Fig. 1.

Selection of bony landmarks for alignment of orthogonal setup images and for determination of residual errors after the alignment. Residual errors are caused by flexible patient anatomy and rotation. The matching positions (open white boxes) are shown in (a) anterior reference image and (b) lateral reference image. The distances between the subregions were within ±2 cm for all patients. The projection of the target breast tissue is illustrated with a dashed line.