What is a DEXA scan?

Dual-Energy X-ray Absorptiometry (DEXA) scans are used to measure the strength of your bones. Our DEXA scans are the gold standard for measuring and monitoring bone mineral density using an advanced form of x-ray scanning technology. DEXA is commonly used to diagnose conditions where the density of your bones is lower than it should be, including osteoporosis and osteopenia. 

 

Understanding your Bone Density scan

Bone Density

  •  A Bone Density (DEXA) scan is a type of x-ray which measures the calcium content of the bone.
  • By measuring your bone mineral content and comparing it to people of the same age and gender we can give you detailed accurate information about your bone strength so your doctor can plan preventative therapy or medical treatment if necessary.
  • If DEXA is repeated over time it can help to track the rate of bone density loss.

 

Body Composition scan

  • Accurate measurement of body composition provides valuable information for assessing, monitoring and treating a variety of diseases and disorders and for monitoring performance.
  • Body composition measurement helps physicians monitor the effects of therapy, diet or exercise.
  • Body composition scans with DEXA provide precise and accurate data on bone and tissue composition, including bone mineral density, lean muscle mass, and fat tissue mass. They provide both total body data and regional results (trunk, arms, legs, pelvis and android/gynoid regions). The measurements are fast and non-invasive.
  • Body composition measurement with DEXA can look beyond weight and the traditional body mass index (BMI) to determine body fat distribution – an important risk factor in a variety of serious diseases including obesity, anorexia nervosa and cystic fibrosis.
  • DEXA can help athletes make decisions on the training regimens they use to achieve the best performance.

 

On the day of your DEXA scan:

  • There is no special preparation needed for a DEXA scan, however, please being a list of current medication to your appointment.
  • On arrival, please check in with reception.
  • You will be asked to fill out a questionnaire to tell us if you:
    - Have any medical conditions.
    - Take certain medications that might increase or decrease your risk of a fracture.
  • We will ask you to change into a gown and you will need to remove any jewellery or metal objects that may interfere with the images. We will give you somewhere safe to store your belongings.
  • It is essential that you let us know if you have any of the following:
    - Metallic implants in your spine
    - Artificial hips
    - Metallic screws or pins in your bones
  • Before your scan, the DEXA technologist will talk you through the process to make sure you are comfortable.

 

During your DEXA scan:

  • We will measure your height and weight first so the computer can gather information about your bone density.
  • You will lie on a padded table which has an x-ray generator underneath. 
  • You will be supported by a cushion as the detector above you passes up and down your body, generating images on the computer monitor.
  • The timing of a DEXA scan varies between 10 and 30 minutes and is dependent on individual scanning machines. Please allow approximately 30 minutes for your appointment.

 

After your DEXA scan:

  • After your appointment, you can resume your normal routine. This includes eating, drinking, exercising and going about your day as usual.
  • The images taken during the examination are interpreted by one of our team of DEXA experts. 
  • We will send the results to your doctor after a detailed report has been written.
  • In some regions, such as Nelson, reports may take to 7-10 days. Please ask at the time of your appointment about when your doctor is likely to receive your diagnostic report.
  • In all urgent cases, results are made available as soon as possible. Your doctor will discuss any important findings and next steps with you.

Frequently asked questions

Current recommendations are that all women should consider having a bone density scan at age 65. Women should consider an earlier scan if they have additional risk factors. The five main risks are:

  • A family history of osteoporosis
  • A previous fracture over the age of 20 years
  • Early menopause (under 45)
  • Low body weight
  • Smoking

Osteoporosis is when the density of your bones is lower than it should be. Osteopenia is less severe than osteoporosis but can lead to it.

There are many conditions that may cause osteoporosis or osteopenia. These include:

  • Kidney failure
  • Long periods of immobility
  • Family history
  • Corticosteroid therapy
  • History of fractures
  • Long-term hormone suppression
  • Early menopause
  • Low body weight
  • Smoking and alcohol intake
  • Hyperparathyroidism
  • Cushing’s Syndrome
  • Gastrointestinal malabsorption disorder, such as Coeliac disease
  • Long-term treatment with Depo Provera, medicines for breast cancer, depression, stomach reflux or epilepsy.

Do not schedule your scan within one week of having:

  • A barium meal
  • An enema
  • An intravenous pyelogram (IVP)
  • A nuclear medicine study
  • A CT scan

You must tell staff if you have recently had one of these tests, as they may interfere with the accuracy of your bone density scan results. You may need to wait 10-14 days before having your scan.

Bone density scans are very safe as they use a very low level of radiation. You can be scanned 3-4 times per year with minimal negative effects. Studies of the radiation dose to patients from DEXA show that patient exposure is small compared to many other sources of exposure.

A DEXA scan involves a small dose of radiation, so it may be unsuitable for some women. Please let us know if you are pregnant, think you might be or are breastfeeding.

Many imaging tests are not performed during pregnancy to avoid foetus exposure to radiation. If a scan is necessary, precautions will be taken to minimise radiation exposure to your baby.

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