Method and device for 3D navigation on slices

The invention relates to an apparatus and a method for the preparation of 2-D slice images of internal structures. The invention enables the 3-D representation of the physical dimension of a tool in the 2-D slice images of internal structures and the representation of changes in the internal structures, in particular of bone structures, by an operation tool in preparation for, conducting, recording, reproduction, follow-up or to learn a surgical procedure.