This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Introduction to Radiology, Subject name: Radiology
[{'content': 'Gamma Rays are used in? \nSelect and explain. \nA. CT scan, B. DEXA Scan, C. Fluoroscopy, D. PET Scan', 'role': 'user'}, {'content': 'Answer: D \nExplanation: *PET Scan uses Gamma Rays. *Gamma Rays are used in SCINTIGRAPHY STUDIES(Tc99m radioisotope studies),SPECT(Single Photon Emission Computerised Tomography) studies and PET scan (Positron Emission Tomography), Bone scan (Tc99m-MDP studies) *All other investigations given in the options use X rays.', 'role': 'assistant'}]