A dual-energy X-ray absorptiometry scan (Dexascan) is a procedure to determine bone density and aid in the diagnosis of osteoporosis. During the procedure, a technologist aims low-dose X-rays at parts of the body prone to bone loss. In a normal X-ray procedure, the X-ray photons strike special X-ray film to produce a picture of the bones. In a dexascan, instead of striking film, the X-ray beam strikes a device that measures the percentage of X-ray photons that were absorbed by the body. By comparing this percentage to the scan results of others your age, your doctor can determine whether you are suffering from abnormal bone loss in the areas examined.

The procedure begins with the technologist having you lie fully clothed on the exam table. A scanner is then passed over several different areas of your body, while a low-dose X-ray beam passes through your body and to the scanner. Even though the X-ray dose is very low, if you are or could be pregnant, notify your technologist so appropriate precautions can be taken to protect the fetus from radiation exposure.

A complete scan takes about 15 minutes. During the exam, you will feel no discomfort, but you will need to lie very still. Holding your breath should be unnecessary. The only preparation required for the procedure is to avoid calcium supplements the day of the scan and to wear clothing without metal, such as zippers or buttons.