1. A digital image data processing system, comprising: at least one data storage device and at least one computer, wherein the at least one data storage device comprises at least one database that is operably coupled to the at least one computer and stores patient image data describing at least two two-dimensional patient images of anatomical body parts of a patient's body, atlas data describing a general structure of at least part of the patient's body comprising correspondence parts corresponding to the anatomical body parts, and correspondence part position data describing the positions of the correspondence parts in the general structure; wherein the at least one computer has at least one processor and at least one memory, wherein a program is running on the at least one processor or loaded into the at least one memory which, when executed by the at least one computer, causes the computer to execute steps of: a) acquiring, at the at least one processor and from the at least one database, the patient image data; b) acquiring, at the at least one processor and from the at least one database, the atlas data; c) acquiring, at the at least one processor and from the at least one database, the correspondence part position data; and d) determining, by the at least one processor and based on the patient image data and the atlas data and the correspondence part position data, virtual image data describing a two-dimensional virtual image of a part of the general structure having a position in the general structure which lies between the positions of the correspondence parts, wherein the virtual image data describes at least two two-dimensional virtual images of the part of the general structure having the position in the general structure which lies between the positions of the correspondence parts, the method further comprising: e) comparing, by the at least one processor, the virtual images with the patient images; and f) determining, by the at least one processor and based on comparing the virtual images with the patient images, which one of the virtual images matches the patient images best, wherein, if it is determined that none of the virtual images matches the patient images within a predetermined degree of accuracy, an imaging transformation comprising at least one of a rotational and a translational positional transformation is applied, by the at least one processor, to the virtual images such that at least one of the virtual images matches the patient images within the predetermined degree of accuracy.