Definition of Bone scan:

A bone scan is an imaging test that shows areas of increased or decreased bone turnover (metabolism).

How the test is performed:

A bone scan involves injecting a radioactive material (radiotracer) into a vein. The substance travels through the bloodstream to the bones and organs. As it wears away, it gives off radiation. This radiation is detected by a camera that slowly scans your body. The camera takes pictures of how much radiotracer collects in the bones.

If a bone scan is done to see if you have a bone infection, images may be taken shortly after the radioactive material is injected and again 3 to 4 hours later, when it has collected in the bones. This is called a 3-phase bone scan.

To evaluate metastatic bone disease, images are taken only after the 3 to 4 hour delay.

The scanning part of the test will last about 1 hour. The scanner's camera may move above and around you. You may need to change positions.

You will probably be asked to drink extra water after you receive the radiotracer to keep the material from collecting in your bladder.

How to prepare for the test:

You must remove jewelry and other metal objects. You may be asked to wear a hospital gown.

Tell your doctor if you are or may be pregnant.

Do not take any medicine with bismuth in it, such as Pepto-Bismol, for 4 days before the test.

How the test will feel:

There is a small amount of pain when the needle is inserted. During the scan there is no pain. You must remain still during the examination, and you will be instructed when to change positions by the technologist.

You may experience some discomfort due to lying still for a prolonged period of time.

Why the test is performed:

A bone scan is used to:

• Diagnose a bone tumor or cancer
• Determine if a cancer that began elsewhere in your body has spread to the bones; common cancers that spread to the bones include breast, lung, prostate, thyroid, and kidney.
• Diagnose a fracture, when it cannot be seen on a regular x-ray (most commonly hip fractures, stress fractures in the feet or legs, or spine fractures)
• Diagnose a bone infection (osteomyelitis)
• Diagnose or determine the cause of bone pain, when no other cause has been identified
• Evaluate metabolic disorders, such as osteomalacia, renal osteodystrophy, primary hyperparathyroidism, osteoporosis, complex regional pain syndrome, and Paget's disease