Isotopes of iodine iodine-123 and iodine-131 can also be seen by single photon emission computed tomography (SPECT) imaging. Iodine-124 is a proton-rich isotope of iodine with a half-life of 4.18 days. Its modes of decay are: 74.4% electron capture, 25.6% positron emission. I decays to Te. Iodine-124 can be made by numereous nuclear reactions via a cyclotron. The most common starting material used is Te. Iodine-124 as the iodide salt can be used to directly image the thyroid using positron emission tomography (PET). Iodine-124 can also be used as a PET radiotracer with a usefully longer half-life compared with fluorine-18 In this use,
Isotopes of iodine and 1970s reached about 10). I differs from Cl in that its half-life is longer (15.7 vs. 0.301 million years), it is highly biophilic, and occurs in multiple ionic forms (commonly, I and IO), which have different chemical behaviors. This makes it fairly easy for I to enter the biosphere as it becomes incorporated into vegetation, soil, milk, animal tissue, etc. Of the many isotopes of iodine, only two are typically used in a medical setting: iodine-123 and iodine-131. Since I has both a beta and gamma decay mode, it can be used for radiotherapy or for imaging. I, which