An electrosurgical system for treating biological tissue that comprises: an electrosurgical generator to supply microwave energy; a surgical scoping device having a steerable insertion cord for insertion to a treatment site; and an electrosurgical instrument dimensioned to fit within an instrument channel that is located within the insertion cord. The electrosurgical instrument comprises: a flexible coaxial cable arranged to convey the microwave energy; and a radiating tip portion connected at an end of the coaxial cable and configured to receive microwave energy. The radiating tip portion comprises: a coaxial transmission line for conveying the microwave energy; and a needle tip mounted at an end of the proximal coaxial transmission line, wherein the electrosurgical instrument is slidable within the instrument channel to extend the needle tip beyond an end of the instrument channel to puncture biological tissue; the needle tip is arranged to deliver the microwave energy into biological tissue.

An energy delivery system comprises a transmission member and an antenna at a distal end of the transmission member. The antenna includes a first conductive arm, an insulator extending around the first conductive arm, and a second conductive arm. The second conductive arm includes a coil. The system also comprises a barrier layer surrounding the transmission member and antenna. The barrier layer extends from a proximal portion of the transmission member to a distal portion of the antenna. The system also comprises a jacket surrounding the barrier layer and forming a fluid channel for receipt of a cooling fluid.

An electrosurgical instrument capable of supporting resonance of microwave energy at multiple frequencies. The instrument comprises a coaxial cable and a radiating distal tip portion arranged to receive microwave energy from the coaxial cable. The radiating tip portion consists of a dielectric material having an electrical length selected in conjunction with its dielectric properties at three or more frequencies of microwave energy to support resonance at each frequency. By providing a single device that can effectively couple microwave energy into biological tissue at three or more frequencies, tissue ablation can be performed rapidly with accuracy. The instrument may be used in an apparatus that includes a generator arranged to supply microwave energy at three or more different frequencies.

An esophageal ablation system including a positioner, an elongated, flexible shaft extending from the positioner, and a microwave emitter assembly disposed near the distal end of the shaft. The emitter assembly includes one or more microwave antennae and a balloon for spacing the antennae relative to target tissue. The device may have an inner balloon for deploying the antenna. The systems, devices and methods disclosed are useful for treating Barrett's Esophagus, Esophageal Adenocarcinoma, and Squamous Cell Carcinoma.

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.

An electrosurgical vessel sealing device that can seal biological vessels using a confined microwave field that yields a well-defined seal location with low thermal margin. The device comprises a pair of jaws that are movable relative to each other to grip biological tissue. A blade for cutting the gripped tissue is slidable between the jaws. A coplanar microstrip antenna is mounted on the inner surface of one or both of the pair of jaws to emit microwave energy into the gap therebetween. The device may comprise a separate dissector element to enable fine tissue cutting and dissection to be performed.

Apparatus and systems of liquid metal-based tunable coaxial antenna for microwave ablation are described. Tunable antennas are capable of maintaining the optimal impedance matching in different organs of treatment as well as actively improving tissue heating during the course of the ablation. Efficient energy delivery to various tumor tissue and tissue conditions is critical in creating larger tumor margins and reducing the risk for local tumor progression. Efficient energy delivery can also help decrease the need for aggressive cooling mechanism from reflected power and antenna shaft heating. The tuning can be achieved by small physical motion of liquid metal plug actuated by pressure regulator.

A variable-length microwave ablation probe is provided. The probe is configured to have a range of resonant frequencies. The probe includes a microwave antenna, an outer conductor, and a cap. The probe further includes a radiation window that is at least partially transparent to microwave energy. The distal boundary of the outer conductor or the proximal boundary of the cap varies in distance from the probe distal end. The probe can have a choke length, an arm length, a radiating portion length, and a cap length. The lengths can each affect the resonant frequency of the antenna. Some examples provide a variable choke length, a variable arm length, a variable radiating portion length, and/or a variable cap length.

Various embodiments provide a microwave amplification apparatus for an electrosurgical instrument. The microwave amplification apparatus comprises: a cable assembly; a proximal launch portion, and a distal amplification portion. The proximal launch portion is connected to a proximal end of the cable assembly, and comprises: a DC source configured to launch a DC signal along the cable assembly, and a microwave source configured to launch a microwave signal along the cable assembly. The distal amplification portion is connected to a distal end of the cable assembly, and comprises: a power amplifier configured to receive the microwave signal as an input signal to be amplified. The distal amplification portion is configured to apply the DC signal as a drain voltage across the power amplifier. The power amplifier has an output that is connectable to deliver an amplified microwave signal to a structure that is configured to deliver microwave energy into biological tissue.

An electrosurgical instrument with a radiating tip portion having a relative permeability and/or relative permittivity that is selected to provide an electrical length for the radiating tip portion that enables effective delivery into biological tissue of microwave EM energy supplied thereto, at two or more frequencies of choice. The instrument has a radiating tip portion disposed to receive microwave EM energy from a coaxial cable, the radiating tip portion having a first effective relative permeability at a first frequency and a second effective relative permeability at a second frequency.