Bone Densitometry

A bone densitometry study measures the calcium content (density) of your bones.  A scanner that emits tiny amounts of radiation is used for this exam.  Scans of your lower back, hip, or forearm are most often taken.  You are having this exam because it has been determined that you are, or may be, at risk for osteoporosis (loss of bone mass).  This exam can also show whether your medications are slowing down bone loss.

Normal Bone and Osteoporotic Bone

DEXA Bone Densitometer

What Is Osteoporosis?
"Osteo-" means bone, and "-porosis" means material which is porous.  Hence, osteoporosis is a disease that causes bones to become more porous, gradually making them weaker and more brittle.

Who Is at Risk for Osteoporosis?
Women who have gone through menopause are most at risk.  Menopause usually begins when a woman is about 50, although it can occur earlier if a woman has had surgery to remove her ovaries.  Other contributing risk factors include:

• Family history of osteoporosis
• Caucasian or Asian descent
• Thin or small build
• Smoking
• Excessive alcohol
• Too little exercise
• Too little calcium (now or as a child)
• A previous broken bone that resulted from a minor injury
• Certain medications, such as steroids (commonly used to treat asthma and arthritis) and thyroid hormone (if the doses are high)
• Early menopause

Before Your Bone Density Test:
Wear clothing with no metal closures, such as zippers.  You may have to remove your watch or other metal items that can affect exam results.  You may also be asked to wear a patient gown.  This test takes between 20 and 30 minutes.

During Your Bone Density Test:
You will be asked to lie down on a specialized table.  For part of the test, your lower legs may be raised on a platform.  This will help ensure the images taken will be clear.  A scanner arm will be above you.  This arm will move back and forth over the part of your body being scanned.  During the exam, the technologist will stand or sit nearby.  You will need to remain very still.

After Your Bone Density Test:
You may return to your normal routine when your exam is over.  Your doctor will let you know when your results are ready.

Let the Technologist Know if You:

• are, or think you might be, pregnant.
• have any metal in the part of your body being imaged, such as spinal fusion rods or a hip replacement.
• have had a recent nuclear medicine scan or a barium enema.
• have a severely curved spine; have had spinal surgery, or cannot lie on your back for any reason.