title: Seed migration in prostate brachytherapy depends on experience and technique.
abstract: OBJECTIVE
  To determine seed loss and pulmonary migration rate over time in permanent seed prostate brachytherapy.
  
  
  METHODS
  We analyzed the first 495 patients treated in our department. All patients were treated with loose (125)I seeds with automated seed delivery system and real-time intraoperative planning. Pelvic fluoroscopic imaging was done 30 days after the implant. Patients were divided into five groups of 100 patients according to the order they were treated, and groups were compared using χ(2) test and one-way analysis of variance.
  
  
  RESULTS
  A total of 22.8% of patients lost at least one seed. The highest percentage of patients losing any number of seeds was in the first 100. Thirty-eight percent lost at least one seed. This number decreased gradually and was only 9% in Patients 400-499. The mean total seed loss rate (number of seeds lost/number seeds implanted) changed significantly over time (p<0.001). There was a continuous significant (p<0.001) decline after the first 100 patients (1.25% for the first 100 patients) followed by a rise in Patients 300-399, followed by another decline (0.21% for the last 100 patients). The seed loss rate to the thorax changed significantly over time (p=0.009). It rose after an initial rate of 0.25-0.42% in Patients 200-299 and 300-399 and declined later to a rate of 0.21% in the last 100 patients.
  
  
  CONCLUSIONS
  We found a learning curve for seed migration. Avoiding implanting seeds outside of the capsule and modern transrectal ultrasound imaging can help decrease migration.
authors.affiliation: Department of Radiation Oncology, Centre hospitalier de l'Université de Montréal, Hôpital Notre-Dame, Montréal, Québec, Canada. daniel.taussky.chum@ssss.gouv.qc.ca
authors.forename: Daniel
authors.initials: D
authors.lastname: Taussky
authors.forename: Camille
authors.initials: C
authors.lastname: Moumdjian
authors.forename: Renée
authors.initials: R
authors.lastname: Larouche
authors.forename: Dominic
authors.initials: D
authors.lastname: Béliveau-Nadeau
authors.forename: Chantal
authors.initials: C
authors.lastname: Boudreau
authors.forename: Yannick
authors.initials: Y
authors.lastname: Hervieux
authors.forename: David
authors.initials: D
authors.lastname: Donath
mesh_terms: D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000295:instrumentation* / Q000379:methods*; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000000981:diagnostic imaging* / Q000209:etiology*; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D019919:Prosthesis Implantation / Q000295:instrumentation; D011859:Radiography; D019275:Radiopharmaceuticals / Q000009:adverse effects* / Q000627:therapeutic use; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods
chemical_list: D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals