What is a bone scan?
A bone scan, also called “bone scintigraphy” is an imaging test. Bone scans are used to see problems in your bones. It looks at the whole skeletal system for disease or infection.
A bone scan is often done so that your provider can have "functional imaging" of the bones. Functional imaging measures the rate of bone metabolism. Bone metabolism is the process of how your bones break down and rebuild themselves. Bone metabolism can be higher with infections, fractures (breaks), and some cancers.
Bones scans are a type of nuclear medicine scan, meaning it uses a radioactive substance. A safe amount of this radioactive substance in put into a vein. In infections, fractures, and cancer, as the body tries to fix the problem, bone cells (called osteoblasts) make more bone. It is this new bone activity (metabolism) that is seen on the bone scan. The radioactive substance goes to areas of bone damage and shows spots where your bone cells are trying to fix the damage. A bone scan may be used when cancer is first diagnosed to see if the cancer has spread to the bone (metastasized).
It is important to understand that without talking to the patient and knowing the medical history, the results of a bone scan can be very hard to interpret. For example, old bone injuries can show up on the scan as an abnormal finding.
How do I prepare for a bone scan?
Often, there is nothing for you to do to prepare for a bone scan. If you take a medication that contains bismuth, like some medications used for upset stomach or ulcers, ask your provider about stopping the medication before the test.
How is the bone scan performed?
An intravenous line (IV, into a vein) is placed and the radioactive substance (typically Technitium-99m-MDP) is given. This is called the tracer. If the scan is being done to look for a bone infection, images will be taken right after the radioactive substance is given, and again 3-4 hours later. If the test is being used to check for bone metastases (cancer that has spread to the bone), images are taken only once, 3-4 hours after the injection.
After the tracer circulates through your body, you will be asked to lie on a flat table. A camera will move slowly around your body to take pictures. You may be asked to change your position. The scan will check the whole body at once, which can take up to an hour. A computer processes the pictures taken to create a picture of the patient. Any areas with higher bone activity (metabolism) show up as a dark spot on the image (see example below).
Example of a bone scan result.
Multiple areas of concern are seen in this patient's bones.
What should I expect after the bone scan?
There are usually no side effects.
How do I receive the results of my bone scan?
Following the scan, the images are processed by a computer and read by a nuclear medicine radiologist. The radiologist then creates and sends a report to the provider who ordered the scan. Your care provider will be able to discuss these results with you.