Temperature controlled rf coagulation

Claim 1

A method of ohmic heating of tissue of a patient in order to induce coagulation, comprising the steps of selecting a temperature at which target tissue is to be coagulated through flow of RF current through tissue disposed between a thermally conductive, tissue-engaging electrode and at least one other patient-contacting RF conductor, said selected temperature being a maximum temperature consistent with avoiding detrimental sticking of the electrode to the tissue directly engaged by the electrode and avoiding undesired desiccation of tissue, repeatedly switching between a power on mode and a power off mode, during said power on mode, applying RF power to said electrode and said at least one other conductor in order to cause RF current of a frequency in the range of about 100 kilohertz to 100 megahertz to flow between said electrode and said at least one other conductor for tissue-coagulation, said thermally conductive, tissue-engaging electrode concentrating RF current in a local region of the patient's tissue in the vicinity of said electrode, during said power off mode, sensing, by means of a temperature sensor carried by and in thermally conductive relationship with said thermally conductive, tissue-engaging electrode, the temperature of said electrode in the absence of RF signal, thereby to sense indirectly the temperature of tissue contacted directly by the electrode, said temperature sensor having a greater accuracy in the absence of interfering RF electrical noise caused by said RF current passing through said thermally conductive electrode than in the presence of said interfering RF electrical noise, comparing said sensed temperature to said selected, maximum temperature, modulating said Rf power applied to said electrode in accordance with comparison of said sensed temperature and said selected, maximum temperature, and coagulating said target tissue at said selected, maximum temperature as said modulated RF current flows between said electrode and said at least one other conductor during said power on mode.

Claim 2

A method of ohmic heating of tissue of a patient in order to induce coagulation, comprising the steps of selecting a temperature at which target tissue is to be coagulated through flow of RF current through tissue disposed between a thermally conductive, tissue-engaging electrode and at least one other patient-contacting RF conductor, said selected temperature being a maximum temperature consistent with avoiding detrimental sticking of the electrode to the tissue directly engaged by the electrode and avoiding undesired desiccation of tissue, repeatedly switching between a power on mode and a power off mode, during said power on mode, applying RF power to said electrode and said at least one other conductor in order to cause RF current of a frequency in the range of about 100 kilohertz to 100 megahertz to flow between said electrode and said at least one other conductor for tissue-coagulation, said thermally conductive, tissue-engaging electrode concentrating RF current in a local region of the patient's tissue in the vicinity of said electrode, during said power off mode, sensing, by means of a temperature sensor carried by and in thermally conductive relationship with said thermally conductive, tissue-engaging electrode, the temperature of said electrode in the absence of RF signal, thereby to sense indirectly the temperature of tissue contacted directly by the electrode, said temperature sensor having a greater accuracy in the absence of interfering RF electrical noise caused by said RF current passing through said thermally conductive electrode than in the presence of said interfering RF electrical noise, comparing said sensed temperature to said selected, maximum temperature, modulating said Rf power applied to said electrode in accordance with comparison of said sensed temperature and said selected, maximum temperature, and coagulating said target tissue at said selected, maximum temperature as said modulated RF current flows between said electrode and said at least one other conductor during said power on mode.