Patent US5417218A successfully refreshed from Google Patents.
US5417218A
Expired / Lapsed
US
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Acoustic imaging device
Assignee: Thermo Fisher Scientific Inc
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Filing: 1994-04-25
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Granted: 1995-05-23
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Expires: 2014-04-25
Abstract
Abstract This invention provides an acoustic imaging device in which a large number of transducers are spaced less than a half acoustic wavelength apart on a circle surrounding an object to be imaged. A signal generator generates discrete acoustic frequencies in the range of 100 kHz to 1.5 MHz. Multiplexer systems are provided to permit each transducer, one at a time, to broadcast a signal while the broadcast signal is detected by the other transducers. Electronic equipment records the detected signal and from the recorded information phase and amplitude data is calculated with respect to each transducer location. A computer programmed with an algorithm computes images of slices through the object using the phase and amplitude data. We utilize single frequency, steady-state acoustic signals which enables the accurate determination of the phase and amplitude of the acoustic signals at each receiver transducer. Finally, in order to reduce the data acquisition time and reduce motion artifacts, we utilize acoustic signals comprised of a plurality of discrete indentifiable frequencies each frequency providing an image of the medium.
Inventors
- 👤 Brett A. Spivey
- 👤 Peter J. Martin
- 👤 Douglas A. Palmer
- 👤 Robert Cram
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:03
CPC Classifications
A; A61; A61B; A61B8/00; A61B8/13; A61B8/46; A61B8/461; A61B8/463; A61B8/52; A61B8/5215; A61B8/5223
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
300 words
An acoustic imaging device for producing a tomographic image along an image slice through a medium defining an average sound speed, said device comprising: A) a large number of acoustic transducers located on a circle said large number being greater than N=2πD/λ where D is the diameter of the circle and λ=0.3 mm each of said large number of transducers being connected electronically so as to broadcast into said medium an acoustic signal when excited with a periodic signal in the range of 100 kHz to 1.5 MHz and also to produce an electrical signal when excited with an acoustic signal transmitted through said medium, B) an electronic signal generation means for generating periodic electronic signals at at least one discrete frequency in the frequency range of 100 kHz to 1.5 MHz said signals being continuous for a time interval of at least D/c where c is the average sound speed of the medium, C) a first multiplexing means for applying said periodic electronic signals to a each of said large number of acoustic transducers in order to cause a plurality of said acoustic transducers, one at a time, to broadcast acoustic energy into said medium at a discrete frequency in the frequency range of 100 kHz to 1.5 MHz, D) a recording means for recording information carried by electronic transducer signals produced by a plurality of said large number of transducers excited by acoustic energy broadcast transmitted through said medium, E) a second multiplexing means for connecting said large number of transducers to said recording means to permit said recording means to record said information carried by said electronic transducer signals, and F) a computer means comprising an algorithm for calculating a tomographic image of said medium along said image slice utilizing said information recorded by said recording means.
Claim 2
Dependent Claim
300 words
An acoustic imaging device for producing a tomographic image along an image slice through a medium defining an average sound speed, said device comprising: A) a large number of acoustic transducers located on a circle said large number being greater than N=2πD/λ where D is the diameter of the circle and λ=0.3 mm each of said large number of transducers being connected electronically so as to broadcast into said medium an acoustic signal when excited with a periodic signal in the range of 100 kHz to 1.5 MHz and also to produce an electrical signal when excited with an acoustic signal transmitted through said medium, B) an electronic signal generation means for generating periodic electronic signals at at least one discrete frequency in the frequency range of 100 kHz to 1.5 MHz said signals being continuous for a time interval of at least D/c where c is the average sound speed of the medium, C) a first multiplexing means for applying said periodic electronic signals to a each of said large number of acoustic transducers in order to cause a plurality of said acoustic transducers, one at a time, to broadcast acoustic energy into said medium at a discrete frequency in the frequency range of 100 kHz to 1.5 MHz, D) a recording means for recording information carried by electronic transducer signals produced by a plurality of said large number of transducers excited by acoustic energy broadcast transmitted through said medium, E) a second multiplexing means for connecting said large number of transducers to said recording means to permit said recording means to record said information carried by said electronic transducer signals, and F) a computer means comprising an algorithm for calculating a tomographic image of said medium along said image slice utilizing said information recorded by said recording means.
Claim 3
Dependent Claim
23 words
An acoustic imaging device as in claim 1 wherein said at least one identifiable discrete frequency is a plurality of identifiable discrete frequencies.
Claim 4
Dependent Claim
15 words
A device as in claim 1 wherein said transducers are equally spaced on said circle.
Claim 5
Dependent Claim
14 words
A device as in claim 1 wherein said large number is at least 256.
Claim 6
Dependent Claim
31 words
A device as in claim 1 wherein said acoustic recording means comprises a plurality of analog-to-digital converter units each having a buffer memory unit for temporary storage of digital acoustic information.
Claim 7
Dependent Claim
22 words
A device as in claim 5 wherein each of said buffer memory units comprise at least one million Bytes of storage capacity.
Claim 8
Dependent Claim
235 words
A process for producing a tomographic image of a slice through a medium defining an average speed of sound comprising the steps of: A) positioning a large number of transducers on a circle surrounding said medium, said large number being greater than N=2πD/λ where D is the diameter of the circle and λ=0.3 mm, said transducers having the capability of broadcasting an acoustic signal into said medium upon being excited with an electrical signal and producing an electrical signal upon being excited with an acoustic signal from said medium, B) exciting a plurality of said large number of transducers, one at a time, with an electronic signal defining at least one discrete frequency in order to cause each of said transducers to broadcast, one at a time, into said medium an acoustic signal containing said at least one discrete frequency, each of said acoustic signals being broadcast for a time interval of at least D/c where c is equal to the average speed of sound in said medium said signal to reach an equilibrium in said medium and excite other transducers on said circle to cause them to produce electrical transducer signals carrying information relating to acoustic properties of said medium, C) record information carried by said electrical transducer signals from said large number of transducers, D) using said recorded information calculate with a computer said tomographic image of said image slice of said medium.
Claim 9
Dependent Claim
235 words
A process for producing a tomographic image of a slice through a medium defining an average speed of sound comprising the steps of: A) positioning a large number of transducers on a circle surrounding said medium, said large number being greater than N=2πD/λ where D is the diameter of the circle and λ=0.3 mm, said transducers having the capability of broadcasting an acoustic signal into said medium upon being excited with an electrical signal and producing an electrical signal upon being excited with an acoustic signal from said medium, B) exciting a plurality of said large number of transducers, one at a time, with an electronic signal defining at least one discrete frequency in order to cause each of said transducers to broadcast, one at a time, into said medium an acoustic signal containing said at least one discrete frequency, each of said acoustic signals being broadcast for a time interval of at least D/c where c is equal to the average speed of sound in said medium said signal to reach an equilibrium in said medium and excite other transducers on said circle to cause them to produce electrical transducer signals carrying information relating to acoustic properties of said medium, C) record information carried by said electrical transducer signals from said large number of transducers, D) using said recorded information calculate with a computer said tomographic image of said image slice of said medium.
Claim 10
Dependent Claim
21 words
A process as in claim 7 wherein said at least one identifiable discrete frequency is a plurality of identifiable discrete frequencies.
Claim 11
Dependent Claim
25 words
A process as in claim 6 comprising the additional step of producing a plurality of said tomographic images of said image slices of said medium.
Claim 12
Dependent Claim
39 words
A process as in claim 9 comprising the additional step of producing a plurality of said tomographic images of said image slices of said medium said image slices being parallel to each other and equally spaced along said medium.
Claim 13
Dependent Claim
46 words
A process as in claim 10 comprising the additional step of producing a plurality of said tomographic images of said image slices of said medium said image slices being parallel to each other and equally spaced along said medium and said image slices overlapping each other.
Claim 14
Dependent Claim
23 words
A process as in claim 11 comprising the additional step of forming a three-dimensional image from said tomographic images of said image slices.
Claim 15
Dependent Claim
92 words
A process as in claim 7 wherein said medium includes human tissue and comprising the following additional steps for monitoring the placement of a biopsy needle in said tissue: A) calculate a sufficient number of tomographic images of said medium in order to identify a biopsy location, B) insert a biopsy needle to said biopsy location, D) calculate at least one tomographic image of said medium with said needle at said biopsy location, E) verify that said biopsy needle is at said location, and F) remove biopsy sample with said biopsy needle.
Claim 16
Dependent Claim
70 words
A process as in claim 7 comprising the following additional steps for measuring temperature distributions of said medium comprising: A) locally heat at least a portion of said image slice of said medium, B) calculate second said tomographic image of said image slice of said medium, and C) subtract first said tomographic image from said second tomographic image to produce a final image representing the effect of heating the medium.
Claim 17
Dependent Claim
69 words
A process as in claim 7 comprising the additional steps of measuring temperature distributions of said medium comprising: A) locally heat at least a portion of said image slice of said medium, B) calculate second said tomographic image of said image slice of said medium, and C) divide first said tomographic image from said second tomographic image to produce a final image representing the effect of heating the medium.
Claim 18
Dependent Claim
18 words
A process as in claim 7 wherein said medium comprises at least some portion of the human body.
Claim 19
Dependent Claim
14 words
A process as in claim 7 wherein said medium comprises the human female breast.
Claim 20
Dependent Claim
13 words
A process as in claim 7 wherein said medium comprises the human abdomen.
References Cited (Backward Citations)
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