414 New Patents

ments converge on a single point. The arrangement of the elements constitutes a trans- ducer. With the transducer applied to a subject through a liquid bag filled with water, ultrasonic shock waves from each piezoelectric element are concentrated on a lithotresis object, or a calculus so as to break it. The ultrasonic shock waves are generated by applying driving impulses (voltage) to each piezoelectric element. In order to locate the calculus, the transducer is coupled to an ul- trasonic diagnosis apparatus having a mechanical scanning type ultrasonic probe. The piezoelectric elements have resonance fre- quencies set such that the piezoelectric element positioned at the center of the transducer has the lowest resonance frequency and the resonance frequency of each piezoelectric element is in- creased in accordance with its distance from the center. Thus, the frequency range of vibration of the transducer is broadened so that the ul- trasonic shock waves become low in negative sound pressure and narrow in pulse width at the point of convergence.

4909240

ULTRASOUND HEAD WITH REMOVABLE RESONATOR

ASSEMBLY

Klau Helmreich, Rolf Langensiepen, Erlangen, Federal Republic Of Germany assigned to Siemens Aktiengesellschaft

An ultrasound head of the type suitable for medical ultrasound therapy has a housing with an opening in which a resonator assembly is in- sertable. The resonator assembly is mounted in the opening of the housing so as to be removable. The assembly includes a carrier for a ceramic resonator disc, the carrier having an outwardly flanged edge which is received against an inside shoulder of the housing surrounding the opening, so that the carrier projects at least par- tially out of the opening. A pressing mechanism is provided for maintaining the assembly tight against the inside shoulder by applying pressure from the interior of the housing.

4911170

HIGH FREQUENCY FOCUSED ULTRASONIC TRANSDUCER FOR

INVASIVE TISSUE CHARACTERIZATION

Lewis J Thomas, Robert Gilmore, Casmir R Trzaskos assigned to General Electric Company

A broadband 25 to 50 MHz spherically focused ultrasonic transducer is placed on the tip of a catheter such that ultrasonic images of arteries and plaque are produced by introducing the catheter into arteries of patients. The high fre- quency transducer has thin piezoelectric poly- mer film as the transducing element and is adhered to a depression in the reduced cross sec- tion catheter tip. A coaxial cable in the catheter connects the transducer to an external signal source and a display for the received signals. The diagnosis and characterization of arterial disease is most often coupled with a therapeutic techni- que such as balloon angioplasty.

4917096

PORTABLE ULTRASONIC PROBE

Theodore M Englehart, Richard Morris, Naren- dra Sanghvi assigned to Laboratory Equipment Corp

A hand-held portable ultrasonic scanning probe for use with energizing and receiving means for imaging sections of a body includes a fluid-filled enclosure coupled to a handle portion which houses a DC drive motor. The output shaft of the drive motor is directly coupled to a level wind drive screw. A holder assembly incorporating a pawl which coacts with the drive screw and a piano-concave transducer moves back and forth across the drive screw as a result of the DC motor output shaft rotation. The linear travel of the transducer creates a linear scan thereby eliminating the diagnostic imaging problems of sector scans,

4920967

DOPPLER TIP WIRE GUIDE

Cliff N Cottonaro, Scott Evans, David R Pflueger, Huntly D Millar assigned to Pfizer Hospital Products Group Inc

An invasive, fluid velocity measuring wire guide particularly adapted and of a size (less than 0.030 inch) for subselective placement in the coronary arterial tree, which includes a Doppler mechanism for determining the blood flow velocity in the region of the distal end of the wire guide. Although the wire guide is particularly adapted for diagnosing coronary arterial disease subselectively; it is of such a size and manipul- ability to be useful in other blood flow and bio- logical fluid flow analyses. Preferably, the wire