title: A comparative optical analysis of laser side-firing devices: a guide to treatment.
abstract: OBJECTIVE
  To compare the optical characteristics of five different laser side-firing fibres used to perform deep laser coagulation of the prostate.
  
  
  METHODS
  The intensity profile, angle of exit and beam divergence from the launch fibre were measured underwater (to simulate endoscopic conditions) for each fibre using both the Helium Neon(633 nm) and Nd:YAG(1064 nm) lasers.
  
  
  RESULTS
  The intensity profiles and spot sizes varied among fibres but broadly fell within two groups characterized by large and small footprints (low and high power density). There was a maximum 5.5 fold difference in average power densities between the fibres.
  
  
  CONCLUSIONS
  Not all side-firing devices are the same. Variations in the power density profiles among the fibres suggest that the choice of fibre is of critical importance in determining the type of laser tissue interaction (i.e. coagulation or vaporization) that will follow the use of that fibre.
authors.affiliation: Department of Urology, Whittington Hospital, University College, London, UK.
authors.forename: K
authors.initials: K
authors.lastname: Anson
authors.forename: G
authors.initials: G
authors.lastname: Buonaccorsi
authors.forename: M
authors.initials: M
authors.lastname: Eddowes
authors.forename: A
authors.initials: A
authors.lastname: MacRobert
authors.forename: T
authors.initials: T
authors.lastname: Mills
authors.forename: G
authors.initials: G
authors.lastname: Watson
mesh_terms: D017075:Laser Coagulation / Q000295:instrumentation*; D055095:Optics and Photonics