3D Atlas Building in the Context of Head and Neck Radiotherapy Based on Dense Deformation Fields

In this paper we present a methodology to build a computational anatomical atlas based on the analysis of dense deformation fields recovered by the Morphons non-rigid registration algorithm. The anatomical atlas construction procedure is based on the minimization of the effort required to register the whole database to a reference. The suitability of our method is demonstrated for atlas construction of the head and neck anatomy. In this application, CT is the most frequently used modality for the segmentation of organs at risk and clinical target volume. One challenge brought by the use of CT images is the presence of important artefacts caused by dental implants. Such artefacts make the use of most atlas building techniques described in the literature impracticable in this context. The results have shown that our model is faithful for representing the shape variability presented in human nature with the advantage that our anatomical atlas does not have any degree of smoothness.