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Arthritis and Rheumatology Centre
A dual-energy X-ray absorptiometry (DEXA) scan is a special type of X-ray that measures bone mineral density (BMD). It provides information about bone strength and the risk of fractures. A higher density generally indicates a lower risk of fracture. The spine and one or both hips are routinely scanned and sometimes the forearm. BMD has been shown to be the best way of predicting the risk of fracture.
Your height and weight will be measured.
The most important aspect of a DEXA scan is to position the hips and spine in the same way each time you are scanned. When scanning the spine, a cushioned box will be placed under your knees. The cushioned box allows the small of your back or lower spine to lie flat on the table. To scan the hip, this box is removed and a triangle will be placed between your feet. These positions are not uncomfortable or painful.
No preparation is required for this procedure. You do not need to fast, and you can take all your medications as usual. It is helpful to wear loose fitting clothing without metal buttons, buckles, or zippers. Fasteners such as metal in bra straps interfere with the scan, you will be asked to remove such undergarments for scanning. A gown or sheet is provided if clothing needs to be removed.
If you have had spinal surgery, particularly with metallic implants, or hip surgery (hip replacements, screws or pins) you will need to inform the technician. It is preferred that you delay DEXA testing if you have had any radiological investigation using contrast media (barium enemas, IVPs and CT scans) or nuclear medicine test within the last week.
There are no after effects of a BMD scan.
A BMD scan varies between individual scanning machines, and can take from 10 minutes to 30 minutes.
Generally, the risks of a BMD scan by DEXA are very small. The radiation doses used are extremely small and significantly less than those used in normal X-ray. No shield or protection is required.
This test is unsuitable for women who are, or might be, pregnant.
A skilled operator will carry out the scan, and ensure you are positioned correctly and you are comfortable. The operator will remain in the room with you for the duration of the scan. The images taken by the operator will be reviewed by a specialist doctor, and a written report provided to your referring doctor.
Your doctor will receive a written report as soon as is practical. It is very important that you discuss the results with your doctor so that they can explain what the results mean for you.
Medicare will cover the cost of the DEXA if the reason for the scan has an associated Medicare item. Please check with your referring doctor. If the scan is not covered by Medicare the cost is $99 payable on the day.