Patent US1850209A successfully refreshed from Google Patents.
Patent US3557777A successfully refreshed from Google Patents.
US3557777A
Expired / Lapsed
US
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Magnetic study of bioelectric phenomena
Assignee: United States Department of Energy
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Filing: 1967-05-04
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Granted: 1971-01-26
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Expires: 1987-05-04
Abstract
Abstract An apparatus and method for magnetic detection of bioelectric activity associated with muscle action or with other living tissue. The system comprises a magnetic shielding facility for establishing an enclosed region within which the ambient level of magnetic noise is below the level of the magnetic fields to be measured and a highly sensitive magnetic field detector positioned within the enclosed space. Also included are adjustable chair means for comfortably supporting a subject to be studied, and suitable electronic signal processing circuitry connected to the magnetic field detector for producing a visual display of the magnetic fields measured. The magnetic field detector is arranged to produce an electrical indication of a component of the magnetic field in a relatively localized region of space, so that a direct mapping of the magnetic fields associated with the bioelectric activity being studied may be made by measurement of a single magnetic field component at a plurality of locations.
Inventors
- 👤 David Cohen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:13
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/24; A61B5/242
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
98 words
A method of studying bioelectric activity in a living subject comprising the steps of: introducing said living subject into an area in which the ambient level of magnetic noise is less than about 10-7 to 10-8 Gauss RMS, introducing a magnetic field detector into said area, positioning said detector in closely spaced relationship to a predetermined portion of the subject to be studied, obtaining a detector output representative of the value of the magnetic field component within the frequency range 1-30 Hz. at a single location in relation to said subject, and visually displaying said detector output signal.
Claim 2
Independent Claim
98 words
A method of studying bioelectric activity in a living subject comprising the steps of: introducing said living subject into an area in which the ambient level of magnetic noise is less than about 10-7 to 10-8 Gauss RMS, introducing a magnetic field detector into said area, positioning said detector in closely spaced relationship to a predetermined portion of the subject to be studied, obtaining a detector output representative of the value of the magnetic field component within the frequency range 1-30 Hz. at a single location in relation to said subject, and visually displaying said detector output signal.
Claim 3
Dependent Claim
56 words
A method of studying bioelectric activity as set forth in claim 1 further including the steps of positioning said detector at a succession of locations in relation to said subject, obtaining detector output signals representative of the value of magnetic field components at each of said succession of locations, and visually displaying said detector output signals.
Claim 4
Dependent Claim
47 words
A method of studying bioelectric activity as defined in claim 1 wherein said step of obtaining said detector output comprises measuring an electric potential representative of the time derivative of the magnetic flux associated with said magnetic field component, and obtaining the time integral of said potential.
Claim 5
Dependent Claim
93 words
Apparatus for detection of magnetic phenomena associated with bioelectric activity in a living subject comprising: means for establishing a magnetically quiet area having an ambient level of magnetic noise of less than about 10-7 to 10-8 Gauss RMS; magnetic field detector means, said detector means providing an output signal representative of the level of a magnetic field component in one localized region of space; means adapted for adjustably supporting a living subject in relation to said detector; and electrical signal processing means connected to said detector for visually displaying said detector output signal.
Claim 6
Dependent Claim
93 words
Apparatus for detection of magnetic phenomena associated with bioelectric activity in a living subject comprising: means for establishing a magnetically quiet area having an ambient level of magnetic noise of less than about 10-7 to 10-8 Gauss RMS; magnetic field detector means, said detector means providing an output signal representative of the level of a magnetic field component in one localized region of space; means adapted for adjustably supporting a living subject in relation to said detector; and electrical signal processing means connected to said detector for visually displaying said detector output signal.
Claim 7
Dependent Claim
40 words
Apparatus for detection of magnetic phenomena as set forth in claim 4 wherein said detector is characterized by an inherent noise output corresponding to a magnetic noise level comparable to or below the ambient magnetic noise level in said area.
Claim 8
Dependent Claim
33 words
A method of studying bioelectric activity as set forth in claim 1 further including immersing said detector into a cool environment to reduce its operating temperature to about minus 196* C. or less.
Claim 9
Dependent Claim
62 words
A method of studying bioelectric activity as set forth in claim 1 wherein said step of obtaining a detector output comprises maintaining said detector at approximately room temperature, measuring an electric potential representative of said magnetic field component, and obtaining a time average of said potential over a period which is large in comparison to the period of bioelectric activity being measured.
Claim 10
Dependent Claim
41 words
A method of studying bioelectric activity as defined in claim 1 including the steps of enclosing said detector iN an electrostatic shield, and establishing a slight positive pressure within said shield by introducing gas therein under pressure slightly above atmospheric pressure.
Claim 11
Dependent Claim
46 words
A method of studying bioelectric activity as defined in claim 8 including the step of immersing said electrostatically shielded detector in liquid nitrogen, said positive pressure within said shield serving to prevent infiltration of the liquid nitrogen and direct contact thereof with the magnetic field detector.
Claim 12
Dependent Claim
54 words
Apparatus as defined in claim 4 wherein the means for establishing said quiet area comprises an enclosure having a plurality of concentric shells of magnetic shielding material, at least one of said shells being characterized by high magnetic permeability, and at least another of said shells by low magnetic permeability and high electric conductivity.
Claim 13
Dependent Claim
25 words
Apparatus as defined in claim 10 including means for coupling an alternating magnetic field into the one of said shells characterized by high magnetic permeability.
Claim 14
Dependent Claim
48 words
Apparatus as defined in claim 11 wherein said coupling means comprises a coil of wire positioned in close proximity to said high magnetic permeability shell, an alternating current source coupled to said coil, and means for controlling said current to establish the desired magnetic field in said shell.
Claim 15
Dependent Claim
85 words
Apparatus as defined in claim 4 wherein said means for establishing said quiet area comprises an enclosure having three concentric shells of shielding material, the outer two of said shells being formed of a material characterized by high magnetic permeability, means for establishing a controlled alternating magnetic field in each of said outer two shells, the innermost of said three shells being formed of a material characterized by a low magnetic permeability and high electric conductivity, and being electrically isolated from said outer two shells.
Claim 16
Dependent Claim
35 words
Apparatus as defined in claim 13, wherein said outer two shells are formed of 4-79 molypermalloy, and wherein said innermost shell is formed of a material selected from the group consisting of aluminum and copper.
Claim 17
Dependent Claim
80 words
Apparatus as defined in claim 4, wherein said means for establishing said quiet area comprises an enclosure having a plurality of concentric shells formed of relatively thin layers of shielding material separated by an interior framework of nonmagnetic material, said quiet area being defined by the interior of the innermost of said shells, and including means within said area for rigidly supporting said detector means to isolate said detector means from any mechanical vibration which may exist within said area.
Claim 18
Dependent Claim
38 words
Apparatus as defined in claim 15 wherein said means for supporting said detector comprises suspension means directly attached to said interior framework, and mechanically isolated from the layers forming the inner one of said shells of shielding material.
Claim 19
Dependent Claim
34 words
Apparatus as defined in claim 4 wherein said detector means comprises means for providing an electrical potential proportional to the time derivative of the magnetic flux associated with the magnetic field to be measured.
Claim 20
Dependent Claim
49 words
Apparatus as defined in claim 4 wherein said detector comprises at least one coil having a plurality of turns of wire, a coil form comprised of plastic material receiving said coil, an electrostatic shield encasing said coil, and cable means connecting said coil to said electrical signal processing means.
Claim 21
Dependent Claim
23 words
Apparatus as defined in claim 18 including means for establishing a positive pressure in said electrostatic shield slightly in excess of atmospheric pressure.
Claim 22
Dependent Claim
50 words
Apparatus as defined in claim 19 including a source of gas under pressure, inlet means connecting said source of gas to the interior of said electrostatic shield, outlet means, and accumulator means connected to said outlet means to maintain the interior of said electrostatic shield at the desired positive pressure.
Claim 23
Dependent Claim
24 words
Apparatus as defined in claim 18 wherein said coil form is comprised of a material selected from the group consisting of ''''TEFLON'''' and nylon.
Claim 24
Dependent Claim
45 words
Apparatus as defined in claim 18 wherein said detector is comprised of two coils of fine copper wire connected in series, each coil having at least about 200,000 turns of copper wire, said wire being of the thickness of standard No. 41 wire or less.
Claim 25
Dependent Claim
40 words
Apparatus as defined in claim 18 further including thermally insulating means for receiving said detector and said electrostatic shield, said thermally insulating means being adapted to establish an operating temperature for said detector of approximately minus 196* C. or less.
Claim 26
Dependent Claim
52 words
Apparatus as defined in claim 18 wherein said cable means is comprised of a metallic signal conductor and a metallic return conductor, said conductors being insulated by an intervening adjacent ''''TEFLON'''' layer, and further including at least one layer of semiconductive noise suppressing material between said signal conductor and said return conductor.
Claim 27
Dependent Claim
50 words
Apparatus as defined in claim 18 wherein said electrostatic shield comprises a cylindrical brass chamber having two circular end plates and a circular body, and a brass tube connecting said end plates and extending through aligned apertures therein, said detector being positioned within said shielded chamber on said brass tube.
Claim 28
Dependent Claim
22 words
Apparatus as defined in claim 4 wherein said means for supporting said subject comprises an adjustable chair formed of substantially nonmagnetic material.
Claim 29
Dependent Claim
60 words
Apparatus as defined in claim 4 wherein said signal processing means comprises a parametric amplifier connected to the output of said magnetic field detector, variable band pass filter means connected to the output of said parametric amplifier, means for producing the time integral of the output of said band pass filter, and means connecting said integrator means to a recorder.
Claim 30
Dependent Claim
42 words
Apparatus as defined in claim 27 wherein said electrical signal processing means further includes a noise averaging signal processor connected to the output of said integrator means for generating the average value of said integrator output over a predetermined period of time.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |