Dual Energy XRay Absorptiometry

A different attenuation of low- and high-energy X-rays by fat and nonfat or bone tissues is the basic principle for the measurement of body composition by dual energy X-ray absorptiometry (DXA). The fat and lean (nonfat) content is determined for each pixel of a scan that does not overlie bone and is reported to be virtually independent of tissue thickness. In addition to whole-body or regional composition values of fat and lean content (Fig. 1), DXA provides estimates for bone mineral content, bone mineral density, and total mass of soft tissues. DXA has been used with poultry,[3] swine,[4] and recently with calves.[5]

Fig. 1 Image produced by a DXA scan of a live pig with defined regions of interest.
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