title: Dosimetric comparison of left-sided whole breast irradiation with 3DCRT, forward-planned IMRT, inverse-planned IMRT, helical tomotherapy, and topotherapy.
abstract: OBJECTIVE
  To compare left-sided whole breast conventional and intensity-modulated radiotherapy (IMRT) treatment planning techniques.
  
  
  METHODS
  Treatment plans were created for 10 consecutive patients. Three-dimensional conformal radiotherapy (3DCRT), forward-planned IMRT (for-IMRT), and inverse-planned IMRT (inv-IMRT) used two tangent beams. For-IMRT utilized up to four segments per beam. For helical tomotherapy (HT) plans, beamlet entrance and/or exit to critical structures was blocked. Topotherapy plans, which used static gantry angles with simultaneous couch translation and inverse-planned intensity modulation, used two tangent beams. Plans were normalized to 50Gy to 95% of the retracted PTV.
  
  
  RESULTS
  Target max doses were reduced with for-IMRT compared to 3DCRT, which were further reduced with HT, topotherapy, and inv-IMRT. HT resulted in lowest heart and ipsilateral lung max doses, but had higher mean doses. Inv-IMRT and topotherapy reduced ipsilateral lung mean and max doses compared to 3DCRT and for-IMRT.
  
  
  CONCLUSIONS
  All modalities evaluated provide adequate coverage of the intact breast. HT, topotherapy, and inv-IMRT can reduce high doses to the target and normal tissues, although HT results in increased low doses to large volume of normal tissue. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned modalities.
authors.affiliation: Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE, USA. lkschubert@unmc.edu
authors.forename: Leah K
authors.initials: LK
authors.lastname: Schubert
authors.forename: Vinai
authors.initials: V
authors.lastname: Gondi
authors.forename: Evan
authors.initials: E
authors.lastname: Sengbusch
authors.forename: David C
authors.initials: DC
authors.lastname: Westerly
authors.forename: Emilie T
authors.initials: ET
authors.lastname: Soisson
authors.forename: Bhudatt R
authors.initials: BR
authors.lastname: Paliwal
authors.forename: Thomas Rockwell
authors.initials: TR
authors.lastname: Mackie
authors.forename: Minesh P
authors.initials: MP
authors.lastname: Mehta
authors.forename: Rakesh R
authors.initials: RR
authors.lastname: Patel
authors.forename: Wolfgang A
authors.initials: WA
authors.lastname: Tomé
authors.forename: George M
authors.initials: GM
authors.lastname: Cannon
mesh_terms: D001940:Breast / Q000528:radiation effects; D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation / Q000379:methods*