Looking Inside the Human Body Using Radioactive Atoms

Abstract

Positron emission tomography (PET) is a method for taking pictures of a disease inside of a sick person’s body, without having to cut them open. In PET imaging, a radioactive chemical called a radiotracer is injected into a patient. All radiotracers have two main parts: a part that targets the disease, and an unstable atom (radioisotope) that emits positive electrons (positrons) as it breaks down (decays). When a positron crashes into an electron, both are destroyed, and two particles of light emerge. Doctors can detect these radioactive signals and use them to create a 3D image of where the tracer (and the disease) is in the body. This article describes PET and PET radioisotopes in greater detail. We focus on fluorine-18, a radioisotope that makes up the “signaling part” of many important PET radiotracers.