title: Treatment planning of a skin-sparing conical breast brachytherapy applicator using conventional brachytherapy software.
abstract: OBJECTIVE
  AccuBoost is a noninvasive image-guided technique for the delivery of partial breast irradiation to the tumor bed and currently serves as an alternate to conventional electron beam boost. To irradiate the target volume while providing dose sparing to the skin, the round applicator design was augmented through the addition of an internally truncated conical shield and the reduction of the source to skin distance.
  
  
  METHODS
  Brachytherapy dose distributions for two types of conical applicators were simulated and estimated using Monte Carlo (MC) methods for radiation transport and a conventional treatment planning system (TPS). MC-derived and TPS-generated dose volume histograms (DVHs) and dose distribution data were compared for both the conical and round applicators for benchmarking purposes.
  
  
  RESULTS
  Agreement using the gamma-index test was > or = 99.95% for distance to agreement and dose accuracy criteria of 2 mm and 2%, respectively. After observing good agreement, TPS DVHs and dose distributions for the conical and round applicators were obtained and compared. Brachytherapy dose distributions generated using Pinnacle for ten CT data sets showed that the parallel-opposed beams of the conical applicators provided similar PTV coverage to the round applicators and reduced the maximum dose to skin, chest wall, and lung by up to 27%, 42%, and 43%, respectively.
  
  
  CONCLUSIONS
  Brachytherapy dose distributions for the conical applicators have been generated using MC methods and entered into the Pinnacle TPS via the Tufts technique. Treatment planning metrics for the conical AccuBoost applicators were significantly improved in comparison to those for conventional electron beam breast boost.
authors.affiliation: Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Yang
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Melhus
authors.forename: Shirin
authors.initials: S
authors.lastname: Sioshansi
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Rivard
mesh_terms: D019985:Benchmarking; D001918:Brachytherapy / Q000295:instrumentation*; D001943:Breast Neoplasms / Q000532:radiotherapy*; D009010:Monte Carlo Method; D058958:Organs at Risk / Q000528:radiation effects*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D012867:Skin / Q000528:radiation effects*; D012984:Software