1, prohibit iodine-containing food (kelp, nori, various kinds of sea fish, etc.) and do not take iodine-containing drugs (potassium iodide, Lugol’s solution or compound iodine solution, vitamin U, cod liver oil, western iodine tablets, X-ray contrast agents, etc.) in January before treatment. 2, stop taking drugs for thyroid diseases for more than 2-4 weeks. Yang Yongdong, Department of Nuclear Medicine, Longyan First Hospital, Longyan City, China.3. You can’t eat any food within 2 hours before taking 131 iodine (you can drink water).4. Undergo all relevant examinations. (The examination time in the Department of Nuclear Medicine of Longyan First Hospital needs to be from 8:00 a.m. on Tuesday to Thursday, and 131 iodine is taken on Friday)