What is a DXA bone density scan?

Bone density scanning, also called dual-energy X-ray absorptiometry (DXA) or bone densitometry, is an imaging technology that uses a very low amount of X-ray energy to measure bone loss. DXA is the standard test for measuring bone mineral density (BMD). A DXA exam is used to diagnose osteoporosis, assess the risk of fracture and monitor the response to treatment. The spine and hips are measured because that is where osteoporotic fractures occur most frequently. Osteoporosis is a disease that gradually weakens bones, leading to bone fragility and an increased chance of fractures. This weakening may be due to aging or caused by other risk factors that combine with age. Often called the “silent disease,” osteoporosis rarely shows symptoms until a lot of bone mass has been lost. The most visible symptoms may include breaking a bone, loss of height, or curvature of the upper back.

DXA scanning can identify low bone density in patients at an early stage, enabling doctors to prescribe appropriate treatment before the condition worsens.

Who needs a DXA bone density scan?

While osteoporosis affects both men and women, 80% of those affected are women. In fact, 8 million American women are affected by osteoporosis. Women have a higher risk for osteoporosis than men because women often have smaller, thinner frames. In addition, menopause causes women to produce less estrogen, a hormone that helps protect them against bone loss; 20% of bone mass can be lost in the 5–7 years following menopause. If you are nearing menopause, your doctor or healthcare professional can give you good advice to help you avoid future problems with osteoporosis. If you are post-menopausal, stay in touch with your doctor to monitor your bone health on a regular basis.

Falling into the categories below may increase the risk of osteoporosis:

• Female
• Caucasian or Asian
• Advanced age
• History of bone fracture
• Small, thin frame
• Family history of osteoporosis
• Post menopause, including early or surgically induced
• Low calcium diet
• Lack of exercise
• Eating disorders
• Abnormal absence of menstrual periods
• Certain medicines (such as steroids and anticonvulsants)
• Alcohol or tobacco use

How do I make an appointment for a bone density exam?

If you don’t know whether or not you have osteoporosis, ask your doctor if a bone density test is right for you. Your doctor will need to refer you for this exam. For your convenience, bone density exams can be scheduled along with your mammogram appointment at RCI’s Imaging Center. Ask your primary care physician for a referral, or call 319-364-0121.

If you’ve recently had a barium examination or have been injected with a contrast material for a CT scan, MRI or radioisotope scan, you may have to wait 2 weeks before getting your DXA scan.

How should I prepare for my bone density exam?

You should not take any calcium supplements 24 hours prior to your exam. Wear comfortable clothing that has no metal zippers or buttons in the abdominal or pelvic areas; otherwise, we may ask you to change into a gown. You may also be asked to remove jewelry, eyeglasses and any metal objects or clothing that might interfere with the X-ray images.

What can I expect?

A technologist will need to ask your name, height, weight, age and ethnicity before the exam begins. This information is used to compare your results to a normal reference group. You will be asked to lie on your back on a padded table while a movable arm passes over your body. A technologist will remain with you and you will feel no sensations from the exam, which typically takes around 15 minutes. The test is very safe and exposes a person to about the same amount of radiation that we are all naturally exposed to in 3 hours of our daily living.

After your bone density exam

Your test results, combined with other factors, give you and your doctor an overall risk of fracture. Knowing your risk of fracture is important because there are many ways to prevent osteoporosis and reduce fracture risks. After reviewing your DXA scan results, your doctor may suggest a number of steps important to building bone strength. Suggestions may include exercise, diet changes, hormone therapy or other medicines known to improve bone strength.

For more information on this and other radiology procedures, visit www.radiologyinfo.org.
RCI is accredited by the American College of Radiology (ACR).