Bone Density/DEXA Scan
What is Osteoporosis?
Bone is living tissue that is constantly being broken down and replaced. Osteoporosis occurs when the creation of new bone doesn't keep up with the removal of old bone. In osteoporosis, the bone remains the same size, but becomes thinner and has larger holes in the spongy part of the bone.
This causes bones to become weak and brittle. Bones can become so brittle that a fall or even mild stresses like bending over or coughing can cause a fracture.
Risk factors for osteoporosis include aging, being female, low body weight, low sex hormones or menopause, smoking and some medications.
Medications, healthy diet and weight bearing exercise can help prevent bone loss or strengthen already weak bones.
Bone Density Screening
Your bone density can be measured by a machine that uses low levels of X-rays to determine the proportion of mineral in your bones. Bone density scanning is also called dual-energy x-ray absorptiometry (DEXA).
This enhanced form of x-ray technology that is today's gold standard for measuring the density of your bones.
The bone density exam delivers approximately 1/10th the radiation during an ordinary chest x-ray. It is a simple and painless and non-invasive screening.
How to Prepare For Your Exam
On the day of the exam, you may eat normally. You should not take calcium supplements for at least 24 hours prior to your exam. Wear loose, comfortable clothing, avoiding garments that have zippers, belts or buttons made of metal.
You may be asked to remove some or all of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, removable dental appliances, eye glasses and any metal objects or clothing that might interfere with the X-ray images.
Women should always inform their physician and X-ray technologist if there is any possibility they are pregnant.
What to Expect During Your Exam
During this outpatient examination, you will lie on a padded table. You will be asked to hold very still and maybe asked to keep from breathing for just a few seconds while the X-ray image is taken to reduce the possibility of a blurred image. The DEXA bone density exam is usually completed within 15 to 30 minutes.
Your exam results will be in the form of two scores:
T Score - This number shows the amount of bone you have compared with a young adult of the same gender with peak bone mass.
- A score above 1 is considered normal
- A score between -1 and -2.5 is classified as osteopenia (low bone mass)
- A score below -2.5 is defined as osteoporosis
Z Score - This number reflects the amount of bone you have compared with other people in your age group of the same size and gender.
Various medications are available to treat osteoporosis. Bisphosphonates are drugs that help slow bone loss, while a form of estrogen, such as raloxifene, can help strengthen bone.