Iodine-125 is preferred for this purpose, due to better radiation penetration and shorter half-life (13 hours). I-125 is useful for Glomerular filtration rate (GFR) testing in the diagnosis or monitoring of patients with kidney disease. I-125 is used in Iodine-125 is used "therapeutically" in brachytherapy treatments of tumors. For radiotherapy ablation of tissues that absorb iodine (such as the thyroid), or that absorb an iodine-containing radiopharmaceutical, the beta-emitter iodine-131 is the preferred isotope. I is created by the electron capture decay of Xe, which is a synthetic isotope of xenon, itself created by neutron capture of the slightly radioactive Xe, which
Iodine-125 Iodine-125 Iodine-125 (I) is a radioisotope of iodine which has uses in biological assays, nuclear medicine imaging and in radiation therapy as brachytherapy to treat a number of conditions, including prostate cancer, uveal melanomas, and brain tumors. It is the second longest-lived radioisotope of iodine, after iodine-129. Its half-life is 59.49 days and it decays by electron capture to an excited state of tellurium-125. This state is not the metastable Te-125m, but rather a lower energy state that decays immediately by gamma decay with a maximum energy of 35 keV. Some of the excess energy of the excited Te-125 may