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Xtheory

DEXA Scanning

A precise picture of what your body is made of.

Dual-energy X-ray absorptiometry passes two low-dose X-ray energies through the body. Because fat, lean tissue and bone absorb them differently, the scan can separate the three and report each one region by region.
Book a ScanHow the Appointment Works

The scanner

The open DEXA scanner and its control console in the Xtheory studio.
DEXA Scanner 1 · Xtheory Walnut Creek

What it measures

Eight measurements from one scan.

Each of these is reported separately, and each can be tracked over time.
  • 01

    Total Body Fat %

    The share of your total mass that is fat tissue, measured directly rather than estimated from height and weight.

  • 02

    Regional Body Fat

    How fat is distributed across arms, legs and trunk, instead of collapsed into a single whole-body figure.

  • 03

    Visceral Fat

    An estimate of fat located around the organs in the abdominal cavity, reported separately from fat under the skin.

  • 04

    Lean Mass

    Total lean soft tissue — the part of you that training and protein intake are meant to build and defend.

  • 05

    Regional Lean Mass

    Lean tissue broken out by limb and trunk, so you can see where mass is actually being added or lost.

  • 06

    Left / Right Imbalances

    A side-by-side comparison of limbs, which is difficult to judge accurately by eye or by feel.

  • 07

    Bone Mineral Density

    Bone mineral content and density from the same scan, reported alongside your soft-tissue results.

  • 08

    ALMI

    Appendicular Lean Mass Index — limb lean mass scaled to height, a standard way to track muscle over time.

During the scan

You lie still. The arm passes over you.

You stay fully clothed on a padded bed while the scanner arm moves along the length of your body. There is nothing enclosed about it, and nothing to hold your breath for.
  • 01Setup and positioning takes a few minutes
  • 02You remain still while the arm passes over you
  • 03Setup and scanning together take about ten minutes
  • 04Your report is generated immediately afterwards

DEXA uses low-dose X-ray technology. [PLACEHOLDER — pending confirmation. Dose figures must come from the scanner manufacturer specifications and be reviewed by a qualified professional before publication.] If you are pregnant or think you may be, do not book a scan; speak with your physician first.

A staff member helping a client into position on the padded scanner bed.
ArmsHeadTrunkLegs

Scope

What a scan can tell you, and what it cannot.

Being clear about the limits is part of the value. A measurement you misread is worse than no measurement.

What DEXA does

  • Separates fat, lean soft tissue and bone mineral
  • Reports each region of the body independently
  • Estimates visceral fat around the organs
  • Gives a repeatable baseline you can measure against later

What DEXA does not do

  • Diagnose any medical condition
  • Replace advice or testing from your physician
  • Measure hydration, sleep, or metabolic rate
  • Predict health outcomes

Preparing

Keep the conditions the same each time.

Consistency matters more than any single rule. Whatever you do before your first scan, repeat it before the next one so the comparison is fair.
  • 01Wear comfortable clothing without metal — no zips, underwire, buckles or heavy hardware.
  • 02Leave jewellery at home where you can, or plan to remove it before the scan.
  • 03Arrive a few minutes early so setup does not cut into your review time.
  • 04[PLACEHOLDER — pending confirmation] Guidance on eating, hydration and training before your scan.

Questions

About the scan.

What is a DEXA scan?

DEXA (dual-energy X-ray absorptiometry) uses two low-dose X-ray energies to distinguish fat, lean soft tissue and bone mineral. It is a long-established method for measuring body composition, and it reports results region by region rather than as a single whole-body estimate.

What does it measure?

Total and regional body fat, lean mass by limb and trunk, an estimate of visceral fat, bone mineral content and density, left-to-right differences, and appendicular lean mass index (ALMI).

How long does the scan itself take?

Setup and scanning together take roughly ten minutes of your appointment. [PLACEHOLDER — exact scan duration pending confirmation from the scanner specifications. Do not publish a specific figure until verified.]

How long is the whole appointment?

Thirty minutes. Approximately ten minutes for setup and scanning, and around twenty minutes reviewing your results with an expert.

Is there radiation?

DEXA uses low-dose X-ray technology, so there is a small radiation exposure. [PLACEHOLDER — pending confirmation. Effective dose figures and any comparison must come from the scanner manufacturer specifications and be reviewed by a qualified professional before publication.] If you are pregnant or think you may be, do not book a scan; talk to your physician first.

What should I wear?

Comfortable clothing free of metal. Zips, underwire, buckles, clasps and heavy hardware can interfere with the scan, so leave them out where you can. You stay fully clothed throughout.

Can I eat before the scan?

[PLACEHOLDER — pending confirmation of Xtheory protocol.] Consistency matters more than the specific rule: whatever you do before your first scan, repeat it before the next one so the comparison is fair.

How should I prepare?

Wear metal-free clothing, arrive a few minutes early, and try to keep the conditions similar each time you scan — same time of day, similar hydration and similar training the day before. [PLACEHOLDER — full preparation protocol pending confirmation.]

All Questions

Measure first. Then make the plan.

One appointment gives you a precise baseline and someone to explain it.

Book Your DEXA Scan
  1. 01Measure
  2. 02Understand
  3. 03Improve
  4. 04Re-measure