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What is Dexa?

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Bone mineral densitometry is also called DEXA (dual-energy x-ray absorptiometry). This test is used to calculate bone mineral density and body composition. A DEXA scanner uses x-rays of 2 different energy levels. These are absorbed by bone, lean tissue and fat tissue differently therefore allowing an image to be made of the body.

The radiation dose for a DEXA scan in both Body Composition and Bone Density is very small. Typically less than a day's natural background radiation.

  • Body Composition (DEXA) 0.5-4.5μSv

  • Bone Density (DEXA) Spine and 1 hip 3-8μSv

  • Natural Background radiation per day 5-8μSv

  • Lumbar Spine x-ray 700μSv

  • Chest xray 20-150μSv

  • Flight from Darwin to Perth 16μSv


How strong are your bones?

Bone density gives us an idea of how strong our bones are. The lower our bone density is, the weaker our bones are and the more likely they are to break (fracture). Low bone density occurs when the bones lose minerals faster than they can be replaced. This results in the bones become thinner and more fragile leading to osteoporosis.

Osteoporosis is a common disease with 1.2 million people in Australia having it and many more with low bone density(1). With osteoporosis you are more likely to break a bone from a minor fall or bump. Spine, hip and wrist fractures are the most common. Fractures can lead to chronic pain, loss of independence and even death. Osteoporosis typically occurs in adults over 50 years of age. However, there are some chronic medical conditions and long term medications that can cause osteoporosis in under 50year olds.  Osteoporosis is treatable with medication and lifestyle changes.

Normal Bone

Osteoporotic Bone


Risk factors for osteoporosis include:

  • menopause,

  • family history ,

  • low calcium and vitamin D,

  • use of corticosteroids for inflammatory conditions which include asthma and rheumatoid arthritis,

  • low hormone levels ie early menopause for women (<45 years of age) and low testosterone in men,

  • overactive thyroid or parathyroid glands,

  • bowel diseases like Coeliac, Crohn’s or irritable bowel syndrome,

  • chronic liver and kidney disease,

  • some medications for breast cancer, prostate cancer, epilepsy and some antidepressants,

  • lifestyle factors such as excess alcohol, smoking, low physical exercise and being very underweight or overweight.

How is the scan done?

You will need a referral from your GP or doctor to have the test done.

The scan takes only a few minutes with you lying on our scanning bed.

There is no  preparation for this test.

No need to change as long as there is no metal on your clothing.

We take images of your lumbar spine,hips and forearm.

You will need a  referral from a medical doctor to have a scan



We can use DXA scans in children and teenagers to provide:

  • BMD (bone mineral density)

  • BMC (bone mineral content)

  • Fat mass and lean mass

  • BMD calculated to bone age (results from a bone age xray required)

  • Monitoring of disease and/or the effects of medication on the body

Assessing and monitoring children and teenagers with:

  • Developmental problems

  • Chronic conditions associated with malnutrition i.e. anorexia nervosa, inflammatory bowel disease, cystic fibrosis

  • Both muscle and skeletal deficits i.e. idiopathic juvenile osteoporosis

Child DEXA scan.jpg
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