Atomic Magnetometer Sensor Array Magnetoencephalogram Systems and Methods

Abstract

Devices disclosed according to various embodiments use one or more arrays of atomic magnetometers to detect biologically derived magnetic fields. The disclosed devices and methods relate to application of utilization of a magnetic sensor with unique properties requiring changes in design, allowing new functions, and requiring alternative analysis methodologies. Various embodiments are also directed to methods for obtaining and processing biological magnetic signals. These methods may take advantage of the unique spatial arrangement of the atomic magnetometers and the capacity sensors to he used in either a scalar or a vector mode. Various embodiments have advantages over current magnetometer arrays for the purpose of detecting biological magnetic fields. Such advantages may include, for example: smaller size, lower power consumption, no necessity for cryogenic cooling, potential wafer-level fabrication, and/or the potential of better localization biological signals. In addition, various embodiments may allow increased target or subject mobility.

1 . A biomagnetic field detection system comprising:
 a portable support structure; and   a plurality of sensors attached adjacent said portable support structure, each of said sensors being adapted for measuring magnetic field changes generated by a target structure within a subject's body; wherein:
 said biomagnetic field detection system is adapted to detect and measure magnetic fields emanating from a target area within said subject's body; and 
 each of said plurality of sensors is an atomic magnetometer. 
   
     
     
         2 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted to continuously monitor brain activity within said subject while said subject moves one or more of said subject's body parts that are selected from a group consisting of: said subject's head, and said subject's neck. 
     
     
         3 . The biomagnetic field detection system of  claim 1 , wherein said support structure is adapted to conform to said target area. 
     
     
         4 . The biomagnetic field detection system of  claim 3 , wherein said support structure is a portable helmet or hat-shaped structure 
     
     
         5 . The biomagnetic field detection system of  claim 3 , wherein said support structure comprises a flexible, form-fitting structure. 
     
     
         6 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted for reducing interference between at least two of said sensors to an extent that is sufficient to allow said system to detect low-magnitude physiologic fields within said subject. 
     
     
         7 . The biomagnetic field detection system of  claim 1 , wherein said system comprises shielding that is sufficient to reduce interference between at least two of said sensors to an extent that is sufficient to allow said system to detect low-magnitude physiologic fields within said subject. 
     
     
         8 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted to employ sensor multiplexing to reduce interference between at least two of said sensors to an extent that is sufficient to allow said system to detect low-magnitude physiologic fields within said subject. 
     
     
         9 . The biomagnetic field detection system of  claim 1 , wherein said sensors are oriented to reduce interference between at least two of said sensors to an extent that is sufficient to allow said system to detect low-magnitude physiologic fields within said subject. 
     
     
         10 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted to employ data optimization and sensor registration techniques to reduce interference between at least two of said sensors to an extent that is sufficient to allow said system to detect low-magnitude physiologic fields within said subject. 
     
     
         11 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted to reduce magnetic noise within said system to a sufficient extent that is sufficient to allow said system to detect low magnitude physiologic fields. 
     
     
         12 . The biomagnetic field detection system of  claim 1 , wherein said system further includes at least one fiber-optic device that is adapted to illuminate one or more of said sensors and to thereby diminish magnetic interference adjacent said one or more sensors. 
     
     
         13 . The biomagnetic field detection system of  claim 1 , wherein said system comprises a non-electric heating system for diminishing signals from sources of magnetic noise within said system. 
     
     
         14 . The biomagnetic field detection system of  claim 13 , wherein said non-electric heating system comprises a fluid or gas system that is adapted for heating one or more of said plurality of sensors and to thereby diminish signals from sources of magnetic noise within said system. 
     
     
         15 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted for using information from said plurality of sensors to:
 register signals from a proximal biomagnetic source, and   distinguish biomagnetic signals more distal than said proximal signals.   
     
     
         16 . The system of  claim 15 , wherein said system is adapted to use one or more mathematical algorithms to distinguish said more distal biomagnetic signals from more proximal biomagnetic signals. 
     
     
         17 . The biomagnetic field detection system of  claim 1 , wherein said neuro-magnetographic system is adapted for registering both: (1) a first sensor sensing a first set of measurements from a first plurality of signals; and (2) a second sensor sensing a second set of measurements from a second plurality of signals, said step of registering comprising the steps of:
 generating a likelihood function associating a data element from said first set of measurements with a data element from a second set of measurements;   generating a systematic error function based at least in part on said likelihood function;   minimizing said systematic error function; and   assigning a signal from said first plurality of signals to the second plurality of signals, based at least in part on said minimized systematic error function.   
     
     
         18 . The biomagnetic field detection system of  claim 17 , wherein said system is adapted to use a linear assignment method in executing said step of assigning. 
     
     
         19 . The biomagnetic field detection system of  claim 17 , wherein said step of minimizing said systematic error function comprises generating a global minimum of said systematic error function. 
     
     
         20 . The biomagnetic field detection system of  claim 17 , wherein said step of minimizing said systematic error function comprises using a Continuous Greedy Randomized Adaptive Search Procedure to minimize said systematic error function. 
     
     
         21 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted for executing a sensor registration method, said method comprising the steps of:
 generating a known magnetic field at one or more locations in proximity to said biomagnetic field detection system;   measuring a response of each sensor within said biomagnetic field detection system to said known magnetic field; and   utilizing information generated from each sensor for the purposes of sensor registration.   
     
     
         22 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted to use fiducial markers to assess the location or motion of target structures or anatomical features relative to the system or other instrumentation. 
     
     
         23 . The system of  claim 1 , wherein said system comprises one or more lasers for generating fiducial information to assess the location of motion of target structures or anatomical features relative to the system or other instrumentation. 
     
     
         24 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted to improve source localization or diminish magnetic noise by using one or more types of information selected from a group consisting of: vector information, scalar information, gradient information, and temporal information. 
     
     
         25 . The biomagnetic field detection system of  claim 1 , wherein said biomagnetic field detection system is adapted to detect one or more biological signals. 
     
     
         26 . The biomagnetic field detection system of  claim 25 , wherein said biomagnetic field detection system is adapted to use anatomical imaging techniques to detect said one or more biological signals. 
     
     
         27 . The biomagnetic field detection system of  claim 25 , wherein said system is adapted to evaluate one or more of said biological signals in response to said subject being exposed to at least one stimulus. 
     
     
         28 . The biomagnetic field detection system of  claim 25 , wherein said system is adapted to localize physiologic wave forms emanating from said target structure. 
     
     
         29 . The biomagnetic field detection system of  claim 25 , wherein:
 said target area is a first target area within said subject's body; and   said system is adapted to utilize signal processing to evaluate a functional interaction between said first target area and a second target area within said subject's body.   
     
     
         30 . The biomagnetic field detection system of  claim 25 , wherein said target area is selected from a group consisting of: said subject's brain, said subject's peripheral nerves, said subject's muscle tissue, said subject's eyes, and said subject's spinal cord. 
     
     
         31 . The biomagnetic field detection system of  claim 25 , wherein said system is adapted to execute functional mapping of one or more biological systems. 
     
     
         32 . The biomagnetic field detection system of  claim 25 , wherein said system is adapted to monitor said subject's state of arousal. 
     
     
         33 . The biomagnetic field detection system of  claim 25 , wherein said system is configured to detect biological signals from a fetus. 
     
     
         34 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted to use one or more of types of information to determine which of said sensors should be activated at a particular time, said one or more types of information being selected from a group consisting of: vector information, gradient information, scalar information, and temporal information. 
     
     
         35 . The biomagnetic field detection system of  claim 1 , wherein:
 said system is adapted for simultaneously triggering a subset of said plurality of sensors, and   said system is adapted for determining which of said plurality of sensors to simultaneously trigger by:
 determining, for each of said plurality of sensors, angles of maximal and minimal detectability; and 
 using information regarding said angles to identify one or more of said plurality of sensors that are located in an area of relatively low. 
   
     
     
         36 . The biomagnetic field detection system of  claim 1 , wherein said system provides sensor shielding adjacent one or more of said plurality of sensors. 
     
     
         37 . The biomagnetic field detection system of  claim 36 , wherein said sensor shielding comprises active field cancellation. 
     
     
         38 . The biomagnetic field detection system of  claim 36 , wherein said sensor shielding comprises a physical shielding mechanism that is disposed distal to an array of said plurality of sensors. 
     
     
         39 . The biomagnetic field detection system of  claim 36 , wherein:
 a first plurality of said sensors is oriented to detect magnetic fields;   a second plurality of sensors is oriented to detect magnetic fields; and   magnetic shielding is interposed between said first plurality of sensors and the second plurality of sensors   
     
     
         40 . The biomagnetic field detection system of  claim 1 , wherein said system comprises magnetic shielding that is disposed around one or more of said sensors. 
     
     
         41 . The biomagnetic field detection system of  claim 1 , wherein said system is adapted to use one or more data processing algorithms in the deconvolution of overlapping sensor signals or noise to generate spatial, temporal, or magnitude information. 
     
     
         42 . The biomagnetic field detection system of  claim 1 , wherein a first plurality of sensors is oriented as an array to detect a target signal, and a second plurality of sensors is oriented as an array to detect environmental magnetic noise. 
     
     
         43 . The biomagnetic field detection system of  claim 1 , wherein said system comprises thermal insulation adjacent one or more sensors. 
     
     
         44 . A subject monitoring system comprising:
 a monitored area, and   a sensor shielding apparatus for shielding sensors within the monitored area from the effects of magnetic fields external to the monitored area, and   a portable biomagnetic field detection system that is adapted to measure magnetic signals from a target area within a living subject while said living subject is within said monitored area.   
     
     
         45 . The subject monitoring system of  claim 44 , wherein said monitored area is a monitored area that is sufficiently large to allow a human subject to walk within said monitored area. 
     
     
         46 . The subject monitoring system of  claim 44 , wherein said portable biomagnetic field detection system comprises:
 a portable support structure; and   a plurality of sensors attached adjacent said portable support structure, each of said sensors being adapted for measuring magnetic field changes generated by a target structure within a subject's body; wherein:
 said biomagnetic field detection system is adapted to detect and measure magnetic fields emanating from a target area within said subject's body; and 
 each of said plurality of sensors is an atomic magnetometer. 
   
     
     
         47 . The subject monitoring system of  claim 46 , wherein:
 said plurality of sensors is a first plurality of sensors;   said subject monitoring system comprises a second plurality of sensors that are disposed within said monitored area, said second plurality of sensors being adapted for monitoring environmental noise within said monitored area.   
     
     
         48 . The subject monitoring system of  claim 47 , wherein said subject monitoring system is adapted to use sensor registration and data optimization techniques to integrate information from said first and second pluralities of sensors.