What is DXA and how does it work?
Dual energy x-ray absorptiometry (DXA) is the most widely used and most thoroughly studied bone mineral density (BMD) measurement technology.  With the subject lying on a scanning bed, two x-ray beams with differing energy levels are aimed at the body. The x-rays come from below the subject, and are measured above by a moving “arm”.  When soft tissue absorption is subtracted out, BMD can be determined from the absorption of each beam by bone.

DXA can measure total or regional BMD (arms, hips, lower spine, legs).  DXA can also measure total and regional body fat content.

Is it safe?
Yes.  The amount of radiation emitted during a DXA scan is very low, less than 1/10th that of a chest x-ray, and less than that of an airport detector.  However, women should always inform study personnel if there is any possibility that they are pregnant.  Many imaging tests are not performed during pregnancy because radiation can be harmful to the fetus.

Testing conditions
You should wear loose, comfortable clothing, avoiding garments that have zippers, belts or buttons made of metal.

Fasting is not required.

How long does a DXA scan take?
A whole body DXA scan takes about 7-10 minutes.

Who makes the DXA?
The lab houses a Discovery WI DXA, manufactured by Hologic (www.hologic.com) in Massachusetts.