A system and method for determining completion of an ablation procedure is provided. An electrosurgical generator provides an electrosurgical energy source to an electrode probe assembly. The generator is connected to a thermal feedback assembly that includes at least one temperature sensor assembly. The generator includes a computer configured to (1) measure a time of energy delivered to the target tissue, (2) receive a temperature reading from the thermal feedback assembly, (3) estimate a size of an ablation volume based on the temperature reading, a distance between the electrode probe assembly and each temperature sensor assembly, and the measured time, (4) calculate a growth rate of the ablation volume based on the estimated size. The computer may also determine the ablation procedure is complete when the growth rate is less than or equal to a threshold.
