A method and system for segmenting three-dimensional (3D) medical images containing an object of interest are provided. The method comprises generating a plurality of successive layers of fixed radius spheres about a circumference of a sphere containing at least one seed point placed within the object of interest when a plurality of respective voxels contained within the spheres exceed a selected threshold. The generation of the layers is repeated until no further voxels contained within an outer surface of each respective layer exceed the selected threshold or a stop seed point is encountered. The layers form a segmented representation of the object of interest.