Abstract

Medullary thyroid carcinoma (MTC) is a rare but clinically distinctive neuroendocrine malignancy arising from the parafollicular C cells of the thyroid gland and accounts for approximately 1-2% of all thyroid cancers. Unlike differentiated thyroid cancers, MTC does not demonstrate iodine uptake, harbors distinct molecular driver mutations, and may exhibit more aggressive biological behavior; therefore, it requires a disease-specific approach throughout the entire clinical spectrum, from diagnosis to treatment and follow-up. From a clinical standpoint, MTC requires careful staging and close surveillance, as it may present with cervical lymph node metastases at an early stage and disseminate to distant organs such as the liver, lungs, and bones in advanced disease. Although serum calcitonin and carcinoembryonic antigen levels are essential biomarkers for diagnosis and follow-up, these biochemical parameters do not always accurately reflect the anatomical extent of disease or overall tumor burden. Consequently, functional imaging modalities play an important complementary role in the assessment of tumor biology and intratumoral heterogeneity. In recent years, the clinical implementation of various PET radiopharmaceuticals, including flour-18 (18F) dihidroksifenilalanin, 18F-fluorodeoxyglucose, and gallium-68-dodecanetetraacetic acid tyr³-octreotate, has enabled separate evaluation of metabolic activity, amino acid metabolism, and somatostatin receptor expression in MTC. These imaging techniques provide not only precise lesion localization but also valuable insights into tumor aggressiveness and suitability for targeted therapeutic approaches, thereby contributing to the development of personalized treatment strategies. This rewiev aims to present up-to-date, evidence-based recommendations on the use of functional imaging modalities in MTC and to promote standardization in clinical practice.