12291
Six patients who received total thyroidectomy underwent radioactive iodine ( RAI ) therapy and T4 suppression .
 Chemical: iodine
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: iodine 
Answer:
 Chemical: iodine