title: Durability of laser probes in interstitial thermotherapy: investigations on an ex vivo model of effect of carbonization.
abstract: OBJECTIVE
  Interstitial laser application is successful for clinical tissue ablation in various organs. One great drawback of this method is the high costs caused by the vulnerability of the probes. Our objective was to investigate whether the prevention of carbonization deposits on laser probes averts reduced transmission after the application of high laser energy.
  
  
  METHODS
  Interstitial laser probes were used to pierce an in vitro kidney model, and 9900 J of energy (Nd:YAG laser) was applied. The transmission of the laser probe was determined and compared with that of a reference probe.
  
  
  RESULTS
  The application of laser energy, up to a total of 49,500 J, did not reduce transmission. The deviation of the transmission comparing working probes and the reference probe was between 2% and 7%. The application of high energy (40 W) over a longer period (>20 seconds) led to carbonization and consequent distinct reduction of transmission.
  
  
  CONCLUSIONS
  The durability of laser probes can be prolonged by preventing carbonization. The economic effect achieved is the repeated use of the probes at less expense.
authors.affiliation: Department of Urology, University Hospital Mannheim, Germany. kai.uwe.koehrmann@uro.ma.uni-heidelberg.de
authors.forename: K U
authors.initials: KU
authors.lastname: Köhrmann
authors.forename: P
authors.initials: P
authors.lastname: Vöhringer
authors.forename: M S
authors.initials: MS
authors.lastname: Michel
authors.forename: T
authors.initials: T
authors.lastname: Henkel
authors.forename: P
authors.initials: P
authors.lastname: Alken
mesh_terms: D000818:Animals; D002244:Carbon; D004868:Equipment Failure; D007668:Kidney / Q000473:pathology / Q000601:surgery; D017075:Laser Coagulation / Q000295:instrumentation* / Q000379:methods; D013552:Swine
chemical_list: D002244:Carbon