Dual-energy

Dual-energy X-ray absorptiometry (also known as DXA, DEXA, or dual X-ray absorptiometry) is a means of measuring bone mineral density (BMD). Two X-ray beams with different energy levels are aimed at the patient's bones. When soft tissue absorption is subtracted out, the BMD can be determined from the absorption of each beam by bone. Dual-energy X-ray absorptiometry is the most widely used and most thoroughly studied bone density measurement technology.

History

The DXA technology was developed in the 1980s. It quickly became the standard for measuring bone mineral density. This was due to its low radiation exposure, high precision and accuracy, and its ability to provide both total body measurements and regional readings of the spine and hip.

Procedure

During a DXA procedure, the patient lies flat on a comfortable table. The scanner, a large device suspended over the table, slowly moves over the patient's body. The procedure is painless and non-invasive. It typically takes about 10 to 20 minutes.

Applications

DXA scans are used primarily to evaluate bone mineral density and to diagnose osteoporosis. They can also be used to track the effects of treatment for osteoporosis and other conditions causing bone loss. The DXA scan can also assess an individual's risk for developing fractures.

Limitations

While DXA is the most commonly used method for measuring bone mineral density, it is not without its limitations. The results can be affected by the size of the patient, the amount of soft tissue, and the location of the tested bone. Additionally, DXA cannot distinguish between cortical and trabecular bone, which have different strengths.

See also

• Bone density
• Osteoporosis
• Radiology

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