title: A treatment-planning comparison of three beam arrangement strategies for stereotactic body radiation therapy for centrally located lung tumors using volumetric-modulated arc therapy.
abstract: The purpose of this study was to determine appropriate beam arrangement for volumetric-modulated arc therapy (VMAT)-based stereotactic body radiation therapy (SBRT) in the treatment of patients with centrally located lung tumors. Fifteen consecutive patients with centrally located lung tumors treated at our institution were enrolled. For each patient, three VMAT plans were generated using two coplanar partial arcs (CP VMAT), two non-coplanar partial arcs (NCP VMAT), and one coplanar full arc (Full VMAT). All plans were designed to deliver 70 Gy in 10 fractions. Target coverage and sparing of organs at risk (OARs) were compared across techniques. PTV coverage was almost identical for all approaches. The whole lung V10Gy was significantly lower with CP VMAT plans than with NCP VMAT plans, whereas no significant differences in the mean lung dose, V5Gy, V20Gy or V40Gy were observed. Full VMAT increased mean contralateral lung V5Gy by 12.57% and 9.15% when compared with NCP VMAT and CP VMAT, respectively. Although NCP VMAT plans best achieved the dose-volume constraints for mediastinal OARs, the absolute differences in dose were small when compared with CP VMAT. These results suggest that partial-arc VMAT may be preferable to minimize unnecessary exposure to the contralateral lung, and use of NCP VMAT should be considered when the dose-volume constraints are not achieved by CP VMAT.
authors.affiliation: Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka, 550-0025, Japan ishii@tane.or.jp.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Ishii
authors.affiliation: Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka, 550-0025, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Okada
authors.affiliation: Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka, 550-0025, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ogino
authors.affiliation: Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka, 550-0025, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kubo
authors.affiliation: Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka, 550-0025, Japan.
authors.forename: Shun
authors.initials: S
authors.lastname: Kishimoto
authors.affiliation: Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka, 550-0025, Japan.
authors.forename: Ryuta
authors.initials: R
authors.lastname: Nakahara
authors.affiliation: Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka, 550-0025, Japan.
authors.forename: Ryu
authors.initials: R
authors.lastname: Kawamorita
authors.affiliation: Department of Radiation Oncology, Yodogawa Christian Hospital, 1-7-50 Kunijima, Higashiyodogawa-ku, Osaka, 533-0024, Japan.
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Ishii
authors.affiliation: Department of Radiology, Izumi Municipal Hospital, 4-10-10 Futyu-cho, Izumi, 594-0071, Japan.
authors.forename: Takuhito
authors.initials: T
authors.lastname: Tada
authors.affiliation: Department of Radiation Oncology, Tane General Hospital, 1-12-21 Kujo-minami, Nishi-ku, Osaka, 550-0025, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Nakajima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D014057:Tomography, X-Ray Computed
keywords: lung tumor; planning study; stereotactic body radiation therapy; volumetric-modulated arc therapy