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DEXA Scan (Dual X-ray Absorptiometry) to Measure Bone Health

How is bone mineral density measured?

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.

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If you've been diagnosed with osteoporosis you know you need to lots of vital nutrients, like calcium and vitamin D. Turns out breakfast may be the best time to give your bone health a lift. Most of the foods and beverages now fortified with calcium are start-your-day kinds of tastes: Orange juice. Milk. Cereal. Sure, the USDA puts baked herring at the top of the list of calcium-rich food. But who knows a good recipe for that? And instant chocolate pudding is pretty high on the list -- but...

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WebMD Medical Reference

Reviewed by David T. Derrer, MD on December 29, 2013
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