Abstract: ¹²³I is a radionuclide for diagnosing thyroid diseases. Its half-life of approximately 13.2 hours is suitable to perform thyroid radioiodine uptake measurement on the patients, and it has important value in thyroid tissue and thyroid cancer metastases imaging. ¹²³I and its labeled compounds has a lower radiation burden for patients and is usually administered in capsule form or by intravenous injection for obtaining functional thyroid images and diagnosing functional diseases. Additionally, it has important applications in the field of medical imaging, particularly playing a significant role in the diagnosis of neurological and cardiovascular diseases. For example, ¹²³I can be used in the diagnosis of neurodegenerative diseases such as Parkinson′s disease, and it is also commonly utilized to assess cardiac function, especially in the diagnosis of coronary artery disease or myocardial ischemia. By reviewing the research advancements in the relevant field over the past decade, the authors summarize the current clinical applications and value of ¹²³I, aiming to contribute to the promotion of its use in clinical imaging.