THE MEDICAL IMAGING EXPERIENCE
INFORMATION FOR THE PATIENT
BONE DENSITY OR DEXA SCAN

WHAT IS IT?
DEXA Bone Densitometry is most used to diagnosis osteoporosis, a condition that often affects women after menopause but may also be found in men. Osteoporosis involves a gradual loss of calcium, causing the bones to become thinner, more fragile and more likely to break. The DEXA test can also assess your risk for developing fractures. If your bone density is found to be low, you and your physician can work together on a treatment plan to help prevent fractures before they occur. DEXA is also effective in tracking the effects of treatment for osteoporosis or for other conditions that cause bone loss.

WHAT WILL HAPPEN TO ME?
You may be asked to undress and put on a hospital gown. You will then be asked to lay on a padded table with an x-ray generator below and a detector above. During the exam your legs will be supported on a padded box to flatten your pelvis and lower your spine. The DEXA machine sends a thin, invisible beam of low-dose x-rays with two distinct energy peaks through your bones. One peak is absorbed mainly by soft tissue and the other by bone. The soft tissue amount can be subtracted from the total and what remains is a patient's bone mineral density. Special software is used to compute data and display them on a computer monitor, allowing your doctor to make an accurate diagnosis. 

HOW LONG WILL THIS TEST TAKE?
This procedure usually takes about 15-20 minutes to complete.

WHAT WILL I FEEL -- WILL IT HURT?
DEXA Bone Densitometry is a simple, non-invasive procedure. Once on the table you may be asked to hold an awkward position for a short time while the arm of the machine passes over your body taking measurements. It is important that you stay as still as possible during the exam to ensure a clear, useful image. The procedure is painless and radiation exposure is minimal.

WHAT WILL THE TEST SHOW?
The radiologist will interpret the images and give them a T-score, which is a number showing the amount of bone you have compared with a young adult of the same gender with peak bone mass. A score above -1 is considered normal. A score between -1 and -2.5 is classified as osteopenia, which is the first stage of bone loss. A score below -2.5 is defined as osteoporosis. The T-score is used to estimate your risk of developing a fracture.

HOW DO I GET READY?
Wear loose, comfortable clothing, avoiding garments that have zippers, belts, buttons, or snaps made of metal. If you have recently had a barium examination you will need to wait 10-14 days before undergoing a DEXA test.

Reviewed: November 2006