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.
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).
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.
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.
The results of the scan will show whether you have:
- normal bone density
- low bone density (osteopenia)
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
|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.
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:
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 firstname.lastname@example.org
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).
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.
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