This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Radiology
[{'content': 'Investigation of choice for recurrent GIST: \nSelect and explain. \nA. MIBG, B. PET CT, C. MRI, D. CECT', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans BRecurrent GIST indicates a small residual focus which can be identified by functional imaging like PET. GIST is not a neuroendocrine tumour and hence does not show uptake of MIBG.', 'role': 'assistant'}]