Iodine 131 therapy is not able to kill lymph nodes. Iodine 131 therapy is generally used in clinical practice to treat hyperthyroidism, and patients with hyperthyroidism can be treated with iodine 131 radiation therapy in addition to surgery if conservative drug therapy is not effective. After oral administration of the isotope iodine 131, the thyroid gland can take in iodine 131 and most of it will be absorbed by the thyroid gland. Iodine 131 can release beta and gamma rays in the body, which can kill the surrounding thyroid cells and have the same effect as surgical removal of the thyroid gland. Although the rays are radioactive, most of the iodine 131 is absorbed by the thyroid gland, and the rays work over a very short distance without causing much damage to the surrounding tissues, so generally the application of iodine 131 does not kill the lymph node cells.