Fig. 1.
Effects of temperature on tissues. Both laser ablation and RF ablation have effects on tissues as a function of temperature. Lower than 44ºC, tissue effects are absent irrespective of time. Damage is time dependent between 44ºC and 59ºC; damage occurs as a function of time and temperature as predicted by the Arrhenius equation. This is the important temperature range for controllable lesions using LITT. At 60ºC or greater, tissue coagulation is instantaneous; these temperature effects occur close to the laser fiber diffuser tip. Instant vaporization occurs greater than 100ºC; the system is generally set to turn off automatically if the temperature near the tip reaches 90ºC to prevent damage to the tip.