A DEXA scan (dual-energy X-ray absorptiometry) is a type of bone density test widely considered the most accurate means of assessing bone mineral density (BMD). It uses highly advanced X-ray technology to measure the amount of calcium, phosphorus, and other vital minerals in your bones. It’s typically used to test the bone density of the forearms, hips, and spine.

The density of your bones is a strong indicator of your risk for bone sprains, fractures, and breaks. Unfortunately, bone density tends to diminish as we age, putting us at risk for conditions like osteoporosis and making us vulnerable to injury.

Why would I need a DEXA scan?

A DEXA scan might be recommended if you are at high risk for osteoporosis or if you experience a bone fracture after a relatively minor injury. A DEXA scan might be appropriate if you experience the following:

  • Diminished height. If your height has decreased by an inch or more, you might have spinal compression fractures, a sign of osteoporosis.
  • Bone fractures. Easily fractured bones are a sign of significantly reduced bone density. For example, fragility fractures can occur after low-level force like a fall from your standing height or even a sneeze.
  • Decrease in hormone production. A reduction in estrogen or testosterone levels can lead to bone weakness. This deficiency can be triggered by lowered hormone production due to advancing age (menopause) or after certain drugs or cancer treatments.
  • History of eating disorders. If you have a history of anorexia nervosa, you might be at particular risk for low bone density and early-onset osteoporosis.

A Dexa scan is generally recommended every 2 years for postmenopausal women over the age of 65 and men over the age of 70, as a screening tool for osteopenia or osteoporosis. Younger postmenopausal women should have a screening if they have at least one major or 2 minor risk factors for osteoporosis.

What does a DEXA scan do?

A DEXA scan is an extremely safe imaging test that checks mineral levels within bones. It involves using low radiation levels (much lower than traditional X-rays) and can be performed with the practitioner in the room.

During the procedure, you lie on a padded table while the scanning device passes over the targeted area, generally the lower spine or hip. Another scanning device (photon generator) simultaneously scans the underside of the body. The images are combined and delivered to a computer, where your healthcare provider analyzes them.

DEXA scan results are measured using the T-score and the Z-score. The T-score is the standard bone density of a 30-year-old in good health. A T-score less than -1.0 is generally considered low enough to constitute a risk for osteoporosis.

The Z-score measures your bone density against what is healthy for a person of your age, ethnic origin, sex, and weight. Deviations from the standard (too high or too low) might indicate the need for further medical evaluation.

How do I prepare for a DEXA scan?

If you take calcium supplements, you might be asked to refrain for 24-48 hours prior to the scan. Jewelry and metal objects must be removed before the scan.

If you recently had contrast material injections or drank oral contrast material for other imaging exams (CT scan or Fluoroscopy/Barium exams) make sure to alert your clinician and the imaging facility.

How long does a DEXA scan take?

A DEXA scan can take between 10 and 30 minutes.

Does a DEXA scan have any risks?

DEXA scans are very safe, though the small amount of radiation makes them inappropriate for pregnant patients.

At Valley Radiology, we offer next-generation technologies and a dedicated team of passionate radiologists. If you have questions about our services, please contact our helpful team today!

Please note that a doctor's referral is required for a DEXA scan.