1. A method for segmentation of an organ of a living subject with a variable shape and boundary and surrounded by structures and tissues in connection with an image containing the organ, wherein the boundary of the organ is embedded as a zero level set of an embedding function, φ, comprising the steps of: a. initializing a contour inside the organ in the image; b. introducing a speed function that is capable of accumulating spatial and temporal information of a propagating front of the contour, wherein the speed function has a term, g 0 ; c. defining an image-dependent static term, g base ; d. setting the term g 0 =g base ; e. computing {(x,y,z)|Φ(x,y,z)=0} at iteration n, so as to obtain a set of points in the zero level set of the embedding function φ, wherein n=1, 2, 3,. .. , and coordinates (x, y, z) represent a point on the propagating front of the contour; f. retrieving the static term g base (x, y, z) for each of the set of points in the zero level set of the embedding function φ; g. extending the retrieved static term g base (x, y, z) to a narrow band in which the embedding function φ is computed so as to generate an extended term g ext ; h. updating the term g 0 =g 0 g ext so as to update the speed function; i. computing the embedding function φ at iteration (n+1) using the updated speed function; and j. iteratively repeating steps (e)-(i) for a predetermined number of iterations or until the propagating front of the contour does not move, wherein the front of the contour corresponds to the boundary of the organ.