title: Using fiducial markers in the prostate bed in postprostatectomy external beam radiation therapy improves accuracy over surgical clips.
abstract: OBJECTIVE
  The purpose of this work was to assess the stability of fiducial markers in the prostate bed and compared their use to surgical clips.
  
  
  METHODS
  In this study, 3-4 gold fiducial markers were transrectally implanted in the prostate bed of 14 patients. The stability of the fiducial markers position (fiducial markers fixity) over an EBRT course was assessed. Furthermore, the advantages of the fiducial markers compared to the surgical clips were assessed and the interobserver variation between the two technologies was compared.
  
  
  RESULTS
  The mean fiducial marker migration during a course of EBRT was small with 1.2 mm (SD ± 0.8 mm). Compared to fiducial markers, the matches with surgical clips were mismatched ≥ 2 mm in 68% of treatments. This discrepancy of > 2 mm was on average 3.7 ± 1.3 mm. There was less interobserver variability for matching of fiducial markers (0.8 ± 0.7 mm) than for surgical clips (2.0 ± 1.6 mm).
  
  
  CONCLUSIONS
  Fiducial markers showed less interobserver variability in matching and less variation in position than surgical clips. Fiducial markers could ultimately help in reducing treatment margins.
authors.affiliation: Département de Radio-Oncologie, Centre Hospitalier de l'Université de Montréal, Centre de recherche du Centre Hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Sherbrooke St. E., 1560, Montréal, Québec, Canada.
authors.forename: I
authors.initials: I
authors.lastname: Fortin
authors.forename: J-F
authors.initials: JF
authors.lastname: Carrier
authors.forename: M-C
authors.initials: MC
authors.lastname: Beauchemin
authors.forename: D
authors.initials: D
authors.lastname: Béliveau-Nadeau
authors.forename: G
authors.initials: G
authors.lastname: Delouya
authors.forename: D
authors.initials: D
authors.lastname: Taussky
mesh_terms: D057918:Fiducial Markers; D005548:Foreign-Body Migration / Q000209:etiology; D006046:Gold; D006801:Humans; D008297:Male; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D015588:Observer Variation; D058958:Organs at Risk; D011467:Prostate; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery*; D011867:Radioisotope Teletherapy / Q000379:methods*; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant; D061089:Radiotherapy, Image-Guided / Q000379:methods*; D012189:Retrospective Studies; D016879:Salvage Therapy; D013525:Surgical Instruments; D014057:Tomography, X-Ray Computed
chemical_list: D006046:Gold