A bone scan for cancer is a nuclear medicine test that looks for abnormalities in bone. An abnormal result on a bone scan may suggest the presence of a tumor in bone, but can also detect fractures, look for bone diseases, and diagnose bone infections.
With cancer, a bone scan may be done to see if symptoms you are experiencing -- for example, pain in your ribs or spine, abnormal blood tests, or an unexpected fracture -- are due to the spread of your cancer to bone. It may also be done to see if your cancer has spread (metastasized) to help define the stage of your cancer and determine the most appropriate treatment.
During a bone scan, a radioactive tracer is injected into a vein in your arm and collects in bone. After a period of time, usually 3 to 4 hours, a scan is done. The radioactive material that has collected in bone gives off gamma rays that can be picked up with a special camera. The scan itself usually takes about an hour to complete.
Though the terms nuclear medicine and radioactive may sound frightening, the procedure is very safe and involves little discomfort other than a needle poke for the injection.
A radiologist will then review the scan looking for abnormalities. "Hot spots" in bone are areas that take up more of the radioactive tracer. These may indicate the presence of cancer, an infection (osteomyelitis), some bone diseases, or arthritis. "Cold spots" are areas in bone that take up less of the tracer. These can be seen with some forms of cancer such as multiple myeloma and some bone diseases.
National Institute of Health. Medline Plus. Bone Scan. Updated 11/02/09. http://www.nlm.nih.gov/medlineplus/ency/article/003833.htm