Bone Density Screening

A bone density test determines if you have osteoporosis — a disorder characterized by bones that are more fragile and more likely to break.
The test uses X-rays to measure how many grams of calcium and other bone minerals are packed into a segment of bone. The bones that are most commonly tested are in the spine, hip and sometimes the forearm.
If you have your bone density test done at a hospital, it'll probably be done on a device where you lie on a padded platform while a mechanical arm passes over your body. The amount of radiation you're exposed to is very low, much less than the amount emitted during a chest X-ray. The test usually takes about 10 to 30 minutes.
A small, portable machine can measure bone density in the bones at the far ends of your skeleton, such as those in your finger, wrist or heel.
Because bone density can vary from one location in your body to another, a measurement taken at your heel usually isn't as accurate a predictor of fracture risk as a measurement taken at your spine or hip. Consequently, if your test on a peripheral device is positive, your doctor might recommend a follow-up scan at your spine or hip to confirm your diagnosis.