A bone density scan is a test that measures the calcium and other minerals in your bones. Since most women's bones become thinner as they age, this test is generally recommended for women over 65 or women who have had one or more bone fractures after the age of 50.
The scan determines whether you have low bone mass (osteopenia) or osteoporosis, a disease that causes the bones to become very thin and brittle. It can also predict the risk of future fractures and check to see if your osteoporosis treatment is working.
Your physician may recommend a bone density test if you have other risk factors for osteoporosis and fractures, including a family history of osteoporosis and/or fracture, frequent falling, vitamin D deficiency, smoking, excessive alcohol intake, malabsorption, and if you have taken some medications, like prednisone.