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.

An end effector structure provided for an ablation apparatus, optionally having a covering balloon structure made from a compliant material such as rubber like materials, as for example silicone, including an antenna to emit microwave energy for cavity ablation that is covered with microwave energy absorbing and heat radiating material so that when end effector inserted into the body cavity, the balloon is filled up with liquid and balloon stretches to conform to a profile of the cavity to be ablated, and the applied microwave energy heats the liquid inside the balloon and heat energy to ablate or otherwise treat the body cavity tissue contacted with the compliant end effector. Other embodiments without the covering balloon apply heat directly to the cavity with the heated liquid.

Examples of a probe for microwave ablation are disclosed. The probe comprises a feed coaxial cable and an antenna that has a cylindrical outer housing with a predetermined diameter and a predetermined length defining a cavity therein and a radiating conductor positioned within the cavity with a matching stepped portion. The antenna further comprises a dielectric material placed in the cavity between the radiating conductor and the outer housing of the antenna to increase the mechanical strength of the probe as well as to improve the power coupling to the tissue to be ablated. The design of the coaxial cavity of the antenna with radiating conductor with a stepped portion fitted into dielectric materials increases antenna's mechanical strength to withstand higher temperatures and reduces an energy reflected back to the feed coaxial cable due to a good impedance match between the antenna and the feed cable such that antennas with smaller length can be used to fit curved paths.

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 ablation probe tip 100 having a shaft 102 with an insertion end 104 and an annular aperture 120 near the insertion end 104. A center of ablation 124 is located within the shaft 102 and surrounded by the annular aperture shaft 102. The ablation probe tip 100 may be part of an ablation probe system 50 that includes an ablation source 60 that provides ablation means 62 to the ablation probe tip 100. The center of ablation 124 is a focal region from which the ablation means 62 radiates through the annular aperture 120 to form an ablation zone 150, 160, 170. The system 50 has at least one intra-operative control selected from the group of: ablation zone positioning control, ablation zone shaping control, ablation center control, ablation zone temperature control, guided ablation volume/diameter control, and power loading control.

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 radially spaced from the insulator and 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 flow of a cooling fluid.

An antenna assembly for microwave ablation can include a radiator for emitting a microwave for ablation; a coaxial cable for transmitting the microwave for ablation generated by a microwave generator to the radiator; an annular composite structure is provided around the coaxial cable for inhibiting an electromagnetic wave from propagating backwards along the coaxial cable. In some embodiment, the annular composite structure comprises an annular nonmetallic layer and an annular metallic layer located outside the annular nonmetallic layer. In some embodiments, the annular metallic layer is electrically insulated from the coaxial cable. In some embodiments, the antenna assembly can be used with a microwave ablation needle. The annular composite structure can inhibit the backward propagation of the microwave along the coaxial cable exterior wall. In some embodiments, circulation water enters the radiation zone, to avoid high temperatures of the head the ablation needle.

A microwave antenna for ablating tissue in a patient includes a radiator configured to radiate microwave radiation. A cable is coupled to the radiator and includes a fluid inflow line and a fluid outflow line. The microwave antenna also includes a ceramic element coaxially disposed around the radiator. The ceramic element includes at least one internal channel configured to transport thermal energy away from the ceramic element.

An adjustable, structure providing an ablation apparatus, having a preformed structure made from compliant material such as rubber like material, foam or gel, with particles made of electromagnetic energy absorbing material. An antenna for radiating emitted microwave energy to generate heat and thus cause cavity ablation is located inside of the conformable adjustable structure. When end effector portion is inserted into the body cavity, the compliant adjustable structure is compliant to conform to a profile of the cavity to be ablated, and microwave energy is received to heat the adjustable structure resulting in heat energy that will ablate the cavity tissue in contact with the compliant end effector. Additionally, the shape of the end-effector compliant structure can be differently formed, depending of shape of tissue cavity to be ablated.

According to one aspect of the present disclosure, a microwave antenna assembly is disclosed. The antenna assembly includes a feedline having an inner conductor, an outer conductor and an inner insulator disposed therebetween and a radiating portion including a dipole antenna having a proximal portion and a distal portion. The antenna assembly also comprises a sheath disposed over the feedline and the radiating portion defining a chamber around the feedline and the radiating portion. The chamber is adapted to circulate coolant fluid therethrough. The antenna assembly further includes a connection hub having cable connector coupled to the feedline, an inlet fluid port and an outlet fluid port. The connection hub includes a bypass tube configured to provide for flow of the coolant fluid from the cable connector directly to the outlet fluid port.