Fig. 2From: Three-dimensional preoperative planning in the weight-bearing state: validation and clinical evaluationGeometry of the EOS System. The EOS imaging systems produces biplanar long-leg standing X-rays by using a fan-beam scan approach, in which only the horizontal axis of the image is affected by projective effects. Frontal (in yellow) and lateral (in blue) emitters are depicted as spherical sources. The emitters move synchronously along the z-axis (shown in green). The vertical y-axes of the lateral and frontal detectors directly relate, without magnification, to the z-axis in the EOS coordinate systemBack to article page