title: Fiducial markers for image-guided partial breast irradiation.
abstract: OBJECTIVE
  This study was undertaken to study the role of fiducial markers for image-guided partial breast irradiation (IG-PBI), and to compare the shifts based on bony anatomy and fiducial markers.
  
  
  METHODS
  Fifteen patients underwent IGPBI. Three fiducial markers were placed in the tumour bed at the time of surgery. Daily orthogonal anterior/ posterior and lateral kV-images were taken before each fraction and compared with the digitally-reconstructed radiographs, both using bony landmarks and fiducial markers as reference. The Student's t test was used to detect a meaningful difference of 3 mm in between the two methods.
  
  
  RESULTS
  A total of 105 image-guided radiation therapy (IGRT) sessions were obtained. The mean superior/inferior, right/left, and anterior/posterior shifts obtained using the bony landmarks vs. the fiducial markers were 2 mm [standard deviation (SD) 10 mm] vs. 0 mm (SD 7 mm), 0 mm (SD 7 mm) vs. 1 mm (SD 4 mm), and 1 mm (SD 7 mm) vs. 0 mm (SD 5 mm), respectively. The mean shift differences in absolute value between the two methods, along the superior/inferior, right/left and anterior/posterior directions were 5 mm (p=0.001), 3 mm [p=not significant (ns)], and 3 mm (p=ns), respectively.
  
  
  CONCLUSIONS
  Fiducial markers for IG-PBI increase set-up accuracy compared to the bony landmarks, in particular along the superior/inferior direction.
authors.affiliation: Department of Radiation Oncology, Centro di Riferimento Oncologico, CRO, Via F. Gallini 2, 33081, Aviano (PN), Italy, marcotrovo33@hotmail.com.
authors.forename: Marco
authors.initials: M
authors.lastname: Trovo
authors.forename: Jerry
authors.initials: J
authors.lastname: Polesel
authors.forename: Cristina
authors.initials: C
authors.lastname: Biasutti
authors.forename: Giovanna
authors.initials: G
authors.lastname: Sartor
authors.forename: Mario
authors.initials: M
authors.lastname: Roncadin
authors.forename: Gaetano Mauro
authors.initials: GM
authors.lastname: Trovo
mesh_terms: D000368:Aged; D001943:Breast Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D057918:Fiducial Markers; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D011879:Radiotherapy Dosage; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D016896:Treatment Outcome
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