US3847141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic bone densitometer
Assignee: National Aeronautics and Space Administration
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Filing: 1973-08-08
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Granted: 1974-11-12
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Expires: 1993-08-08
Abstract
Abstract A device for measuring the density of a bone structure so as to monitor the calcium content thereof. A pair of opposed spaced ultrasonic transducers are held within a clamping apparatus closely adjacent the bone being analyzed. These ultrasonic transducers incude piezoelectric crystals shaped to direct signals through the bone encompassed in the heel and finger of the subject being tested. A pulse generator is coupled to one of the transducers and generates an electric pulse for causing the transducers to generate an ultrasonic sound wave which is directed through the bone structure to the other transducer. An electric circuit, including an amplifier and a bandpass filter couples the signals from the receiver transducer back to the pulse generator for retriggering the pulse generator at a frequency proportional to the duration that the ultrasonic wave takes to travel through the bone structure being examined. An oscilloscope and frequency counter is coupled to the bandpass filter for determining the frequency that the pulse generator is retriggered so as to determine changes in the calcium content of the bone being analyzed.
Inventors
- 👤 J Hoop
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:17
CPC Classifications
A; A61; A61B; A61B8/00; A61B8/08; A61B8/0875; A61B8/13; A61B8/15
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
216 words
An apparatus for measuring the density of a bone structure so as to monitor the calcium content thereof comprising: a. A pair of opposed spaced ultrasonic transducers, one acting as a transmitter and the other acting as a receiver; b. a clamping means supporting said transducers in spaced relation for accommodating said bone structure to be examined therebetween; c. said clamping means including means for positioning said bone structure in a constant orientation with respect to said pair of opposed spaced ultrasonic transducers; d. means for regulating the pressure applied by said pair of opposed spaced transducers on said bone structure being examined; e. a pulse generator means coupled to said transmitter transducer generating an electric pulse for causing said transmitter transducer to generate an ultrasonic sound wave which is directed through said bone structure to said receiver transducer; f. an electrical circuit means coupled between said receiver transducer and said pulse generator for retriggering said pulse generator responsive to said receiver transducer receiving said ultrasonic sound wave; and g. frequency indicating means coupled to said circuit means; whereby the frequency that said pulse generator is retriggered is proportional to the duration that said ultrasonic wave takes to travel through said bone being examined which varies according to the calcium content of said bone being examined.
Claim 2
Independent Claim
216 words
An apparatus for measuring the density of a bone structure so as to monitor the calcium content thereof comprising: a. A pair of opposed spaced ultrasonic transducers, one acting as a transmitter and the other acting as a receiver; b. a clamping means supporting said transducers in spaced relation for accommodating said bone structure to be examined therebetween; c. said clamping means including means for positioning said bone structure in a constant orientation with respect to said pair of opposed spaced ultrasonic transducers; d. means for regulating the pressure applied by said pair of opposed spaced transducers on said bone structure being examined; e. a pulse generator means coupled to said transmitter transducer generating an electric pulse for causing said transmitter transducer to generate an ultrasonic sound wave which is directed through said bone structure to said receiver transducer; f. an electrical circuit means coupled between said receiver transducer and said pulse generator for retriggering said pulse generator responsive to said receiver transducer receiving said ultrasonic sound wave; and g. frequency indicating means coupled to said circuit means; whereby the frequency that said pulse generator is retriggered is proportional to the duration that said ultrasonic wave takes to travel through said bone being examined which varies according to the calcium content of said bone being examined.
Claim 3
Dependent Claim
52 words
The apparatus as set forth in claim 1, wherein each of said pair of spaced ultrasonic transducers includes: a. piezoelectric crystals; and b. said piezoelectric crystals being arcuately shaped for focusing energy produced by said transmitting transducer towards the bone of a finger when said finger is positioned between said ultrasonic transducers.
Claim 4
Dependent Claim
55 words
The apparatus as set forth in claim 2, further comprising: a. a calibrated adjustable abutting member carried adjacent said spaced ultrasonic transducers for engaging the tip of the finger when said finger is inserted between said transducers for insuring that said finger is in the same position when the measurements are taken at different times.
Claim 5
Dependent Claim
54 words
The apparatus as set forth in claim 1, wherein each of said pair of spaced ultrasonic transducers includes: a. piezoelectric crystals; b. inclined spaced supporting members having said piezoelectric crystals mounted thereon; and c. means for adjusting said supporting members to vary the spacing therebetween for closely accommodating the heel bone of a person.
Claim 6
Dependent Claim
70 words
The apparatus as set forth in claim 1, wherein said electrical circuit means coupled between said receiver transducer and said pulse generator includes: a. an amplifier coupled to said receiver transducer for amplifying signals produced by said receiver transducer responsive to said receiver transducer receiving said ultrasonic sound waves; and b. a bandpass filter coupled between said amplifier and said pulse generator for passing signals in a predetermined frequency range.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |