Abstract: An isolating circuit for electrosurgical generator arranged to produce radiofrequency (RF) energy and microwave energy for treating biological tissue. The generator has an RF channel and a microwave channel which are combined at signal combiner to enable the RF energy and microwave energy to be delivered into tissue along a common feed path. The isolating circuit comprises a tunable waveguide isolator at a junction between the microwave channel and signal combiner, and can include a capacitive structure between a ground conductor of the signal combiner and a conductive input section of the waveguide isolator to inhibit coupling of the RF energy and leakage of the microwave energy. The isolating circuit can combine into a single tunable unit all the necessary components to isolate the microwave and RF channels from one another whilst providing a high withstanding voltage.

Abstract: An electrosurgical apparatus having a feed structure comprising a radiofrequency (RF) channel for conveying RF electromagnetic (EM) radiation from an RF signal generator to a probe and a microwave channel for conveying microwave EM radiation from a microwave signal generator to the probe, wherein the RF channel and microwave channel comprise physically separate signal pathways, wherein the feed structure includes a combining circuit having an input connected to the signal pathway on the RF channel, another input connected to the signal pathway on the microwave channel, and an output connected to a common signal pathway for conveying the RE EM radiation and EM radiation separately or simultaneously to the probe, and wherein the microwave channel includes a waveguide isolator connected to isolate the signal pathway on the microwave channel from the RF EM radiation.

Abstract: A pulsed RF cut waveform profile for electrosurgery, in which each pulse is formed of a composite of different pulse portions. The pulse includes a controllable treatment portion whose duration can be truncated as necessary to ensure that the average power delivered by the pulse as a whole does not exceed a predetermined value. A limit for the average power delivered by the composite pulse (i.e. total energy delivered over the duration of the ON and OFF portions divided by the pulse duration) may be selectable by the operator. The ON portion may have multiple sub-portions, which have different purposes. Each pulse may be automatically controlled for pulse width in this manner, so that the RF signal effectively responds intelligently to conditions at the probe tip during treatment.

Abstract: A method of controlling RF power delivered from a bipolar electrosurgical instrument into a biological tissue. The method comprises controlling the profile of a RF waveform by: setting a maximum voltage limit for a voltage applied across the bipolar electrosurgical instrument; calculating a tissue resistance, the calculating step including a correction for an impedance associated with the RF channel; determining an objective tissue current limit from the calculated tissue resistance and a predetermined power dissipation target; and dynamically adjusting the current limit based on the determined objective tissue current limit. This control method may ameliorate the impact of an increased cable length on the accuracy of control of RF waveforms delivered to the tip of the probe.

Abstract: An isolating circuit for electrosurgical generator arranged to produce radiofrequency (RF) energy and microwave energy for treating biological tissue. The generator has an RF channel and a microwave channel which are combined at signal combiner to enable the RF energy and microwave energy to be delivered into tissue along a common feed path. The isolating circuit comprises a tunable waveguide isolator at a junction between the microwave channel and signal combiner, and can include a capacitive structure between a ground conductor of the signal combiner and a conductive input section of the waveguide isolator to inhibit coupling of the RF energy and leakage of the microwave energy. The isolating circuit can combine into a single tunable unit all the necessary components to isolate the microwave and RF channels from one another whilst providing a high withstanding voltage.

Abstract: An isolating circuit for an electrosurgical generator arranged to produce radiofrequency (RF) energy and microwave energy for treating biological tissues is provided. The generator has an RF channel and a microwave channel which are combined at a signal combiner to enable the RF energy and microwave energy to be delivered into tissues along a common feed path. The isolating circuit includes a tunable wavelength isolator at a junction between the microwave channel and the signal combiner, and can include a capacitive structure between a ground conductor of the signal combiner and a conductive input section of the waveguide isolator to inhibit coupling of the RF energy and leakage of the microwave energy. The isolating circuit can combine into a single tunable unit all the necessary components to isolate the microwave and RF channels from one another while providing a high withstanding voltage.

Abstract: An electrosurgical apparatus having a feed structure comprising a radiofrequency (RF) channel for conveying RF electromagnetic (EM) radiation from an RF signal generator to a probe and a microwave channel for conveying microwave EM radiation from a microwave signal generator to the probe, wherein the RF channel and microwave channel comprise physically separate signal pathways, wherein the feed structure includes a combining circuit having an input connected to the signal pathway on the RF channel, another input connected to the signal pathway on the microwave channel, and an output connected to a common signal pathway for conveying the RE EM radiation and EM radiation separately or simultaneously to the probe, and wherein the microwave channel includes a waveguide isolator connected to isolate the signal pathway on the microwave channel from the RF EM radiation.

Abstract: An electrosurgical apparatus having a feed structure comprising a radiofrequency (RF) channel for conveying RF electromagnetic (EM) radiation from an RF signal generator to a probe and a microwave channel for conveying microwave EM radiation from a microwave signal generator to the probe, wherein the RF channel and microwave channel comprise physically separate signal pathways, wherein the feed structure includes a combining circuit having an input connected to the signal pathway on the RF channel, another input connected to the signal pathway on the microwave channel, and an output connected to a common signal pathway for conveying the RE EM radiation and EM radiation separately or simultaneously to the probe, and wherein the microwave channel includes a waveguide isolator connected to isolate the signal pathway on the microwave channel from the RF EM radiation.

Abstract: An isolating circuit for electrosurgical generator arranged to produce radiofrequency (RF) energy and microwave energy for treating biological tissue. The generator has an RF channel and a microwave channel which are combined at signal combiner to enable the RF energy and microwave energy to be delivered into tissue along a common feed path. The isolating circuit comprises a tunable waveguide isolator at a junction between the microwave channel and signal combiner, and can include a capacitive structure between a ground conductor of the signal combiner and a conductive input section of the waveguide isolator to inhibit coupling of the RF energy and leakage of the microwave energy. The isolating circuit can combine into a single tunable unit all the necessary components to isolate the microwave and RF channels from one another whilst providing a high withstanding voltage.

Abstract: A pulsed RF cut waveform profile for electrosurgery, in which each pulse is formed of a composite of different pulse portions. The pulse includes a controllable treatment portion whose duration can be truncated as necessary to ensure that the average power delivered by the pulse as a whole does not exceed a predetermined value. A limit for the average power delivered by the composite pulse (i.e. total energy delivered over the duration of the ON and OFF portions divided by the pulse duration) may be selectable by the operator. The ON portion may have multiple sub-portions, which have different purposes. Each pulse may be automatically controlled for pulse width in this manner, so that the RF signal effectively responds intelligently to conditions at the probe tip during treatment.

Abstract: A method of controlling RF power delivered from a bipolar electrosurgical instrument into a biological tissue. The method comprises controlling the profile of a RF waveform by: setting a maximum voltage limit for a voltage applied across the bipolar electrosurgical instrument; calculating a tissue resistance, the calculating step including a correction for an impedance associated with the RF channel; determining an objective tissue current limit from the calculated tissue resistance and a predetermined power dissipation target; and dynamically adjusting the current limit based on the determined objective tissue current limit. This control method may ameliorate the impact of an increased cable length on the accuracy of control of RF waveforms delivered to the tip of the probe.

Abstract: An electrosurgical apparatus having a feed structure comprising a radiofrequency (RF) channel for conveying RF electromagnetic (EM) radiation from an RF signal generator to a probe and a microwave channel for conveying microwave EM radiation from a microwave signal generator to the probe, wherein the RF channel and microwave channel comprise physically separate signal pathways, wherein the feed structure includes a combining circuit having an input connected to the signal pathway on the RF channel, another input connected to the signal pathway on the microwave channel, and an output connected to a common signal pathway for conveying the RE EM radiation and EM radiation separately or simultaneously to the probe, and wherein the microwave channel includes a waveguide isolator connected to isolate the signal pathway on the microwave channel from the RF EM radiation.