A DEXA scan is a test using X-rays to determine how strong and dense bones are. Bone that is less dense can be more prone to fracture. DEXA scans can be used to diagnose osteoporosis.

How does a DEXA scan work?

DEXA means ‘dual energy X-ray absorptiometry. This test measures the density of bone. If bone is very dense, it will only let a certain amount of X-rays pass through it. Less dense bone will let more X-ray pass through. The machine will send low dose x-rays from two different sources through the bone as this improves accuracy.

A detector measures the density of the x-rays that have passed through the body and sends this information to a computer that produces an image of the area scanned and calculates the density of the bone.

What happens in a DEXA scan?

Before the start of the scan your height and weight will be measured.

You will lie on the couch on your back while the scans are performed. The scanner arm moves across your body while scanning but does not touch you. The scan will usually take 30 minutes.

Your results will be analysed by our consultant radiologist and a report and a copy of your scans will be sent to your referring clinician.

Who should have a DEXA scan?

A DEXA scan may be advised if you are at increased risk of osteoporosis.  Osteoporosis leads to increased risk of breaking bones although usually does not cause immediate symptoms. DEXA scans may help to diagnose this condition.

DEXA scans may also be recommended if you:

  • Have disorders related to osteoporosis such as rheumatoid arthritis or coeliac disease.
  • Have a family history on your mother’s side of hip fracture.
  • Have been taking steroids for three months or more.
  • Experienced an early menopause (under 45 years old).
  • Experienced periods stopping (amenorrhoea) a year before the menopause.
  • Are very underweight (body mass index or BMI of under 19)
  • Have suffered a fall or injury resulting in a fracture.
  • Have fractured a vertebra (back bone) resulting in a loss of height.