title: [Motion analysis of target in stereotactic radiotherapy of lung tumors using 320-row multidetector CT].
abstract: Multi-detector computed tomography (MDCT) has rapidly evolved and is increasingly used for treatment simulation of thoracic and abdominal radiotherapy. A 320-detector row CT scanner has recently become available that allows axial volumetric scanning of a 16-cm-long range in a patient without table movement. Current radiotherapy techniques require a generous margin around the presumed gross tumor volume (GTV) to account for uncertainties such as tumor motion and set up error. Motion analysis is useful to evaluate the internal margin of a moving target due to respiration and to improve therapeutic precision. The purpose of this study is to propose a method using phase-only correlation to automatically detect the target and to assess the motion of the target in numerical phantoms and patients. Free-breathing scans using 320-detector row CT were acquired for 4 patients with lung tumor(s). The proposed method was feasible for motion analysis of all numerical phantoms and patients. The results reproduced the facts that the motion of tumors in the patients varied in orbits during the respiratory cycle and exhibited hysteresis. The maximum distance between peak exhalation and inhalation increased as the tumors approached the diaphragm. The proposed method detected the three-dimensional position of the targets automatically and analyzed the trajectories. The tumor motion due to respiration differed by region and was greatest for the lower lobe.
authors.affiliation: Department of Radiology, University of Tokyo Hospital.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Imae
authors.forename: Akihiro
authors.initials: A
authors.lastname: Haga
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Ino
authors.forename: Kenichirou
authors.initials: K
authors.lastname: Tanaka
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: Takashi
authors.initials: T
authors.lastname: Oritate
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yano
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shinohara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009038:Motion; D019047:Phantoms, Imaging; D016634:Radiosurgery; D012119:Respiration; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods*