ion1238 Followers, 198 Following, 0 Posts - See photos and videos from ion (@ion123._)Iodine-123 (123 I) is a radioactive isotope of iodine used in nuclear medicine imaging, including single-photon emission computed tomography (SPECT) or SPECTCT exams. The isotope's half-life is 13.2232 hours; [1] the decay by