title: Establishing the impact of temporary tissue expanders on electron and photon beam dose distributions.
abstract: OBJECTIVE
  This study investigates the effects of temporary tissue expanders (TTEs) on the dose distributions in breast cancer radiotherapy treatments under a variety of conditions.
  
  
  METHODS
  Using EBT2 radiochromic film, both electron and photon beam dose distribution measurements were made for different phantoms, and beam geometries. This was done to establish a more comprehensive understanding of the implant's perturbation effects under a wider variety of conditions.
  
  
  RESULTS
  The magnetic disk present in a tissue expander causes a dose reduction of approximately 20% in a photon tangent treatment and 56% in electron boost fields immediately downstream of the implant. The effects of the silicon elastomer are also much more apparent in an electron beam than a photon beam.
  
  
  CONCLUSIONS
  Evidently, each component of the TTE attenuates the radiation beam to different degrees. This study has demonstrated that the accuracy of photon and electron treatments of post-mastectomy patients is influenced by the presence of a tissue expander for various beam orientations. The impact of TTEs on dose distributions establishes the importance of an accurately modelled high-density implant in the treatment planning system for post-mastectomy patients.
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia. Electronic address: a.asena@qut.edu.au.
authors.forename: A
authors.initials: A
authors.lastname: Asena
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia; Genesis CancerCare Queensland, The Wesley Medical Centre, Suite 1, 40 Chasely St, Auchenflower, QLD 4066, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Kairn
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia.
authors.forename: S B
authors.initials: SB
authors.lastname: Crowe
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Australia.
authors.forename: J V
authors.initials: JV
authors.lastname: Trapp
mesh_terms: D001943:Breast Neoplasms / Q000532:radiotherapy / Q000601:surgery; D004583:Electrons / Q000627:therapeutic use*; D006801:Humans; D008408:Mastectomy; D017785:Photons / Q000627:therapeutic use*; D011829:Radiation Dosage; D011879:Radiotherapy Dosage; D015625:Tissue Expansion Devices
keywords: Dose distribution; Film; High-density; Magnet; Tissue expander