Dual Energy X-Ray Absorptiometry (DEXA), or bone density, scanners use low-energy x-rays to identify your risk for bone conditions, such as osteoporosis. Here are some frequently asked questions about DEXA scans:
How do DEXA scans work?
DEXA scans help radiologists determine your risk for bone fractures by measuring your bone mass density. “DEXA scanners take images of your hips and spine, two areas most prone to bone loss and fractures,” says Bruce Bortnick, MD, a radiologist with Adventist HealthCare Imaging. “After the scan, you will be assigned a T-score, which compares your bone density to that of a young, healthy adult.”
Scores above -1.0 are normal, scores between -1.0 and – 2.5 indicate osteopenia while scores below -2.5 indicate osteoporosis. Both conditions increase your risk of bone fractures. “Your doctor will use your medical history and DEXA results to determine if you need medical therapy to improve your bone density,” says Dr. Bortnick.
Why would a physician recommend a DEXA scan?
DEXA scans help your doctor clearly identify your risk for fractures and osteoporosis. “Osteoporosis occurs when bones become brittle from a lack of calcium, vitamin D or other minerals. It affects 1 in 4 women and 1 in 20 men over 65 years old,” says Dr. Bortnick. “Most doctors recommend the scan for women who are at least 65, men who are 70 and those at high risk for bone fractures.” These risk factors may lead to you getting scanned earlier:
- A family history of osteoporosis
- A medical history of rheumatoid arthritis, diabetes, anorexia nervosa and cancer treatments
- Long-term use of steroids
- Height loss
- Long-term tobacco or alcohol use
What can I expect on the day of my exam?
Before your exam, a technologist will ask you to remove all metal from your body and assist you to an exam table. You will lie on your back and lay still on an x-ray table. A C-shaped scanner will pass over your lower spine and hip. The scan is painless and usually takes about five minutes to complete. After the scan is complete, you should be able to leave and continue with your normal routine.
Are DEXA scans safe?
DEXA scans are generally safe. While DEXA scans do contain small amounts of radiation, Dr. Bortnick says the benefits of finding bone loss far outweigh the risk of radiation. If you know you have bone loss, there are lifestyle changes, medications and other treatments available to help increase your bone mass and prevent fractures. “The exception is women who are pregnant. Any amount of radiation is of special concern to unborn babies,” he says. “Always let your technologist know if you are pregnant before taking any imaging test.”
Sources: National Institutes of Health, U.S. National Library of Medicine, American Bone Health