systemGE HealthCareBone Densitometry

GE Lunar iDXA

Manufacturer: GE HealthCare · Modality: Bone Densitometry / DXA

Premium dual-energy X-ray absorptiometry (DXA) scanner. The flagship in GE's Lunar bone-densitometry line, used for osteoporosis diagnosis, fracture-risk assessment, and whole-body composition measurements that extend DXA beyond traditional T-score / Z-score reporting into visceral-fat quantification and trabecular bone microarchitecture evaluation.

Platform architecture

  • Direct-to-digital detector + staggered array with MVIR (Multi-View Image Reconstruction) — improves image quality and precision vs prior Lunar generations.
  • Narrow-angle fan-beam geometry — the X-ray beam emerging from beneath the table follows a square-wave raster from head to feet. Narrow-angle (vs wide-angle) fan beam reduces geometric magnification error on the DXA result — precision is the defining DXA metric and is tightly specified on iDXA.
  • Low dose — typical DXA exam delivers 3–6 µGy, substantially below almost any other diagnostic X-ray exam.

Clinical applications

  • Bone mineral density — AP spine, proximal femur, total body, forearm, radius/ulna. T-score and Z-score reporting per WHO / ISCD standards.
  • Vertebral fracture assessment (VFA) — lateral spine imaging to identify vertebral compression fractures.
  • CoreScan (visceral adipose tissue, VAT) — quantitative visceral-fat measurement from the whole-body scan, clinically meaningful for metabolic-syndrome assessment and endocrinology workflows.
  • Advanced Hip Assessment (AHA) — hip-strength analysis: hip axis length, CSMI, CSA, Z.
  • TBS (Trabecular Bone Score) — optional licensed feature that derives trabecular bone microarchitecture from the lumbar spine DXA image. Clinically used alongside BMD to refine fracture-risk assessment.
  • Body composition — fat mass, lean mass, bone mineral mass by region and total body.
  • Pediatric and small-patient protocols — supported via enCORE.

Specs

  • 1.5 kW X-ray generator class, narrow-angle fan beam
  • Direct-to-digital detector + staggered array, MVIR reconstruction
  • Total-body scan time 7:16 – 13:16 min (patient-size dependent)
  • Typical exam dose 3–6 µGy
  • Max patient dimensions: 198 cm height × 66 cm width × 204 kg weight
  • enCORE host + analysis software (CoreScan, VFA, AHA, TBS optional)

Clinical positioning

  • Osteoporosis diagnosis and monitoring — the foundational DXA use case.
  • Fracture-risk refinement — TBS and AHA extend beyond simple BMD for more accurate risk stratification.
  • Body composition / metabolic assessment — obesity clinics, endocrinology, sports medicine, and research use the whole-body composition output.
  • Pediatric endocrinology — growth and bone-health monitoring in children.

Operational

  • Low-dose, non-licensed X-ray — most jurisdictions require general radiology license but no special radioactive-materials license (contrast with PET / nuclear medicine).
  • QC discipline — daily phantom QC is mandatory for reliable longitudinal BMD measurement; precision-error assessment per ISCD is part of a well-run DXA program.

Relationship to siblings and competitors

  • Lunar Prodigy — predecessor-class Lunar DXA, still widely deployed in legacy installations.
  • Hologic Horizon — primary competitor; narrow-angle fan-beam equivalent. Horizon and iDXA use different proprietary BMD algorithms — cross-vendor BMD results are not directly comparable without standardization.
  • Hologic Discovery / Hologic QDR-4500 — predecessor-class Hologic DXA.

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