Bone mineral content and soft-tissue assessment in limb segments by dual-energy X-ray absorptiometry: optimal scan speed and pixel size.

The aim of this study was to define the best scanning parameters to assess bone mineral content (BMC) and bone mineral density (BMD) in specific dual-energy X-ray absorptiometry (DXA) applications, such as those encountered in orthopedics for the measurements of the peripheral skeleton. To simulate soft tissues and bones in a limb, we used simple phantoms made with plastic bottles (500 mL and 1500 mL) filled with tap water and cylinders of hydroxyapatite (HAP) powder set in a polymer at various concentrations (range, 0.150-1.500 g HAP/cm3). Data obtained from 204 measurements of these phantoms with different scanning speeds and pixel sizes showed that the best compromise for obtaining precise measurements in the shortest scan time was a scanning speed of 50 mm/s and a pixel size of 1.5 mm x 1.5 mm.