Abstract: Disclosed herein is a method and system for controlling radio frequency (RF) output according to the change in impedance of biological cells. In the method of controlling radio frequency (RF) output according to a change in impedance of biological cells, phases of RF voltage and current applied to the electrode are detected and a difference between the phases is obtained. A change in impedance such as a resistance component and a capacitive reactance component (XC) of the biological cells at the time of performing cauterization is obtained. An inductive reactance component (XL) is connected to an RF output terminal so as to cancel the capacitive reactance component (XC) (XC=XL), thus enabling the output impedance to have a resistance component.

Abstract: Disclosed herein is a common-mode noise filter of an RF generator for radiofrequency ablation. The common-mode noise filter of the RF generator for RFA amplifies an oscillation frequency provided by an oscillator to AC output using amplification means, and providing the amplified oscillation frequency to electrodes. The common-mode noise filter is disposed between the amplification means and the electrodes, thus eliminating harmonic components generated by the electrodes depending on conditions of medical treatment when the electrodes are used. Accordingly, the present invention can prevent the distortion of images or waveforms attributable to harmonic components from occurring in a diagnostic imaging device such as a diagnostic ultrasound system used together with the RF generator for RFA as well as in the RF generator's own display unit.

Abstract: Disclosed herein is the resonant inverter of a radio frequency (RF) generator for radiofrequency ablation (RFA). The resonant inverter of RF generator for RFA amplifies to high power an oscillation frequency output from an oscillator and provides the amplified oscillation frequency to an electrode. The resonant inverter processes the oscillation frequency output from the oscillator as a high-power sine wave having a frequency of 480 kHz and a Root Mean Square (RMS) power of 30 to 200 watts, and transfers the high-power sine wave to the electrode.

Abstract: Provided are a guide wire and a catheter system. The catheter system includes a hollow catheter inserted into a fistula of a living body, the catheter having two open ends and a coaxially-formed lumen; and a bipolar electrode type guide wire including a wire body formed of a metal and elongated to be inserted into the catheter in one direction, an insulating material coated on an outer periphery of the wire body to insulate the wire, a first electrode attached to one end of the wire body, a second electrode spaced a predetermined distance apart from the first electrode, a first lead elongated along the wire body to be attached to the first electrode to electrically connect a radio-frequency generator for generating radio-frequency current to the first electrode, and a second lead elongated along the wire body to be attached to the second electrode to electrically connect the radio-frequency generator to the second electrode, the second lead being electrically insulated from the first lead.

Abstract: The object of this invention is to provide a stent for high frequency thermotherapy, which is fabricated by knitting first superlastic shape-memory alloy wires as a way to allow the first superelastic shape-memory alloy wires to cross each other at different positions to make a hollow cylindrical stent body having a net structure with a plurality of meshes. The stent body is covered with an insulating substance. A hollow cylindrical conductive body surrounds a waist part of the stent body while any one end or both ends of the conductive body is attached to the waist part of the stent body. At this time, the conductive body is fabricated by knitting second superelastic shape-memory alloy wires as a way to allow the second superelastic shape-memory alloy wires to cross each other at different positions.

Abstract: The object of the present invention is to provide an electrode device for high frequency thermotherapy, including a main casing, an electrode needle, a first engaging part, and a guide unit coupled to the engaging part to be longitudinally moved relative to the electrode needle. The guide unit has a guide tube to receive therein the electrode needle to expose a tip of the electrode needle to the outside of an end of the guide tube. Thus, the exposed length of the tip of the electrode needle is varied according to a position that the guide unit is coupled to the engaging part. The electrode device may further include a three-way valve -provided between the main casing and the guide unit to supply a liquid medicine or water t a desired part of a patient body.

Abstract: Disclosed is an esophageal stent placed in a stenosed part of the esophagus having a flexible tube to prevent the reverse flow of gastric contents from the stomach is coupled to the lower end of the esophageal stent. The flexible tube has an inside membrane and an outside membrane adhered to each other, thus having a twofold structure with at least one core longitudinally placed between the adhered inside and outside membranes while the core extends from the upper end toward the lower end of the flexible tube. Thus, the flexible tube is prevented from being inverted, and prevents the reverse flow of the gastric contents, and maximizes the operational reliability of the esophageal stent. The flexible tube does not cause a patient pain or discomfort due to frictional contact of the tube with the inner surface of the stomach when the tube moves in the stomach.

Abstract: A flexible self-expandable stent has inside and outside stent bodies each fabricated by knitting first and second super-elastic shape memory alloy wires into a net-like structure with the first wire zigzagged with a diagonal length P interlocked with the second wire zigzagged with a diagonal length 2P at a plurality of interlocked points with intersecting points therebetween to allow the stent bodies to apply force against longitudinal contraction of the stent bodies. The interlocked points and the intersecting points form a plurality of diamond-shaped meshes in the net-like structure of each stent body. A hollow rubber tube is closely fitted between the inside and outside stent bodies, with each of the overlapped ends of the rubber tube and the stent bodies being integrating into a single structure.

Abstract: Disclosed herein is a flexible self-expandable stent using shape memory alloy for expanding stenosal portions and method and apparatus for fabricating the same.

Abstract: A flexible self-expandable stent which is made of a super-elastic shape memory alloy and used for insertion in the desired part of a contracted muscular passage, a contracted blood vessel, or an artery having an aneurysm so as to open the contracted part or repair the arterial dilatation. The stent has inside and outside stent bodies each fabricated by knitting first and second super-elastic shape memory alloy wires to make a net-like structure in that the first wire, which is zigzagged with a diagonal length P, is interlocked with the second wire, which is zigzagged with a diagonal length 2P, to form a plurality of interlocked points at which the stent bodies are contracted and expanded in a longitudinal direction. A repeated intersection of the first and second wires forms a plurality of intersecting points to allow the stent bodies to apply force against the longitudinal contraction of the stent bodies.