title: Helical tomotherapy for locoregional irradiation including the internal mammary chain in left-sided breast cancer: dosimetric evaluation.
abstract: OBJECTIVE
  To compare a standard 3- or 4-field technique to intensity modulated radiotherapy with helical tomotherapy (IMRT-HT) in the planning of locoregional breast radiation including the internal mammary chain (IMC).
  
  
  METHODS
  For 10 women with stage III left-sided breast cancer with a planning target volume (PTV) defined by the breast/chest wall and regional nodes, radiotherapy to a dose of 50 Gy in 25 fractions was planned using a standard 3- or 4-field technique and using IMRT-HT. Various metrics were extracted from dose-volume histograms, and were compared using the paired Student's t-test.
  
  
  RESULTS
  The PTV receiving at least 95% of the prescribed dose did not differ between the two plans, but the VD115% was significantly lower with IMRT-HT. The dose conformality was significantly better with IMRT-HT. The cardiac V30(Gy) was reduced with IMRT-HT. The mean lungs dose was lower with IMRT-HT, as well the V20(Gy). With IMRT-HT, a greater volume of contralateral breast was irradiated to 5 Gy, but a smaller volume of soft tissue received dose above 50 Gy.
  
  
  CONCLUSIONS
  Compared to a standard technique, IMRT-HT provides similar target coverage, improves dose conformality and dose homogeneity within the PTV, decreases mean lung dose and spares heart, lung and soft tissue from high dose exposure.
authors.affiliation: Department of Radiation Oncology, The Ottawa Hospital Cancer Centre, Ont., Canada. jcaudrelier@ottawahospital.on.ca
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Caudrelier
authors.forename: Scott C
authors.initials: SC
authors.lastname: Morgan
authors.forename: Lynn
authors.initials: L
authors.lastname: Montgomery
authors.forename: Manon
authors.initials: M
authors.lastname: Lacelle
authors.forename: Balazs
authors.initials: B
authors.lastname: Nyiri
authors.forename: Miller
authors.initials: M
authors.lastname: Macpherson
mesh_terms: D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000528:radiation effects*; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D011881:Radiotherapy, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D016896:Treatment Outcome