This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
Isotope for thyroid scaning – a) I129b) I131c) Technetium99d)  Selenium 
Select and explain. 
A. bc, B. c, C. ac, D. ad
A: bc
Answer: A: bc 
Explanation: Isotopes used for thyroid scanning are 1234 131, and technetium - 99m pertechnate. 
	Note - Some books have given II" also. But it is not used for thyroid scintigraphy.