title: Tomotherapy and multifield intensity-modulated radiotherapy planning reduce cardiac doses in left-sided breast cancer patients with unfavorable cardiac anatomy.
abstract: OBJECTIVE
  For patients with left-sided breast cancers, radiation treatment to the intact breast results in high doses to significant volumes of the heart, increasing the risk of cardiac morbidity, particularly in women with unfavorable cardiac anatomy. We compare helical tomotherapy (TOMO) and inverse planned intensity modulated radiation therapy (IMRT) with three-dimensional conformal radiotherapy using opposed tangents (3D-CRT) for reductions in cardiac volumes receiving high doses.
  
  
  METHODS
  Fifteen patients with left-sided breast cancers and unfavorable cardiac anatomy, determined by a maximum heart depth (MHD) of >or=1.0 cm within the tangent fields, were planned for TOMO and IMRT with five to seven beam angles, in addition to 3D-CRT. The volumes of heart and left ventricle receiving >or=35 Gy (V35) were compared for the plans, as were the mean doses to the contralateral breast and the volume receiving >or=20 Gy (V20) for the ipsilateral lung.
  
  
  RESULTS
  The mean MHD was 1.7 cm, and a significant correlation was observed between MHD and both heart and left ventricle V35. The V35s for IMRT (0.7%) and TOMO (0.5%) were significantly lower than for 3D-CRT (3.6%). The V20 for IMRT (22%) was significantly higher than for 3D-CRT (15%) or TOMO (18%), but the contralateral breast mean dose for TOMO (2.48 Gy) was significantly higher than for 3D-CRT (0.93 Gy) or IMRT (1.38 Gy).
  
  
  CONCLUSIONS
  Both TOMO and IMRT can significantly reduce cardiac doses, with modest increases in dose to other tissues in left-sided breast cancer patients with unfavorable cardiac anatomy.
authors.affiliation: Department of Radiation Oncology, Rush University Medical Center, Chicago, IL 60612, USA. Alan_Coon@rush.edu
authors.forename: Alan B
authors.initials: AB
authors.lastname: Coon
authors.forename: Adam
authors.initials: A
authors.lastname: Dickler
authors.forename: Michael C
authors.initials: MC
authors.lastname: Kirk
authors.forename: Yixiang
authors.initials: Y
authors.lastname: Liao
authors.forename: Anand P
authors.initials: AP
authors.lastname: Shah
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Strauss
authors.forename: Sea
authors.initials: S
authors.lastname: Chen
authors.forename: Julius
authors.initials: J
authors.lastname: Turian
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Griem
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D006321:Heart / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000528:radiation effects*; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000528:radiation effects; D006801:Humans; D011832:Radiation Injuries / Q000517:prevention & control*; D011859:Radiography; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*