What Is a DEXA Scan and What Do Your Results Mean
Quick Summary
- A DEXA scan is the most accurate and widely used test for measuring bone density and diagnosing osteoporosis and osteopenia
- The scan is painless, takes around 10 to 20 minutes, and does not require you to undress
- Results are reported as a T-score, which compares your bone density to that of a healthy young adult of the same sex
- A T-score of minus 2.5 or lower indicates osteoporosis, while a score between minus 1 and minus 2.5 indicates osteopenia
- Medicare rebates are available for eligible Australians, and all adults over 70 are recommended to discuss a scan with their GP
A DEXA scan, also known as a bone density test or dual-energy x-ray absorptiometry, is the most accurate and widely used method for diagnosing osteoporosis and measuring bone mineral density. According to Healthdirect Australia, the scan is common, painless and safe, and the cost is sometimes covered by Medicare. For older adults in Malvern, Blackburn and across Melbourne who have been referred for a bone density test or who are wondering whether they should ask their GP for one, understanding what the scan involves and how to interpret the results is an important first step.
What Is a DEXA Scan and How Does It Work
A DEXA scan uses two low-dose x-ray beams at different energy levels to measure the density of bone tissue at the hip and lumbar spine, and sometimes the forearm. The two beams pass through the body and the difference in how they are absorbed by bone versus soft tissue gives an accurate measurement of bone mineral density at each site scanned.
The hip and spine are the primary measurement sites because these are the areas most commonly affected by osteoporosis and the locations where fractures have the greatest impact on independence and quality of life. Scanning these sites provides the most clinically relevant information about fracture risk.
The scan itself is performed by a radiographer at a radiology centre, hospital or medical imaging clinic. It is a widely available procedure across Melbourne and does not require a hospital stay.
What to Expect During the Scan
Many older adults feel uncertain about what a DEXA scan involves. The process is straightforward and nothing to be concerned about.
On arrival your height and weight will be measured, as these are used to generate additional information in the report. You will then be taken to the scanning room and asked to lie flat on a padded table. You do not need to undress. You should wear loose, comfortable clothing without metal fasteners such as zips, buttons or underwire, and avoid wearing jewellery on the day.
Once you are positioned on the table, the scanning arm of the machine passes slowly over your body. A foam support may be placed under your knees to help your lower back lie flat for the spine scan. A positioning frame may also be used at your feet for the hip scan to keep the leg correctly aligned.
The entire scan takes approximately 10 to 20 minutes and is completely painless. Most people feel nothing at all during the procedure. The radiation dose is very low, less than that of a standard chest x-ray, and carries no meaningful risk.
Results are sent directly to your referring doctor, who will discuss them with you at a follow-up appointment.
How to Read Your DEXA Scan Results: Understanding T-Scores and Z-Scores
Your DEXA scan report will include two types of scores: a T-score and a Z-score. Understanding what these mean helps you have a more informed conversation with your GP.
T-Score
The T-score compares your bone density to that of a healthy young adult of the same sex at peak bone mass. It is the primary score used to diagnose osteoporosis or osteopenia.
A T-score of minus 1 or above is considered normal bone density for an older adult. A certain degree of bone loss with age is entirely expected and a T-score in this range does not indicate a problem.
A T-score between minus 1 and minus 2.5 indicates osteopenia, meaning bone density is lower than normal but not yet at the level classified as osteoporosis. This is the stage at which proactive management through diet, exercise and lifestyle can make the most difference.
A T-score of minus 2.5 or lower indicates osteoporosis. This means bone density is significantly reduced and the risk of fracture from a minor fall or bump is elevated. Our guide to how osteoporosis affects older adults explains what that means day to day. Medical treatment, supervised exercise and lifestyle management are all recommended at this level.
Z-Score
The Z-score compares your bone density to other people of the same age, sex and body size. A Z-score of minus 2 or lower in an older adult suggests bone loss greater than expected for your age group, which may prompt your doctor to investigate secondary causes such as medication effects or other health conditions.
Who Should Have a DEXA Scan in Australia
Medicare provides rebates for bone density scans in specific circumstances. All adults aged 70 and over are recommended to discuss a bone density scan with their GP. Younger adults with risk factors may also be eligible for a Medicare-rebated scan.
Medicare rebates apply for adults over 70, women who are postmenopausal and concerned about osteoporosis, anyone who has experienced a fracture from a minor injury, people with medical conditions that affect bone density such as rheumatoid arthritis, coeliac disease, overactive thyroid or chronic kidney disease, and those on long-term corticosteroid medications.
For older adults in Malvern and Blackburn who have not yet had a bone density scan and are over 70, or who have any of the risk factors above, speaking with your GP about a referral is a straightforward and sensible step. The scan is available at most radiology centres and medical imaging clinics across Melbourne’s inner east and eastern suburbs.
Note that portable heel ultrasound devices sometimes available in pharmacies or shopping centres are not a reliable substitute for a DEXA scan and are not recommended as a method of diagnosing osteoporosis.
What Happens After Your DEXA Scan
Once you have your results, your GP will discuss what they mean for your individual situation and recommend next steps. The appropriate response depends on your T-score, your other risk factors and your overall health.
If your bone density is normal, maintaining adequate calcium and vitamin D intake, staying physically active and having a repeat scan in two years is the standard recommendation.
If your results indicate osteopenia, your GP may recommend dietary changes, a calcium or vitamin D supplement, and a structured exercise program. An accredited exercise physiologist can design a supervised program specifically targeted to your bone density level and health history.
If your results indicate osteoporosis, your GP will likely recommend medical treatment alongside lifestyle management. Exercise remains an essential component of osteoporosis management at this level, and working with an accredited exercise physiologist ensures your program is both safe and clinically appropriate.
For older adults in Malvern and Blackburn who have received a DEXA scan result indicating osteoporosis or osteopenia, Summit Health Group’s exercise physiology for over 60s is specifically designed to support bone health through progressive, supervised exercise. Our safe strength training for osteoporosis is designed to support bone health through progressive, supervised exercise.
How Often Should You Have a DEXA Scan
For people managing osteoporosis or osteopenia, a repeat DEXA scan is typically recommended every 18 to 24 months. This allows your doctor and exercise physiologist to monitor whether your bone density is stable, improving or declining, and to adjust your management plan accordingly.
Having repeat scans at the same facility and on the same machine where possible improves the accuracy of comparisons between results over time.
Frequently Asked Questions
What is a DEXA scan used for?
A DEXA scan is the most accurate method for measuring bone mineral density and diagnosing osteoporosis and osteopenia. It is used to assess fracture risk, monitor bone density over time and evaluate the effectiveness of treatment.
Is a DEXA scan covered by Medicare in Australia?
Yes, in many cases. Medicare rebates apply for all adults over 70, people with specific medical conditions that affect bone density and those who have experienced a fragility fracture. Your GP will advise whether you qualify for a rebated scan.
Does a DEXA scan hurt?
No. A DEXA scan is completely painless. You lie on a padded table while the scanning arm passes over your body. The radiation dose is very low, less than that of a standard chest x-ray, and the procedure takes approximately 10 to 20 minutes.
What does a T-score of minus 2.5 mean?
A T-score of minus 2.5 or lower indicates osteoporosis. It means your bone density is significantly below that of a healthy young adult of the same sex, and your risk of fracture from a minor fall or impact is elevated. Your GP will discuss treatment and management options with you.
What should I do after a DEXA scan showing osteoporosis?
Your GP will recommend a management plan that may include medication, calcium and vitamin D supplementation and a structured exercise program. An accredited exercise physiologist can design a supervised program appropriate for your bone density level that combines resistance training, weight-bearing exercise and balance training to reduce falls risk, the single biggest driver of fractures.
