Durability of Laser Probes in Interstitial Thermotherapy: Investigations on an ex VivoModel of Effect of Carbonization

Background and Purpose: 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.Materials and Methods: Interstitial laser probes were used to pierce an in vitrokidney 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.