Body Composition DEXA

A body composition DEXA uses the same scanning technology as a bone-density test, but instead of focusing on bone alone it measures how the body is made up — the amounts of fat, lean muscle and bone, and how these are distributed. It is used in health and fitness assessment, in research, and clinically in situations where changes in muscle or fat matter, such as monitoring muscle loss.

Because bone, muscle and fat each absorb the scanner's two X-ray energies differently, the machine can separate the body into these components and estimate how much of each is present, region by region. A whole-body scan produces a breakdown of total and regional fat and lean mass alongside bone measurements. This gives a more detailed and consistent picture than simple weight or body mass index, which cannot tell muscle and fat apart.

The experience is the same relaxed, painless process as a bone-density DEXA. You lie still on the table, usually fully clothed but without metal items, while the scanning arm passes over your whole body, typically for around ten to twenty minutes. The radiation dose is very low. You may be asked to follow simple preparation instructions so that results can be compared reliably over time.

While body composition DEXA is not a routine spinal test, it can be relevant to spinal health in specific ways. Low muscle mass and poor overall condition can affect recovery and rehabilitation, and monitoring muscle and fat can be useful in some patients being prepared for or recovering from spinal treatment. It is offered when this broader assessment of the body genuinely adds to a person's care.

• —International Society for Clinical Densitometry (ISCD) — Official Positions
• —Royal Osteoporosis Society — Clinical Guidance
• —Royal College of Radiologists — iRefer: Making the Best Use of Clinical Radiology

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.