Tumor ablation devices and related systems and methods are disclosed. Some tumor ablation devices include an RF energy delivery probe with two conductors and one or more thermocouples. The thermocouple measures a temperature at a location on one of the conductors. A generator can produce a current to be conducted between the first conductor and the second conductor via tissue within a desired ablation region. The ablation regions created by the RF energy delivery probe are symmetric about poles of the first conductor and the second conductor. A distal portion of the RF energy delivery probe may articulate, enabling a user to position the RF energy delivery probe in a proper position to ablate the tumor. The thermocouples may be disposed on a flexible or wired thermocouple circuit that is disposed between insulators.