title: Inter-observer variation in delineation of the heart and left anterior descending coronary artery in radiotherapy for breast cancer: a multi-centre study from Denmark and the UK.
abstract: OBJECTIVE
  To determine the extent of inter-observer variation in delineation of the heart and left anterior descending coronary artery (LADCA) and its impact on estimated doses.
  
  
  METHODS
  Nine observers from five centres delineated the heart and LADCA on fifteen patients receiving left breast radiotherapy. The delineations were carried out twice, first without guidelines and then with a set of common guidelines.
  
  
  RESULTS
  For the heart, most spatial variation in delineation was near the base of the heart whereas for the LADCA most variation was in its length at the apex of the heart. Common guidelines reduced the spatial variation for the heart and the length of the LAD, but increased the variation in the anterior-posterior/right-left plane. The coefficients of variation (CV) in the estimated doses to the heart were: mean dose 7.5% without and 3.6% with guidelines, maximum dose 8.7% without and 4.0% with guidelines. The CVs in the estimated doses to the LADCA were: mean dose 27% without and 29% with guidelines, maximum dose 39% without and 31% with guidelines.
  
  
  CONCLUSIONS
  For the heart, there was little inter-observer variation in the estimated dose, especially when guidelines were used. In contrast, for the LADCA there was substantial variation in the estimated dose, which was not reduced with guidelines.
authors.affiliation: Laboratory of Radiation Physics, Odense University Hospital, Denmark; Institute of Clinical Research, University of Southern Denmark, Odense, Denmark. Electronic address: ebbe.lorenzen@rsyd.dk.
authors.forename: Ebbe L
authors.initials: EL
authors.lastname: Lorenzen
authors.forename: Carolyn W
authors.initials: CW
authors.lastname: Taylor
authors.forename: Maja
authors.initials: M
authors.lastname: Maraldo
authors.forename: Mette H
authors.initials: MH
authors.lastname: Nielsen
authors.forename: Birgitte V
authors.initials: BV
authors.lastname: Offersen
authors.forename: Maria R
authors.initials: MR
authors.lastname: Andersen
authors.forename: Dean
authors.initials: D
authors.lastname: O'Dwyer
authors.forename: Lone
authors.initials: L
authors.lastname: Larsen
authors.forename: Sharon
authors.initials: S
authors.lastname: Duxbury
authors.forename: Baljit
authors.initials: B
authors.lastname: Jhitta
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Darby
authors.forename: Marianne
authors.initials: M
authors.lastname: Ewertz
authors.forename: Carsten
authors.initials: C
authors.lastname: Brink
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D003331:Coronary Vessels / Q000528:radiation effects*; D003718:Denmark; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006321:Heart / Q000528:radiation effects*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D015412:Mastectomy, Segmental / Q000379:methods; D008875:Middle Aged; D015588:Observer Variation; D058958:Organs at Risk / Q000528:radiation effects*; D061214:Patient Safety; D017410:Practice Guidelines as Topic; D011832:Radiation Injuries / Q000517:prevention & control; D011874:Radiometry / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000009:adverse effects / Q000379:methods*; D018714:Radiotherapy, Adjuvant; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects / Q000379:methods*; D018570:Risk Assessment; D012494:Sampling Studies; D016896:Treatment Outcome; D006113:United Kingdom
keywords: Breast cancer radiotherapy; Delineation; Heart dose; Inter-observer variation; Left anterior descending coronary artery