Bone densitometry (or DEXA) uses a very small dose of radiation to measure bone density and bone loss. The test can help determine if you have osteoporosis. Learn more about bone densitometry, and why your healthcare provider may recommend this test.
What is Bone DEXA?
As we age, the bones in our body begin to weaken. While this is part of the aging process, your healthcare provider will often order tests to measure your bone density (or how strong your bones are). One common test doctors will order is called a bone densitometry test.
Bone densitometry (or DEXA) measures bone density and bone loss. The scan focuses on two main areas of your body – the hip and the spine. During the test, the machine will produce two x-ray beams that will measure how thick the bones are in your body. The results will produce two scores that will help your healthcare provider determine if you have osteoporosis.
Osteoporosis is a condition in which the bones of the body weaken from a gradual loss of calcium. The condition often affects women after menopause, but may also affect men and sometimes children.
Bone DEXA takes about 10-30 minutes. Your doctor may recommend this test if you:
- Are post-menopausal
- Use medications that are known to cause bone loss
- Have a family history of osteoporosis
- Had x-rays that show signs of osteoporosis
- Have a history of falls
What are the Risks and/or Side Effects?
DEXA has no side effects.
What are the Benefits?
DEXA offers the following benefits:
- The procedure is noninvasive
- No medication is required
- Only a low dose of radiation is used
- It is accurate for diagnosing osteoporosis
- It provides a risk assessment for developing bone fractures
- There are no side effects
How Do I Prepare?
This procedure requires little to no preparation. For your appointment, you should wear loose, comfortable clothing. Be sure to leave your jewelry at home. If you are taking calcium supplements, inform your healthcare provider. You may be asked to avoid taking calcium supplements for at least 24 hours before the test.
When you arrive, be sure to tell the physician if there is a possibility that you may be pregnant, or if you recently had other imaging tests.
How is it Done or Administered?
The DEXA scan generally takes about 10-20 minutes. You will be asked to carefully lie on an open X-ray table. During the scan, you will be asked to stay still as the scanner passes over your body.
The bone DEXA machine produces two x-ray beams. One is high energy and the other is low energy. Based on the difference between the two beams, your healthcare provider can accurately measure your bone density.
When Will I Know the Results?
The results from the test will include two scores:
- T score. This value is used to estimate your risk of developing a fracture in the future.
- Z score. This value reflects the density of your bones compared to other people in your age group (same weight, height, and gender).
A radiologist will analyze the images and your score and send a report to your primary care or referring physician, who will discuss the results with you. This may take 24 to 72 hours.
What are Follow-up Requirements and Options?
If your scores show signs of osteoporosis, your healthcare provider may recommend additional testing.