Figure 1

The radial distances from the center of mass to each delineation is a function of the angles θ and ∅ . The distance in different directions for an individual delineation was calculated as the average distance over a small solid angle in each direction, (left (l), left-posterior (lp), posterior (p), right-posterior (rp), right (r), anterior (a), superior (s), inferior (i)). The area A, corresponding to the right-posterior direction, illustrates the relation between the 3D and 2D representation. The example in the figure is based on one delineation of one prostate.