DXA body composition properties: inherent in the physics or specific to scanner type?

Experimental results with DXA body composition are partly attributable to the DXA technology itself (X-ray physics) and partly to the particular implementation (Lunar DPX, Hologic QDR, etc). This paper identifies a number of advantages and disadvantages of DXA body composition measurement, distinguishing between those which are common to all DXA and those which are specific to particular instruments.