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
[{'content': 'Positron emission tomography imaging is commonly performed using: September 2011 \nSelect and explain. \nA. Barium sulphate, B. 2-18 fluoro-2-deoxy D-glucose (18 FDG), C. Myodil, D. Oxygen 15', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: 2-18 fluoro-2-deoxy D-glucose (18 FDG) The majority of clinical PET imaging is now performed with the glucose analogue 2-18 fluoro-2-deoxy D-glucose (18 FDG) which has a half life of 110 min. PET scan: Differentiates radiation necrosis from active neoplasm following therapy Recent role is in investigation of recurrent GIST tumours', 'role': 'assistant'}]