title: Introduction of moderate deep inspiration breath hold for radiation therapy of left breast: Initial experience of a regional cancer center.
abstract: OBJECTIVE
  Practical aspects of introducing moderate deep inspiration breath hold (mDIBH) for treatment of left breast cancer in a regional cancer program in terms of workflow and treatment delivery requirements are described. Differences in heart and lung doses between free breathing (FB) and mDIBH plans are presented as well as heart position reproducibility and resulting dosimetric impact using cone beam computed tomography (CBCT).
  
  
  METHODS
  A mDIBH process was established. Therapists observed duration and quantity of breath holds required for setup, imaging, and beam delivery during treatment. Treatment plans were generated on the FB and mDIBH CT datasets allowing comparison of heart and lung dose-volume data for 50 patients. Five consecutive CBCT images were used to measure the distance between the heart and chest wall for 5 patients. Estimates of dose to the translated heart were then made with the treatment planning system.
  
  
  RESULTS
  When compared with FB delivery, mDIBH treatment time for tangents and boosts increased by 5 minutes, while 3- or 4-field techniques increased by 10 minutes. Differences in heart dose D10 cc, mean, V30 and V10 were statistically significant between the FB and mDIBH tangents and 3- or 4-field treatment plans. Statistically significant differences in V20, V10, V5, and mean lung doses were observed for 3- and 4-field FB and mDIBH plans. Differences between lung V5 dose metrics for FB and mDIBH 2-field plans were statistically significant. Interfraction mean translations in heart position coronally ranged from -6.2 to 2.6 mm and resulted in non-negligible increases in the heart dose.
  
  
  CONCLUSIONS
  Moderate deep inspiration breath hold has been successfully implemented in our regional cancer center for treatment of left breast cancer and is now a standard practice. This change in practice from FB to mDIBH treatment has not impacted our ability to meet provincial guidelines for patient throughput.
authors.affiliation: Medical Physics, Radiation Medicine Program, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario, Canada; Radiation Oncology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Daria
authors.initials: D
authors.lastname: Comsa
authors.affiliation: Medical Physics, Radiation Medicine Program, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario, Canada. Electronic address: ebarnett@southlakeregional.org.
authors.forename: Erin
authors.initials: E
authors.lastname: Barnett
authors.affiliation: Radiation Therapy, Radiation Medicine Program, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario, Canada.
authors.forename: Ken
authors.initials: K
authors.lastname: Le
authors.affiliation: Radiation Therapy, Radiation Medicine Program, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario, Canada.
authors.forename: Gulaid
authors.initials: G
authors.lastname: Mohamoud
authors.affiliation: Radiation Therapy, Radiation Medicine Program, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario, Canada.
authors.forename: Dana
authors.initials: D
authors.lastname: Zaremski
authors.affiliation: Radiation Oncology, Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada; Radiation Oncology, Radiation Medicine Program, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario, Canada.
authors.forename: Louis
authors.initials: L
authors.lastname: Fenkell
authors.affiliation: Radiation Oncology, Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada; Radiation Oncology, Radiation Medicine Program, Stronach Regional Cancer Centre, Southlake Regional Health Centre, Newmarket, Ontario, Canada.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Kassam
mesh_terms: D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D062485:Breath Holding; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000000981:diagnostic imaging / Q000528:radiation effects; D006752:Hospital Planning; D006801:Humans; D007103:Immobilization; D001239:Inhalation; D008168:Lung / Q000000981:diagnostic imaging / Q000528:radiation effects; D008875:Middle Aged; D011379:Prognosis; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000517:prevention & control*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D035441:Thoracic Wall / Q000000981:diagnostic imaging / Q000528:radiation effects; D014057:Tomography, X-Ray Computed