11813
21 patients ( 77 % ) had adjuvant therapy : 15 ( 55 % ) RAI only , 3 ( 11 % ) postoperative external beam radiation ( PORT ) only and 3 ( 11 % ) had both RAI and PORT .
 RAI, RAI
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 RAI, RAI