors Medical Radiology, 2009, Part 5, 471-480
Katrina Ray Imaging: FDG-PET predicts neuroendocrine tumor survival Nature Reviews Clinical Oncology 7, 184 (April 2010)
Jessica E Maxwell1 and James R Howe,Imaging in neuroendocrine tumors: an update for the clinician, Int J Endocr Oncol. 2015; 2(2): 159–168.
NETSPOT Prescribing Information 2018
Read the Layperson version here.