title: Seed loss in prostate brachytherapy : Operator dependency and impact on dosimetry.
abstract: BACKGROUND
  The aim of our study was to review seed loss and its impact on dosimetry as well as the influence of the treating physician on seed loss and dosimetry in patients treated with prostate brachytherapy using permanent loose (125)I implant.
  
  
  METHODS
  We analyzed 1087 consecutive patients treated by two physicians between July 2005 and April 2015 at a single institution. Pelvic fluoroscopic imaging was done 30 days post implant and a chest X-ray when seed loss was observed.
  
  
  RESULTS
  Seed loss occurred in 19.4 % of patients: in 20.0 % of implants done by the most experienced physician and in 17.2 % by the less experienced physician (p = 0.4) and migration to the thorax occurred in 5.9 % (6.9 vs. 2.2 %, p = 0.004). The mean seed loss rate was 0.57 % [standard deviation (SD) 1.39] and the mean rate of seeds in the thorax was 0.14 % (SD 0.65). The most experienced physician had a higher mean number of seeds lost: 0.36 versus 0.25 (p = 0.055), and a higher mean number of seed migration to the thorax: 0.1 versus 0.02 (p < 0.001). When at least one seed was lost, a decrease of 4.2 Gy (p < 0.001) in the D90 and a decrease of 3.5 % (p = 0.002) in the V150 was observed.
  
  
  CONCLUSIONS
  We found a significant decrease in V150 and D90 with the occurrence of seed loss. Furthermore, we found a difference in seed migration among the physicians demonstrating that seed loss is operator dependant.
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal-Hôpital Notre-Dame, 1560 Sherbrooke St. E., H2L 4M1, Montreal, QC, Canada.
authors.forename: Nancy
authors.initials: N
authors.lastname: El-Bared
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal-Hôpital Notre-Dame, 1560 Sherbrooke St. E., H2L 4M1, Montreal, QC, Canada.
authors.forename: Natanel
authors.initials: N
authors.lastname: Sebbag
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal-Hôpital Notre-Dame, 1560 Sherbrooke St. E., H2L 4M1, Montreal, QC, Canada.
authors.forename: Dominic
authors.initials: D
authors.lastname: Béliveau-Nadeau
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal-Hôpital Notre-Dame, 1560 Sherbrooke St. E., H2L 4M1, Montreal, QC, Canada.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Hervieux
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal-Hôpital Notre-Dame, 1560 Sherbrooke St. E., H2L 4M1, Montreal, QC, Canada.
authors.forename: Renée
authors.initials: R
authors.lastname: Larouche
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal-Hôpital Notre-Dame, 1560 Sherbrooke St. E., H2L 4M1, Montreal, QC, Canada. daniel.taussky.chum@ssss.gouv.qc.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Taussky
authors.affiliation: Département de Radio-Oncologie, Centre hospitalier de l'Université de Montréal-Hôpital Notre-Dame, 1560 Sherbrooke St. E., H2L 4M1, Montreal, QC, Canada.
authors.forename: Guila
authors.initials: G
authors.lastname: Delouya
mesh_terms: D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000295:instrumentation* / Q000592:standards*; D015984:Causality; D002983:Clinical Competence; D015897:Comorbidity; D005548:Foreign-Body Migration / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy*; D019736:Prostheses and Implants; D011792:Quebec / Q000453:epidemiology; D011874:Radiometry / Q000706:statistics & numerical data; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Complications; Implant radiotherapy; Learning curve; Radiation dose; Seed migration to thorax