Dual-energy X-ray absorptiometry (DEXA) is the most widely used test for measuring bone density. It can accurately and precisely monitor changes in bone density in patients with osteoporosis who are undergoing treatments. This machine takes a picture of the bones in the spine, hip, total body and wrist and calculates their density. It is painless and noninvasive, requiring no special preparations.
For this exam, you lie on a padded table while the X-ray scanning machine moves over your body to capture images of your hip, spine or entire body. The exam takes about 20 minutes to complete, and the radiation dosage from the X-ray is less than that used for a chest X-ray. Your bone density and risk of fracture are compared to the "normal" range for people your age as well as to the maximum bone density possible