A system including a catheter navigable to a location within a patient, a lumen extending through the catheter and ending at the distal end in an orifice, a fluid controller in fluid communication with the lumen of the catheter and capable of supplying a fluid to or removing a fluid from an area proximate the desired location. The control of the fluid in the area proximate the desired location affecting a dielectric constant of the area proximate the desired location. The system includes a microwave energy source, and a microwave ablation probe connected to the microwave energy source, the microwave ablation probe being navigable to a desired location within the patient. Application of energy from the microwave energy source to the microwave ablation probe in an area proximate the desired location having the affected dielectric constant results in a substantially spherical tissue effect in the area proximate the desired location.

An electrosurgical instrument capable of performing both thermal ablation and electroporation in a minimally invasive manner. The instrument is dimensioned to fit within an instrument channel of an endoscope to enable non-percutaneous insertion. The instrument comprises a radiating tip mounted at a distal end of a coaxial transmission line to receive microwave EM energy from the coaxial transmission line and emit it as a field around the radiating tip. The instrument further comprises an auxiliary transmission line arranged to convey electromagnetic energy having an electroporation waveform to a microelectrode array mounted on the radiating tip. The electroporation waveform may be a radiofrequency or low frequency electromagnetic (EM) signal. The microelectrode array may comprise a plurality of nanoscale conductive electrode elements.

An electrosurgical device (10) is provided that is operable to deliver microwave energy within a controlled angular expanse to cause targeted tissue ablation. The device (10) comprises a blocking or reflecting material such as cylindrical members (34) that are laterally spaced from the antenna (20) that is operable to emit the microwave energy. The reflecting material creates regions in and/or surrounding the device into which sensors (51), such as thermocouple wires, may be placed to monitor a condition associated with the device or the patient's body.

An electrosurgical instrument having a microwave ablation antenna dimensioned to be suitable for insertion into a pancreas via a surgical scoping device, to provide a rapid and accurate alternative to known RF ablation techniques. The electrosurgical instrument comprises: a proximal coaxial transmission line for conveying microwave electromagnetic (EM) energy; a distal radiating portion; and an intermediate impedance transformer arranged to match an impedance of the coaxial transmission line to an impedance of the distal radiating portion, wherein the distal radiating portion comprises a microwave antenna for emitting the microwave EM energy conveyed by the coaxial transmission line, wherein the distal radiating portion has a maximum outer diameter less than an outer diameter of the coaxial transmission line. With these features, the instrument is able to deliver microwave energy via a small diameter structure.

A system including a catheter navigable to a location within a patient, a lumen extending through the catheter and ending at the distal end in an orifice, a fluid controller in fluid communication with the lumen of the catheter and capable of supplying a fluid to or removing a fluid from an area proximate the desired location. The control of the fluid in the area proximate the desired location affecting a dielectric constant of the area proximate the desired location. The system includes a microwave energy source, and a microwave ablation probe connected to the microwave energy source, the microwave ablation probe being navigable to a desired location within the patient. Application of energy from the microwave energy source to the microwave ablation probe in an area proximate the desired location having the affected dielectric constant results in a substantially spherical tissue effect in the area proximate the desired location.

A microwave ablation device including a cable assembly configured to connect a microwave ablation device to an energy source and a feedline in electrical communication with the cable assembly. The microwave ablation device further includes a balun on an outer conductor of the feedline, and a temperature sensor on the balun sensing the temperature of the balun.

An antenna system is provided. The antenna system includes a coaxial cable, an antenna, and an impedance matching structure. The coaxial cable includes a center conductor extending a length of the coaxial cable, a dielectric material surrounding the center conductor along the length of the coaxial cable, and a conductive shield surrounding the dielectric material along the length of the coaxial cable. The antenna includes a conductor having an electrical length of half a wavelength at a selected operating frequency. The impedance matching structure includes a second center conductor mounted between an end of the center conductor of the coaxial cable and a feed end of the antenna. The impedance matching structure is configured to match an impedance of the coaxial cable to an impedance of the antenna.

A surgical instrument for ablating tissue includes a handle portion and a shaft assembly extending distally from the handle portion. The shaft assembly includes an outer shaft, a coaxial cable extending through the outer shaft, and an electrode coupled to a distal portion of the outer shaft. The coaxial cable has a distal portion that forms a microwave antenna configured to transmit microwave energy radially outward and through the outer shaft. The electrode is configured to transmit radiofrequency energy. An actuation of the handle portion activates the transmission of the microwave energy from the microwave antenna and/or the transmission of the radiofrequency energy from the at least one electrode.

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.

A microwave ablation probe (200; 300; 400), comprising: an applicator (202; 302; 402) arranged to apply microwave radiation to heat surrounding tissue; a feeding cable (204; 304; 404) arranged to supply electromagnetic energy to the applicator; a coolant flow path (206) via which coolant is able to flow; and a choke arranged to reduce power reflected from the applicator (202; 302; 402) along the feeding cable (204; 304; 404). The choke comprises a choke member (208; 209; 308; 408) cooled by coolant flowing in the coolant flow path (206). The choke member (208; 209; 308; 408) extends between two points spaced apart in a direction having at least a component parallel to a longitudinal axis of the feeding cable. The choke member (208; 209; 308; 408) comprises one or more turns extending around the longitudinal axis of the feeding cable. The choke member may be a spiral member (208; 308; 408).