5. Explain more about a DXA scan

• How should I prepare for a DXA scan?
On the day of the exam you may eat normally. You should not take calcium supplements for at least 24 hours before your exam. You should wear loose, comfortable clothing, avoiding garments that have zippers, belts or buttons made of metal.
You may be asked to remove some of your clothes and to wear a gown during the exam. You may also be asked to remove jewelry, eye glasses and any metal objects or clothing that might interfere with the x-ray images.
Inform the DXA operator if you recently had a barium examination or have been injected with a contrast material for a computed tomography (CT) scan or radioisotope scan. You may have to wait 10 to 14 days before undergoing a DXA test.
Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant. Many imaging tests are not performed during pregnancy because radiation can be harmful to the fetus.

• What does the DXA equipment look like?

Central DXA devices measure bone density in the hip and spine. It has a large, flat table and an "arm" suspended overhead.

• How does the procedure work?
The DXA machine sends a thin, invisible beam of low-dose x-rays with two distinct energy peaks through the bones being examined. One peak is absorbed mainly by soft tissue and the other by bone. The soft tissue amount can be subtracted from the total and what remains is a patient's bone mineral density.
DXA machines feature special software that compute and display the bone density measurements on a computer monitor.

• How is the procedure performed?
This examination is done on an outpatient basis.
To assess the spine, the patient's legs are supported on a padded box to flatten the pelvis and lower (lumbar) spine. To assess the hip, the patient's foot is placed in a brace that rotates the hip inward. In both cases, the detector is slowly passed over the area, generating images on a computer monitor.
The patient must hold very still and may be asked to keep from breathing for a few seconds while the x-ray picture is taken to reduce the possibility of a blurred image. The technologist will walk behind a wall or into the next room to activate the x-ray machine.The DXA bone density test is usually completed within 10 to 30 minutes, depending on the equipment used and the parts of the body being examined.

• What will I experience during and after the x-ray procedure?
Bone density tests are a quick and painless procedure.

• Who interprets the results and how do I get them?
An internationally accredited physician will interpret and report the DXA scan. The DXA scan results will be explained to you. The results will be classified as :

• normal osteopenic degree of severity of bone loss
• osteoporotic

• What are the benefits vs. risks?

Benefits

• DXA bone densitometry is a simple, quick and non-invasive procedure.


• No anesthesia is required.


• The amount of radiation used is extremely small—less than one-tenth the dose of a standard chest x-ray.


• DXA bone density testing is the most accurate method available for the diagnosis of osteoporosis and is also considered an accurate estimator of fracture risk.


• No radiation remains in a patient's body after an x-ray examination.


• X-rays usually have no side effects.

Risks

• The effective radiation dose from this procedure is about 0.01 mSv, which is about the same as the average person receives from background radiation in one day.


• Women should always inform their physician or x-ray technologist if there is any possibility that they are pregnant.


• No complications are expected with the DXA procedure.

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