title: [Gated Radiotherapy]
abstract: Recent external radiotherapy requires precise localization of the target because advance in diagnostic imaging has made it possible to visualize a tiny tumor which would be curable with focused high dose irradiation. However, tumors in respiratory and bowel organs have been difficult to be given the high dose because of 1 to 3 cm movement during delivery of irradiation. Respiratory-gating techniques have been used with medical linear accelerators and particle therapy machines. Real-time tumor-tracking radiotherapy has been realized using fluoroscopic x-rays, internal gold-markers, and pattern recognition technology. Advantage and disadvantage of each gating technique have been realized. Active breath control method would be a cost-effective way of precise treatment without gating. More work is required to find the relationship between abdominal wall and internal movement of the tumor in many respiratory-gating radiotherapy and between the internal markers and target volume in real-time tracking radiotherapy.
authors.affiliation: Department of Radiology, Hokkaido University Hospital.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shirato
authors.forename: Rikiya
authors.initials: R
authors.lastname: Onimaru
authors.forename: Kei
authors.initials: K
authors.lastname: Kitamura
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Teruo
authors.initials: T
authors.lastname: Furuya
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Fujita
authors.forename: Junya
authors.initials: J
authors.lastname: Nangumo
authors.forename: Makoto
authors.initials: M
authors.lastname: Oda
authors.forename: Masataka
authors.initials: M
authors.lastname: Oita