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A bone scan produces an image of the entire skeleton. A scanning camera views the body after injection of a radioactive substance. This substance has no health risk and collects preferably in bone tissue that is growing or more active. Such active sites include areas of injury, infection, and bone cancer. Other uses of a bone scan are to track certain bone diseases or evaluate unexplained bone pain. A bone scan can often detect problems long before they would show up on a plain x-ray.
About 3 hours before the scan, the person receives an injection of the substance into a vein. The bones absorb it rapidly. During the waiting period, the person drinks 4 to 6 glasses of water to get rid of excess substance. For this reason, doctors may advise against drinking very much fluid before the injection. People taking pain killers may continue to do so. Although the thought of radioactive material in the body may be scary, this substance is very safe. The amount is slight and gives off less radiation than one standard chest x-ray. The scanning generally lasts about 1 hour and is painless. The bladder is emptied right before the scan. The person may be asked to assume various positions on the scanner table. It is important to keep still during the scan. As the scanner moves over the body, it detects low-level radiation from the skeleton. The image is developed on a film or paper chart. Areas of concentrated radioactive substance show up as so-called "hot spots." After a bone scan, one should check the injection site for redness or swelling. The substance is eliminated from the body within 36 hours. This means that one can safely repeat the scan after about 2 days. Although the substance is safe for adults, it may not be safe for a foetus or infant. Therefore, bone scans are not performed on women who are pregnant or breastfeeding. Article #6404 Copyright (c) 2002 McKesson. All Rights Reserved. |
