title: Improving target coverage and organ-at-risk sparing in intensity-modulated radiotherapy for cervical oesophageal cancer using a simple optimisation method.
abstract: OBJECTIVE
  To assess the performance of a simple optimisation method for improving target coverage and organ-at-risk (OAR) sparing in intensity-modulated radiotherapy (IMRT) for cervical oesophageal cancer.
  
  
  METHODS
  For 20 selected patients, clinically acceptable original IMRT plans (Original plans) were created, and two optimisation methods were adopted to improve the plans: 1) a base dose function (BDF)-based method, in which the treatment plans were re-optimised based on the original plans, and 2) a dose-controlling structure (DCS)-based method, in which the original plans were re-optimised by assigning additional constraints for hot and cold spots. The Original, BDF-based and DCS-based plans were compared with regard to target dose homogeneity, conformity, OAR sparing, planning time and monitor units (MUs). Dosimetric verifications were performed and delivery times were recorded for the BDF-based and DCS-based plans.
  
  
  RESULTS
  The BDF-based plans provided significantly superior dose homogeneity and conformity compared with both the DCS-based and Original plans. The BDF-based method further reduced the doses delivered to the OARs by approximately 1-3%. The re-optimisation time was reduced by approximately 28%, but the MUs and delivery time were slightly increased. All verification tests were passed and no significant differences were found.
  
  
  CONCLUSIONS
  The BDF-based method for the optimisation of IMRT for cervical oesophageal cancer can achieve significantly better dose distributions with better planning efficiency at the expense of slightly more MUs.
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, China.
authors.forename: Jia-Yang
authors.initials: JY
authors.lastname: Lu
authors.affiliation: Department of Clinical Oncology, Prince of Wales Hospital, Shatin, Hong Kong, China.
authors.forename: Michael Lok-Man
authors.initials: ML
authors.lastname: Cheung
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, China.
authors.forename: Bao-Tian
authors.initials: BT
authors.lastname: Huang
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, China.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Wu
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, China.
authors.forename: Wen-Jia
authors.initials: WJ
authors.lastname: Xie
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, China.
authors.forename: Zhi-Jian
authors.initials: ZJ
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, China.
authors.forename: De-Rui
authors.initials: DR
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, China.
authors.forename: Liang-Xi
authors.initials: LX
authors.lastname: Xie
mesh_terms: D000328:Adult; D000368:Aged; D004938:Esophageal Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000528:radiation effects*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012189:Retrospective Studies