title: Dosimetric comparison of intensity-modulated radiotherapy plans, with or without anterior myocardial territory and left ventricle as organs at risk, in early-stage left-sided breast cancer patients.
abstract: OBJECTIVE
  We evaluated heart sparing using an intensity-modulated radiotherapy (IMRT) plan with the left ventricle (LV) and/or the anterior myocardial territory (AMT) as additional organs at risk (OARs).
  
  
  METHODS
  A total of 10 patients with left-sided breast cancer were selected for dosimetric planning. Both lungs, the right breast, heart, LV, and AMT were defined as OARs. We generated one tangential field plan and four IMRT plans for each patient. We examined the dose-volume histogram parameters of the planning target volume and OARs.
  
  
  RESULTS
  Compared with the tangential field plan, the mean dose to the heart in the IMRT plans did not show significant differences; however, the dose to the AMT and LV decreased by 18.7-45.4% and 10.8-37.4%, respectively. The maximal dose to the heart decreased by 18.6-35.3%, to the AMT by 22.0-45.1%, and to the LV by 23.5-45.0%, And the relative volumes of the heart (V≥12), AMT (V>11) and LV (V>10) decreased significantly with different levels, respectively. The volume of the heart, AMT, LV, both lungs, and right breast receiving≥5 Gy showed a significant increase. Compared with the IMRT (H) plan, the mean dose to the heart, AMT, and LV decreased by 17.5-21.5%, 25.2-29.8%, and 22.8-29.8% and the maximal dose by 13.6-20.6%, 23.1-29.6%, and 17.3-29.1%, respectively. The IMRT plans for both lungs and the right breast showed no significant differences.
  
  
  CONCLUSIONS
  The IMRT plans with the addition of the AMT and/or LV as OARs considerably increased heart sparing. We recommend including the LV as an additional OAR in such plans.
authors.affiliation: Key Laboratory of Molecular Biophysics of the Ministry of Education, Huazhong University of Science and Technology College of Life Science and Technology, and Department of Radiotherapy, Hubei Cancer Hospital, Wuhan, People's Republic of China. tanwyym@yahoo.com.cn
authors.forename: Wenyong
authors.initials: W
authors.lastname: Tan
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.forename: Dasheng
authors.initials: D
authors.lastname: Qiu
authors.forename: Dong
authors.initials: D
authors.lastname: Liu
authors.forename: Shaohui
authors.initials: S
authors.lastname: Jia
authors.forename: Fanyu
authors.initials: F
authors.lastname: Zeng
authors.forename: Zhengwang
authors.initials: Z
authors.lastname: Chen
authors.forename: Beihui
authors.initials: B
authors.lastname: Li
authors.forename: Jiaozhen
authors.initials: J
authors.lastname: Xu
authors.forename: Lai
authors.initials: L
authors.lastname: Wei
authors.forename: Desheng
authors.initials: D
authors.lastname: Hu
mesh_terms: D001940:Breast / Q000528:radiation effects; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D017023:Coronary Angiography / Q000379:methods; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging / Q000528:radiation effects*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000528:radiation effects; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000528:radiation effects; D009206:Myocardium; D059351:Organ Sparing Treatments / Q000379:methods; D058958:Organs at Risk / Q000000981:diagnostic imaging / Q000528:radiation effects*; D011832:Radiation Injuries / Q000517:prevention & control*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden / Q000528:radiation effects