Abstract: A probe for ultrasonically removing unwanted biological material, for example, from a vessel in a patient's cardiovascular system, includes a catheter assembly having distal and proximal catheter sections, each defining a respective lumen. A subassembly is connected to and between these catheter sections and houses piezoceramic transducer elements which are adapted to vibrate at ultrasonic frequencies. An elongate flexible working element (e.g., one or more wire elements) is housed within the distal catheter section and projects beyond that section's distal end so as to be adapted to contact unwanted biological material. The proximal end of the working element is coupled to the transducer elements via ultrasonic coupling structures so as to responsively vibrate at ultrasonic frequencies.

Abstract: An ultrasonic emulsion fluid is provided for use in ultrasonic probes of medical ultrasonic diagnostic systems, in which the fluid couples ultrasonic energy between a transducer and human tissue. The emulsion outer phase is a water and velocity enhancer mixture. Suitable enhancers include alcohols such as ethylene glycol, propylene glycol, or glycerol. The suspended phase of the emulsion is an oil phase such as a silicone fluid. The silicone fluid droplets in the emulsion exhibit an average size which provides the emulsion with desired attenuation characteristics over a given band of ultrasonic frequencies.

Abstract: A pressurizing syringe includes one or more dimple-shaped snapdomes located between the plunger and piston of a syringe assembly. When the plunger is depressed, the snapdomes will deflect at a known pressure level, giving the user a tactile and audible indication that the syringe is compressing fluid at the desired pressure. A method for using a pressurizing syringe to pressurize the fluid-filled compartment of an ultrasonic scan head is also described.

Abstract: An ultrasonic scanning system is provided in which an ultrasonic transducer is oscillated for scanning purposes by a piezoelectric bender. One end of the bender is fixedly mounted in a sector scanner head, while the other end is connected to the ultrasonic transducer. The bender is deflected through the application of a drive voltage to electrodes plated on the piezoelectric material, causing the bender to deflect by a distance which is proportional to the applied voltage. The transducer is thereby caused to oscillate or rock by the motion of the bender.

Abstract: Method and apparatus for enhancing the reflection coefficient of a surgical instrument for use in conjunction with an apparatus for pulse-echo ultrasound imaging of an area of the body, by means of a diffraction grating disposed on the surgical instrument.

Abstract: The resonant frequency of piezoelectric transducers is made more uniform from unit to unit by reducing the sensitivity of that frequency to manufacturing variations in the diameter of the ceramic sensing disk that forms a part of the vibratory diaphragm assembly. The diaphragm member proper is stiffened, as by integrally formed radial ribs, within the zone of variability of the disk perimeter, effectively establishing a uniform boundary edge for the diaphragm area that is stiffened by presence of the disk.

Abstract: The invention reduces variability of the resonant frequency in piezoelectric ceramic transducers having a vibratory assembly comprising a flexible diaphragm carrying a ceramic disk sensor. The clamped edge of the diaphragm is typically offset from the plane of the vibratory assembly and is coupled to that assembly by generally cylindrical structure having flexibility in a radial direction. That flexibility partially isolates the vibratory assembly from effects such as structural variability of the clamping means and differential thermal expansion at the clamp. The degree of that isolation is preferably selected by suitable design of the coupling structure to provide approximate compensation for thermal effects due to other parameters of the system.

Abstract: Communication units for hand-held use, combining a microphone for voice communication with means for generating at least two code frequencies for signaling, are made more compact and economical by dual capability of a single amplifying circuit in oscillating mode for tone generation and in substantially linear mode for amplifying the microphone output.