A bone scan is a test that can find damage to the bones, find cancer that has spread to the bones, and watch problems such as infection and trauma to the bones. A bone scan can often find a problem days to months earlier than a regular X-ray test.
During a bone scan, a radioactive substance called a tracer is injected into a vein in your arm. The tracer travels through your bloodstream and into your bones. Then a special camera takes pictures of the tracer in your bones.
Areas that absorb little or no amount of tracer appear as dark or "cold" spots. This could show a lack of blood supply to the bone or certain types of cancer.
Areas of fast bone growth or repair absorb more tracer and show up as bright or "hot" spots in the pictures. Hot spots may point to problems such as arthritis, a tumor, a fracture, or an infection.
Why It Is Done
A bone scan is done to:
- Find bone cancer or determine whether cancer from another area, such as the breast, lung, kidney, thyroid gland , or prostate gland , has spread (metastasized) to the bone.
- Help diagnose the cause or location of unexplained bone pain, such as ongoing low back pain. A bone scan may be done first to help determine the location of an abnormal bone in complex bone structures such as the foot or spine. Follow-up evaluation then may be done with a computed tomography (CT) scan or magnetic resonance imaging (MRI).
- Help diagnose broken bones, such as a hip fracture or a stress fracture, not clearly seen on X-ray.
- Find damage to the bones caused by infection or other conditions, such as Paget's disease.
How To Prepare
Before the bone scan, tell your doctor if:
- You are or might be pregnant.
- You are breast-feeding. The radioactive tracer used in this test can get into your breast milk. Do not breast-feed your baby for 1 or 2 days after this test. During this time, you can give your baby breast milk you stored before the test, or you can give formula. Discard the breast milk you pump in the 1 or 2 days after the test.
- Within the past 4 days, you have had an X-ray test using barium contrast material (such as a barium enema) or have taken a medicine (such as Pepto-Bismol) that contains bismuth. Barium and bismuth can interfere with test results.