title: GPU accelerated voxel-driven forward projection for iterative reconstruction of cone-beam CT.
abstract: BACKGROUND
  For cone-beam computed tomography (CBCT), which has been playing an important role in clinical applications, iterative reconstruction algorithms are able to provide advantageous image qualities over the classical FDK. However, the computational speed of iterative reconstruction is a notable issue for CBCT, of which the forward projection calculation is one of the most time-consuming components.
  
  
  RESULTS
  In this study, the cone-beam forward projection problem using the voxel-driven model is analysed, and a GPU-based acceleration method for CBCT forward projection is proposed with the method rationale and implementation workflow detailed as well. For method validation and evaluation, computational simulations are performed, and the calculation times of different methods are collected. Compared with the benchmark CPU processing time, the proposed method performs effectively in handling the inter-thread interference problem, and an acceleration ratio as high as more than 100 is achieved compared to a single-threaded CPU implementation.
  
  
  CONCLUSIONS
  The voxel-driven forward projection calculation for CBCT is highly paralleled by the proposed method, and we believe it will serve as a critical module to develop iterative reconstruction and correction methods for CBCT imaging.
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084, China.|Department of Engineering, Macquarie University, Sydney, NSW, 2109, Australia.
authors.forename: Yi
authors.initials: Y
authors.lastname: Du
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084, China.|Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai, 200032, China.
authors.forename: Gongyi
authors.initials: G
authors.lastname: Yu
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084, China.
authors.forename: Xincheng
authors.initials: X
authors.lastname: Xiang
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084, China. wangxiangang@tsinghua.edu.cn.
authors.forename: Xiangang
authors.initials: X
authors.lastname: Wang
mesh_terms: D003196:Computer Graphics; D054893:Cone-Beam Computed Tomography; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D013997:Time Factors
keywords: Cone-beam CT; Forward projection; GPU