DXA Scan (Bone Density Test): What Is It & How It's Done (original) (raw)

How is a bone density test done?

A bone density scan uses low levels of X-rays to measure the density and mineral content of your bones. It’s similar to a typical X-ray. That’s what the X in DXA stands for.

DXA scans are outpatient procedures, which means you won’t have to stay in the hospital. There are no needles or injections in this test, and you won’t feel any pain.

You might be able to wear your regular clothes during the test, or you may have to change into a hospital gown.

Here’s how a bone density scan works:

• You’ll lie on a special X-ray table.
• A technician (a radiologic technologist) will help you position your body. They might put foam blocks under or around you to hold your legs in the proper position.
• The technician will pass a scanning arm over your body that takes pictures of your bones. Technicians usually scan your hips and spine, but they may take scans of other bones throughout your body, too, like your forearms.

A bone density scanner uses two types of low-level radiation to translate your bone density into pictures and graphs on a computer. Your bones will show up as white. Fat, muscles and other soft tissue will look like dark shadows in the background of the test images.

What should you not do before a DXA scan?

You probably won’t have to change your usual routine before having a bone density test. In general, you can:

• Eat and drink before your test.
• Take all your usual medications, unless your provider asks you not to.
• Wear comfortable, loose-fitting clothing to your test. Try to wear items that don’t have metal (zippers, buttons or buckles). You’ll have to remove clothing and jewelry that contains metal before the test.

If you take a calcium supplement or other over-the-counter (OTC) vitamins, don’t take them 24 hours before your test. Tell your provider which vitamins and supplements you take. They’ll let you know which ones you can or can’t take before a DXA scan.

You won’t be able to have a DXA scan within 24 hours of certain other kinds of imaging tests. Tell your scheduler when you’re having other tests before you make your DXA scan appointment.

How long does a bone density test take?

A bone density test usually lasts around 30 minutes. Your test might be slightly shorter or longer depending on how many of your bones need scanning.

What are the disadvantages of a DXA scan?

There are very few risks to having a bone density test. You won’t feel any pain or have any side effects after the scan.

Pregnant people shouldn’t have a bone density test. Tell your provider if you’re pregnant or think you might be pregnant. DXA scans use such a low level of radiation that they’re harmless for almost everyone, but pregnant people should avoid all forms of radiation if possible.

Some studies have found that results and readings from DXA scans can vary between manufacturers of the scanning machines, but that’s not usually something you need to worry about. Your provider will monitor changes in your bone density over time and will suggest repeated or different tests if needed.