US3771355A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic inspection and diagnosis system
Assignee: Individual
•
Filing: 1971-09-30
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Granted: 1973-11-13
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Expires: 1991-09-30
Abstract
Abstract A system for the inspection of the internal nature of a material utilizes an exciting ultrasonic field which is directed at a focal point to be inspected and heats that focal point. An ultrasonic sensing beam is directed through the material and through the heated focal point and is received by a transducer. A differential measurement of a propagation parameter of the sensing beam is accomplished by comparing a burst of its ultrasonic waves through the focal point without the heating effect of the exciting field, with an identical burst of the same duration, amplitude and frequency, but immediately after the heating effect has been accomplished by the exciting field. This system may be used to determine tissue characteristics, internal blood flow, and for other medical diagnostic functions.
Inventors
- 👤 T Sachs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:28
CPC Classifications
A; A61; A61B; A61B8/00; A61B8/08; G; G01; G01N; G01N29/00; G01N29/22; G01N29/24; G01N29/2437; G01N29/245; G01S; G01S7/00; G01S7/52; G01S7/52017; G01S7/52023; G01S7/52025; G01N2291/00; G01N2291/02; G01N2291/028; G01N2291/0289; Y; Y02; Y02A; Y02A90/00; Y02A90/10
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
179 words
A system for ultrasonic inspection of a substance including a thermoacoustic exciting means to heat an interior volume of said substance by exciting ultrasonic waves, said thermoacoustic means including a first ultrasonic transducer, a first oscillator connected to said first transducer, and means to focus the ultrasonic waves produced by said first transducer to produce a heated focal point, means to produce a collimated ultrasonic sensing beam directed through said focal point, said sensing beam means including a second ultrasonic transducer to produce said collimated beam, a second reference oscillator which is a source of continuous waves of ultrasonic frequency, and gating means connected between said source and said second transducer to produce coherent bursts of oscillations which are discrete trains of ultrasonic waves to said second transducer, an ultrasonic receiving transducer positioned to receive said sensing beam, and a phase comparison circuit connected to said receiving transducer and to said second reference oscillator to respond to phase changes in the sensing beam caused by transmission through said focal point compared to transmission through said focal point without heating.
Claim 2
Independent Claim
179 words
A system for ultrasonic inspection of a substance including a thermoacoustic exciting means to heat an interior volume of said substance by exciting ultrasonic waves, said thermoacoustic means including a first ultrasonic transducer, a first oscillator connected to said first transducer, and means to focus the ultrasonic waves produced by said first transducer to produce a heated focal point, means to produce a collimated ultrasonic sensing beam directed through said focal point, said sensing beam means including a second ultrasonic transducer to produce said collimated beam, a second reference oscillator which is a source of continuous waves of ultrasonic frequency, and gating means connected between said source and said second transducer to produce coherent bursts of oscillations which are discrete trains of ultrasonic waves to said second transducer, an ultrasonic receiving transducer positioned to receive said sensing beam, and a phase comparison circuit connected to said receiving transducer and to said second reference oscillator to respond to phase changes in the sensing beam caused by transmission through said focal point compared to transmission through said focal point without heating.
Claim 3
Dependent Claim
20 words
The instrument of claim 1 wherein the frequency of said reference oscillator being within one part per 1 X 108.
Claim 4
Dependent Claim
43 words
The instrument of claim 1 wherein said phase comparison circuit includes a data window circuit in timed relationship with said gating circuit means, whereby said data window is opened substantially with the arrival of the sense bursts produced by said gating circuit means.
Claim 5
Dependent Claim
45 words
An instrument as in claim 1 and also including a changeable phase shifter connected between said reference oscillator and said phase comparison circuit, and means including a propagation path compensation logic circuit connected to said phase shifter for controlling the shifting of said phase shifter.
Claim 6
Dependent Claim
23 words
An instrument as in claim 1 and also including means to move all three ultrasonic transducers in concert to produce a three-dimensional scan.
Claim 7
Dependent Claim
85 words
An instrument as in claim 1 and also including computational means connected to said phase comparison circuit for determining corrections for acoustic intensity of said ultrasonic field at said focal point due to passage of said ultrasonic field from said focusable ultrasonic transducer to said focal point through intervening material, said corrections being made based on acoustic absorption coefficients at points in said intervening material as approximated by perturbation measurements which have been previously determined by scanning through said intervening material from its surface inward.
Claim 8
Dependent Claim
30 words
An instrument as in claim 1 and also including means to control the power output of said reference oscillator so that the intensity at said focus remains constant during scanning.
Claim 9
Dependent Claim
30 words
An instrument as in claim 1 including means connected to said phase comparison circuit to correct the said phase change measurements on the basis of the intensity at said focus.
Claim 10
Dependent Claim
39 words
An instrument as in claim 4 wherein said propagation path compensAtion logic circuit includes a delay circuit, said delay being based on the reference oscillator frequency, which is the same as that transmitted and received as an ultrasonic burst.
Claim 11
Independent Claim
106 words
The method of analyzing the perturbation (P) of living tissue having an ultrasonic beam; consisting of passing a collimated ultrasonic beam in the form of coherent bursts of ultrasonic waves through a focal point within said tissue; exciting and heating the tissue by focusing an ultrasonic field at said focal point within the said tissue; again passing the collimated ultrasonic beam in the form of coherent bursts of ultrasonic waves through said focal point after the tissue at the focal point has been heated; receiving the two said ultrasonic beams and measuring the relative changes in their phase caused by passing through said heated focal point.
Claim 12
Independent Claim
106 words
The method of analyzing the perturbation (P) of living tissue having an ultrasonic beam; consisting of passing a collimated ultrasonic beam in the form of coherent bursts of ultrasonic waves through a focal point within said tissue; exciting and heating the tissue by focusing an ultrasonic field at said focal point within the said tissue; again passing the collimated ultrasonic beam in the form of coherent bursts of ultrasonic waves through said focal point after the tissue at the focal point has been heated; receiving the two said ultrasonic beams and measuring the relative changes in their phase caused by passing through said heated focal point.
Claim 13
Dependent Claim
66 words
The method of claim 10 wherein the perturbation (P) is equal to VT Alpha / Rho C; where VT is the relative temperature coefficient of the velocity of the tissue for the sensing beam, Alpha is the acoustic amplitude absorption coefficient for the exciting beam in the tissue, Rho is the mass density of the tissue and C is the specific heat capacity of the tissue.
Claim 14
Dependent Claim
69 words
The method of claim 11 wherein the speed of disappearance of said perturbation P is measured by multiple passage of said ultrasonic beam through said focal point and determination of the speed with which the phase shift difference decreases as a measurement of rate of heat flow away from said focal point, said rate of heat flow is a meassure of fluid flow (perfusion) at said point in tissue.
Claim 15
Dependent Claim
27 words
The method of claim 10 wherein the sensing beam is not passed through said focal point the second time until the exciting ultrasonic field is turned off.
References Cited (Backward Citations)
US3233450A
Cited
US3250120A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |