| 单词 | pet scanning |
| 释义 | PET scanningPET scanningPositron emission tomography. This is a diagnostic imaging technique based on the detection of gamma rays produced by the annihilation of positively charged electrons (positrons) emitted by specially prepared radioactive substances that have been injected intravenously. Substances labelled with oxygen-15, fluorine-18, carbon-11 or nitrogen-13 are most commonly used. PET scanning provides uniquely valuable images of tissues showing local metabolic activity, especially in the brain, the rate of glucose and oxygen consumption at various sites, blood flow, neurotransmitter activity and the fate of drugs. Positron-emitting substances have a very short half-life and must be prepared on site in a cyclotron. This limits the application of the technique. |
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