title: Dosimetric differences in flattened and flattening filter-free beam treatment plans.
abstract: This study investigated the dosimetric differences in treatment plans from flattened and flattening filter-free (FFF) beams from the TrueBeam System. A total of 104 treatment plans with static (sliding window) intensity-modulated radiotherapy beams and volumetric-modulated arc therapy (VMAT) beams were generated for 15 patients involving three cancer sites. In general, the FFF beam provides similar target coverage as the flattened beam with improved dose sparing to organ-at-risk (OAR). Among all three cancer sites, the head and neck showed more important differences between the flattened beam and FFF beam. The maximum reduction of the FFF beam in the mean dose reached up to 2.82 Gy for larynx in head and neck case. Compared to the 6 MV flattened beam, the 10 MV FFF beam provided improved dose sparing to certain OARs, especially for VMAT cases. Thus, 10 MV FFF beam could be used to improve the treatment plan.
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, USA; Department of Human Oncology, University of Wisconsin, Madison, USA.
authors.forename: Yue
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Department of Human Oncology, University of Wisconsin, Madison, USA; Riverview Cancer Center, University of Wisconsin, Wisconsin Rapids, Wisconsin, USA.
authors.forename: Poonam
authors.initials: P
authors.lastname: Yadav
authors.affiliation: Riverview Cancer Center, University of Wisconsin, Wisconsin Rapids, Wisconsin, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Bassetti
authors.affiliation: Riverview Cancer Center, University of Wisconsin, Wisconsin Rapids, Wisconsin, USA.
authors.forename: Kaifang
authors.initials: K
authors.lastname: Du
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, USA; Department of Human Oncology, University of Wisconsin, Madison, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Saenz
authors.affiliation: Riverview Cancer Center, University of Wisconsin, Wisconsin Rapids, Wisconsin, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Harari
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, USA; Department of Human Oncology, University of Wisconsin, Madison, USA.
authors.forename: Bhudatt R
authors.initials: BR
authors.lastname: Paliwal
keywords: Flattening filter-free beam; intensity-modulated radiotherapy; treatment plan