title: Intensity modulated radiation therapy (IMRT) reduces the dose to the contralateral breast when compared to conventional tangential fields for primary breast irradiation.
abstract: OBJECTIVE
  To determine the dose received by the contralateral breast during primary breast irradiation using IMRT compared to conventional tangential field techniques.
  
  
  METHODS
  Between March 2003 and March 2004, 83 patients with breast carcinoma were treated using 6, 10, or mixed 6/18 MV photons (65 with tangential IMRT technique and 18 with 3-dimensional technique using tangential fields with wedges) for primary breast irradiation following breast-conserving surgery. Paired thermoluminescent dosimeters (TLDs) were placed on each patient's contralateral breast, 4 and 8 cm from the center of the medial border of the tangential field. The TLDs were left on the patient during a single fraction and then measured 24 h afterwards.
  
  
  RESULTS
  The mean dose delivered with photons to the primary breast for all patients was 4999 cGy (SD = 52) with a mean single fraction dose of 199 cGy (SD = 8). The mean percent of the prescribed dose to the contralateral breast measured at the 4- and 8-cm positions were 7.19% (SD = 2.28) and 4.63% (SD = 2.12), respectively, for patients treated with IMRT compared to 11.22% (SD = 2.73) and 10.70% (SD = 3.44), respectively, for the patients treated with conventional tangential field techniques. This represented a 36% and 57% reduction at the 4 and 8-cm contralateral positions, respectively, in the mean dose to the contralateral breast using IMRT compared to 3-D technique which was statistically significant (p < 0.0005, <0.0005, respectively).
  
  
  CONCLUSIONS
  Primary breast irradiation with tangential IMRT technique significantly reduces the dose to the contralateral breast compared to conventional tangential field techniques.
authors.affiliation: Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA,
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Bhatnagar
authors.forename: Edward
authors.initials: E
authors.lastname: Brandner
authors.forename: Deborah
authors.initials: D
authors.lastname: Sonnik
authors.forename: Andrew
authors.initials: A
authors.lastname: Wu
authors.forename: Shalom
authors.initials: S
authors.lastname: Kalnicki
authors.forename: Melvin
authors.initials: M
authors.lastname: Deutsch
authors.forename: Dwight E
authors.initials: DE
authors.lastname: Heron
mesh_terms: D001940:Breast / Q000528:radiation effects; D001943:Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D009381:Neoplasms, Radiation-Induced / Q000517:prevention & control*; D016609:Neoplasms, Second Primary / Q000517:prevention & control*; D011446:Prospective Studies; D011874:Radiometry; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed