- 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.
Related Posts
G495 ‘Fields and Particle Pictures’ Revision Notes – Everything YOU Need To Know
In this article, I will cover every topic from G495 including the (in chronological order) Rutherford Scattering, electron…
Chapter 13 and 14 Physics A2 OCR Revision
When looking at the macroscopic world and gases, we need to have macroscopic properties to measure the gases…
How Conservations Laws Led To The Discovery Of The Neutrino
The conservation law in fundamental particles of matter is the idea that which every decay of a nucleus, the charge,…