Evaluation of 18F-FDOPA PET-CT in the Preoperative Initial Assessment of Medullary Thyroid Carcinoma

Medullary thyroid carcinoma (MTC) develops at the expense of calcitonin cells and is often characterized by lymph node metastases and sometimes visceral metastases. Improvement of preoperative diagnosis is of major importance in CMT because the quality of the initial surgery determines the prognosis. In recent years, 18F-fluorodihydroxyphenylalanine (18F-FDOPA) PET / CT was considered the most sensitive functional imaging tool in the evaluation of persistent CMT. To date, 18F-FDOPA PET at initial diagnosis has been reported in a few clinical cases. The main objective is to demonstrate that 18F-FDOPA PET provides additional information compared to conventional imaging on the initial diagnosis of CMT patients. The secondary objectives are to describe the nature of the information provided by PET / CT imaging, the main factors influencing tracer uptake and the positivity of PET / CT, and the impact of the examination on the care of the patient. This is a prospective, multicenter and open study. Patients with TCM who have serum calcitonin\> 150 pg / ml at initial diagnosis and have performed baseline imaging examinations within the last 3 months will be included in the study . A PET at 18F-FDOPA will be performed according to a very powerful acquisition protocol. Image analysis will be performed blindly from the results of conventional imaging. All exams will be compared, in accordance with the gold standard. Therapeutic intentions will be collected before and after the PET imaging, as well as the actual management in place.