title: Effect of daily setup errors on individual dose distribution in conventional radiotherapy: an initial study.
abstract: Recent linear accelerators can perform cone-beam computed tomography to correct setup errors immediately before dose delivery. We calculated the dose distribution with setup errors acquired from cone-beam computed tomography to determine a more realistic and individual effect of setup errors. The differences in dose distribution were analyzed. The setup errors of three patients who were irradiated in the neck, esophagus, and pelvic area were obtained retrospectively. We found that the maximum dose variances for the three cases were 19.9-35.9%. The maximum dose variance points were relatively far from the isocenter. The volume of the 10% dose difference had widths of 1.3-1.85 cm around the beam edges. The V95 and mean doses at the clinical target volume were mostly unchanged. Doses around the beam edges were more varied than those around the isocenter for every case. The dose on the spinal cord located near the beam edges varied by 5-10% compared with the dose of the radiotherapy plan in two of the cases. We demonstrated the individual dose distributions of the cases affected by daily setup errors for all fractions.
authors.affiliation: Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kodatsuno, Kanazawa, Japan. at@mhs.mp.kanazawa-u.ac.jp
authors.forename: Akihiro
authors.initials: A
authors.lastname: Takemura
authors.forename: Saori
authors.initials: S
authors.lastname: Shoji
authors.forename: Sinichi
authors.initials: S
authors.lastname: Ueda
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kurata
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Kumano
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Takamatsu
authors.forename: Masayuki
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D000368:Aged; D054893:Cone-Beam Computed Tomography; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D019300:Medical Errors; D008875:Middle Aged; D009369:Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy; D012189:Retrospective Studies; D013997:Time Factors
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