How does a PET scan work?

How does a PET scan work?

A PET scan works in this way, that when a radio tracer is distributed in the body, the positron, which is actually an antielectron, travels a small amount before it hits a tissue electron in the body of the patient. When an anti-electron and an electron meet each other they annihilate each other, just like what Einstein stated in his E=mc² equation. That annihilation basically produces two gamma rays which are emitted from that point of annihilation at approximately 180 degrees from each other, and they travel out of the body. The PET camera system detects these two gamma rays that are emitted opposite to each other in what we call a "coincidence mode". In other words, if those two gamma rays are seen to occur at approximately a very short amount of time from each other, it is considered to be an event, and that is recorded by the PET camera system. That is what the PET camera system basically does. It records all of these events, and by recording those events, uses a computer to form an image.