This is a technique to demonstrate abnormal metabolic activity in bone. The procedure involves intravenous injection of the radionuclide which is usually sodium pertechnetate (technetium Tc99m methylene diphosphonate) which is taken up in areas of active growth in bone.It is possible to differentiate normal growth and excessive growth from the level of radioactivity emitted. This method can detect metastatic tumor to bone from the prostate, breast, lung, kidney, bladder and thyroid, arthritis, osteomyelitis, and new fractures. Other methods include WBC scan and gallium scan.