Evaluation of Response to Therapy in Thyroid Carcinoma Patients after Radioactive Iodine Therapy

Radioactive iodine therapy is an important treatment modality for differentiated thyroid carcinoma patients. Radioactive iodine, similar to elementary iodine, is concentrated in the thyroid follicular cells after oral application, and it can damage the remnant or malignant thyroid cells. Unlike many antineoplastic drugs, radioactive iodine can easily be applied without causing serious side effects. Radioactive iodine was first used for the treatment of a differentiated thyroid carcinoma patient in 1949. In Turkey, it has been used in many nuclear medicine centers for treatment of both differentiated thyroid carcinoma and hyperthyroid patients since 1954. For evaluation of response to therapy with radioactive iodine, different clinical, biochemical, scintigraphic, and radiological imaging modalities are available. Today, many international guidelines aid the clinicians in the assessment of therapy response after radioiodine application. This review aims to discuss the methods recommended in current guidelines for therapy response assessment in differentiated thyroid carcinoma patients after radioactive iodine therapy