What is Nuclear Medicine?

Nuclear is an imaging modality in Radiology, or Diagnostic Imaging. Other modalities include MRI, CAT Scan, Ultrasound (sonography) and general radiography (x-ray).
Nuclear machines can be also called Scintillation Cameras, Gamma Cameras, Functional Imaging Machines, or "that thing that looks like a CT scanner."
Here is a picture of what one looks like:



This is a Picker camera, about ten years old. It works fairly well still, although we would love to have a shiny new model (hint, hint).
The machine picks up where radiation is and forms a picture of it. It is like a giant Geiger Counter, but relies upon very tiny amounts of radioactivity.
Usually a shot is given of a radioisotope which has been bound to a particular chemical or substance used by the body part we want to image. For example, a phosphate for viewing the bones, a potassium analog to view the heart.