What Is A DEXA Scan?

Traditional X-ray technology is probably the most basic and rudimental form of imaging, yet even still it is a fundamental tool in the use of newer, more advanced imaging devices such as computed tomography (CT), fluoroscopy, and radiography (“conventional X-ray” including mammography).

Another imaging procedure that heavily relies on X-rays is the DEXA scan, which utilizes ionizing technology to image the quality of bones and can be used to diagnose bone conditions and diseases. In order to understand more about the DEXA scan, let’s take a little dive into what it is, how it functions, and what to expect from it.

What Is A DEXA Scan?

DEXA (dual-energy x-ray absorptiometry) scans, which are also called bone densitometry scans, use small doses of ionizing radiation (X-rays) to image bones and measure bone mineral density to see if there is any bone loss.

DEXA scans are mostly performed for imaging the lower spine and hips, typically on children or older adults whose bones tend to be more fragile. The scans are also especially helpful in diagnosing bone diseases, such as osteoporosis, and in determining an individual’s risk for fractures by measuring their bone mineral density.

Some other common reasons for when a DEXA scan is used include:

  • To measure bone loss for people taking medication that affects bone density, including corticosteroids such as Prednisone, various anti-seizure medications such as Dilantin and certain barbiturates, or high-dose thyroid replacement drugs.

  • Have type 1 diabetes, liver disease, kidney disease or a family history of osteoporosis.

  • Have a thyroid or parathyroid condition.

  • Post-menopausal woman who are not taking estrogen.

How Is A DEXA Scan Done?

A DEXA scan, much like regular X-ray scans, is performed depending on which area of the body is being imaged. If it is for the spine or hips, the patient will be lying down on a padded table; for other cases the patient may stand. As with other imaging tests, the patient will be asked to remove any metal objects including dentures, jewelry, belts, etc. before the exam begins. During the exam, the patient may be asked to hold their breath for several seconds to reduce any blurriness from the images.

How Does A DEXA Scan Work?

As discussed before, DEXA scans use low doses of ionizing radiation to measure bone density and bone loss. The way that the scan does this is by emitting two distinct energy peaks, or rays, through the bones being examined. One peak is absorbed by soft tissue and the other by bone; the soft tissue amount can be subtracted from the total and the remainder is the amount of bone mineral density. The test usually takes anywhere from 10 to 30 minutes.

More Information

DEXA bone density scans are super useful and important in diagnosing and properly treating bone conditions and diseases. If you or someone you know have been recommended to take a DEXA scan, feel free to contact. To meet with one of our radiologists about your bone density, make an appointment today!

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