title: Assessment of Intrafraction Breathing Motion on Left Anterior Descending Artery Dose During Left-Sided Breast Radiation Therapy.
abstract: To use 4-dimensional computed tomography (4D-CT) imaging to predict the level of uncertainty in cardiac dose estimates of the left anterior descending artery that arises due to breathing motion during radiation therapy for left-sided breast cancer.
  
  
  
  The fast helical CT (FH-CT) and 4D-CT of 30 left-sided breast cancer patients were retrospectively analyzed. Treatment plans were created on the FH-CT. The original treatment plan was then superimposed onto all 10 phases of the 4D-CT to quantify the dosimetric impact of respiratory motion through 4D dose accumulation (4D-dose). Dose-volume histograms for the heart, left ventricle (LV), and left anterior descending (LAD) artery obtained from the FH-CT were compared with those obtained from the 4D-dose.
  
  
  
  The 95% confidence interval of 4D-dose and FH-CT differences in mean dose estimates for the heart, LV, and LAD were ±0.5 Gy, ±1.0 Gy, and ±8.7 Gy, respectively.
  
  
  
  Fast helical CT is a good approximation for doses to the heart and LV; however, dose estimates for the LAD are susceptible to uncertainties that arise due to intrafraction breathing motion that cannot be ascertained without the additional information obtained from 4D-CT and dose accumulation. For future clinical studies, we suggest the use of 4D-CT-derived dose-volume histograms for estimating the dose to the LAD.
authors.affiliation: Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada; Department of Physics, London Regional Cancer Program, London, Ontario, Canada. Electronic address: Omar.ElSherif@lhsc.on.ca.
authors.forename: Omar
authors.initials: O
authors.lastname: El-Sherif
authors.affiliation: Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada.
authors.forename: Edward
authors.initials: E
authors.lastname: Yu
authors.affiliation: Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada; Department of Physics, London Regional Cancer Program, London, Ontario, Canada.
authors.forename: Ilma
authors.initials: I
authors.lastname: Xhaferllari
authors.affiliation: Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada; Department of Physics, London Regional Cancer Program, London, Ontario, Canada; Department of Radiation Oncology, London Regional Cancer Program, London, Ontario, Canada.
authors.forename: Stewart
authors.initials: S
authors.lastname: Gaede
mesh_terms: D000328:Adult; D003331:Coronary Vessels / Q000528:radiation effects*; D019583:Dose Fractionation, Radiation; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008297:Male; D009038:Motion; D058958:Organs at Risk / Q000528:radiation effects*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D015203:Reproducibility of Results; D015656:Respiratory Mechanics; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D000069584:Unilateral Breast Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*