A bone scan is a radionuclide-based imaging technique. A radiopharmaceutical, usually Tc99m-HDP is injected. Early images may be acquired for some specific indications. Delayed images around 3 hours post-injection show a functional map of osteoblastic activity. Areas with increased osteoblastic activity are seen as hot spots. Areas of reduced osteoblastic activity compared to adjacent bone appear as cold spots.
Usually a static only whole body image with additional spot views as required.
Occasionally early blood pool assessment of specific single area, then static with additional views of hands and feet. The pattern of uptake may be diagnositic for osteoarthritis, sero-positive arthritis or sero-negative arthritis
Useful for trauma, avascular necrosis, osteomyelitis and joint infections. Commonly used for painful prostheses prior to white cell imaging as technically easier and no risk of HAMA reaction. If normal infection is excluded.