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.

1 . Ultrasonic bone testing apparatus comprising a pair of ultrasonic transducers at least one of which comprises a piezoelectric copolymer; mounting structure supporting the transducers in facing spaced relation to each other, so as to be respectively positionable on opposite sides of and both coupled ultrasonically to an animal portion containing a bone, for respectively transmitting ultrasonic energy through and receiving ultrasonic energy transmitted through said animal portion including the bone; and electrical circuitry connected to the transducers to energize one transducer to transmit ultrasonic energy and to detect an electrical signal generated by the other transducer in response to received ultrasonic energy.  
   
   
       2 . Apparatus as defined in  claim 1 , wherein the mounting structure includes a support for positioning the animal portion between the transducers, and a device for coupling the transducers ultrasonically to the animal portion; and wherein each of the transducers comprises a piezoelectric copolymer transducer.  
   
   
       3 . (canceled)  
   
   
       4 . Apparatus as defined in  claim 2 , wherein said coupling device comprises a pair of pads, respectively disposed in contact with said transducers, and respectively engageable with opposed surface regions of an animal portion positioned in said support as aforesaid.  
   
   
       5 . (canceled)  
   
   
       6 . Apparatus as defined in  claim 2 , wherein said coupling device includes a container for holding a body of a coupling fluid in which the animal portion is immersed when positioned by the support as aforesaid and with which said transducers are in ultrasonic energy transmitting contact.  
   
   
       7 . Apparatus as defined in  claim 2 , in which the animal portion is a human heel containing a calcaneal bone, said support positioning said heel, and said transducers and coupling device being disposed, so that ultrasonic energy transmitted from said one transducer to said other transducer passes through the calcaneal bone.  
   
   
       8 . Apparatus as defined in  claim 2 , in which said electrical circuitry is arranged to use the detected electrical signal for deriving a value representative of the speed of sound through the bone through which the ultrasonic energy is transmitted as aforesaid.  
   
   
       9 . Apparatus as defined in  claim 2 , in which said electrical circuitry is arranged to use the detected electrical signal in deriving a value representative of broadband ultrasonic attenuation in the bone through which the ultrasonic energy is transmitted as aforesaid.  
   
   
       10 . A method of determining a characteristic of a bone in a bone-containing portion of an animal comprising disposing a pair of ultrasonic transducers at least one of which comprises a piezoelectric copolymer respectively on opposite sides of, and ultrasonically coupling both transducers to, a bone-containing animal portion; electrically energizing one transducer to transmit ultrasonic energy through the animal portion including the bone, such that the transmitted ultrasonic energy is received and converted to an electrical signal by the other transducer; detecting the electrical signal; and using the detected signal to derive a value representative of the bone characteristic to be determined.  
   
   
       11 . A method according to  claim 10  wherein each of the transducers is a disk of piezoelectric copolymer.  
   
   
       12 . (canceled)  
   
   
       13 . Apparatus as defined in  claim 1 , wherein at least one of said transducers is a piezoelectric copolymer transducer having a curved surface for focusing.  
   
   
       14 . Apparatus as defined in  claim 1 , wherein at least one of said transducers is a copolymer array transducer.  
   
   
       15 . A method according to  claim 10 , wherein at least one of said transducers is a copolymer array transducer.  
   
   
       16 . A method according to  claim 15 , wherein the step of deriving a value includes correcting for phase cancellation.  
   
   
       17 . (canceled)  
   
   
       18 . Ultrasonic bone testing apparatus comprising a pair of ultrasonic transducers at least one of which comprises a poly(vinylidene fluoride-trifluoroethylene) copolymer; mounting structure supporting the transducers in facing spaced relation to each other, so as to be respectively positionable on opposite sides of and both coupled ultrasonically to an animal portion containing a bone, for respectively transmitting ultra-sonic energy through and receiving ultrasonic energy transmitted through said animal portion including the bone; and electrical circuitry connected to the transducers to energize one transducer to transmit ultrasonic energy and to detect an electrical signal generated by the other transducer in response to received ultrasonic energy.  
   
   
       19 . Apparatus as defined in  claim 18 , wherein said one transducer is an array transducer.  
   
   
       20 . Apparatus as defined in  claim 19 , wherein said one transducer is a transducer for transmitting ultrasonic energy as aforesaid.  
   
   
       21 . Apparatus as defined in  claim 19 , wherein said one transducer is a transducer for receiving ultrasonic energy as aforesaid.  
   
   
       22 . Apparatus as defined in  claim 18 , wherein each of said transducers is an array transducer comprising a poly(vinylidene fluoride-trifluoroethylene) copolymer.  
   
   
       23 . (canceled)  
   
   
       24 . Apparatus as defined in  claim 1 , wherein the mounting structure includes a support for positioning the animal portion between the transducers, and a device for coupling the transducers ultrasonically to the animal portion.  
   
   
       25 - 28 . (canceled)