title: Dosimetric and delivery characterizations of full-arc and half-arc volumetric-modulated arc therapy for maxillary cancer.
abstract: We compared the efficiency and accuracy of full-arc and half-arc volumetric-modulated arc therapy (VMAT) delivery for maxillary cancer. Plans for gantry rotation angles of 360° and 180° (full-arc and half-arc VMAT) were created for six maxillary cancer cases with the Monaco treatment planning system, and delivered using an Elekta Synergy linear accelerator. Full-arc and half-arc VMAT were compared with regard to homogeneity index (HI), conformity index (CI), mean dose to normal brain, total monitor units (MU), delivery times, root mean square (r.m.s.) gantry accelerations (°/s(2)), and r.m.s. gantry angle errors (°). The half-arc VMAT plans achieved comparable HI and CI to the full-arc plans. Mean doses to the normal brain and brainstem with the half-arc VMAT plans were on average 16% and 17% lower than those with the full-arc VMAT plans. For other organs at risk (OARs), no significant DVH differences were observed between plans. Half-arc VMAT resulted in 11% less total MU and 20% shorter delivery time than the full-arc VMAT, while r.m.s. gantry acceleration and r.m.s. gantry angle error during half-arc VMAT delivery were 30% and 23% less than those during full-arc VMAT delivery, respectively. Furthermore, the half-arc VMAT plans were comparable with the full-arc plans regarding dose homogeneity and conformity in maxillary cancer, and provided a statistical decrease in mean dose to OAR, total MU, delivery time and gantry angle error. Half-arc VMAT plans may be a suitable treatment option in radiotherapy for maxillary cancer.
authors: Hyogo College of Medicine, Department of Radiology, Nishinomiya, 1-1, Mukogawa-cho, Nishinomiya City, Hyogo 663-8501 Japan. hide-miura@osaka-igrt.or.jp
authors: Hideharu
authors: H
authors: Miura
authors: Masayuki
authors: M
authors: Fujiwara
authors: Masao
authors: M
authors: Tanooka
authors: Hiroshi
authors: H
authors: Doi
authors: Hiroyuki
authors: H
authors: Inoue
authors: Yasuhiro
authors: Y
authors: Takada
authors: Norihiko
authors: N
authors: Kamikonya
authors: Shozo
authors: S
authors: Hirota
mesh_terms: D001921:Brain / Q000528:radiation effects; D001933:Brain Stem / Q000528:radiation effects; D006801:Humans; D008441:Maxillary Neoplasms / Q000532:radiotherapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*