One of the most striking aspects of physics is antimatter. Every substance has an antimatter and if matter and antimatter come in contact with each other then they disappear from each other and become energy. Many may think that this is a theoretical subject of physics and in reality it does not exist in any corner ; But that's not true , it's not just the existence of matter and the transformation of matter and antimatter into energy . Glucose is injected into such a radioactive isotope mixture by emitting positrons into the person's body before taking a picture inside the body . The more active the cell in the body, the more glucose it uses, and this is where the radioactive isotope accumulates. From this isotope comes the antimatter of an electron called positron, and almost immediately upon contact with an electron at a nearby angle, S is converted to energy and emits two gamma rays as energy. This device, called PET , detects two gamma rays and accurately calculates exactly where the two gamma rays came from. With that information, it is found out where the body cells are more active. Position Emission Tomography can also be used to find out which part of the brain is more active.