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Bone scan How the Test is Performed:
A tracer, or bone-seeking nuclide, is injected into a vein. The tracer emits gamma radiation, which is detected by the scanner. When the tracer has collected in the bones (about 2 to 4 hours) after the injection, the scan is performed. The distribution of gamma rays is recorded by the scanner, and the information is recorded in a computer. The image then appears on the computer screen. Normal or even distribution areas appear gray. "Hot spots" are areas where there is an increased absorption of the tracer; these appear dark. "Cold spots" are areas where there is less absorption of the tracer. These appear light. The scanning part of the test will last about 1 hour and may require moving to various positions.
How to Prepare:
You or a responsible family member must sign an informed consent form. You must remove jewelry, dentures, or other metal objects. You will wear a hospital gown.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
How it Feels:
There is a small amount of pain when the needle is inserted. Afterward, the injection site may be tender to the touch. During the scan there is no pain. You must remain still during the scan, and you will be instructed when to change positions.
Risks:
If the patient is pregnant or nursing a baby, the test may be postponed to decrease the chance of affecting the baby. The amount of radioactivity in the tracer is very small, less than that of a conventional X-ray . Almost all of the radioactivity is out of the body within 1 to 2 days. A person with a hypersensitive reaction may develop a rash , swelling , or other allergic side effects.
Why this Test is Performed:
Detecting areas of abnormal bone metabolism is valuable in determining whether there are lesions, fractures , degenerative disorders, or cancer . This test can also help detect infection.
Normal Values:
Normal absorption appears uniformly gray. When bone is growing or new bone is created as a result of a fracture , there will be elevated levels of the tracer (hot spots).
Abnormal Results:
Greater-than-normal absorption ("hot spots," which appear dark): Less-than-normal absorption ("cool spots," which appear light): - Paget's disease (sometimes)
Additional conditions under which the test may be performed:
Cost:
The estimated cost is $700 to $800.
The cost includes hospital charges (equipment and procedure) and radiologist's fees.
Special Considerations:
This test, when used in conjunction with the patient's history, X-rays, and other laboratory tests is very helpful in determining if the patient has bone lesions or other bone disorders. It is about 50 to 80% accurate.
A bone scan is most often used to look for bone infections (osteomyelitis) or bone tumors, both benign and malignant. The person is given a radioactive substance (isotope) that is readily deposited in bone. The scan can be very sensitive to early bone infection and can detect changes before a conventional X-ray would.
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