Abstract: A cardiac ablation apparatus including a solenoidal antenna, monitoring electrodes, and a coupling network at a distal end of a catheter transmission line, and another coupling network at the proximal end of the catheter transmission line to connect the catheter to the source of radiofrequency (RF) power and to an intracardiac electrogram monitor. Solenoidal antenna design includes single and multiple windings with varying geometrical features. Plated plastic tri-axial design of a transmission line offers unitary fabrication. A catheter with variable impedance electrode and gap coatings has features useful for both ablation and for hyperthermia applications.

Abstract: The invention provides a thermal design of a catheter where the active electrode is partially covered by a heat conducting and electrically insulating heat-sink layer for localizing and controlling an electrical heating of tissue and cooling of the active electrode by convective blood flow. The invention further comprises a current equalizing coating for gradual transition of electrical properties at a boundary of a metallic active electrode and an insulating catheter tube. The current equalizing coating controls current density and the distribution of tissue heating.

Abstract: Liquid metal gallium-filled balloon catheter is connected to a source of heating power. An improved method of hyperthermia and ablation is made possible by ease of insertion and conformity to complex intracavitary geometry by liquid metal. Closeness of gallium melting point to body temperature makes insertion of solid gallium possible and subsequent melting after insertion. Method of balloon ablation of endometrium is described.

Abstract: A cardiac ablation apparatus including a solenoidal antenna, monitoring electrodes, and a coupling network at a distal end of a catheter transmission line, and another coupling network at the proximal end of the catheter transmission line to connect the catheter to the source of radiofrequency (RF) power and to an intracardiac electrogram monitor. Solenoidal antenna design includes single and multiple windings with varying geometrical features. Plated plastic tri-axial design of a transmission line offers unitary fabrication. A catheter with variable impedance electrode and gap coatings has features useful for both ablation and for hyperthermia applications.

Abstract: The invention provides a thermal design of a catheter where the active electrode is partially covered by a heat conducting and electrically insulating heat-sink layer for localizing and controlling an electrical heating of tissue and cooling of the active electrode by convective blood flow. The invention further comprises a current equalizing coating for gradual transition of electrical properties at a boundary of a metallic active electrode and an insulating catheter tube. The current equalizing coating controls current density and the distribution of tissue heating.

Abstract: The invention provides an intracavitary ultrasonic scanner with a helical scan. Mechanical and electronic steerable array implementations of the helical scan are described. A plastic cover sheath, filled with coupling fluid, covers the probe of the scanner. Portions of probe are porous allowing the coupling fluid to penetrate to the outside of the sheath. An improved polar coordinate decoding system provides an accurate control of the scan and allows storage of scan information in voxel memory.

Abstract: Improvement in active noise reduction based on a negative feedback electro-acoustical system which consists of an Electronic Earplug seated in the concha fossa combining active and passive noise reduction in the quiet zone at the ear, a bilateral transducer circuit which drives a speaker as an acoustical velocity source, a shunt feedback control filter network which improves stability and increases noise reduction, and a combined input noise-filter/feedback system. A typical application is in a noisy environment for hearing protection and for improved communication capability, e.g., in vehicular communication, telephone, intercom, hearing aids, and stethoscopes.

Abstract: Radiofrequency (RF) heating applicator, located at the distal end of a coaxial line catheter, produces deeper and more uniform heat dissipation. The active applicator element is a conductor helix fed via the coaxial line. The applicator has provisions for interception of intracardiac electrogram signal. A cardiac ablation system using the above catheter, ablates cardiac tissue responsible for ventricular tachycardia. The ablation system provides means to monitor intracardiac electrograms and to control the RF power. A variation of the helical applicator can be used in a hyperthermia system for treatment of malignant tumors.

Abstract: Piezopolymer actuator, wound in a bifilar fashion on two pins, is operated in a compressive mode without buckling. In addition to constraining motion of the winding along the surface of the pins, the pins also provide wide area electrical contacts with conductive electrodes on the surfaces of the piezopolymer strip. The electrodes consist of a thin film of metallization coated with graphite. Graphite coating heals microcracks in metallization, adds body to the piezopolymer strip, and lubricates winding-pin interfaces. Modular linear arrays of actuators are readily built from a single strip of piezopolymer. Linear array modules are in turn clamped together to form a two-dimensional array. Typical application is a tactile array for the blind.