A bone scan is a test used to find cancer, infection, or injuries in the bone. It may also be used to check a person's response to treatment for certain bone conditions.
Who is a candidate for the test?
A healthcare professional may recommend this test to:
- detect whether cancer has spread to the bone
- find an infection in the bone
- detect a tumor in the bone
- follow a person's response to treatment for conditions like Paget's disease, a condition that destroys bone
- find a fracture or injury to the bone
How is the test performed?
As with most tests, a consent form is required. A radioactive substance is injected into the individual's arm. Usually, scanning begins after this substance has had about 2 to 3 hours to circulate through the body. In the case of a 3-phase study, however, the test begins right away and then resumes after a wait of 2 hours.
Once the actual scanning begins, it takes about an hour. The person lies flat on his or her back on a table. A special camera is positioned so the entire body can be scanned. Rays from the radioactive substance are detected by the camera, which sends pictures to a computer. In a normal study, the table will not move during each scan.
However, in some instances, more focused views may be needed, so the scanner may move 10 to 15 centimeters (4 to 6 inches) per minute while pictures are being taken.
In the 3-phase study, the first scans are done every 5 seconds for 60 seconds. A blood pool image, a special image to follow the radioactive substance while it travels through the blood vessels, is done next. Then the person needs to wait for 2 hours before scans are resumed.
After the bone scan is done, the person will be asked to wait to get dressed until the technologist is sure the pictures are adequate.
What is involved in preparation for the test?
Before the test, the person will undress completely and put on an exam gown. All jewelry and metal objects-including pierced body jewelry-must be removed so they will not interfere with the exam. A woman will be asked if she is pregnant.
Usually no other special preparation is needed. However, the person should check with the exam center or healthcare professional before the day of the exam to be sure.
What do the test results mean?
This test can:
- show specific areas of irregular bone metabolism, which may suggest certain diseases based on the pattern of abnormality
- detect abnormal blood flow to a particular bony region
- help evaluate metabolic diseases that affect bone, such as certain thyroid conditions
- detect the spread of cancer to the bones and evaluate results of cancer treatment
- diagnose bone changes from a condition called reflex sympathetic dystrophy, a disorder of nerves that may cause pain, usually in the hands or feet