title: Effect of heterogeneity correction on dosimetric parameters of radiotherapy planning for thoracic esophageal cancer.
abstract: The present study aimed to investigate the effect of heterogeneity correction (HC) on dosimetric parameters in 3-dimensional conformal radiotherapy planning for patients with thoracic esophageal cancer. We retrospectively analyzed 20 patients. Two treatment plans were generated for each patient using a superposition algorithm on the Xio radiotherapy planning system. The first plan was calculated without HC. The second was a new plan calculated with HC, using identical beam geometries and maintaining the same number of monitor units as the first. With regard to the planning target volume (PTV), the overall mean differences in the prescription dose, maximum dose, mean dose, and dose that covers 95% of the PTV between the first and second plans were 1.10Gy (1.8%), 1.35Gy (2.2%), 1.10Gy (1.9%), and 0.56Gy (1.0%), respectively. With regard to parameters related to the organs at risk (OARs), the mean differences in the absolute percentages of lung volume receiving greater than 5, 10, 20, and 30Gy (lung V5, V10, V20, and V30) between the first and second plans were 7.1%, 2.7%, 0.4%, and 0.5%, respectively. These results suggest that HC might have a more pronounced effect on the percentages of lung volume receiving lower doses (e.g., V5 and V10) than on the dosimetric parameters related to the PTV and other OARs.
authors.affiliation: Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan. Electronic address: naka2008@med.kobe-u.ac.jp.
authors.forename: Masao
authors.initials: M
authors.lastname: Nakayama
authors.affiliation: Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Nishimura
authors.affiliation: Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Miyawaki
authors.affiliation: Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Uehara
authors.affiliation: Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Okamoto
authors.affiliation: Radiology Department, Kobe University Hospital, Kobe, Hyogo, Japan.
authors.forename: Takanobu
authors.initials: T
authors.lastname: Okayama
authors.affiliation: Division of Radiation Oncology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Sasaki
mesh_terms: D000465:Algorithms; D016477:Artifacts; D004938:Esophageal Neoplasms / Q000532:radiotherapy*; D006801:Humans; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013899:Thoracic Neoplasms / Q000532:radiotherapy*; D016896:Treatment Outcome; D047368:Tumor Burden
keywords: Dosimetric parameter; Esophageal cancer; Heterogeneity correction; Radiotherapy planning