Isotopes of iodine has no beta activity, is more suited for routine nuclear medicine imaging of the thyroid and other medical processes and less damaging internally to the patient. There are some situations in which iodine-124 and iodine-125 are used in medicine, also. Due to preferential uptake of iodine by the thyroid, radioiodine is extensively used in imaging of and, in the case of I-131, destroying dysfunctional thyroid tissues. Other types of tissue selectively take up certain iodine-131-containing tissue-targeting and killing radiopharmaceutical agents (such as MIBG). Iodine-125 is the only other iodine radioisotope used in radiation therapy, but only as an implanted capsule
Iodine lack of the element. The addition of iodine to table salt has largely eliminated this problem in the wealthier nations, but iodine deficiency remains a serious public health problem today in the developing world. Iodine deficiency is also a problem in certain areas of Europe. Information processing, fine motor skills, and visual problem solving are improved by iodine repletion in moderately iodine-deficient children. Elemental iodine (I) is toxic if taken orally undiluted. The lethal dose for an adult human is 30 mg/kg, which is about 2.1–2.4 grams for a human weighing 70 to 80 kg (even if experiments on rats