Bone Densitometry is a non-invasive means of measuring the density of bones. DEXA is widely used for the evaluation of osteoporosis. Bone density scanning measures the bone mineral density, which is related to bone mass. Decreased bone mass causes decreased bone strength and subsequent risk of fractures. Bone mass peaks in men and women at about the age of 30. Men are generally larger and hence have a greater overall amount of bone mass. Both women and men experience a loss of bone mass of 3-5% per decade. Once women reach menopause, the rate of bone loss accelerates to 1% - 3% per year. This rate is slowed by hormone replacement.
Fractures are the first clinical signs of osteoporosis. It is desirable to identify patients who have osteoporosis before development of fractures. People are considered at risk of developing osteoporosis based on risk factors and whether pre- or post-menopausal.
How the Exam is Performed
Bone density scans are non-invasive and painless. You will lay on a table while a scanner moves over the areas of concern. A computer then determines the bone mineral density based on the relative absorption of a detector on the other side of the bone. Generally, the lower spine (lumbar area) and the left hip are measured.
Preparing for Your Exam
You will be asked to wear a comfortable two piece outfit or a gown is supplied for you. Do not wear any metal buttons, buckles or zippers.