Dual X-ray absorptiometry (DXA) is the preferred technique for measuring bone mineral density (BMD). DXA has also been called dual energy X-ray absorptiometry, or DEXA. DXA is relatively easy to perform and the amount of radiation exposure is low. A DXA scanner is a machine that produces two X-ray beams, each with different energy levels. One beam is high energy while the other is low energy. The amount of X-rays that pass through the bone is measured for each beam. This will vary depending on the thickness of the bone. Based on the difference between the two beams, the bone density can be measured.
At present, DXA scanning focuses on two main areas -- the hip and spine. In certain situations -- if the hip or spine can't be measured, for instance -- it is measured in the forearm. Although osteoporosis involves the whole body, measurements of BMD at one site can be predictive of fractures at other sites. Scanning generally takes 10 to 20 minutes to complete and is painless and noninvasive.
If your experience with bones is pretty much limited to putting on that
skeleton costume every Halloween, then you could be cheating yourself out of
important preventive care.
Take this quiz to find out how much you know about bone health, and learn a
bit about what you can do to protect your skeleton from head to toe!
1. The largest bone in the human body
Femur (thigh bone)
Tibia (shin bone)