DEXA scan

A DEXA scan is a painless test that measures the density of bones. DEXA stands for dual energy X-ray absorptiometry. Generally, the denser your bones are the stronger they are, and the less likely they are to break.

DEXA scans help find out whether you have osteoporosis or are at risk of developing it. They can also be used to detect other bone disorders and conditions, and to monitor the relative amounts of body fat and muscle in your body.

A DEXA scan is fast and accurate and is preferred over a normal X-ray for detecting bone density because it is more sensitive. For example, normal X-rays can only detect osteoporosis (weakened bones) when around one third of the bone mass has already gone. DEXA scans can measure the calcium content in your bones, which cannot be measured in an ordinary X-ray.

There are two different types of DEXA scanning devices:

• Central DEXA devices are large machines that can measure bone density in the centre of your skeleton, such as your hip and spine.
• Peripheral DEXA devices are smaller, portable machines that are used to measure bone density on the periphery of your skeleton, such as your wrist, heel or finger.

Central DEXA devices are more sensitive than peripheral devices. Bone mass often varies between parts of the body, so it is more accurate to measure the spine or hip than a heel or wrist. The peripheral devices may help predict the risk of fracture in your spine or hip, but cannot accurately follow changes in your bones during certain types of treatment, such as chemotherapy.

DEXA scans are sometimes called bone densitometry scans, QDR scans, or BMD (bone mineral density) measurement.