PET that uses FDG (a type of tagged sugar) is not all that sensitive in neuroendocrine cancers(NET). This means that it may not pick up some neuroendocrine cancers. Specificity means that what it does pick up is really cancer and not some other false positive. However, other imaging modalities also had disadvantages as well as advantages. One study revealed that for neuroendocrine tumors, PET that used 18F-FDOPA was more accurate (sensitivity, 100%; specificity, 91%) in the detection of skeletal lesions than octreotide scintigraphy or CAT scan but was insensitive (sensitivity, 20%; specificity, 94%) in the lung, ostensibly because respiratory motion during image acquisition degrade the accuracy of PET. 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 contrast should be implemented in the diagnostic process of well-differentiated NET. NCCN on p. MS-12 does not recommend FDG PET for neuroendocrine cancer.
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