PETscanner
A PET scanner, or Positron Emission Tomography scanner, is a medical imaging device that produces three-dimensional images of metabolic or biochemical processes within the human body. It works by detecting pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (a radiotracer) that is introduced into the body on a biologically active molecule. This radiotracer accumulates in specific organs or tissues depending on the molecule it is attached to. For example, a common radiotracer is fluorodeoxyglucose (FDG), a glucose analog that is taken up by cells with high metabolic activity, such as cancer cells.
When the unstable nucleus of the radiotracer decays, it emits a positron. This positron then travels a