When it comes to getting a clear idea of what’s going on inside a person’s body, few medical devices are as useful as a PET scanner.  PET stands for Positron Emission Tomography, but simply put, it involves using radioactive positrons, or positively charged particles, to detect how parts of the body are functioning. An area of increased metabolic or chemical activity—such as the division of cancer cells—will show up on a colored image. {read more here}