[{"from": "human", "value": "Could you provide a description of this molecule? [C][11C][=Branch1][C][=O][O]"}, {"from": "gpt", "value": "The molecule is the acetate salt of the radioisotope carbon-11. Although the mechanism is unclear, carbon-11 acetate preferentially accumulates in tumor tissue, serving as a tracer for imaging tumors with positron emission tomography (PET). (NCI04)"}]