title: Improving the reproducibility of voluntary deep inspiration breath hold technique during adjuvant left-sided breast cancer radiotherapy.
abstract: BACKGROUND
  Adjuvant radiotherapy (RT) of left-sided breast cancer (LSBC) with voluntary deep inspiration breath hold (vDIBH) technique reduces the cardiac dose. In this study, the effect of marker block position and the efficacy of breath hold level (BHL) correction based on lateral kV setup images are evaluated to improve the daily reproducibility.
  
  
  METHODS
  A total of 148 consecutive LSBC patients treated with vDIBH RT were included in this study. The real-time position management (RPM) marker block was placed on the abdominal wall in 63 patients (group A) and on the sternum in 85 patients (group S). Acquired 900 (group A) + 1040 (group S) orthogonal image pairs were retrospectively analyzed. The actual BHL was determined from the lateral kV images. The height of the BHL gating window in RPM was corrected if errors of the actual BHL exceeded 4 mm. Setup margins were calculated for the chest wall and for bony surrogates of the lymph node regions.
  
  
  RESULTS
  The sternal marker block reduced the random residual errors in the actual BHL (p < 0.05). The BHL correction was required for 26/63 patients in group A and for 26/85 patients in group S. Correction of the BHL window significantly reduced both the systematic and the random residual error in both groups. In patients with lymph node irradiation, the effect of both marker placement and BHL window correction was significant in the superior-inferior direction. Correction of the BHL reduced the mean cardiac dose by 0.5 Gy (p < 0.01) in group A and 0.6 Gy (p < 0.05) in group S.
  
  
  CONCLUSIONS
  Reproducibility of the BHL can be improved by placing the marker block on the sternum and correcting the height of the BHL window based on lateral kV setup images. Acquisition of lateral kV images in the first 3 fractions and once a week during RT is recommended.
authors.affiliation: a Department of Oncology , Tampere University Hospital (TAUH) , Tampere , Finland ;|b School of Medicine , University of Tampere , Tampere , Finland ;
authors.forename: Tanja
authors.initials: T
authors.lastname: Skyttä
authors.affiliation: a Department of Oncology , Tampere University Hospital (TAUH) , Tampere , Finland ;|c Department of Medical Physics , Tampere University Hospital (TAUH) , Tampere , Finland.
authors.forename: Mika
authors.initials: M
authors.lastname: Kapanen
authors.affiliation: a Department of Oncology , Tampere University Hospital (TAUH) , Tampere , Finland ;
authors.forename: Marko
authors.initials: M
authors.lastname: Laaksomaa
authors.affiliation: a Department of Oncology , Tampere University Hospital (TAUH) , Tampere , Finland ;|c Department of Medical Physics , Tampere University Hospital (TAUH) , Tampere , Finland.
authors.forename: Seppo
authors.initials: S
authors.lastname: Peltola
authors.affiliation: a Department of Oncology , Tampere University Hospital (TAUH) , Tampere , Finland ;
authors.forename: Mikko
authors.initials: M
authors.lastname: Haltamo
authors.affiliation: a Department of Oncology , Tampere University Hospital (TAUH) , Tampere , Finland ;|c Department of Medical Physics , Tampere University Hospital (TAUH) , Tampere , Finland.
authors.forename: Eeva
authors.initials: E
authors.lastname: Boman
authors.affiliation: c Department of Medical Physics , Tampere University Hospital (TAUH) , Tampere , Finland.
authors.forename: Simo
authors.initials: S
authors.lastname: Hyödynmaa
authors.affiliation: a Department of Oncology , Tampere University Hospital (TAUH) , Tampere , Finland ;|b School of Medicine , University of Tampere , Tampere , Finland ;
authors.forename: Pirkko-Liisa
authors.initials: PL
authors.lastname: Kellokumpu-Lehtinen
mesh_terms: D000005:Abdomen; D000328:Adult; D000368:Aged; D062485:Breath Holding; D005260:Female; D057918:Fiducial Markers; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology / Q000528:radiation effects; D008875:Middle Aged; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D018714:Radiotherapy, Adjuvant / Q000379:methods*; D011897:Random Allocation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013249:Sternum; D014057:Tomography, X-Ray Computed; D000069584:Unilateral Breast Neoplasms / Q000532:radiotherapy* / Q000601:surgery