This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2018, Subject name: Radiology
[{'content': 'Which of the following investigation work on the same principle? \nSelect and explain. \nA. CT and MRI, B. CT and X-ray, C. USG and HIDA Scan, D. MRI and PET Scan', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Principle of: CT :Linear attenuation ofXrays Xray:Xrays (Fluoroscopy also works on the principal of Xrays) MRI: Gyromagnetic propey of H+ USG: Pulse-Echo Principle with Piezoelectric effect PET scan: Annihilation and coincidence imagine, gamma rays -511 key HIDA Scan: Radioisotope scintigraphy, gamma rays.', 'role': 'assistant'}]