Ultrasonic bone testing with copolymer transducers

Abstract

Ultrasonic bone testing apparatus including a pair of spaced piezoelectric copolymer transducers for transmitting and receiving ultrasonic energy through a bone-containing portion of a human or other animal disposed between the transducers, and circuitry for detecting an electrical signal generated by the receiving transducer in response to reception of ultrasonic energy. The transducers are disks of the copolymer supported by rigid rings spaced inwardly of their peripheries. A method of determining a characteristic of bone in a bone-containing portion of an animal includes positioning a pair of piezoelectric copolymer ultrasonic transducers respectively on opposite sides of, and ultrasonically coupling both transducers to, the animal portion, and transmitting ultrasonic energy through the animal portion including the bone to be tested from one transducer to the other. The animal portion may be a human heel.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims the priority benefit, under 35 U.S.C. §119(e) (1), of applicants' copending U.S. provisional application Ser. No. 60 / 140,638, filed Jun. 23, 1999, which is incorporated herein in its entirety by this reference.BACKGROUND OF THE INVENTION [0002] This invention relates to apparatus and methods for testing characteristics of animal bones, for example human bones, by transmitting ultrasonic energy through bone tissue to be tested. [0003] The testing of bone tissue characteristics such as bone mineral density (BMD) in living humans is widely utilized in present-day medical practice to determine whether and to what extent a patient has osteoporosis or other bone disease. One convenient and effective way of testing bone tissue characteristics is by transmitting ultrasonic energy through a bone in a patient's limb or extremity, between ultrasonic transducers respectively disposed on opposite sides of the limb or extremity...

AI Technical Summary

Benefits of technology

[0014] In the apparatus and method of the invention, the use of piezoelectric copolymer disks as transducers affords significant economies, as well as effective performance. The piezoelectric copolymer material requires fewer manufacturing steps and is less variable in ultrasonic properties than conventional ceramic piezoelectric transducers; hence the use of this material enables a more uniform product to be manufactured. The provision of the rigid support structure, spaced inwardly of the periphery of the copolymer disk, enables such use of these relatively deformable and / or frangible thin disks without distortion or breakage.

Problems solved by technology

These transducers are extremely labor-intensive to manufacture, requiring an extensive amount of machining, gluing and compressing in production.

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