What is a DXA scan? How is bone mineral density (BMD) calculated?
Dual-energy X-ray absorptiometry (DXA) is the most widely used bone densitometric technique and the examination of choice for diagnosing and following up osteoporosis
The bone mineral content is assessed by measuring the relative absorption of two distinct energy x-ray beams (usually 70 kVp and 140 kVp). The bone mineral content is then divided by the area measured, yielding bone mineral density (BMD). Note that the unit of measure for BMD is g/cm 2 and is technically not a density measurement.