title: Clinical experience with a 3D surface patient setup system for alignment of partial-breast irradiation patients.
abstract: OBJECTIVE
  To assess the utility of surface imaging on patient setup for accelerated partial-breast irradiation (APBI).
  
  
  METHODS
  A photogrammetry system was used in parallel to APBI setup by laser and portal imaging. Surface data were acquired after laser and port-film setup for 9 patients. Surfaces were analyzed in comparison to a reference surface from the first treatment session by use of rigid transformations. The surface model after laser setup was used in a simulated photogrammetry setup procedure. In addition, breathing data were acquired by surface acquisition at a frame rate of 7 Hz.
  
  
  RESULTS
  Mean 3D displacement was 7.3 mm (SD, 4.4 mm) and 7.6 mm (SD, 4.2 mm) for laser and port film, respectively. Simulated setup with the photogrammetry system yielded mean displacement of 1 mm (SD, 1.2 mm). Distance analysis resulted in mean distances of 3.7 mm (SD, 4.9 mm), 4.3 mm (SD, 5.6 mm), and 1.6 mm (SD, 2.4 mm) for laser, port film, and photogrammetry, respectively. Breathing motion at isocenter was smaller than 3.7 mm, with a mean of 1.9 mm (SD, 1.1 mm).
  
  
  CONCLUSIONS
  Surface imaging for PBI setup appears promising. Alignment of the 3D breast surface achieved by stereo-photogrammetry shows greater breast topology congruence than when patients are set up by laser or portal imaging. A correlation of breast surface and CTV must be quantitatively established.
authors.affiliation: Abteilung Biophysik, Gesellschaft für Schwerionenforschung, Darmstadt, Germany. cbert@gsi.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Bert
authors.forename: Katherine G
authors.initials: KG
authors.lastname: Metheany
authors.forename: Karen P
authors.initials: KP
authors.lastname: Doppke
authors.forename: Alphonse G
authors.initials: AG
authors.lastname: Taghian
authors.forename: Simon N
authors.initials: SN
authors.lastname: Powell
authors.forename: George T Y
authors.initials: GT
authors.lastname: Chen
mesh_terms: D001943:Breast Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D009068:Movement; D010780:Photogrammetry / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D012119:Respiration; D012984:Software