CALCA and medullary thyroid gland carcinoma: It has been also demonstrated that 18F-FDOPA PET/CT produces better results than other functional/anatomical imaging procedures in patients with persistent or recurrent MTC, regional metastases, and basal calcitonin over 60 pg/ml, in which case scanning with 18F-FDOPA seems to be the most useful functional imaging method for detecting regional lymph node disease and identifying candidates for surgery with a curative intent [20,22].