title: Assessing residual motion for gated proton-beam radiotherapy.
abstract: Gated radiation therapy is a promising method for improving the dose conformality of treatments to moving targets and reducing the total volume of irradiated tissue. Target motion is of particular concern in proton beam radiotherapy, due to the finite range of proton dose deposition in tissue. Gating allows one to reduce the extent of variation, due to respiration, of the radiological depth to target during treatment delivery. However, respiratory surrogates typically used for gating do not always accurately reflect the position of the internal target. For instance, a phase delay often exists between the internal motion and the motion of the surrogate. Another phenomenon, baseline drifting refers to a gradual change in the exhale position over time, which generally affects the external and internal markers differently. This study examines the influence of these two physiological phenomena on gated radiotherapy using an external surrogate.
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital.
authors.forename: Gregory C
authors.initials: GC
authors.lastname: Sharp
authors.forename: Hsiao Ming
authors.initials: HM
authors.lastname: Lu
authors.forename: Alexei
authors.initials: A
authors.lastname: Trofimov
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Tang
authors.forename: Steve B
authors.initials: SB
authors.lastname: Jiang
authors.forename: Julie
authors.initials: J
authors.lastname: Turcotte
authors.forename: David P
authors.initials: DP
authors.lastname: Gierga
authors.forename: George T Y
authors.initials: GT
authors.lastname: Chen
authors.forename: Theodore S
authors.initials: TS
authors.lastname: Hong
mesh_terms: D006801:Humans; D009038:Motion; D009068:Movement; D011522:Protons; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012119:Respiration
chemical_list: D011522:Protons