Uses of DXA

DXA (Dual-energy X-ray Absorptiometry) scanning is a vital tool in modern healthcare. While it’s most well-known use is diagnosing osteoporosis, DXA has several important clinical applications that support early detection, prevention, and effective treatment planning.

Blackrock DXA's technician reviews a patient’s bone density scan results on a computer monitor, displaying a spinal image alongside a colour-coded graph indicating bone health levels.

Diagnosing Osteoporosis

DXA is the internationally recognised standard for diagnosing osteoporosis. It measures Bone Mineral Density (BMD) to determine whether your bones are strong, weakened (osteopenia), or osteoporotic.

  • Osteoporosis is a progressive disease that weakens bones, increasing the risk of fractures.
  • Your results are presented as a T-score or a Z-score, which compares your BMD to the average of a healthy young adult.

 

Fracture Risk Assessment (FRAX)

DXA scans of the hip region are often used in combination with the FRAX tool, which estimates your 10-year risk of fracture. FRAX takes into account:

  • Bone density measurements
  • Age and gender
  • History of previous fractures
  • Lifestyle factors (e.g. smoking, alcohol use)
  • Family history and medical conditions

This data helps guide preventative strategies and treatment decisions, particularly for older adults and postmenopausal women.

Trabecular Bone Score (TBS)

TBS is an advanced tool that evaluates the quality of your bone structure, beyond what bone density alone can show.

  • TBS is calculated from the same DXA scan of the spine.
  • It provides valuable insight into bone microarchitecture, and when combined with FRAX, it offers a more comprehensive picture of your fracture risk.
  • No additional scan or radiation exposure is required.

 

Monitoring Bone Health Over Time

For individuals already diagnosed with low bone density or osteoporosis, DXA scans are essential for monitoring:

  • How well your current treatment is working
  • Whether your bone density is improving, stable, or declining

Routine monitoring allows healthcare providers to adjust treatments as needed, usually with follow-up scans every 1–3 years, depending on individual needs and on current result.

Vertebral Fracture Assessment (LVA/VFA)

In certain cases, an additional scan called Lateral Vertebral Assessment (LVA) or Vertebral Fracture Assessment (VFA) is performed during your visit.

  • This involves lying on your side while the spine is imaged.
  • The purpose is to detect silent spinal fractures that may not yet cause symptoms but are often linked to osteoporosis.
  • Early detection can lead to earlier intervention and better outcomes.

 

Body Composition Analysis

In addition to bone health, DXA can also assess body composition, which is especially useful in:

  • Sports medicine
  • Weight management
  • Metabolic health assessments

This scan provides a breakdown of:

  • Lean mass
  • Fat mass
  • Fat distribution

To prepare for a body composition scan, you may be asked to fast for 4–6 hours, avoid physical activity beforehand, and empty your bladder before the scan.

As this is a separate, whole-body scan, it must be specifically requested by your referring doctor.

Blackrock DXA's technician in blue scrubs gently positions a patient's legs using a foam support block during a bone density scan at Blackrock DXA. The patient lies on the scanning table beneath the DXA machine in a bright, clinical setting.

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