What Is a Bone Density Scan?
Bone density scans also referred to as bone mineral density testing, is a medical test used as an indirect indicator of osteoporosis. This disorder makes your bones more fragile and likely to break. When you undergo a bone density scan, it measures the amount of mineral material per square centimeter in your bones.
The bone density test can show if your bones are at risk of fracturing by using X-rays to measure the grams of calcium and bone minerals packed into a segment of bone. Generally, radiologists will test the spine, the hip or the forearm. High bone mineral content indicates denser bones. The denser your bones are, the stronger they are and less prone to breakage.
Common Uses of Bone Density Scans
In the past, the only way to determine if a patient had osteoporosis was if you broke a bone. However, by the time that happened, the bones would already be in a weakened state. Osteoporosis is more common in older women, but it can develop in anyone regardless of sex or age. That’s why doctors will recommend bone density scans if you present with certain indicators:
- Loss of height of at least 1.6 inches
- Bones that fracture or seem fragile
- If you’re taking certain drugs that interfere with the bone rebuilding process, like steroid medications
- Those who’ve received a transplant due to the anti-rejection drugs
- Dropped sex hormone levels
The bone density scan can be used to:
- Identify if your bone density has decreased
- Determine if you have a fracture risk
- Confirm an osteoporosis diagnosis
- Monitor osteoporosis treatment
How to Prepare for Bone Density Imaging
There is virtually no preparation needed before a bone density scan. You may be asked to avoid certain food, medications or supplements for at least 24 hours before the procedure. The day of the scan, you will want to wear loose, comfortable clothing and remove all metal objects including jewelry, keys, and other items.
What to Expect During a Bone Density Scan
A bone density scan is quick and painless. Before the procedure, you will probably be asked to fill out a questionnaire to help determine if you have certain risk factors that increase your chance of fracturing a bone.
Bone density scans are generally done on those bones most likely to break due to osteoporosis, like the lower spine bones, your femur next to your hip joint or the bones in your forearm. Depending on what part of your body being scanned, the technologist will position you on a padded table. A dual-energy X-ray absorptiometry, or DEXA (DXA), machine will send an invisible beam of very low dose X-ray through your bones. It will slowly pass over the area being scanned and generate images on a computer monitor.
While the procedure is in progress, you must hold still, and you may be asked to hold your breath for a few seconds. This reduces the risk of a blurred image. The amount of radiation you’re exposed to is minimal and is actually much less than what’s emitted during a chest X-ray. The entire bone density scan is usually completed within 10 to 30 minutes, depending on which part of the body is examined.
