A bone density test, formally known as a Dual-Energy X-ray Absorptiometry (DEXA or DXA) scan, is a specialized, low-dose X-ray procedure. This non-invasive test is the established standard for measuring bone mineral density (BMD). The DEXA scan helps diagnose conditions like osteopenia (low bone mass) and the more severe osteoporosis. Osteoporosis involves a loss of bone tissue that makes bones brittle and significantly increases the risk of fractures, particularly in the hip and spine. The results help healthcare providers determine an individual’s fracture risk and guide treatment decisions.
Clothing Requirements for the Scan
You do not typically have to undress completely for a bone density test, but you must prepare your clothing carefully. The goal is to ensure the X-ray beam, which measures the density of the hip and lower spine, can pass through the body without interference. If your clothing is free of all metal components, you may be permitted to keep it on during the scan.
Loose-fitting, comfortable garments made from materials like cotton or jersey are the best choice. If your clothing contains any metal that cannot be easily taken off, the technician will provide you with a hospital gown to wear instead.
Specific Materials to Avoid
Interference that can skew DEXA results comes primarily from metal, which is denser than bone and tissue. You must avoid wearing any clothing items that contain metal closures or embellishments, as these can create artifacts on the image. This includes items that fall directly over the scanned areas:
- Metal zippers
- Buttons and snaps
- Underwire bras
- Large belt buckles
Beyond clothing, all jewelry located near the trunk of the body must be removed before the examination begins. Necklaces and pendants are particularly problematic because they rest over the spine and chest area being imaged. You should also remove any body piercings in the abdomen or hip region, as well as watches and bracelets, even if they are not directly in the scanning field.
What to Expect During the Procedure
The DEXA scan is a straightforward and painless procedure that usually takes between 10 and 20 minutes to complete. You will be asked to lie still on your back on a padded table designed for comfort and proper positioning. A trained technologist will help place your body, often using a padded box to slightly elevate your legs to flatten the lower back for the spine scan.
Once positioned, a scanning arm or detector will slowly pass over the areas being measured, typically the lower spine and one hip. During this time, it is important to remain motionless to prevent blurring the image. The dose of radiation used is extremely low, allowing the technologist to remain in the room with you throughout the entire process. After the scan is complete, you can immediately get up and resume your normal daily activities.