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 used in myocardial perfusion scan is: 
Select and explain. 
A. Technetium, B. Thallium, C. Stannous pyrophosphate, D. Gallium
B: Thallium
Answer: B: Thallium 
Explanation: Ans. Thallium