title: Analysis of seed loss and pulmonary seed migration in patients treated with virtual needle guidance and robotic seed delivery.
abstract: OBJECTIVE
  To determine whether automated seed delivery system and real-time intraoperative (IO) virtual needle guidance reduce seed loss and pulmonary seed migration.
  
  
  METHODS
  We analyzed 279 patients with low and intermediate risk prostate cancer treated in our institution with radioactive iodine (I-125) permanent seed implants. Loose seeds were exclusively used. To account for lost seeds, pelvic fluoroscopic imaging from 3 different angles was done 30 days after the implant. Posteroanterior and lateral chest x-rays were done when seed loss was confirmed. Patients were compared using the χ(2) test and Fisher exact test.
  
  
  RESULTS
  At least 1 seed was lost in 31.5% of patients with a migration rate of 1.02%; 9.3% of patients had at least 1 seed in the lung with a migration rate of 0.22%. The population was divided into 3 groups according to the order in which they were treated. Seed loss (P=0.02) and pulmonary seed embolization (P=0.008) were significantly lower in the second hundred than in the first hundred patients. No difference was noted between groups 1 and 3 (patient, 201-279). Peri- or extracapsular seed placement was not correlated to seed loss (P=0.780 and P=0.092, respectively). No serious complications from seed migration were reported. Seed loss did not influence dosimetry parameters (V100, V150, and D90).
  
  
  CONCLUSIONS
  Our pulmonary seed migration and total seed loss rates are comparable to the ones reported in the literature. Virtual needle guidance and automated seed delivery system are in our hand as accurate as the manual technique.
authors.affiliation: Department of Radiation Oncology, University of Montreal Medical, CHUM, Quebec, Canada.
authors.forename: Lara
authors.initials: L
authors.lastname: Hathout
authors.forename: David
authors.initials: D
authors.lastname: Donath
authors.forename: Camille
authors.initials: C
authors.lastname: Moumdjian
authors.forename: Audrey
authors.initials: A
authors.lastname: Tétreault-Laflamme
authors.forename: Renée
authors.initials: R
authors.lastname: Larouche
authors.forename: Dominic
authors.initials: D
authors.lastname: Béliveau-Nadeau
authors.forename: Yannick
authors.initials: Y
authors.lastname: Hervieux
authors.forename: Daniel
authors.initials: D
authors.lastname: Taussky
mesh_terms: D000368:Aged; D001918:Brachytherapy; D015331:Cohort Studies; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000150:complications*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009339:Needles; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000532:radiotherapy*; D019736:Prostheses and Implants; D011655:Pulmonary Embolism / Q000209:etiology*; D012371:Robotics; D015996:Survival Rate; D016896:Treatment Outcome; D014463:Ultrasonography
chemical_list: D007457:Iodine Radioisotopes