Apparatus for process for making biomagnetic measurements

• US 4,793,355 A
• Filed: 04/17/1987
• Issued: 12/27/1988
• Est. Priority Date: 04/17/1987
• Status: Expired due to Fees

• Current Assignee: Biomagnetic Technologies, Inc.
• Original Assignee: Biomagnetic Technologies, Inc.
• Inventors: Toussaint, Roberta M., Wesley, Ronald C., Greenblatt, Richard E., Hirschkoff, Eugene C., Crum, Duane B.
• Primary Examiner(s): King, Lloyd L.
• Application Number:
  US07/039,515
• Time in Patent Office: 620 Days
• Field of Search: 357/5, 357/68, 307/306, 324/201, 324/204, 324/248, 128/731, 128/733, 128/630, 128/640, 128/644, 128/653
• US Class Current: 600/409
• CPC Class Codes: A61B 5/245 specially adapted for magnetoencephalographic [MEG] signals
• CPC Class Codes: G01R 33/00 Arrangements or instruments for measuring magnetic variables

Abstract

Apparatus for making biomagnetic measurements includes a biomagnetometer for measuring magnetic fields produced by the body and an electromagnetic location measurement and recording system for automatically determining the location of the portion of the body from which the magnetic signals are being gathered. The electromagnetic location recording system permits establishing a real time body frame of reference with respect to the biomagnetometer, so that biomagnetic signals can be correlated directly with body location and structure. The electromagnetic location recording system may be operated continuously at radiation wavelengths which do not interfere with the taking of data, or intermittently with the taking of biomagnetic data, to avoid interference with the measured values of the biomagnetic data. The elements of the electromagnetic location recording system have substantially no residual magnetism when the location recording system is not operating, as the biomagnetic signals are typically so small that even normal residual magnetism might be erroneously recorded as a biomagnetic signal.

Claims

1. Apparatus for making magnetic measurements of the human body, comprising:

biomagnetometer means including a magnetic sensing coil for measuring magnetic fields arising form a selected portion of the body; and

means for recording in real time the location of the selected portion of the body from which the magnetic fields emanate, said means for recording including electromagnetic means for sensing the location of the selected portion of the body using an electromagnetic signal, said electromagnetic means including a transmitter and a receiver of electromagnetic signals.

2. The apparatus of claim 1, wherein said biomagnetometer means includes a superconducting quantum interference device to measure the magnetic fields produced by the body.

3. The apparatus of claim 1, wherein the selected portion of the body is the head.

4. The apparatus of claim 1, wherein said electromagnetic means includes sending means for transmitting an electromagnetic signal through the air, and receiving means for receiving the transmitted electromagnetic signal, one of said sending means and said receiving means being mounted on the selected portion of the body and the other being mounted separated from the body.

5. The apparatus of claim 1, wherein said electromagnetic means includes at least two receiving units mounted on the selected portion of the body.

6. The apparatus of claim 1, wherein said electromagnetic means includes at least one receiving unit mounted on the selected portion of the body, said receiving unit having an antenna which receives electromagnetic signals in three axes.

7. The apparatus of claim 1, wherein said electromagnetic means includes sending means for transmitting an electromagnetic signal through the air, mounted on the body.

8. The apparatus of claim 1, wherein said electromagnetic means includes sending means for transmitting an electromagnetic signal through the air, mounted on said biomagnetometer means.

9. The apparatus of claim 1, wherein said electromagnetic means includes sending means for transmitting an electromagnetic signal through the air, mounted separately from the body and from said biomagnetometer means.

10. The apparatus of claim 1, wherein said electromagnetic means includes at least one receiving unit mounted on the selected portion of the body by an elastic band.

11. The apparatus of claim 1, further including a magnetically shielded room enclosing said biomagnetometer and the body being measured.

12. The apparatus of claim 1, wherein said electromagnetic means is constructed to have substantially no residual magnetism when not operating.

13. A process for obtaining biomagnetic data from the human body and correlating that data to the structure of the body, comprising the steps of:

supplying apparatus according to claim 1;

operating said means for recording intermittently to record the location of the selected portion of the body;

taking data from said biomagnetometer means when said means for recording is not operating, thereby avoiding magnetic interference of the biomagnetic data from said means for recording; and

recording the biomagnetic data with the information on the location of the selected portion of the body, whereby the biomagnetic data is correlated with the position of the body.

14. A process for obtaining biomagnetic data from the human body and correlating that data to the structure of the body, comprising the steps of:

supplying apparatus according to claim 1;

operating said means for recording conitnuously to record the location of the selected portion of the body, said means for recording operating at a frequency greater than about 10 KHz;

taking data from said biomagnetometer means and filtering out signals having a frequency greater than about 10 KHz, thereby avoiding magnetic interference of the biomagnetic data from said means for recording; and

recording the biomagnetic data with the information on the location of the selected portion of the body, whereby the biomagnetic data is correlated with the position of the body.

15. Apparatus for making magnetic measurements of the human body, comprising:

a biomagnetometer including a sensor for measuring magnetic fields arising from a selected portion of the body;

an elecromagnetic transmitter adjacent the body being measured, said transmitter having substantially no residual magnetism when no electric current is flowing therethrough;

at least one electromagnetic receiver mounted on the selected part of the body, said electromagnetic receiver having substantially no residual magnetism when no electric current is flowing therethrough;

an electromagnetic wand receiver that may be touched to points on the selected portion of the body to indicate the location of such points relative to said electromagnetic transmitter; and

computer means for controlling and recording the locations of said receivers and said wand receiver, for taking data from said biomagnetometer, and for controlling said transmitter.

16. The apparatus of claim 15, wherein said receivers are mounted to the body by means of an elastic band.

17. The apparatus of claim 15, wherein said transmitter includes three orthogonal antennas, said antennas having no ferromagnetic cores therein.

18. The apparatus of claim 15, wherein said receivers include three orthogonal antennas, said antennas having no ferromagnetic cores therein.

19. The apparatus of claim 15, wherein said transmitter is potted in a nonmagnetic potting compound.

20. The apparatus of claim 15, wherein said receivers are potted in a nonmagnetic potting compound.

21. A process for obtaining biomagnetic data from the human body and correlating that data to the structure of the body, comprising the steps of:

supplying apparatus according to claim 15;

operating said transmitter and said receivers and said wand receiver intermittently to record the location of the selected portion of the body;

taking data from said biomagnetometer when said transmitter, said receivers, and said wand receiver are not operating, thereby avoiding magnetic interference of the biomagnetic data from said transmitter, said receivers, and said wand receiver; and

recording in said computer means the biomagnetic data with the information on the location of the selected portion of the body, whereby the biomagnetic data may be correlated with the location of the body.

22. The process of claim 21, wherein said step of operating includes the steps of:

touching the wand receiver to selected reference points on the selected portion of the body with said transmitter on, to record the locations of said reference points with respect to said transmitter;

operating the transmitter and said receivers to record the positions of said receivers with respect to said transmitter, thereby also correlating the positions of the reference points with respect to said receivers, whereby the locations of the reference points may be correlated with biomagnetic data taken from the selected portion of the body.

23. The processes of claim 21, wherein the selected portion of the body is the head, and the reference points are the left and right perauricular points and the nasion.

24. A process for obtaining biomagnetic data from the human body and correlating that data to the structure of the body, comprising the steps of:

supplying apparatus according to claim 15;

operating said transmitter and said receivers and said wand receiver continuously at a frequency greater than about 10 KHz to record the location of the selected portion of the body;

taking data continuously from said biomagnetometer and filtering signals from said data having a frequency greater than about 10 KHz; and

recording in said computer means the biomagnetic data with the information on the location of the selected portion of the body, whereby the biomagnetic data may be correlated with the location of the body.