An electrosurgical system includes an electrosurgical power generating source, an energy applicator operably associated with the electrosurgical power generating source, a heat-distribution indicator adapted to change echogenic properties in response to heat generated by energy delivered by the energy applicator, and a processor unit configured to generate at least one electrical signal for controlling at least one operating parameter associated with the electrosurgical power generating source. The system also includes an imaging system capable of acquiring image data. The imaging system is communicatively-coupled to the processor unit. The processor unit is adapted to determine an ablation rate at least in part based on analysis of one or more images acquired by the imaging system.
