Abstract: A process for preparing digital images for realising a biomorphic multicompartmental phantom, includes a phase A.1 of acquisition of images of the organ belonging to the analysed living being, forming a volumetric image defined by voxels, a phase A.2 of identification of tissues and/or tissue liquids and a phase B of selection of at least three tissues and/or tissue liquids, a phase C.1 for verifying the adjacency of the voxels belonging to each single tissue or tissue liquid, a phase C.3 for preparing an image presenting the surfaces of the volumes defined in phase C.1 according to a sub-phase C.3.2 which determines a number of surfaces equal to the number of tissues, and a phase C.3.3 which assigns a thickness to the surfaces.