A bone density test, also known as a DEXA (Dual-Energy X-ray Absorptiometry) scan, is a common imaging procedure that assesses bone health. This test plays an important role in identifying conditions such as osteoporosis, where bones become thin and fragile. Understanding the procedure and how to prepare can help ensure accurate results.
Understanding a Bone Density Test
A bone density test is a non-invasive imaging method that measures the mineral content and strength of your bones. It utilizes low-dose X-rays to determine bone mineral density (BMD), primarily in the hips and spine. Healthcare providers use these scans to diagnose osteopenia, a condition of low bone mass, and osteoporosis. The test also helps assess future fracture risk and monitor the effectiveness of treatments for bone loss.
Dressing for Your Scan
You typically do not need to fully undress for a bone density test, but wearing appropriate clothing is important. You should choose loose, comfortable attire that does not contain metal components.
Metal objects, such as zippers, buttons, buckles, underwire bras, and metal embellishments, can interfere with the X-ray imaging process. These items can block or distort the X-ray beams, leading to inaccurate readings and obscuring important details about your bone density. To ensure the most accurate scan, patients are often asked to remove jewelry, body piercings, and any other metallic accessories before the test. If your clothing contains metal, or if it is not loose enough, you may be provided with a hospital gown to wear during the procedure.
Additional Preparations and What to Expect During the Test
Beyond clothing considerations, certain preparations help improve the accuracy of your bone density scan. It is often recommended to avoid taking calcium supplements for 24 to 48 hours before the test, as they can interfere with results. Inform the technologist if you recently had imaging procedures involving contrast dye, such as CT scans or barium examinations. Depending on the contrast material, you may need to wait 7 to 14 days before your DEXA scan. Also, notify your healthcare provider if you are pregnant, as DEXA scans are generally not recommended during pregnancy.
During the bone density test, you will lie still on a padded table while a scanner arm passes over your body. The technologist will help position you correctly to ensure proper alignment, particularly for scans of the hips and spine. The procedure is quick, typically lasting 10 to 30 minutes, and is generally painless. This imaging test uses a very low dose of radiation, comparable to or even less than natural background radiation in a single day.