A bone scan is performed by injecting a radioactive substance into the vein and the substance then circulates and is taken up by the skeleton. The patient is placed into a scanner and a picture of the skeleton is taken. Hot spots are areas where the radioacitve tracer is concentrated. These hot spots indicate increased blood flow to bone or increased activity of the cells in the bone. This test frequently is used to image the entire skeleton. A bone scan is non-specific which means the findings do not prove an actual diagnosis but indicates a potential area to invetigate further. Further investigation could include CT scan or MRI scan. This test is commonly used in suspected fractures, tumors, and infection.