This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Positron Emission Tomography of Non-Oncological Disorders, Subject name: Radiology
Dye used in SPECT - 
Select and explain. 
A. 0-14, B. Tc - 99, C. Nitrogen - 16, D. Iodine 124
B: Tc - 99
Answer: B: Tc - 99 
Explanation: Ans. is 'b' i.e., Tc - 99 o The radioisotopes typically used in SPECT to label tracers are Iodine - 123, technetium - 99m, xenon -133, thallium - 201, and fluorine - 18.