title: A randomized trial comparing seed displacement of coated seeds to regular loose seeds at 30 days postimplant.
abstract: OBJECTIVE
  To compare 30-day seed displacement and seed loss of standard loose seeds to specially engineered coated seeds.
  
  
  METHODS
  Forty patients with prostate cancer were randomized and treated with either loose seeds or loose "coated" seeds. Implants were preplanned using transrectal ultrasound and performed using preloaded needles containing either standard or coated iodine-125 seeds according to randomization. Pelvic X-rays and CT were performed on Days 0 and 30 and a pelvic magnetic resonance scan on Day 30. Cranial-caudal displacement relative to the center of mass (COM) of the seed cloud of the six most peripheral basal and apical seeds was determined from Day 0 and 30 CT scans using custom software. Day 30 magnetic resonance-CT fusion was performed using a seed-to-seed match for soft tissue contouring on MRI.
  
  
  RESULTS
  The mean displacement for the six basal seeds was 0.32 cm (standard deviation [SD], 0.25 cm) and 0.33 cm (SD, 0.27 cm) toward the COM for the regular and coated seeds, respectively (p = 0.35). For the apical seeds, mean displacement was 0.31 cm (SD, 0.35 cm) and 0.43 cm (SD, 0.26 cm) (p = 0.003) toward the COM. More regular seeds (n = 8) were lost from the apical region as compared with one coated seed (p = 0.015). There was a trend to reduction in total seeds lost: 1% for regular seeds as compared with 0.3% for coated seeds.
  
  
  CONCLUSIONS
  Coated seeds were found to have a significant anchoring effect that was effective in reducing the number of apical seeds lost because of venous migration.
authors.affiliation: Department of Radiation Oncology, Nova Scotia Cancer Center, Halifax, Nova Scotia, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Bowes
authors.forename: Miren
authors.initials: M
authors.lastname: Gaztañaga
authors.forename: Cynthia
authors.initials: C
authors.lastname: Araujo
authors.forename: David
authors.initials: D
authors.lastname: Kim
authors.forename: Brent
authors.initials: B
authors.lastname: Parker
authors.forename: Deidre
authors.initials: D
authors.lastname: Batchelar
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Milette
authors.forename: Rasika
authors.initials: R
authors.lastname: Rajapakshe
authors.forename: David
authors.initials: D
authors.lastname: Petrik
authors.forename: Ross
authors.initials: R
authors.lastname: Halperin
authors.forename: Juanita M
authors.initials: JM
authors.lastname: Crook
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods*; D005548:Foreign-Body Migration; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008875:Middle Aged; D011108:Polymers; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D019736:Prostheses and Implants / Q000009:adverse effects*; D011879:Radiotherapy Dosage
chemical_list: D007457:Iodine Radioisotopes; D011108:Polymers