A bone scan uses radiation to make images showing areas of bone where cells are unusually active. Unusually active cells can indicate cancer, bone trauma, infection or other disorders.
First, a radioactive chemical called an isotope is injected into a vein. The isotope enters the bloodstream and travels to the bones, where it emits gamma rays, which are similar to X-rays. A gamma camera can detect gamma rays. A computer analyzes the rays and forms an image (or scan) of the bones. Areas with potential problems send out more intense rays and appear as bright spots on the scan.