DEXA bone density scan

A DEXA scan helps to:

• Assess whether the bones have lost strength, as in osteoporosis
• Estimate the risk of a future fracture, alongside your other risk factors
• Decide whether treatment to protect the bones is needed
• Monitor the bones over time, including the response to any treatment

There is very little to organise, but a few simple things help the scan run smoothly:

• Clothing. Wear something comfortable and easy to move in. Metal zips, buttons, clasps, metal fastenings, and underwired bras can show up on the images, so plain clothing is ideal. You may be given a gown if needed, though most people stay fully dressed.
• Supplements. You may be asked to pause calcium or vitamin D supplements on the morning of the scan, as undissolved tablets in the gut can affect the spine measurement. Your other regular medicines can usually be taken as normal, but check with the team if you are unsure.
• Recent tests. If you have recently had a barium study, or an X-ray or scan using contrast dye, do mention it, as a short wait of a few days may be advised so the contrast does not interfere with the result.
• Pregnancy. Although the radiation dose is very low, a DEXA scan is usually delayed in pregnancy. Let the team know if there is any chance you could be pregnant.

The scan itself is short. You will be asked to lie still while the scanning arm passes over you, and you may be positioned with a foam block under the knees, or a foot held slightly turned in, to give a clear view of the spine and hip. There are no injections and nothing to swallow.

The scan is straightforward. You lie comfortably on a couch while a scanning arm passes over you, usually measuring the hip and spine. It takes only a short time, you usually remain fully clothed, and there is nothing to recover from afterwards. You can return to your normal activities straight away.

The result is given as a score that compares your bone density with an expected value. On its own, though, a number means little. What matters is how it is interpreted alongside your age, history and other risk factors to build a complete picture of your bone health and fracture risk.

Dr Borukhson arranges DEXA scanning where appropriate as part of a wider bone-health assessment, and explains what the results mean for you and what, if anything, should be done. You can read more on the osteoporosis page.

Your GP can also help arrange a DEXA scan. Seeing Dr Borukhson, however, often means the scan can be arranged more quickly, and that the result is reviewed by a rheumatology specialist and acted on without delay, all as part of a single, joined-up assessment of your bone health.

There is no recovery period. A DEXA scan does not make you radioactive, there are no after-effects to watch for, and you can drive, eat and carry on with your day as normal.

The images and measurements are reviewed and reported rather than read out on the spot, so the result is not usually given to you in the room. It is often considered alongside a recognised fracture-risk tool rather than viewed in isolation.

What happens next depends on what is found. A reassuring result may simply mean a sensible interval before any repeat scan. Where bone strength is reduced, the conversation turns to protecting the bones, which may include lifestyle and dietary measures, making sure you are getting enough calcium and vitamin D, and considering whether bone-protecting treatment is appropriate. If you take, or are about to start, long-term steroid treatment, the result helps judge whether bone protection is needed alongside it. You can read more about what the scores mean on the understanding your DEXA results page, and about treatment on the osteoporosis page.

Is a DEXA scan safe, and how much radiation does it involve?

A DEXA scan is very safe. It uses only a very low dose of radiation, much less than many ordinary X-rays and a small fraction of what you receive from the natural background over a year. The scan is painless, you usually stay fully clothed, and there is nothing to recover from afterwards. Pregnancy is the main reason to delay it, so do mention if there is any chance you could be pregnant.

How should I prepare for a DEXA scan?

Very little preparation is needed. You can eat and drink as normal beforehand. It helps to wear comfortable clothing without metal zips, buttons or clasps over the hip and spine, as metal can interfere with the images. You may be asked to pause any calcium supplements for a short period before the scan. If you have recently had a contrast X-ray or barium study, let the team know, as a short wait may be advised.

What do the T-score and Z-score mean?

The result is given as a score comparing your bone density with an expected value. The T-score compares you with a healthy young adult and is used to assess osteoporosis, while the Z-score compares you with others of your own age. On its own a number means little. What matters is how it is interpreted alongside your age, history and other risk factors to build a complete picture of your bone health and fracture risk.

How often should a DEXA scan be repeated?

This varies from person to person. A repeat scan is generally not needed for at least a couple of years, as bone changes slowly and scanning too soon rarely adds useful information. The right interval depends on your initial result, your fracture risk and whether you are on treatment. When a scan is used to monitor the response to treatment, it is usually compared on the same machine so the change is measured reliably.

Do I need a referral, or can I arrange a DEXA scan privately?

Your GP can help arrange a DEXA scan, and so can a rheumatology specialist. Seeing Dr Borukhson often means the scan can be arranged more quickly, and that the result is reviewed by a specialist and acted on without delay, all as part of a single, joined-up assessment of your bone health.