Diagnostic impact of PET with 18F-FDG, 18F-DOPA and 3-O-methyl-6-[18F]fluoro-DOPA in recurrent or metastatic medullary thyroid carcinoma.

Purpose In patients with medullary thyroid carcinoma (MTC), rising levels of the tumour markers calcitonin and CEA after primary surgery indicate tumour recurrence or metastases. The only chance of cure is the resection of localised tumour tissue. For positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) and 18F-dihydroxyphenylalanine (18F-DOPA), sensitivities of 78% and 63% have been reported, but in a considerable percentage of MTC patients the source of tumour marker elevation is not detected. The aim of this retrospective data evaluation was to compare the value of PET with 18F-FDG, 18F-DOPA and the amino acid tracer 3-O-methyl-6-[18F]fluoro-DOPA (18F-OMFD) in the detection of MTC recurrence.