RADIOTHERAPEUTIC TREATMENT PLANNING APPARATUS AND METHODS

摘要

A treatment planning apparatus comprises a means for receiving a three dimensional representation of a patient, a means for displaying at least a part of the representation, a means for user-designation of sub-regions of the representation, and a computing means adapted to segment the representation into a region within an anatomical structure and a region outside the anatomical structure on the basis of the locations of the sub-regions and the degree of similarity of voxels to neighbouring voxels in the representation. The treatment planning apparatus preferably further comprises means for designating sub- regions as being inside the structure, means for designating sub-regions as being outside the structure, and/or means for designating sub-regions as being at a border of the structure. In the latter case, we prefer that the size of border sub-regions is adjustable. The computing means can segment the representation by minimising a cost function. We also prefer that the initial values of the function in sub-regions designated as being in a border region are constrained to a different preset value. In an particularly useful aspect of this invention, after minimisation of the function the values in sub-regions designated as being in a border region are then un-constrained, the remaining values are constrained, and the function is then minimised a second time.