Dual energy X-ray absorptiometry (DXA) for measuring bone remodelling and body composition

DXA utilises two x-ray beams of different energy to measure bone mineral, lean mass (=muscle) and fat (Figure 4, 5) with very little radiation for the patient (less than 1 day of background radiation) 8. We have used DXA for different clinical studies 9-11 and for experimental studies 12-14. Our clinical studies cover a broad range from effect of training on body composition in obese children to the effect of zoledronic acid on new fractures in hip fracture patients. We have also done several methodological DXA studies concerning timing of reference measurement and the effect of radiopacity in the bone cement 15, 16. We have established quality control for the measurements, which demonstrates very low variation and high reproducibility. DXA is the golden standard for bone mineral and body composition measurement at present. High resolution quantitative CT (HR-pQCT, Figure 6) gives architectural information in addition to bone mineral content, but can only be used for the distal lower leg and arm.

Fig 4	Fig 5	Fig 6