Bone density scan (DXA scan)
A bone density scan (DXA) scan can be used to check your bone mass. It checks the thickness of your bones to see if you have a higher risk of a bone fracture.
What is a bone density scan?
A bone density scan checks the density of your bones. If your bone density is low, you have a higher risk of a bone fracture.
This scan may also be called a bone mineral density scan (BMD scan) or a dual energy x-ray absorptiometry scan (DXA or DEXA scan).
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Who has a bone density scan?
Your GP or hospital doctor may arrange for you to have a DXA scan depending on a number of risk factors:
- a fracture risk assessment tool shows your risk of fracture is intermediate (between low risk and high risk)
- you are under the age of 40 and have a significant risk of fracture – for example, you have had more than one fragility fracture, or have recently taken high doses of steroids
- you have had an early menopause and not had hormone replacement therapy (HRT)
- you have prostate cancer and you are going to start treatment with hormonal therapies that reduce testosterone levels
- you are taking steroids.
You may also have a DXA scan if you have early invasive breast cancer and may develop bone loss because you:
- are going to start treatment with an aromatase inhibitor
- have had an early menopause because of your treatment
- are going to have treatment to stop your ovaries working.
How the scan is done
During a DXA scan, you lie on your back on a couch while a scanner moves above your body. The amount of radiation from a DXA scan is much less than from a normal x-ray.
The scan only takes a few minutes and is painless. It is important that there are no metal fastenings such as zips in the area being scanned. You may be asked to wear a hospital gown for the scan.
Bone density scan results
The results of the scan will show whether you have:
- normal bone density
- low bone density (osteopenia)
- osteoporosis
Your DXA scan results are given as a number called a T-score. Your T-score is worked out by comparing your bone density with the bone density of an average healthy adult of your gender. Your T-score is the number of units that your bone density is above or below the average.
What your T-score means
|
T-score |
What it means |
|
-1 and above |
Your bone density is normal. |
|
Between -1 and -2.5 |
Your bone density is below normal – doctors call this osteopenia. |
|
-2.5 and below |
Your bone density is low, and your bones are at higher risk of fracture. This score suggests you have osteoporosis. |
Your doctor may also talk about a Z-score. This score compares your bone density measurement with someone of the same age. If your Z score is below -2, your bone density is lower than it should be for someone of your age.
After a bone density scan
If tests to check your bone health show you have low bone density or a high risk of fracture, your GP may advise you to:
- eat a healthy, balanced diet
- get enough sunshine (if this is possible)
- keep physically active.
- increase the amount of calcium in your diet
- ttake a drug treatment, such as a bisphosphonates.
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References
Below is a sample of the sources used in our bone health information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk
National Institute for Health and Care Excellence (NICE). Bisphosphonates for treating osteoporosis. TA464. 2019 www.nice.org.uk/guidance/ta464 (accessed Sept 2019).
National Institute for Health and Care Excellence (NICE). Osteoporosis: assessing the risk of fragility fracture. CG146. 2017. www.nice.org.uk/guidance/cg146 (accessed Sept 2019).
National Institute for Health and Care Excellence (NICE). Osteoporosis: Quality standard QS149. 2017. www.nice.org.uk/guidance/qs149 (accessed Sept 2019).
Royal Osteoporosis Society (ROS). Care: Frameworks and guidance. 2019. theros.org.uk/healthcare-professionals/courses-and-cpd/osteoporosis-resources-for-primary-care/frameworks-and-guidance (accessed Sept 2019).
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