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Bone Densitometry (DXA) Scan

Dual-energy x-ray absorptiometry (DXA) is the most precise scan for diagnosing osteoporosis and other bone fractures.

What Is a DXA Scan?

A DXA (DECK-sa) scan is a painless, noninvasive test to measure bone mineral density (BMD).

DXA scans are the most accurate ways to diagnose and review:

  • The first stage of bone loss (osteopenia).
  • Osteoporosis.
  • The thinning of bones that can cause fractures in aging men and women.
  • Body composition (body fat percentage, muscle mass).

When to avoid DXA scans

You should not have a DXA scan if you are or might be pregnant.

Also, do not have a DXA test if you've had another scan with contrast dye in the last seven days, such as:

  • Barium enema.
  • Upper GI.
  • Some CT scans.
  • Thyroid test.


UPMC Imaging Services offers DXA scans at over 100 imaging centers throughout Pennsylvania, western New York, and western Maryland.

Find an imaging location near you

What Are the Benefits of a DXA Scan?

More precise images

Compared to standard x-rays, DXA scans:

  • Take sharper, more detailed pictures of both bone and soft tissue.
  • Can detect even the smallest changes in bone loss.

More accurate diagnoses and earlier treatment

DXA scans:

  • Are the most accurate disgnositc tool avalable for diagnosing and treating bone loss.
  • Can assess your risk of bone fractures.
  • Help doctors treat osteoporosis early and prevent further bone loss.
  • Provide data on overall body composition.

Low radiation and noninvasive

DXA scans:

  • Use less radiation than the body normally gets in a day from natural radiation exposure.
  • Leave no remaining radiation in the body after the scan.
  • Are fast, simple, and don't require anesthesia.

How Do I Prep for My DXA Scan?

24 to 48 hours before the test

If you take calcium supplementsstop taking them 24 to 48 hours before your DXA scan.

The day of your test

  • Do not take medicines for osteopenia or osteoporosis if you usually take them.
  • Eat normally.
  • Wear loose, comfortable clothing.
  • Don't wear jewelry or clothes with metal zippers, belts, or buttons.
  • You may need to remove any external devices that manage diabetes or other health issues.

What to Expect During Your DXA Scan

A DXA scan takes between 10 and 30 minutes. You must lie very still during the scan to get clear, crisp images.

Before the test begins, be sure to:

  • Tell the technologist if you have had any hip or back injuries.
  • Take off any metal jewelry.

Next, your imaging tech will place you lying down on a table with the scanner above you.

The DXA scanner will:

  • Pass over your body and send a thin, invisible beam of low-dose x-rays through your bones to measure your BMD. The amount of radiation is less than 1/10 the dose of a standard chest x-ray.
  • Take a picture of your skeleton based on how much the x-rays changed after passing through your bones.
  • Match your BMD with the average values for your age and gender. Your doctor will use this data to design your treatment plan.

After Your DXA Scan

A radiologist studies your scans and reports the results to your doctor. We'll send the digital images to your doctor via our state-of-the-art computer system.

Your test results

The results of your DXA scan have two scores: T score and Z score.

T score shows the amount of bone you have compared to a young adult of the same gender with peak bone mass. It also assesses your risk of bone fractures.

A T score:

  • Above -1 = normal.
  • Between -1 and -2.5 = osteopenia, the first stage of bone loss.
  • Below -2.5 = osteoporosis.

Z score shows the amount of bone you have compared to others of the same size and gender in your age group.

If your Z score is unusually high or low, you may need more tests to rule out other health issues.

Learn More About Bone Loss and Tests

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