DEXA stands for Dual Energy X-Ray Absorptiometry. DEXA scanning is a form of bone densitometry, which measures bone mineral density. A bone density test is a test that can diagnose osteoporosis before a broken bone occurs. This test helps to estimate the density of your bones and your chance of breaking a bone.
Whereas, osteoporosis is basically means porous bones. Bone is a living tissue that is constantly being removed and replaced. As we get older, more bone is naturally lost than replaced, but people with osteoporosis lose more bone than people who do not have the disease. Osteoporosis causes the bone to become fragile and therefore break easily and the early stages of osteoporosis, is called osteopenia.. Osteoporosis can affect the whole skeleton, but the most common areas to break are the wrist, spine and hips and the disease affects all age groups and both sexes.
DEXA is relatively easy to perform and the amount of radiation exposure is low. A DEXA scanner is a machine that produces two X-ray beams, each with different energy levels. One beam is high energy while the other is low energy. The amount of X-rays that pass through the bone is measured for each beam. This will vary depending on the thickness of the bone. Based on the difference between the two beams, the bone density can be measured.
Firstly in patient preparation, patient has to remove any metallic things from their clothing and body such as watches, ring, necklaces, bracelets, earrings, spectacles, hairpins and dentures. There is no specific preparation required for a DEXA scan. You should inform your doctor and the radiographer in advance if there is any possibility that you might be pregnant as low dose of X-rays are used during the DEXA scan. The amount of radiation used is less than an ordinary X-ray of the chest or body.
Currently, our Department of Radiology is equipped with the HOLOGIC QDR SERIES DISCOVERY A, that is acquired under Women Imaging Unit. It is a fan-beam system like other Hologic Systems that delivers fast, high resolution images with unsurpassed precision and low patient dose.