Tehran University of Medical Sciences Frontiers in Biomedical Technologies 2345-5837 7 3 2020 09 30 192 200 Ali Abdulhasan Kadhim Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran Peyman Sheikhzadeh Department of Nuclear Medicine, Vali-Asr Hospital, Tehran university of Medical sciences, Tehran, Iran Saeed Farzanefar Department of Nuclear Medicine, Vali-Asr Hospital, Tehran university of Medical sciences, Tehran, Iran Shima Yavari Department of Nuclear Medicine, Vali-Asr Hospital, Tehran university of Medical sciences, Tehran, Iran Majdi Mousa Jber Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Ay Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran AND Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran 2020 03 17 2020 06 30 This review paper aimed to examine radiation safety issues related to relatives as well as caregivers of patients with thyroid diseases treated with radioiodine (I-131). During I-131 therapy for thyroid disorders such as hyperthyroidism, patients receiving I-131 doses (200-800 MBq) emit radioactive radiations which pose a prospective risk to other people. Critical groups are patients’ visitors and families, especially children. Following the updated international guidelines, the doses received by members of the public as a proportion of the therapy of a patient have been decreased. The public annual dose limits are 1 mSv, although higher doses are permitted for adults in the patient’s family, provided that the maximum 5 mSv is not surpassed for 5 years. Without compliance with the current recommendations, extended hospitalizations for patients are essential. Family members should therefore limit close interactions with an individual for some duration following thyroid therapy with I-131. https://fbt.tums.ac.ir/index.php/fbt/article/view/248 https://fbt.tums.ac.ir/index.php/fbt/article/download/248/164