Bone density scan

What is a bone density scan

A DEXA scan (short for Dual Energy X-ray Absorptiometry)

A DEXA scan is a special type of X-ray that measures bone mineral density (BMD) and body composition. That is, the density of your bones and the proportion of muscle fat and connective tissue within your body.

As well as being quick and painless, a DEXA scan is more effective than normal X-rays in identifying low bone mineral density.

Unlike a magnetic resonance imaging (MRI) scan or a computerised tomography (CT) scan, a DEXA scan doesn't involve being enclosed inside a tunnel or a ring, so you won't feel claustrophobic.


DEXA scans use a much lower level of radiation than standard X-ray examinations, which means that the radiographer (the technical specialist carrying out the scan) can stay in the scanning room with you during the scan.

The amount of radiation used during a DEXA scan varies depending on the area of the body being examined, but is very low and less than two days' exposure to natural background radiation (NBR). By comparison, a chest X-ray uses the equivalent of about three days' exposure to NBR, and a flight to North America is equivalent to approximately a week's exposure to NBR.

Exclusion criteria

Despite being very safe procedures, DEXA scans and X-rays aren't recommended for pregnant women, as X-rays can damage an unborn child.