title: A novel 3D volumetric voxel registration technique for volume-view-guided image registration of multiple imaging modalities.
abstract: OBJECTIVE
  To provide more clinically useful image registration with improved accuracy and reduced time, a novel technique of three-dimensional (3D) volumetric voxel registration of multimodality images is developed.
  
  
  METHODS
  This technique can register up to four concurrent images from multi-modalities with volume view guidance. Various visualization effects can be applied, facilitating global and internal voxel registration. Fourteen computed tomography/magnetic resonance (CT/MR) image sets and two computed tomography/positron emission tomography (CT/PET) image sets are used. For comparison, an automatic registration technique using maximization of mutual information (MMI) and a three-orthogonal-planar (3P) registration technique are used.
  
  
  RESULTS
  Visually sensitive registration criteria for CT/MR and CT/PET have been established, including the homogeneity of color distribution. Based on the registration results of 14 CT/MR images, the 3D voxel technique is in excellent agreement with the automatic MMI technique and is indicatory of a global positioning error (defined as the means and standard deviations of the error distribution) using the 3P pixel technique: 1.8 degrees +/- 1.2 degrees in rotation and 2.0 +/- 1.3 (voxel unit) in translation. To the best of our knowledge, this is the first time that such positioning error has been addressed.
  
  
  CONCLUSIONS
  This novel 3D voxel technique establishes volume-view-guided image registration of up to four modalities. It improves registration accuracy with reduced time, compared with the 3P pixel technique. This article suggests that any interactive and automatic registration should be safe-guarded using the 3D voxel technique.
authors: Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. ligeorge@mail.nih.gov
authors: Guang
authors: G
authors: Li
authors: Huchen
authors: H
authors: Xie
authors: Holly
authors: H
authors: Ning
authors: Jacek
authors: J
authors: Capala
authors: Barbara C
authors: BC
authors: Arora
authors: C Norman
authors: CN
authors: Coleman
authors: Kevin
authors: K
authors: Camphausen
authors: Robert W
authors: RW
authors: Miller
mesh_terms: D000465:Algorithms; D006257:Head / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D049268:Positron-Emission Tomography; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D013679:Technology, Radiologic / Q000379:methods*; D014057:Tomography, X-Ray Computed