title: Real-time motion compensated patient positioning and non-rigid deformation estimation using 4-D shape priors.
abstract: Over the last years, range imaging (RI) techniques have been proposed for patient positioning and respiration analysis in motion compensation. Yet, current RI based approaches for patient positioning employ rigid-body transformations, thus neglecting free-form deformations induced by respiratory motion. Furthermore, RI based respiration analysis relies on non-rigid registration techniques with run-times of several seconds. In this paper we propose a real-time framework based on RI to perform respiratory motion compensated positioning and non-rigid surface deformation estimation in a joint manner. The core of our method are pre-procedurally obtained 4-D shape priors that drive the intra-procedural alignment of the patient to the reference state, simultaneously yielding a rigid-body table transformation and a free-form deformation accounting for respiratory motion. We show that our method outperforms conventional alignment strategies by a factor of 3.0 and 2.3 in the rotation and translation accuracy, respectively. Using a GPU based implementation, we achieve run-times of 40 ms.
authors.affiliation: Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany. jakob.wasza@cs.fau.de
authors.forename: Jakob
authors.initials: J
authors.lastname: Wasza
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bauer
authors.forename: Joachim
authors.initials: J
authors.lastname: Hornegger
mesh_terms: D000465:Algorithms; D003199:Computer Systems; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D056888:Patient Positioning / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013902:Radiography, Thoracic / Q000379:methods*; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*