title: Target localisation for tumour bed radiotherapy in early breast cancer.
abstract: BACKGROUND
  To compare clinical and CT techniques in localisation of the tumour bed in patients undergoing adjuvant breast radiotherapy for breast cancer.
  
  
  METHODS
  Patients were CT scanned in the treatment position following clinical delineation of the whole breast, surgical scar and boost volume. Computed tomography boost volumes were contoured in three dimensions. A definitive treatment plan was generated to encompass the CT-localised planning target volume (PTV) with ≥90% isodose using electrons. A hypothetical plan was also generated to cover the clinically determined boost field for comparison. The primary end point was the difference in PTV coverage by the 90% isodose between the plans based on clinically and CT localised boost volumes.
  
  
  RESULTS
  The plans for 50 patients were evaluated. The median percentage of PTV encompassed by the 90% isodose using the clinical and CT techniques was 29% (range 5-90%) and 83% (range 25-100%), respectively. PTV coverage by the 90% isodose using the clinical technique was at least 10% less than that using CT technique in 88% of patients (95% confidence interval 77-95%; P < 0.0001).
  
  
  CONCLUSIONS
  Tumour bed boost PTV coverage was insufficient using clinical determination as compared with CT localisation. This study supports CT planning for target volume localisation of the tumour bed boost in patients treated with breast-conserving therapy for breast cancer.
authors.affiliation: Department of Radiation Oncology Radiation Therapy Service, East Melbourne University of Melbourne, Melbourne, Victoria, Australia. carmen.hansen@ncahs.health.nsw.gov.au
authors.forename: Carmen J
authors.initials: CJ
authors.lastname: Hansen
authors.forename: Emma
authors.initials: E
authors.lastname: de Winton
authors.forename: Sam
authors.initials: S
authors.lastname: Guglani
authors.forename: Evi
authors.initials: E
authors.lastname: Vamvakas
authors.forename: David
authors.initials: D
authors.lastname: Willis
authors.forename: Boon H
authors.initials: BH
authors.lastname: Chua
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D042241:Early Diagnosis; D005260:Female; D057918:Fiducial Markers; D006801:Humans; D008875:Middle Aged; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D061089:Radiotherapy, Image-Guided / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000379:methods; D016896:Treatment Outcome