Various embodiments provide an electrosurgical apparatus for treating biological tissue with microwave energy. The apparatus comprises: a microwave energy signal generator for generating a microwave energy waveform; an electrosurgical instrument arranged to deliver the microwave energy waveform from a distal end thereof for tissue treatment; and a controller in communication with the microwave energy signal generator. The microwave energy signal generator is configured to deliver the microwave energy waveform as one microwave energy signal pulse. The controller is configured to control the profile of the one microwave energy signal pulse to cause ablation or coagulation of the biological tissue and to substantially prevent the one pulse from causing heat to build-up in the electrosurgical instrument.

An antenna 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 wound around at least a first portion of the insulator to form a second conductive arm coil. A property of the insulator varies along an insulator longitudinal axis of the insulator. The insulator includes a set of formed patterns along at least a portion of the insulator longitudinal axis.

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 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 antennas and a balloon for spacing the antennas 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.

Flexible instruments and associated systems and methods are disclosed herein. In some embodiments, a flexible instrument comprises an elongate device having an inner conductor, an outer conductor surrounding the inner conductor, and a dielectric layer insulating the inner conductor from the outer conductor. The flexible instrument further includes a recess formed in the outer conductor. An insert is positioned within the recess and about the inner conductor.

A microwave ablation antenna based on a spiral slot, including a conical ablation needle head and a semi-rigid coaxial needle rod. A front end of the semi-rigid coaxial needle rod is interconnected with a tail end of the ablation needle head. An outer conductor behind a connection is provided with a plurality of optimizable spiral slots for radiation, and a plurality of annular slots are not formed or formed behind the spiral slots for impedance matching and radiation. Energy is transmitted along a semi-rigid co-axis and is efficiently radiated at the slots.

An electrosurgical device (10) operable to deliver microwave energy to cause targeted tissue ablation is provided. The electrosurgical device (10) comprises an antenna (26), a reflector (30), and a dielectric material (34) disposed therebetween. The selection of the dielectric material (30) and the relative positioning of the antenna (26) and the reflector (30) provide impedance matching between the antenna (26) and a transmission line (12) so as to minimize heating along the length of the device (10) during use.

A method for forming a resonating structure within a body lumen, the method including advancing a flexible microwave catheter into a body lumen of a patient, the flexible microwave catheter including a radiating portion at the distal end of the flexible microwave catheter, the radiating portion configured to receive microwave energy, and at least one centering device proximate the radiating portion configured to deploy radially outward from the flexible microwave catheter; positioning the radiating portion near tissue of interest; deploying the at least one centering device radially outward from the flexible microwave catheter within the body lumen such that a longitudinal axis of the radiating portion is substantially parallel with and at a fixed distance from a longitudinal axis of the body lumen near the targeted tissue; and delivering microwave energy to the radiating portion such that a circumferentially balanced resonating structure is formed with the body lumen.

An electrosurgical device (10) operable to deliver microwave energy to cause targeted tissue ablation is provided. The electrosurgical device (10) comprises an antenna (26), a reflector (30), and a dielectric material (34) disposed therebetween. The selection of the dielectric material (30) and the relative positioning of the antenna (26) and the reflector (30) provide impedance matching between the antenna (26) and a transmission line (12) so as to minimize heating along the length of the device (10) during use.

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.