Bone Densitometry (DEXA, DXA)

• Bone densitometry, also called dual-energy x-ray absorptiometry, DEXA or DXA, uses a very small dose of ionizing radiation to produce pictures of the inside of the body (usually the lower (or lumbar) spine and hips) to measure bone loss.
• It is commonly used to diagnose osteoporosis, to assess an individual’s risk for developing osteoporotic fractures.
• DXA is simple, quick and non-invasive.
• This exam requires no special preparation. Tell your doctor and the technologist if there is a possibility you are pregnant or if you recently had a barium exam or received an injection of contrast material for a CT or radioisotope scan.
• Leave jewellery at home and wear loose, comfortable clothing.
•  You should not take calcium supplements for at least 24 hours before your exam.

What are some common uses of the procedure?

• DEXA is most often used to diagnose osteoporosis, a condition that often affects women after menopause but may also be found in men and rarely in children.
• DEXA is also effective in tracking the effects of treatment for osteoporosis and other conditions that cause bone loss.

Bone density testing is strongly recommended if you

• Are a post-menopausal woman
• Have a personal or maternal history of hip fracture or smoking.
• Are a man with clinical conditions associated with bone loss, such as rheumatoid arthritis, chronic kidney or liver disease.
• Have type 1 (formerly called juvenile or insulin-dependent) diabetes, liver disease, kidney disease or a family history of osteoporosis.
• Have high bone turnover, which shows up in the form of excessive collagen in urine samples.
• Have a thyroid condition, such as hyperthyroidism.
• Have a parathyroid condition, such as hyperparathyroidism.
• Have experienced a fracture after only mild trauma.
• Have had x-ray evidence of vertebral fracture or other signs of osteoporosis.

Inform your physician if you recently had a barium examination or have been injected with a contrast material for a computed tomography (CT) scan or radioisotope scan. You may have to wait 10 to 14 days before undergoing a DEXA test.

Women should always inform their physician and x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy so as not to expose the fetus to radiation. If an x-ray is necessary, precautions will be taken to minimize radiation exposure to the baby. See the Safety page for more information about pregnancy and x-rays.