What is a bone scan?
A bone scan, also known as bone scintigraphy, is a medical test used to evaluate the entire skeleton for abnormalities in the bones. A bone scan is often useful to obtain "functional imaging" to evaluate the bones. Functional imaging is a measure of the rate of bone metabolism, which can be elevated with infections, fractures, and certain cancers.
Bones scans are a type of nuclear medicine scan, meaning a scan that uses a radioactive substance to examine the body. In infections, fractures, and cancer, as the body attempts to repair the problem, bone cells called osteoblasts create more bone. It is this new bone activity (metabolism) that is detected on the bone scan. A bone scan may be used when cancer is first diagnosed to determine if the cancer has spread to the bone.
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 difficult 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?
Typically, no preparation is needed. If you take a medication that contains bismuth, you should speak to your provider about stopping the medication 4 days prior to the test.
How is this test performed?
An intravenous line (IV) is placed and an injection of a radioactive material, typically Technitium-99m-MDP, is given. This is called the tracer. If the scan is being performed to look for a bone infection, images will be taken almost immediately after the radioactive material is injected, and again 3-4 hours later. If the test is being used to check for bone metastases, images are taken only once, 3-4 hours after the injection.
After the tracer has had the appropriate amount of time to circulate 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 evaluate 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 increased bone activity 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 to expect after the bone scan?
There are generally no side effects.
How do you receive the results of your 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.