Antimatter

When they meet, antimatter and matter particle sdestroy each other and radiation is released. This effect is made use of in PET hospital scanners. The P in PET stands for positron which is the antiparticle of the electron. When a PET scanner is used for a brain scan, a positron emitting isotope is administered to the patient and some of it reaches the brain via the blood system. Each positron emitted travels no further than a few millimeters before it meets an electron and they annihilate each other. Two gamma photons, produced as a result, are sensed by detectors linked to computers. Gradually, an image is built up from the detector signals of where the positron-emitting nuclei are inside the brain.

Positron emission takes place when a proton changes into a neutron in an unstable nucleus with too many protons. The positron is the antiparticle of the electron, so it carries a positive charge. In addition,…