PET and Other Functional Imaging

Abstract

Positron emission tomography (PET) and other functional imaging using radiopharmaceuticals are widely used as diagnostic tools in oncology. In this chapter, I review various functional imaging for pancreatic cancer and compare diagnostic performance among imaging modalities. ¹⁸F-labeled fludeoxyglucose (FDG) PET or PET/CT has a limited role in the initial diagnosis of pancreatic cancer; however, it has benefits in initial staging and prognosis evaluation in patients with pancreatic adenocarcinoma. FDG PET has an ability to identify distant metastases. Unnecessary surgical exploration can be avoided. According to National Comprehensive Cancer Network (NCCN) guideline, FDG PET/CT can be considered as an adjunct to a formal pancreatic CT protocol in high-risk patients including borderline resectable disease, markedly elevated CA 19-9, large primary tumors, large regional lymph nodes, and patients who are very symptomatic. FDG PET or PET/CT also differentiates malignant or benign lesion of intraductal papillary mucinous neoplasm. Somatostatin receptor imaging is available as PET/CT and SPECT/CT for diagnosing neuroendocrine tumor. If we substitute therapeutic radionuclide for diagnostic radionuclide, molecular targeting imaging can be easily translated into molecular targeted therapy. Peptide receptor radionuclide therapy with radiolabeled somatostatin analogs controls the disease status in patients with metastatic neuroendocrine tumors.