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A bone scan is an imaging test that shows areas of increased or decreased bone turnover (metabolism).
Scintigraphy - bone
A bone scan involves injecting a very small amount of radioactive material (radiotracer) into a vein. The substance travels through your blood to the bones and organs. As it wears off, it gives off a little bit of 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 process 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.
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.
Follow any other instructions you are given.
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 scan. You will be instructed when to change positions by the technologist.
You may experience some discomfort due to lying still for a long period.
A bone scan is used to:
Test results are considered normal if the radiotracer moves evenly throughout all the bones.
An abnormal scan will show “hot spots” and/or “cold spots” as compared to surrounding bone. Hot spots are areas where there is an increased accumulation of the radioactive material. Cold spots are areas that have taken up less of the radioactive material.
Bone scan findings must be compared with other imaging studies, in addition to clinical information. Your health care provider will discuss any abnormal findings with you.
If you are pregnant or nursing, the test may be postponed to prevent exposing the developing baby to radiation. If you must have the test while breastfeeding, you should pump and throw away the breast milk for the next 2 days.
The amount of radiation injected into your vein is very small. All radiation is gone from the body within 2 to 3 days. The radiotracer that is used exposes you to a very small amount of radiation. The risk is probably no greater than with routine or conventional x-rays.
Risks related to the bone radiotracer are rare, but may include:
There is a slight risk of infection or bleeding when the needle is inserted into a vein.
Coleman RE, Holen I. Bone metastases. In: Abeloff MD, Armitage JO, Niederhuber JE, Kastan MB, McKena WG, eds. Clinical Oncology. 4th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 57
Newberg A. Bone scans. In: Pretorius ES, Solomon JA, eds. Radiology Secrets Plus. 3rd ed. Philadelphia, Pa: Elsevier Mosby; 2010:chap 54.