Iodine-131 (as sodium iodide I-131) (I-131)

Iodine-131 (I-131) is a radioactive isotope of iodine used as a radiopharmaceutical primarily in the treatment of hyperthyroidism and well-differentiated thyroid carcinoma. When administered orally as sodium iodide I-131, it is selectively taken up by thyroid tissue due to the organ’s expression of the sodium/iodide symporter. I-131 emits beta particles, which cause local cell death and tissue ablation, and gamma particles, which allow for imaging. This compound enables targeted ablation of thyroid tissue (in hyperthyroidism or ablation of remnant or metastatic thyroid cancer), as well as diagnostic procedures to evaluate thyroid function and disease extent. The molecule itself is not a receptor, enzyme, or signaling molecule, but a radioactive therapeutic agent designed to exploit physiological iodine uptake in thyroid tissues.

Other names

Radioiodine I-131Sodium iodide I-131I-131 radiopharmaceuticalRadiopharmaceutical I-131

Delivers targeted radiation to thyroid tissue through the emission of beta particles (for tissue destruction) and gamma particles (for imaging/diagnosis); uptake is mediated by the sodium/iodide symporter in thyroid cells