Imaging
DEXA Scan (Bone Density)
A DEXA scan is a quick, low-dose X-ray that measures bone strength. It is the main test used to diagnose osteoporosis and assess fracture risk.
Quick answer
DEXA Scan (Bone Density): what it is and what the results mean
A DEXA (dual-energy X-ray absorptiometry) scan measures bone mineral density, usually at the hip and spine, using a very low dose of X-rays. It is the standard way to assess bone strength.
- Why it is done: It is used to diagnose osteoporosis and osteopenia, to estimate the risk of breaking a bone, and to monitor bone health over time, particularly in people with risk factors or after a fragility fracture.
- Understanding results: Bone density is reported as a "T-score", where lower (more negative) values indicate weaker bones.
What it is
A DEXA (dual-energy X-ray absorptiometry) scan measures bone mineral density, usually at the hip and spine, using a very low dose of X-rays. It is the standard way to assess bone strength.
Why it is done
It is used to diagnose osteoporosis and osteopenia, to estimate the risk of breaking a bone, and to monitor bone health over time, particularly in people with risk factors or after a fragility fracture.
What to expect
You lie still on a padded table while a scanning arm passes over you; it is painless, takes about 10–20 minutes and does not involve going inside a tunnel.
Understanding the results
Bone density is reported as a "T-score", where lower (more negative) values indicate weaker bones. Specific thresholds define osteopenia and osteoporosis, and results are combined with other risk factors to guide treatment.
Good to know
Risks and limitations
The radiation dose is very low. A DEXA scan measures density but not bone quality alone, so results are interpreted alongside your age, history and fracture-risk assessment.
Education and reference only. This explains the test in general terms and is not medical advice. Always follow the specific instructions from the team arranging your test, and discuss your results with your clinician.
Answers
DEXA Scan (Bone Density): frequently asked questions
What is a T-score?
A T-score compares your bone density with that of a healthy young adult. Lower (more negative) scores mean weaker bones; defined thresholds indicate osteopenia or osteoporosis, guiding whether treatment is advised.
Is a DEXA scan safe?
Yes. It uses a very low dose of radiation — much less than a standard chest X-ray — and is a quick, painless way to measure bone strength.
Related tests
Other imaging investigations
Sources
Where this is drawn from
- NHS — Tests and treatments
- NICE — diagnostic guidance
- Royal College of Radiologists / relevant professional body
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