title: Problems with rigid seed strand lodging during prostate implantation: a proposed mechanism and solution.
abstract: Since the introduction of rigid strands of radioactive seeds embedded in absorbable suture material, many brachytherapists have experienced problems with the strands lodging inside the implant needle during the deposition process. By using a scanning electron microscope, we examined some potential factors which could lead to this problem. It seems plausible that the lodging is due to two factors: prostate tissue hindering the motion of the strand initially, and friction between the strand braids and the inner surface of the needle. Both result in an "accordion effect" as the stylet applies pressure on the strand. Based on this assumption, a solution was found. A combination of using needles with a polished inner surface, and repeated clockwise and counterclockwise 360 degrees twisting of the needle about the stylet during the deposition process allows for smooth deposition of the strand at the intended location. By using this technique, one is able to exploit the potential dosimetric advantages of rigid seed strand implants without additional problems.
authors.affiliation: Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Friedland
authors.forename: V
authors.initials: V
authors.lastname: Feygelman
authors.forename: E M
authors.initials: EM
authors.lastname: Haller
authors.forename: L M
authors.initials: LM
authors.lastname: Bradley
authors.forename: R M
authors.initials: RM
authors.lastname: Sanders
authors.forename: B K
authors.initials: BK
authors.lastname: Noriega
mesh_terms: D001918:Brachytherapy / Q000009:adverse effects / Q000295:instrumentation; D004564:Electrocoagulation; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D009339:Needles; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D013537:Sutures