Doctors use bone density scans like DEXA scans to diagnose or assess the risk of osteoporosis and other conditions that can affect your bones. Osteoporosis can change your bones’ structure and density, making them weaker and more likely to break.
Your doctor may suggest you undergo a DEXA scan to check your bone health. They might request a DEXA scan if you broke a bone while experiencing a minor injury or if they suspect you have osteoporosis, arthritis, or any other condition that can affect your bones.
How does a DEXA scan work?
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When you arrive at the facility, a specialist who takes X-ray images (called a radiographer) will ask you to lie on your back on the X-ray table. The X-ray machine for a DEXA scan is typically open.
Once the scan begins, a large mechanical arm will pass over the parts of your body that need examination. It will send a narrow beam of low dose X-rays through them. You must remain still during the exam to prevent the X-ray machine from taking blurred images.
Bone density can vary in different parts of your body, so the radiographer may need to scan multiple areas. (The term “bone density” refers to how much space inside your bones is filled with minerals.)
An X-ray detector can measure the number of X-rays that have passed through your body. With this data, the machine can create an image of your bones and measure their density.
The whole procedure typically lasts 10–20 minutes. When the DEXA scan ends, you will be able to go home.
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Before attending a DEXA scan, you do not need any specific preparation. On the day of the exam, you can eat and drink as usual. But if you’re taking calcium supplements, a healthcare professional may recommend you stop taking them 24–48 hours before the exam.
You should also let a healthcare professional know if you have recently undergone a CT scan with an injection of contrast material or a barium examination. In this case, you may need to wait a couple of weeks before you can have a DEXA scan.
Depending on the area that needs to be scanned, a healthcare professional may ask you to wear a gown or take off some clothing, especially if it has any of the following:
zippers
metal fasteners
hooks
buckles
You may also need to remove jewelry, such as necklaces, earrings, or watches.
In some cases, though, you may be able to remain fully clothed. The radiographer will let you know what you can and cannot wear during the exam.
What can you expect after the scan?
The results of the DEXA scan are calculated based on a system called the T score. This score compares the density of your bones with the bone density of a healthy 30-year-old adult. A low T score may indicate that you have some bone loss.
–1.0 or higher: This result is considered typical bone density.
–1.0 to –2.5: This means that your bone density has lowered and you may be at risk of developing osteoporosis in the future. This condition is called osteopenia.
–2.5 or lower: This result means that osteoporosis is likely.
You may also receive a Z score with your results. This compares your bone density with the bone density of people who are the same age as you.
If your result is lower than the typical bone density for your age, a healthcare professional may recommend a treatment plan and some changes in your lifestyle to help improve your bone strength and prevent osteoporosis.
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Research from 2017 states that the DEXA scan is the preferred method for evaluating bone density, due to its high precision in measuring body and bone composition.
A DEXA scan is more effective than X-rays at measuring bone density. This test can effectively identify low bone density and it can significantly help prevent and diagnose osteoporosis.
What are the risks of a DEXA scan?
DEXA scans are typically very safe. Compared with X-rays, DEXA scans use a lower amount of radiation. There are no specific risk factors involved for people who need to undergo the exam.
But if you are pregnant or think you may be pregnant, speak with a healthcare professional first. Radiation from the DEXA scan may harm the fetus.
What is the difference between a bone scan and a DEXA scan?
A DEXA scan measures your bone density and does not require any specific preparation. A bone scan, on the other hand, requires an injection of radioactive material into your body.
Bone scans are typically performed to detect:
fractures
infections
cancer
other atypical conditions in the bone
Medication options for osteoporosis
If your test results indicate that you do have osteoporosis, a healthcare professional may recommend medication to help treat symptoms. Examples include:
These medications are available as pills to be taken on a weekly or monthly basis. A healthcare professional will discuss which option will be most suitable for your condition.
If you need help covering the cost of medications, Optum Perks free Discount Card could help you save up to 80% on prescription drugs. Follow the links on drug names for savings on that medication, or search for a specific drug here.
Summary
A DEXA scan can help healthcare professionals diagnose reduced bone density, which may increase the risk of fractures in the bones. Doctors also use this test to diagnose osteoporosis.
The procedure usually lasts about 10–20 minutes and uses only a low dose of radiation. This test is painless and is generally safe. However, people who are pregnant are not advised to undergo a DEXA scan because the radiation may harm the fetus.
Depending on the test result, a healthcare professional can recommend a treatment plan to prevent osteoporosis or any additional damage to your bones.
