What is the uses of PET scans- Brain function

PET scans provide colour-coded images of person's brain as they undertake different sorts of task, such as reading words, solving mental arithmetic and listening to music. The technique relies on the fact that active neurons use more glucose (fuel), so, shortly before the scan; a small amount of radioactively labelled glucose is given to the participant by injection, some of which will be taken up by active neurons. Several different radioactive markers are now available; some have longer or shorter half-lives; others may have specific targets in the brain. A commonly used isotope is oxygen 15, which has a half-life of about 2 minutes. This means it can only be used for relatively brief scanning periods so repeated administration will be necessary in complex or lengthy studies. As it decays it gives off gamma rays that are detected by the PET scanner, and activity level of different regions of the brain can be assessed.