title: Fabrication of novel bundled fiber and performance assessment for clinical applications.
abstract: OBJECTIVE
  During laser vaporization of benign prostate hyperplasia (BPH), high precision of optical fiber handling is pivotal to minimize any post-operative complications. The aim of the study was to evaluate the feasible applications of a bundled fiber to treat BPH by directionally and selectively manipulating laser light onto the targeted tissue.
  
  
  METHODS
  A bundled optical fiber, consisting of four side-firing fibers, was fabricated to selectively emit laser beams in from one to four directions. Both transmission efficiency and light distribution were qualitatively and quantitatively characterized on the bundled fiber. In terms of interstitial application of the proposed fiber with 1064 nm on porcine liver tissue, the extent of thermal denaturation was estimated and compared at various laser parameterizations and for different directions of light.
  
  
  RESULTS
  From the laser source to the fiber tip, the fabricated fiber device demonstrated a total light transmission of 52%. Due to internal light reflection, a secondary beam was emitted backward from the fiber tip and was responsible for 25% of the transmission loss. According to tissue testing, the extent of tissue denaturation generally increased with laser power, irradiation time, and number of light directions. The geometrical shape of thermal coagulation correlated well with the direction of light emission. Thermal damage to the glass tube occurred during excessive heat accumulation generated by continuous irradiation.
  
  
  CONCLUSIONS
  The proposed fiber can be beneficial for laser vaporization of BPH by providing a selective light direction irradiation along with minimal thermal damage. Further studies will extend the applicability of the bundled fiber to treat tubular tissue structure.
authors.affiliation: School of Mechanical Engineering, Kyungpook National University, Daegu, 702-701, Korea.
authors.forename: Changhwan
authors.initials: C
authors.lastname: Kim
authors.forename: Myung Jin
authors.initials: MJ
authors.lastname: Jeon
authors.forename: Jin Hyang
authors.initials: JH
authors.lastname: Jung
authors.forename: Jung Dug
authors.initials: JD
authors.lastname: Yang
authors.forename: Hoyong
authors.initials: H
authors.lastname: Park
authors.forename: Hyun Wook
authors.initials: HW
authors.lastname: Kang
authors.forename: Ho
authors.initials: H
authors.lastname: Lee
mesh_terms: D000818:Animals; D004867:Equipment Design; D005240:Feasibility Studies; D053685:Laser Therapy / Q000295:instrumentation*; D053844:Lasers, Solid-State; D008099:Liver / Q000528:radiation effects*; D055100:Optical Fibers; D011468:Prostatectomy / Q000295:instrumentation*; D013552:Swine
keywords: endoscopy surgery; fiber optics; laser-assisted prostatectomy; laser-induced damage