Why does high-dose radioiodine treatment for differentiated nail cancer need to be performed in a special protective ward? High-dose radioactive iodine is an indispensable treatment for post-operative differentiated nail cancer, but because radioactive iodine has radioactive radiation, it may be harmful to the patient’s family and the public. According to studies, patients who take 100 millijuice of radioactive iodine orally can have a range of 10-15 meters of radiation in their body. Therefore, if the patient stays in a hotel or home after taking the drug, it will be harmful to the public in a radius of 10-15 meters around the patient, especially if there are children or pregnant women in this area. Therefore, high-dose radioiodine treatment of differentiated nail cancer must be performed in a special protective ward.