Abstract: A system and method of treating tissue of a patient's body includes providing a power source coupled to at least one probe assembly. The probe assembly has at least one an elongate member with a distal region and a proximal region. The distal region has an electrically and thermally-conductive energy delivery device that includes one or more internal lumens and an electrically and thermally-conductive protrusion having a temperature sensing element. The method also includes inserting the energy delivery device into the patient's body. Further, the method includes routing the energy delivery device to the tissue of the patient's body. Moreover, the method includes simultaneously circulating the cooling fluid through the internal lumens via at least one pump assembly and delivering energy from the power source to the tissue through the energy delivery device.