Don't miss

A Positron Emission Tomography




  • Brain activity causes an increase blood flow to certain areas of the brain. The oxygen carried by the flood to the brain is labelled with a small amount of radioactive isotope oxygen-15. This has a short half life decaying by emitting antimatter called a positron.
  • The positron emitted then annihilates with a nearby electron. Due to E = mc², the mass vanishes and is destroyed but the energy is still there in the form of a pair of gamma-ray photons travelling in opposite directions.
  • The detectors around the brain pick up these photons and generate a computer generated map of the activity of the brain
  • The detectors detect the gamma-ray photons almost simultaneously (as they are a pair). The change in time will help work out the location of the source of gamma rays.

About Will Green

A student in England studying Automotive Engineering with Motorsport, Will created Ask Will Online back in 2010 to help students revise and bloggers make money. You can follow AskWillOnline via @AskWillOnline.

0 comments so far:

Post a Comment