Preparing for Your Exam
On the day of your bone density exam:
- You may eat normally.
- Do not take calcium supplements for at least 24 hours before your exam.
- Wear loose, comfortable clothing, avoiding garments that have zippers, belts or buttons made of metal.
- Inform your physician if you recently had a barium examination or have been injected with a contrast material for a CT scan or radioisotope. If so, you may have to wait 10 to 14 days before undergoing a DXA test.
North Shore Medical Center uses dual-energy x-ray absorptiometry (DXA) to conduct bone density tests. This is the most accurate way to measure bone mass. The DXA is fast, uses very low doses of radiation and can measure as little as two percent of bone loss per year.
DXA uses two different X-ray beams to estimate bone density in your spine and hip. The area scanned is the lumbar spine (lower back), hips and sometimes forearm. Since strong, dense bones allow less of the X-ray beam to pass through them, the DXA test compares the percentage of each X-ray beam blocked by bone and soft tissue.