5449
Methods : SGS was performed just before RAI ablation ( pre - SGS ) and ~ 5 years after RAI ablation ( F / U SGS ) in 213 subjects who underwent thyroidectomy for thyroid cancer .
 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