Segmentation of CT image. From an input 3D CT image (A), we segmented the three regions by different methods. (B) The kidney region was segmented by the graph cut method [8, 9]. We specified several foreground (red) and background (blue) points on a cross section and the method computed the kidney region from the points. (C) The urinary tract region was segmented by region growing . The method grew the urinary tract region from several seeds (red points). (D) The tumor region was segmented by the contour-based method . The method computed the boundary surface from specified multiple contours.