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Technical note: A novel boundary condition using contact elements for finite element based deformable image registration
Author(s) -
Zhang Tiezhi,
Orton Nigel P.,
Mackie T. Rockwell,
Paliwal Bhudatt R.
Publication year - 2004
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1774131
Subject(s) - image registration , finite element method , boundary (topology) , medical imaging , computer vision , image processing , image (mathematics) , computer science , mathematics , medical physics , artificial intelligence , mathematical analysis , physics , thermodynamics
Deformable image registration is an important tool for image‐guided radiotherapy. Physics‐model‐based deformable image registration using finite element analysis is one of the methods currently being investigated. The calculation accuracy of finite element analysis is dependent on given boundary conditions, which are usually based on the surface matching of the organ in two images. Such a surface matching, however, is hard to obtain from medical images. In this study, we developed a new boundary condition to circumvent the traditional difficulties. Finite element contact‐impact analysis was employed to simulate the interaction between the organ of interest and the surrounding body. The displacement loading is not necessarily specified. The algorithm automatically deforms the organ model into the minimum internal energy state. The analysis was performed on CT images of the lung at two different breathing phases (exhalation and full inhalation). The result gave the displacement vector map inside the lung. Validation of the result showed satisfactory agreement in most parts of the lung. This approach is simple, operator independent and may provide improved accuracy of the prediction of organ deformation.