title: [Development of stereotactic irradiation system of body tumors under respiratory gating].
abstract: Stereotactic radiosurgery for body tumors is hampered by the difficulties in body fixation and respiratory motions of the tumor. We have developed a Microton-based system for the stereotactic irradiation of body tumors, which delivers radiation at a predetermined respiratory phase. The patients are fixed non-invasively in the custom-made bed, and CT images are obtained. The isocentor is calculated with reference to those images and is marked onto the patient's skin and the custom-made bed. The patient lying on the bed is transferred to the treatment couch of the Microtoron. After reproducing the isocenter, actual treatment is started. The treatment couch as well as the gantry move automatically around the isocenter according to the treatment planning. The circular collimator moves by computer control to reduce geometrical errors to less than 0.5 mm, which is evoked by gantry movement. Respiratory movement of the abdominal wall is measured by laser displacement monitor. The Microtron delivers X-rays at a predetermined respiratory phase with a lag time of 20 msec after the on-signal from the monitor.
authors.affiliation: Department of Radiation Therapy and Oncology, International Medical Center of Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Hara
authors.forename: Jun
authors.initials: J
authors.lastname: Itami
authors.forename: Takashi
authors.initials: T
authors.lastname: Aruga
authors.forename: Takuyo
authors.initials: T
authors.lastname: Kozuka
authors.forename: Hideomi
authors.initials: H
authors.lastname: Yamashita
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Abe
authors.forename: Masashi
authors.initials: M
authors.lastname: Fuse
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kondo
authors.forename: Dai
authors.initials: D
authors.lastname: Shinohara
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nagaoka
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kobiki
mesh_terms: D006801:Humans; D009369:Neoplasms / Q000601:surgery*; D016634:Radiosurgery / Q000295:instrumentation* / Q000379:methods; D012119:Respiration