PET Scans

PET stands for Positron Emission Tomography

PET stands for Positron Emission Tomography. A tomograph is a “slice”. You’ve heard of CAT scans. That stands for Computer Assisted Tomography, where the computer generates “slice” images of a person’s lungs, or brain, or abdomen. But where CAT scans show brain anatomy, PET scans show brain function.

PET scans can show which areas of the brain are active, compared to other areas, as in the example below.


Positrons are radioactive particles. Even though the doses used in PET scans are small, designed to be as safe as possible, there is radiation exposure from PET scan so they’re not used very often except in research.

One use of PET scanning is getting more attention “clinically”, i.e. in regular medical practice: testing for Alzheimer’s Disease.

If you really need to learn more about PET scanning, here’s a decent explanation.