DEXA scan

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A DEXA scan is a painless test that detects the density of bones. DEXA stands for dual-energy X-ray absorptiometry.

It is a fast and accurate test, and is preferred over normal X-rays 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 measure the calcium content in the bones - this cannot be evaluated in an ordinary X-ray.

These scans are sometimes called bone densitometry scans, QDR scans, or BMD (bone mineral density) measurement. They are usually used to scan the lumbar region (the lower back) and the hips.

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 the body.

There are two different types of DEXA scanning devices, central and peripheral. Central DEXA devices are more sensitive than peripheral ones. 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 (eg chemotherapy).