Tm:Fiber laser ablation with real-time temperature monitoring for minimizing collateral thermal damage: Ex vivo dosimetry for ovine brain

Background and Objective The thermal damage of the surrounding tissue can be an unwanted result of continuous-wave laser irradiations. In order to propose an effective alternative to conventional surgical techniques, photothermal damage must be taken under control by a detailed dose study. Real-time temperature monitoring can be also an effective way to get rid of these negative effects. The aim of the present study is to investigate the potential of a new laser-thermoprobe, which consists of a continuous-wave 1,940-nm Tm:fiber laser and a thermocouple measurement system for brain surgery in an ex vivo study. Study Design/Materials and Methods A laser-thermoprobe was designed for using the near-by tissue temperature as a real-time reference for the applicator. Fresh lamb brain tissues were used for experiments. 320 laser shots were performed on both cortical and subcortical tissue. Results The relationship between laser parameters, temperature changes, and ablation (removal of tissue) efficiency was determined. The correlation between rate of temperature change and ablation efficiency was calculated. Conclusion Laser-thermoprobe leads us to understand the basic laser-tissue interaction mechanism in a very cheap and easy way, without making a change in the experimental design. It was also shown that the ablation and coagulation (thermally irreversible damage) diameters could be predicted, and carbonization can be avoided by temperature monitoring. Lasers Surg. Med. 45: 48-56, 2013. © 2013 Wiley Periodicals, Inc.