Abstract: A multi-layer piezoelectric transducer includes a first polymeric layer of piezoelectric material having spaced apart first and second surfaces and a second polymeric layer of piezoelectric material having spaced apart first and second surfaces. A first ground layer overlies the first surface of the first polymeric layer and a second ground layer overlies the first surface of the second polymeric layer. A signal layer is sandwiched between the second surfaces of the first and second polymeric layers.

Abstract: An apparatus and method for applying sonic energy within the body of the living subject. A probe for applying sonic energy within the body of a subject includes a probe body having a proximal and a distal end adapted for insertion into the body of a subject, a spatially-distributed sonic transducer disposed adjacent to the distal end of the probe body and a device for moving one portion of the spatially-distributed transducer relative to another portion of the transducer while the distal end of the probe is disposed within the body of the subject.

Abstract: Apparatus and methods for attaching and forming enclosed inflatable members on an endoscope assembly with a disposable sheath are disclosed. In one embodiment, an apparatus includes a flexible and resilient cuff member that is positioned on the outer surface of the disposable sheath and sealably and fixedly bonded to the sheath cover material at the cuff edges to form an annular space capable of being inflated. The inflatable member formed thereby is inflated through a lumen internal to the sheath that has an opening into the interior annular space. In another embodiment, the annular space may be divided into separate inflatable lobes. In still another embodiment, the cuff member is a flexible and resilient member that is substantially toroidal in shape that is positioned on the outer surface of the sheath. In a further embodiment, the inflatable member is formed from an excess length of sheath cover material disposed on the disposable sheath.

Abstract: Apparatus and methods for attaching and forming enclosed inflatable members on an endoscope assembly with a disposable sheath are disclosed. In one embodiment, an apparatus includes a flexible and resilient cuff member that is positioned on the outer surface of the disposable sheath and sealably and fixedly bonded to the sheath cover material at the cuff edges to form an annular space capable of being inflated. The inflatable member formed thereby is inflated through a lumen internal to the sheath that has an opening into the interior annular space. The inflatable member may be inflated to exert a longitudinal force on the insertion tube, thereby moving the endoscope assembly along a body passage. Alternately, a sheath may include a plurality of inflatable cuffs that may be inflated to create an isolated space therebetween within the body passage.

Abstract: Apparatus and methods for ablating tissue surrounding a tubular anatomical structure such as the wall of a blood vessel or prostatic tissue surrounding the urethra. The apparatus includes an ultrasonic emitter such as a cylindrical emitter and an inflatable annular lens balloon surrounding the ultrasonic emitter. The lens balloon is inflated with a liquid having acoustic velocity different than that of the surrounding medium, so as to form an annular refracting surface. The acoustic energy from the emitter is focused into an annular focal region.

Abstract: A collapsible ultrasonic reflector incorporates a gas-filled reflector balloon, a liquid-filled structural balloon an ultrasonic transducer disposed within the structural balloon. Acoustic energy emitted by the transducer is reflected by a highly reflective interface between the balloons. In a cardiac ablation procedure, the ultrasonic energy is focused into an annular focal region to ablate cardiac tissue extending in an annular path along the wall. Devices for stabilizing the balloon structure and for facilitating collapse and withdrawal of the balloon structure are also disclosed.

Abstract: A lens for focusing an ultrasound wave having a wavelength, includes a plurality of substantially concentric rings disposed about a central point, at least one of the rings having a substantially triangular cross-section defined by first, second, and third sections, the first section extending from a proximal end radially away from the central point to a distal end, the second section extending from the distal end of, and substantially perpendicular to, the first section and terminating at a peak, and the third section smoothly sloping from the proximal end of the first section to the peak of the second section, and wherein the first, second and third sections have lengths with respect to the wavelength of the ultrasound wave such that (i) phases of the ultrasound wave are substantially additive at a focal point located on an axis perpendicular to the lens that passes through the central point, and (ii) aggregate focused ultrasound energy would not be predicted at the focal point by Snell's law refraction.

Abstract: A pressure equalized flow control apparatus and method controls the flow of fluid through a resilient tube. The resilient tube is surrounded by an enclosed chamber having inlet and outlet ports in fluid communication with the interior of the resilient tube. A vent connecting the interior of the resilient tube with the interior of the enclosed chamber equalizes the fluid pressure inside the resilient tube with the fluid pressure outside the resilient tube within the enclosed chamber. By equalizing the pressures inside and outside of the resilient tube, the vent prevents the resilient tube from collapsing when the resilient tube is under suction. Similarly, the pressure equalization prevents a positive fluid pressure from exerting an outward force on the wall of the tube which must be overcome to pinch the tube. Thus, by using pressure equalization, the vent enables the resilient tube to have a relatively thin wall that is easily pinched to close the resilient tube.