title: [Accurate 3D free-form registration between fan-beam CT and cone-beam CT].
abstract: Because the X-ray scatters, the CT numbers in cone-beam CT cannot exactly correspond to the electron densities. This, therefore, results in registration error when the intensity-based registration algorithm is used to register planning fan-beam CT and cone-beam CT. In order to reduce the registration error, we have developed an accurate gradient-based registration algorithm. The gradient-based deformable registration problem is described as a minimization of energy functional. Through the calculus of variations and Gauss-Seidel finite difference method, we derived the iterative formula of the deformable registration. The algorithm was implemented by GPU through OpenCL framework, with which the registration time was greatly reduced. Our experimental results showed that the proposed gradient-based registration algorithm could register more accurately the clinical cone-beam CT and fan-beam CT images compared with the intensity-based algorithm. The GPU-accelerated algorithm meets the real-time requirement in the online adaptive radiotherapy.
authors: School of Automation, University of Electronic Science and Technology of China, Chengdu 611731, China.
authors: Yueqiang
authors: Y
authors: Liang
authors: Hongbing
authors: H
authors: Xu
authors: Baosheng
authors: B
authors: Li
authors: Hongsheng
authors: H
authors: Li
authors: Fujun
authors: F
authors: Yang
mesh_terms: D000465:Algorithms; D016477:Artifacts; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D061089:Radiotherapy, Image-Guided / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods*