1. A method comprising: obtaining data from a computed tomography device; receiving a user selection of a set of voxels of a target object comprised by said initial image; deriving an initial segmentation of said target object, said initial segmentation based on a prominent intensity of said target object; rendering an initial image based upon said initial segmentation; determining a principal mode from a prior segmentation via a mean shift algorithm that comprises an evaluation of a determined voxel intensity change within said initial segmentation, wherein said mean shift algorithm comprises an evaluation of an equation: ( x i + 1 , y i + 1 , z i + 1 ) = ∑ ( u , v , w ) ∈ Si ⁢ k ⁡ (  ( u - x i ) , ( v - y i ) , ( w - z i )  2 ) ⁢ ω ⁡ ( u , v , w ) ⁢ ( u , v , w ) ∑ ( u , v , w ) ∈ Si ⁢ k ⁡ (  ( u - x i ) , ( v - y i ) , ( w - z i )  2 ) ⁢ ω ⁡ ( u , v , w ) where (x i ,y i ,z i ), i=0, 1, 2,. .. , is a sequence of positions starting from a given position (x 0 ,y 0 ,z 0 ) Si is said initial segmentation of said object; k is a kernel function; and ω is a weight function; providing said principal mode to an algorithm that is adapted to derive an improved image of said target object; and rendering said improved image of said target object.