title: [Development of the image registration program for portal and DRR images in radiation therapy].
abstract: In this article, the authors propose an image registration program of portal images and digitally reconstructed radiography (DRR) images used as simulation images for external beam radiation therapy planning. First, the center of the radiation field in a portal image taken using a computed radiograhy cassette is matched to the center of the portal image. Then scale points projected on a DRR image and the portal image are deleted, and the portal image with the radiation field is extracted. Registration of the DRR and portal images is performed using mutual information as the registration criterion. It was found that the absolute displacement misregistrations in two directions (x, y) were 1.2 +/- 0.7mm and 0.5 +/- 0.3 mm, respectively, and rotation disagreement about the z axis 0.3 +/- 0.3 degrees. It was concluded the proposed method was applicable to image registration of portal and DRR images in radiation therapy.
authors.affiliation: Department of Radiology, Showa University Northern Yokohama Hospital, Kanagawa, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Watanabe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ito
authors.forename: Kazuma
authors.initials: K
authors.lastname: Nakazeko
authors.forename: Atsuhi
authors.initials: A
authors.lastname: Tachibana
authors.forename: Takeyuki
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shinohara
mesh_terms: D003198:Computer Simulation; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D010315:Particle Accelerators / Q000295:instrumentation; D019047:Phantoms, Imaging; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D012985:Software Design; D014057:Tomography, X-Ray Computed / Q000379:methods*