Short answer: A DEXA scan uses a very low dose of ionising radiation. At WLC Medical in Belmont, Perth, we use a GE Lunar iDXA medical-grade DEXA scanner for bone density and total body composition assessments. One way to put the radiation exposure into perspective is to compare it with other everyday and medical exposures. A flight between Perth and the Pilbara can expose a person to several times the radiation of a typical DEXA scan due to naturally occurring cosmic radiation at altitude. DEXA also uses considerably less radiation than many other forms of medical imaging. Depending on the examination, a standard X-ray may involve tens of times more radiation than a typical DEXA scan, while CT scans generally involve substantially higher radiation doses again. At WLC Medical, we follow the radiation protection principle of As Low As Reasonably Achievable (ALARA) and do not perform DEXA scans during pregnancy. Overall, DEXA provides detailed information about bone density and body composition using a very low radiation dose.
Long answer:
Why Does a DEXA Scan Use Radiation?
DEXA stands for Dual-Energy X-ray Absorptiometry.
The scanner uses two low-dose X-ray energy levels to assess what is happening inside the body. Depending on the type of scan, this can be used to measure Bone Mineral Density (BMD) or provide detailed information about muscle mass, body fat and bone mass.
Because DEXA uses X-rays, it does involve ionising radiation. However, the amount used is very low.
How Much Radiation Does Our DEXA Scanner Use?
At WLC Medical, we use a GE Lunar iDXA.
The exact radiation dose varies depending on the type of examination, scan mode and individual being scanned.
For example, published estimates for the GE Lunar iDXA show that a Total Body iDXA scan in standard mode has an estimated effective dose of approximately 0.96 microsieverts (µSv).
While numbers such as microsieverts can be difficult to put into perspective, comparisons with radiation we encounter in everyday life can make the amount easier to understand.
How Does a DEXA Scan Compare With Flying?
When we fly, we are exposed to a small amount of additional naturally occurring cosmic radiation because there is less atmosphere above us to provide shielding at higher altitudes.
As a practical example for people living and working in Western Australia, a flight between Perth and the Pilbara can involve several times the radiation exposure of a typical DEXA scan.
Many FIFO workers make this journey regularly as part of their normal working lives.
This comparison helps put the very low radiation exposure associated with DEXA scanning into perspective.
The exact radiation exposure from any flight varies depending on factors including the route, altitude and duration of the flight.
How Does DEXA Compare With an X-ray or CT Scan?
DEXA generally involves considerably less radiation than many other forms of medical imaging.
The exact dose from an X-ray depends on which part of the body is being examined and how the examination is performed. For perspective, commonly performed X-rays such as a chest X-ray can involve tens of times the effective radiation dose of a typical DEXA scan.
CT scans generally involve substantially higher radiation doses again because they use multiple X-ray measurements to create detailed cross-sectional images of the body.
The amount of radiation from any medical imaging examination varies according to the type of examination, equipment, technique and individual being examined. However, DEXA sits at the very low end of the radiation-dose range used in medical imaging.
Does a Body Composition DEXA Scan Use Radiation?
Yes.
A Total Body Composition DEXA scan uses a small amount of ionising radiation to distinguish between different tissues within the body.
The scan can provide detailed measurements including:
- Lean muscle mass
- Fat mass
- Visceral fat
- Bone mass
- Regional fat distribution
This provides information that body weight or BMI alone cannot show and can be useful for establishing a baseline or monitoring changes over time.
Does a Bone Density DEXA Scan Use Radiation?
Yes. Bone Density DEXA scanning also uses low-dose X-rays.
A Bone Density DEXA scan measures Bone Mineral Density (BMD) and provides measurements including T-scores and Z-scores.
These results can help identify reduced bone density and provide useful information about bone health and fracture risk.
The radiation dose differs from a Total Body scan and can vary depending on the areas being examined and the scan mode required.
Can You Have DEXA Scans More Than Once?
Yes, although how often a DEXA scan should be repeated depends on why you are having the scan.
For body composition, repeating a scan may be useful when you are actively making changes to your nutrition, exercise or lifestyle. In these circumstances, a repeat Body Composition DEXA scan approximately every 3 to 6 months may provide useful information about changes in muscle mass and body fat.
Bone density generally changes more slowly, so Bone Density DEXA scans are usually performed at longer intervals depending on your individual circumstances, risk factors and recommendations from your healthcare provider.
For more information, read our article How Often Should You Have a DEXA Scan?
What If I Am Pregnant?
At WLC Medical, we do not perform DEXA scans on anyone who is pregnant, at any stage of pregnancy.
We follow the radiation protection principle of As Low As Reasonably Achievable (ALARA). This means radiation exposure should be kept as low as reasonably achievable while still obtaining the information required from an appropriate examination.
Although the radiation dose associated with DEXA is very low, a DEXA scan would not generally be required during pregnancy. As a precaution, we therefore advise against DEXA scanning during pregnancy.
If you are pregnant or think you may be pregnant, please let our team know before your appointment.
Key Takeaways
- DEXA uses a very low dose of ionising radiation.
- The exact radiation dose varies depending on the type of DEXA scan, scan mode and individual being scanned.
- A Total Body scan on the GE Lunar iDXA uses a very small amount of radiation.
- A flight between Perth and the Pilbara can involve several times the radiation exposure of a typical DEXA scan due to naturally occurring cosmic radiation at altitude.
- DEXA generally involves considerably less radiation than many standard X-ray examinations, while CT scans typically involve substantially higher radiation doses again.
- WLC Medical follows the As Low As Reasonably Achievable (ALARA) radiation protection principle.
- WLC Medical does not perform DEXA scans during pregnancy.
- DEXA can be used to assess Bone Mineral Density or provide detailed information about body composition, including lean mass, body fat and visceral fat.
- How often a DEXA scan should be repeated depends on the reason for the scan and the individual’s circumstances.
How WLC Medical Can Help
At WLC Medical in Belmont, we provide medical-grade GE Lunar iDXA scanning onsite for people wanting to better understand their bone density or body composition.
Our DEXA assessment options include:
- Bone Density DEXA Scan – measures Bone Mineral Density and provides T-score and Z-score measurements to help assess bone health.
- Total Body Composition DEXA Scan – provides detailed information about lean mass, body fat, visceral fat, bone mass and regional body composition.
- Combined Bone Density and Body Composition DEXA Scans – provides both assessments during the same appointment.
- DEXA Sports Package – combines a Total Body Composition DEXA Scan with ECAL Resting Metabolic Rate testing to provide information about body composition and resting energy expenditure.
- Health Insights Package – combines a Bone Density DEXA Scan, Total Body Composition DEXA Scan and ECAL Resting Metabolic Rate testing, providing a broader assessment of bone density, body composition and metabolism.
Our DEXA Sports Package and Health Insights Package are completed during a 60-minute appointment with an Accredited Practising Dietitian.
No GP referral is required to book a DEXA scan, although referrals from GPs and other healthcare providers are welcome. With your consent, your results can also be sent to your GP or treating healthcare provider.
Related Articles
Continue learning about DEXA scanning, bone health and body composition:
- How Often Should You Have a DEXA Scan?
- Why Body Weight Doesn’t Tell the Whole Story
- Why Muscle Mass Matters More Than You Think
- What Is Visceral Fat and Why Does It Matter?
- What Is Resting Metabolic Rate (RMR) and Why Is It Important?
Want to Learn More About DEXA Scanning?
If you have questions about DEXA scanning, radiation exposure or which assessment option may be suitable for you, our team at WLC Medical can provide information about the DEXA services available.
To speak with our friendly team or book an appointment, call (08) 6263 7778, or book online through our website.
If you have concerns about radiation exposure, bone health or whether a DEXA scan is appropriate for your circumstances, please speak with your GP or another qualified healthcare professional.
References
- Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). RPS G-2 – Radiation Protection Principles. Guidance on justification, optimisation and the As Low As Reasonably Achievable (ALARA) principle.
- Australian Radiation Protection and Nuclear Safety Agency (ARPANSA). Flying and Health: Cosmic Radiation Exposure for Casual Flyers and Aircrew. Information on cosmic radiation exposure during air travel and estimated radiation doses for Australian flight routes.
- RadiologyInfo.org – American College of Radiology (ACR) and Radiological Society of North America (RSNA). Bone Density Scan (DEXA or DXA). Information on DEXA, radiation exposure and radiation safety.
- RadiologyInfo.org – American College of Radiology (ACR) and Radiological Society of North America (RSNA). Radiation Dose from X-Ray and CT Exams. Comparative effective radiation doses for DEXA, X-ray and CT examinations.
- GE HealthCare. Lunar iDXA – Entrance Dose and Effective Dose Estimates. Manufacturer information regarding estimated radiation doses associated with GE Lunar iDXA examinations.
Last reviewed: October 2026
This article is intended for general educational purposes only and should not replace personalised medical advice. If you have questions or concerns about radiation exposure, DEXA scanning, bone health or your overall health, please speak with your GP or another qualified healthcare professional.
