Positron emission is a type of radioactive decay where an unstable atomic nucleus releases a positron, which is the antimatter counterpart of an electron. This process occurs when a proton in the nucleus is transformed into a neutron, resulting in the emission of a positron and a neutrino. The emitted positron can interact with nearby matter, leading to the production of gamma rays. This phenomenon is commonly used in medical imaging techniques, such as Positron Emission Tomography (PET) scans. In PET scans, a radioactive tracer that emits positrons is introduced into the body, allowing doctors to visualize metabolic processes and detect abnormalities in tissues.