EOS or DEXA: Which Scan Answers Which Question?
A DEXA scan measures bone mineral density, telling you how strong your bones are and whether you are at risk of osteoporosis. An EOS scan shows the shape, position and alignment of your bones while you stand. They answer completely different questions, so the right choice depends on what you need to know.
Key takeaways
- DEXA measures bone density (strength). EOS maps bone alignment (shape and position).
- A DEXA scan cannot show whether your skeleton is aligned properly, and an EOS scan cannot measure bone density.
- Some people benefit from both scans, especially after a fracture or when investigating ongoing pain alongside known low bone density.
- EOS uses about 90% less radiation than a standard X-ray, around ten times less.
- Neither scan replaces MRI when soft tissue, discs or nerves need to be assessed.
What does a DEXA scan show compared with an EOS scan?
A DEXA scan (dual-energy X-ray absorptiometry) measures how much mineral is packed into a section of bone, usually the hip and lower spine. The result is a T-score that tells your doctor whether your bone density is normal, low (osteopenia) or very low (osteoporosis). It is the standard test for fracture risk.
An EOS scan does something entirely different. It captures a full-length image of your skeleton while you are standing, bearing your own weight. This reveals how your spine curves, whether your pelvis is level, and how your hips, knees and ankles line up under real-life loading. You can learn more about EOS compared with x-ray, CT and MRI.
How do DEXA and EOS scans compare side by side?
The table below sets out the main differences. The key point is that these scans measure different things, so one does not replace the other.
| Feature | DEXA scan | EOS scan |
|---|---|---|
| What it measures | Bone mineral density (strength) | Bone shape, position and alignment |
| Position during the scan | Lying down | Standing up, weight-bearing |
| Main clinical use | Diagnosing osteoporosis and assessing fracture risk | Mapping whole-body skeletal alignment under load |
| Body areas covered | Usually hip and lower spine | Full length, head to feet |
| Radiation | Very low | About 90% less than a standard X-ray, around ten times less |
| Shows soft tissue or discs | No | No |
| Shows alignment under gravity | No | Yes |
When should you choose a DEXA scan and when should you choose EOS?
The choice depends entirely on the question your clinician (or you) needs answered.
- You need to check for osteoporosis or osteopenia
- You are monitoring bone density over time, for example during treatment
- You want a fracture-risk assessment based on a T-score
- A condition such as osteomalacia has raised concerns about bone strength
- You have ongoing back, hip or knee pain that standard imaging has not explained
- You need a full picture of how your skeleton lines up while standing
- A surgeon or specialist needs weight-bearing measurements before planning treatment
- You want to understand whether misalignment in one area is causing pain elsewhere
A note on MRI. EOS shows bones, joints and alignment. For soft tissue, discs or nerves, MRI is usually the better tool. If your symptoms include nerve pain, numbness or disc problems, your clinician may recommend MRI instead of, or alongside, an EOS scan.
Do some people need both a bone density scan and an alignment scan?
Yes. Bone density and bone alignment are separate pieces of the puzzle. Knowing your bones are weaker than expected (DEXA) is important, but it does not tell you whether those weakened bones are also carrying load unevenly because your spine or pelvis is out of line (EOS).
After a vertebral fracture, for example, a DEXA scan confirms the bone-density problem. A standing EOS scan then shows how that fracture has changed your overall alignment, whether your body is compensating in ways that could lead to further problems. The body is a connected chain from feet to head, and a change in one place often shifts the load elsewhere.
If your clinician is investigating both bone strength and skeletal shape, the two scans complement each other rather than overlap.
Not sure which type of imaging you need? Our radiographer can help you work it out.
Book a free video consultationHow do you book a standing alignment scan at ScanAlign?
You do not need a GP referral. You can book a standing alignment scan yourself in four simple steps.
Speak with our specialist radiographer by video. He will listen to your symptoms, review any previous imaging and confirm whether an EOS scan is the right next step.
The scan itself takes only a few minutes. You stand naturally inside the EOS system while it captures full-length images from head to feet, using about 90% less radiation than a standard X-ray, around ten times less.
A specialist radiologist analyses the images and produces a detailed alignment report, covering your spine, pelvis, hips, knees and ankles.
You receive the report and images, which you can share with any clinician involved in your care. ScanAlign is a diagnostic imaging clinic and does not provide treatment, but the findings give your treating team the information they need.
Frequently asked questions
A DEXA scan measures bone mineral density and produces a T-score used to diagnose osteoporosis. An EOS scan does not measure density. It shows the shape and alignment of your bones under weight-bearing conditions.
No. They answer different questions. If you need to know how strong your bones are, you need a DEXA scan. If you need to know how your skeleton lines up under load, you need an EOS scan.
Yes. An EOS scan uses about 90% less radiation than a standard X-ray, around ten times less. This makes it one of the lowest-dose skeletal imaging options available.
No. ScanAlign accepts self-referred adults. You can book directly through a free video consultation with our specialist radiographer.
ScanAlign is a private self-pay clinic. For current pricing details, please visit our FAQs and cost page.
DEXA scans are widely available on the NHS (usually through a GP referral) and at many private clinics across the UK. ScanAlign does not offer DEXA scans. We provide ScanAlign standing EOS imaging for skeletal alignment assessment.
A DEXA scan can identify low bone density, which may contribute to fractures that cause pain. However, it cannot show alignment problems, disc issues or soft-tissue causes of back pain. A standing alignment scan or MRI may be more appropriate depending on your symptoms.
Bone density refers to how much mineral is packed into the bone, which determines its strength. Bone shape refers to the structure and position of bones within your skeleton. You can have normal density but poor alignment, or low density with good alignment. They are separate measurements.
When you lie down, gravity is no longer compressing your spine and joints, so muscles relax and the skeleton shifts into a different position. A standing scan captures the alignment your body actually uses throughout the day, which can reveal problems that lying-down imaging misses.
You speak with Abbas Dhami, our specialist diagnostic radiographer. He will ask about your symptoms and any previous imaging, explain what an EOS scan can and cannot show, and help you decide whether a standing alignment scan is the right next step for you.
Not sure which scan you need?
Our specialist radiographer will talk you through your options in a free, no-obligation video call.
Book a free video consultationWritten by Abbas Dhami (Specialist Diagnostic Radiographer)
Sources
- NHS. "DEXA (DXA) scan." nhs.uk. Accessed 2025.
- Deschênes S, et al. "Diagnostic imaging of spinal deformities: reducing patients' radiation dose with a new slot-scanning X-ray imager." Spine, 2010;35(9):989-994.
- International Society for Clinical Densitometry (ISCD). "Official Positions: Adult." iscd.org. Accessed 2025.
This page is general information and not a diagnosis.
ScanAlign is the trading name of CoreMed Solutions Ltd and operates under The Harley Street Hospital's CQC licence.