title: [Motion analysis of target during stereotactic radiotherapy of lung tumors using volumetric modulated arc therapy].
abstract: Volumetric modulated arc therapy (VMAT) is a rotational intensity-modulated radiotherapy (IMRT) technique capable of acquiring projection images for cone-beam computed tomography (CBCT). Respiratory-correlated cone-beam computed tomography, namely 4D-CBCT, serves to assess the displacement of a tumor position between planning and treatment due to organ motion and respiration, and is important for more accurate radiation therapy. On the other hand, recently, a 320-detector row CT scanner, namely 4D-CT, has become available that allows axial volumetric scanning of a 16-cm-long range in a patient without table movement. The goal of our research is to establish a new method of verification during treatment in stereotactic body radiotherapy. In this study, we compare the movement of the tumor between "before treatment" using 4D-CT and "in treatment" using 4D-CBCT. Three patients (55-68 years of age) with lung tumors underwent CT scans for radiotherapy planning using 4D-CT scans to analyze the movement of the tumor before treatment. The patients were treated by VMAT while acquiring projection images. 4D-CBCT datasets were reconstructed from the projection images using in-house programs. The tumor positions in 4D-CT and 4D-CBCT were detected and the movement of the tumor between "before treatment" and "in treatment" was similar. The movement of the tumors during treatment was predictable from 4D-CT before treatment. Furthermore, 4D-CBCT clarified the tumor position during treatment and could reevaluate the actual tumor position and dose distribution. We have successfully shown the movement of the tumor between "before treatment" using 4D-CT and "in treatment" using 4D-CBCT.
authors.affiliation: Department of Radiology, University of Tokyo Hospital.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Imae
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shinohara
authors.forename: Kenji
authors.initials: K
authors.lastname: Ino
authors.forename: Yukari
authors.initials: Y
authors.lastname: Okano
authors.forename: Katsutake
authors.initials: K
authors.lastname: Sasaki
authors.forename: Shigeki
authors.initials: S
authors.lastname: Saegusa
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiraki
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yano
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kida
authors.forename: Akihiro
authors.initials: A
authors.lastname: Haga
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Kuni
authors.initials: K
authors.lastname: Ohtomo
mesh_terms: D000368:Aged; D054893:Cone-Beam Computed Tomography; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009038:Motion; D016634:Radiosurgery / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012119:Respiration