JP7289125B2 - In vivo electrical conduction path evaluation device - Google Patents

Description

The present invention relates to an apparatus for evaluating electrical conduction pathways in vivo.

The electrical excitation of the heart is measured not only on the chest surface but also on the extremities and used as an electrocardiogram. Cranial nerve activity is also measured as electroencephalograms on the scalp surface. These facts support the existence of various electrical conduction paths in living organisms.

However, in actual electrocardiogram and electroencephalography, the measurement results are affected not only by changes and disturbances in the electrical excitation sources such as the heart and brain, but also by changes in the electrical conduction path between them. It is considered. Furthermore, Non-Patent Document 1 describes that the electrical resistance inside the living body fluctuates due to physiological changes, pain, psychological stress, and the like.

On the other hand, in oriental medicine and alternative medicine, there is a so-called "acupuncture point" as a part that gives a great therapeutic effect. This acupuncture point was discovered from empirical knowledge derived from traditional Chinese medicine, and its effects are now recognized worldwide. Furthermore, according to electrophysiological experiments conducted in Japan in the 1950s and 1960s, the site called acupuncture points is a highly conductive site on the surface of the skin, and an electrical conduction path that connects multiple acupuncture points. has been found to exist. Conductive paths that connect a plurality of acupuncture points are called "meridians" (Non-Patent Document 2).

Patent Literature 1 discloses an apparatus for estimating the position of an acupuncture point by setting electrodes at two points on the skin surface and energizing them to measure the resistance between the two points. On the other hand, regarding meridians, which are conduction paths that connect multiple acupuncture points, the distribution in the body, physiological changes, and the effects of pathological conditions have not been clarified.

JP 2006-296809

Eiichiro Nonami: Journal of the Japanese Dermatological Association, 68(6), 357-379, 1958. Yoshio Nakatani: Clinical practice of the latest Ryodoraku, 166pp., Ryodoraku Research Institute, Tokyo, 1960 Nakayama, S.; , Uchiyama, T.; Real-time measurement of biomagnetic vector fields in functional syncytium using amorphous metal. Scientific Reports 5, 8837. (2015)

As described above, since meridians are electrical conduction paths that connect a plurality of acupuncture points, it is thought that there are portions in the body where current relatively easily flows along meridians. However, even if an electric current is applied between two acupuncture points, it has been difficult to determine which part of the body, in other words, how deep the electric current has flowed. Therefore, even if a relatively large amount of current flows, it cannot be determined whether or not it flows through a conduction path corresponding to the meridians between acupuncture points.

In the electrical activity generated by the organism itself, the current circuit is closed inside the organism. For example, an inward current generated in an electrically excitable cell penetrates the cell membrane and functions like a battery. After the current is conducted inside the cell, when it is connected to an adjacent cell by an electrically coupled channel, the current flows into the cell membrane of the adjacent cell, and the cell membrane acts like an electric capacitance (capacitor). In this way, a closed circuit is formed by the battery and the electric capacity, and the size of the closed circuit is considered to be at a level similar to that of the cell (in other words, the same order and scale as the size of the cell). Therefore, even if the cell conducts a large current inside the cell, the same return current flows outside the cell, and the magnetic fields generated by the two opposite currents cancel each other out. Therefore, in particular, when the distance from the cell, which is the generation source, increases, the magnetic field generated by the living cell itself is significantly attenuated. (Non-Patent Document 3)

The present invention has been made based on such knowledge, and the purpose thereof is to analyze the current applied to the living body, and to evaluate the position in the living body where the current has flowed. The purpose is to provide a device capable of

The feature of the first invention for achieving the above object is (a) a conduction path for evaluating current conduction state by electrical intervention from the outside to the inside of a living body using a pair of electrodes attached to the living body. An evaluation device comprising: (b) an electrical intervention unit that applies a DC current as the electrical intervention to a living body; (d) a conduction state between the pair of electrodes in the living body based on information about the magnetic field intensity detected by the detecting section and a relationship obtained in advance; and (e) the evaluating unit evaluates according to the position on the skin surface to which the electrical intervention is applied in the living body. (f) the electrical intervention propagates through a plurality of conduction paths in the living body ; (h) the evaluation unit evaluates the depth of the conduction path through which the electrical intervention propagated, among the conduction paths in the plurality of paths; It is something to do.

According to the first invention, the electrical intervention section applies an electrical intervention from outside the living body to the living body, and the detection section detects a magnetic field change occurring when the electrical intervention is applied outside the living body. Then, the conducting state in the living body is evaluated by the evaluating section based on the information about the detected magnetic field. Therefore, it is preferable to evaluate the conducting state of the current induced in the living body by electrical intervention. can be done. In addition, by detecting different magnetic field changes in the detection unit according to the position on the skin surface to which the electrical intervention is energized, the depth to which the electrical intervention is energized can be evaluated. , it is possible to evaluate at what path or depth the electrical intervention was conducted in the body. Also, even if the electrical intervention propagates through multiple paths, the conduction paths can be evaluated.

In the first invention, the electrical intervention (intervention current) is unidirectionally conducted in order to conduct electricity from outside the living body to the living body, and the living cell itself does not generate an excitation current under a subthreshold energization condition, or after being excited once If it is a refractory period to electrical intervention immediately after , there is no return current path inside the body. Therefore, a magnetic field generated when current is conducted through an electrical conduction path inside a living body can be efficiently measured even by a magnetic detection device located at a distance from the generation source.

A second aspect of the present invention is characterized by (a) a conduction path evaluation apparatus for evaluating a current conduction state by electrical intervention from the outside to the inside of a living body using a pair of electrodes attached to the living body, (b) an electrical intervention unit for applying a DC current to the living body as the electrical intervention; and (d) the conduction as an evaluation of the conduction state between the pair of electrodes in the living body based on the information on the magnetic field intensity detected by the detection unit and the relationship obtained in advance. (e) the pre- obtained relationship is information about the magnetic field strength detected by the detector and the depth of the pathway through which the electrical intervention propagated; (f) the electrical intervention unit applies electrical intervention to locations on the skin surface corresponding to the meridians of the living body; With this configuration, the electrical intervention unit applies an electrical intervention to the living body from outside the living body, and the detection unit detects a magnetic field change generated when the electrical intervention is applied outside the living body, Based on the information about the strength of the magnetic field detected by the evaluation unit, the depth of the conduction path in the living body is calculated . and assess the depth of the pathways that carry electrical intervention between the meridians.

Preferably, the electrical intervention performed by the electrical intervention section is application of current having a rectangular waveform. In this way, an electrical intervention can be applied, such as said rectangular waveform, for example a current rise, fall, DC component, etc., or a repetition thereof.

Also preferably, the evaluation unit evaluates the depth of the conduction path based on information about the magnetic field strength detected by the detection unit at two or more positions on the skin surface . In this way, by detecting the change in the magnetic field at two or more positions on the skin surface by means of the detection unit, the change in the magnetic field, which differs according to the conduction state of the electrical intervention, is detected when the electrical intervention is performed in the living body. The depth of the conduction path can be assessed.

Preferably, the application of the electrical intervention by the electrical intervention section and the detection of the magnetic field by the detection section are executed synchronously. By doing so, it is possible to appropriately detect changes in the extracorporeal magnetic field caused by the electrical intervention.

Also preferably, the electrical intervention applied by the electrical intervention unit flows unidirectionally through a conduction path in the body and is not accompanied by a return current at the cellular level. Specifically, in order to energize the living body from outside the body, the electrical intervention is unidirectionally conducted, and the current is applied under a sub-threshold condition in which the living cells themselves do not generate an exciting current, or the current is applied immediately after being excited once. refractory period, there is no return current path in the body. In this way, the magnetic field generated when electrical intervention is conducted inside the living body can be efficiently measured even by a magnetic detection device located at a distance from the source.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the outline|summary of a structure of the conduction path evaluation apparatus which is one Example of this invention. It is a figure explaining the structure of the sensor apparatus in the conduction path evaluation apparatus of FIG. 1, and the positional relationship of a sensor apparatus and a conduction path. FIG. 2 is a functional block diagram for explaining an outline of a control function of an electronic control device in the conduction path evaluation device of FIG. 1; FIG. 2 is a diagram showing the time variation of the interventional current applied to the subject by the power supply circuit and the output signal of one of the magnetic sensors in the conduction path evaluation device of FIG. 1; FIG. 4 is a diagram schematically showing a conduction path in vivo. 8 is a diagram showing the relationship between the distance from the skin surface of subject 8 to the magnetic sensor and the magnetic field intensity. FIG. FIG. 7 is a diagram for explaining a process in which a depth evaluation unit evaluates the depth of a conduction path, and is a diagram for explaining a part of the relationship between the distance from the conduction path and the magnetic field strength shown in FIG. 6 by enlarging it. . 4 is a flow chart for explaining an overview of the control operation of the driveway evaluation device of the present invention;

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram illustrating the outline of the configuration of a conduction path evaluation apparatus 10 that is an embodiment of the present invention. The conduction path evaluation apparatus 10 includes electrodes 18a and 18b (hereinafter simply referred to as "electrodes 18" when not distinguishing between them) that apply electrical intervention to the skin of the subject 8, and the pair of electrodes 18 of the subject 8 are A magnetic sensor device 20 that detects changes in the magnetic field in the vicinity of the provided site, a power supply circuit 14 that generates a current to be applied to the subject 8 via an electrode 18, and an evaluation of the conduction path based on the signal detected by the magnetic sensor 20. An electronic control unit 12 including a computer for realizing the function of the evaluation unit 18 and the like and for driving the power supply circuit 14, and a display for displaying information on the operation of the conduction path evaluation device 10 It is configured including the device 16 and the like.

For the electrode 18, for example, a so-called gel electrode having an electrically conductive gel material on its surface is used. The electrode 22 is attached to the skin surface of the subject 8 due to the viscosity of the gel material. In this embodiment, the two electrodes 18a and 18b are attached, for example, to two known adjacent acupuncture points, so-called acupuncture points.

The magnetic sensor device 20 is arranged near the skin surface of the subject 8 between the pair of electrodes 18 . When electrical intervention is applied from a power supply circuit 14 described later between a pair of electrodes 18 provided at the positions of two acupuncture points, the electrical intervention causes the conduction path in the body of the subject 8 to become a unidirectional current. It will flow. The magnetic sensor device 20 detects changes in the magnetic field caused by the current flowing through its conduction path. selected as much as possible.

Moreover, the magnetic sensor device 20 is configured by including a plurality of magnetic sensors on the same surface. When the magnetic sensor device 20 is attached to the skin surface of the subject 8, the plurality of magnetic sensors are arranged at a plurality of positions in a direction substantially parallel to the skin surface and a plurality of positions at different distances from the skin surface. (that is, a plurality of positions in a direction substantially perpendicular to the skin surface), and the magnetic field intensity can be measured at the plurality of positions at the same time. In this embodiment, as shown in FIG. 2, the magnetic sensor device 20 includes nine magnetic sensors S11, S12, S13, S21, S22, S23, S31, S32, and S33 on the same plane. It is Three sensors S11, S21 and S31 are located at a distance of ds1 (mm) from the skin surface, and three sensors S12, S22 and S32 are located at a distance of ds2 (mm) from the skin surface. However, three sensors S13, S23, and S33 are provided at positions where the distance from the skin surface is ds3 (mm). The three sensors S11, S12, and S13, the three sensors S21, S22, and S23, and the three sensors S31, S32, and S33 are arranged on a straight line perpendicular to the skin surface at distances ds1, They are arranged in a lattice so as to be ds2 and ds3 (mm).

In addition, when the magnetic sensor device 20 is attached to the skin surface of the subject 8, the surface on which the sensors S11 to S33 are arranged is the conduction path to be evaluated, in other words, the straight line connecting the pair of electrodes 18. placed at right angles to the Thus, the plurality of sensors S11 to S33 simultaneously measure the magnetic field generated by the current flowing through the conduction path based on Ampere's law, and the conduction path can be evaluated more accurately. In order to hold the measurement position, the magnetic sensor device 20 may be attached and fixed to the skin surface of the subject 8 at the measurement site, or may be held using a clamp device (not shown) or the like.

Here, among the plurality of sensors S11 to S33, the sensors S21, S22, and S23, whose measured values are used by the depth evaluation unit 40, which will be described later, are preferably the true sensors of the conduction paths 50a, 50b, and 50c as shown in FIG. When the position and attitude of the magnetic sensor device 20 are determined in this way, the sensors S11 and S31 adjacent to the sensor S21, the sensors S12 and S32 adjacent to the sensor S22, and the sensors S12 and S32 adjacent to the sensor S22 are positioned upwardly. Alternatively, the output of a pair of sensors S13 and S33 adjacent to the sensor S23 becomes substantially equal. This is because the distances between the sensors S11 and S31, the sensors S12 and S32, or the sensors S13 and S33, and the conduction paths 50a, 50b, and 50c are approximately equal.

Further, the magnetic sensor device 20 includes a reference magnetic sensor SR in addition to the plurality of magnetic sensors S11 to S33 described above. This magnetic sensor SR is for constructing a differential magnetic sensor together with each of the sensors S11 to S33. The reference magnetic sensor SR is provided at a position to which an environmental magnetic field such as geomagnetism is commonly applied to the magnetic sensors S11 to S33 described above, but is not affected by the magnetic field caused by the current flowing through the conduction path. By differentially connecting the sensors S11 to S33 and the reference magnetic sensor SR arranged in this manner, the influence of the environmental magnetic field can be removed from the detected values of the sensors S11 to S33, and the resolution of the sensor is improved. .

Further, since the magnetic sensor device 20 is placed in contact with or in close proximity to the skin surface of the subject 8, each of the magnetic sensors S11 to S33 is non-invasive to the subject 8 and preferably operates at room temperature. . For example, an MI sensor (magnetoimpedance sensor) and an IPA sensor, which are small and capable of measuring minute magnetic fields such as nanotesla (nT) units, can be used. These magnetic sensors utilize so-called amorphous wires and similar metallic structures.

Returning to FIG. 1, the power supply circuit 14 corresponds to an electrical intervention unit, and is connected to the electrode 18 described above by a lead wire to apply an electrical intervention, that is, an electric current (intervention current) to the subject 8 from the outside. It is. The energization of this electrical intervention is a pulsed (intermittent) DC current having a preset magnitude and time interval.

The electronic control unit 14 includes a so-called microcomputer comprising a CPU, a ROM, a RAM, an input/output interface, etc., and performs signal processing according to a program pre-stored in the ROM while utilizing the temporary storage function of the RAM. By doing so, the power supply circuit 14 is controlled to generate an electrical intervention having a predetermined waveform, and an operation such as evaluating a conduction path, which will be described later, is performed based on the output signal from the magnetic sensor device 20 .

The display device 16 displays information on the operation of the conduction path evaluation device 10 based on the output from the electronic control device 14, specifically, information on the evaluation result of the conduction path in the depth evaluation unit 40, which will be described later, in characters or graphics. and so on. As the display device 16, a known liquid crystal display or the like is used.

FIG. 3 is a functional block diagram for explaining the outline of the control functions of the electronic control unit 14. As shown in FIG. The electronic control unit 14 functionally includes a timer 30, an electrical intervention unit 32, a magnetic sensor drive unit 34, a signal detection unit 36, a magnetic field intensity calculation unit 38, a depth evaluation unit 40, a storage unit 42, and the like.

The timer 30 supplies a time signal necessary for the synchronous operation of an electrical intervention unit 32, a magnetic sensor drive unit 34, a signal detection unit 36, etc., which will be described later.

The electrical intervention unit 32 drives the power supply circuit 14 to generate a current that is a predetermined electrical intervention (hereinafter also referred to as intervention current). In other words, the electrical intervention section 32 and the power supply circuit 14 constitute the electrical intervention section of the present invention. Specifically, for example, the power supply circuit 14 is caused to repeatedly generate a pulsed current of a constant magnitude. This current is applied to the subject 8 via the electrodes 18 and flows through conductive pathways in the body of the subject 8 . In this pulsed current, the pulse width is set so that the magnetic sensor device 20 can detect the magnetic field generated by the current flowing through the conduction path. The electrical intervention portion 32 and the power supply circuit 14 described above correspond to the electrical intervention portion of the present invention. Here, the magnitude of the pulse is determined as follows. In other words, the intervention current flows through the excitable cells located in or near the conduction path via the electrode 18, but the magnitude of the pulse of the intervention current is such that the excitable cells are not in an excited state. is set. In other words, the maximum magnitude of the intervention current that does not cause the excitable cell to become excited by the current flowing through the excitable cell is taken as a threshold, and the magnitude of the intervention current is made below the threshold. When an excitatory cell becomes excited, electric charges are transferred inside and outside the excitatory cell and between neighboring cells. For example, in jumping conduction of nerve axons, ion channels transiently open at the site of excitation, playing the same role as a battery. At this time, a current flows inside the cell, and a current paired with the current flows in the opposite direction outside the cell. This gives rise to a return current at the cellular level, in other words a looped current. When the return current occurs, the intervening current does not flow unidirectionally in the body. Therefore, an intervention current is set such that the excitable cells are not in an excited state. It should be noted that the aforementioned threshold value is obtained in advance through experiments or the like.

The magnetic sensor driving section 34 performs control for driving the magnetic sensors S11 to S33 that constitute the magnetic sensor device 20 . For example, it supplies power to drive the magnetic sensors S11 to S33, and generates control signals for starting and ending detection. For example, when an MI sensor is used as the magnetic sensors S11 to S33, a drive current is supplied to an amorphous wire in the MI sensor. Further, the magnetic sensor driving section 34 can detect the magnetic field by the magnetic sensor device 20 as the electrical stimulation is applied by the electrical intervention section 32 .

The signal detection unit 36 receives output signals from the magnetic sensors S11 to S33 forming the magnetic sensor device 20 and performs appropriate processing. Specifically, predetermined amplification is performed by a preamplifier or the like, and sampling processing and AD conversion are performed at predetermined intervals using a sample hold circuit. At this time, the sample hold circuit performs processing by referring to the time signal from the timer 30 . At this time, the signal detection unit 36 may always process the signal, or in synchronism with the application of the electrical intervention by the electrical intervention unit 32, for example, from immediately before any application to after completion of the application, The signal processing may be repeated only until a predetermined time elapses when the change in the magnetic field caused by is completed. This signal detection section 36 corresponds to the detection section of the present invention.

Further, when the signal detection unit 36 makes a difference between each of the magnetic sensors S11 to S33 and the differential sensor SR, the signal detection unit 36 uses a differential amplifier or the like to convert the outputs of the magnetic sensors S11 to S33 and the differential sensor SR. After generating the difference from the output, the above-described amplification, AD conversion, and the like are performed on the difference.

FIG. 4 shows temporal changes in the intervention current applied to the subject 8 by the power supply circuit 14 and the output signal of one of the magnetic sensors S11 to S33 in a way that they can be compared on a common time axis (horizontal axis). is. The intervention current is applied in rectangular pulses from time t1 to t2. Note that the interval between the times t1 and t2, that is, the width of the pulse, the duration of the pulse, the amplitude of the pulse, etc., can be changed as appropriate. On the other hand, the output signal of the magnetic sensor sharply rises at time t1 when the intervention current rises, and then converges to a steady-state value corresponding to the value of the intervention current. Also, at time t2 when the intervention current falls (turns off), it abruptly becomes a negative value and then converges toward zero. Here, the length of the pulse width of the intervention current (duration of the current) is set to be longer than the convergence time of the output signal of the magnetic sensor.

Returning to FIG. 2, the magnetic field intensity calculator 38 calculates the magnetic field intensity at the positions where the magnetic sensors S11 to S33 are arranged based on the outputs of the magnetic sensors S11 to S33 obtained by the signal detector 36. calculate. The calculation of the magnetic field strength by the magnetic field strength calculation unit 38 is performed based on the relationship between the output value of the magnetic sensor and the magnetic field strength, which is stored in the storage unit 42 or the like in advance as a map, relational expression, or the like.

The depth evaluation unit 40 evaluates the conduction path to which the electrical intervention is applied based on the magnetic field intensity at the positions where the magnetic sensors S11 to S33 are arranged, which is calculated by the magnetic field intensity calculation unit 38 . This pathway assessment relates to the location of the pathway, ie depth from the skin surface. The depth evaluation unit 40 and the like correspond to the evaluation unit of the present invention. The evaluation operation of the conduction path by the depth evaluation unit 40 will be described below.

FIG. 5 is a diagram schematically showing a conduction path in vivo, which was created by the inventors of the present application. As described above, it is believed that there may be an electrical conduction path between the pair of electrodes 18a and 18b through which current may flow. It is difficult to directly grasp the capacitor component). For example, as illustrated in FIG. 5, between a pair of electrodes 18a and 18b, there may be at least one of, eg, three conductive paths 50a, 50b, 50c. These three conduction paths 50a, 50b, 50c are arranged in the order of 50a, 50b, 50c in order of proximity to the skin surface, and are located at different depths. Of these, the conduction paths 50a and 50b respectively have resistances R1 and R2 (Ω) and capacitor components C1 and C2 (F), and the conduction path 50c has only the resistance component R3. and has no capacitor component. According to the studies of the present inventors, the resistance value in each electric path increases as the depth from the skin surface increases. becomes smaller with increasing depth, that is, C1>C2.

FIG. 6 shows the distance ds (m) from the skin surface of the subject 8 to the magnetic sensor and the magnetic field strength M (T ) is a diagram showing the relationship between This relationship is obtained in advance, for example, experimentally or by simulation, is stored in the storage unit 42, and is read out and used as appropriate. The magnetic field strength M is the strength of the magnetic field generated due to the flow of a predetermined current through the conducting path 50 . As shown in FIG. 6, there is a general tendency for the magnetic field intensity M to decrease as the distance ds increases.

FIG. 6 also shows three curves as the relationships La to Lc. The relationships La-Lc correspond to the conduction paths 50a-50c at three different depths, respectively. In FIG. 6, the horizontal axis represents the distance ds from the skin surface to the magnetic sensor. The magnetic field generated by the current flowing through the conduction path is transmitted through the body of the subject 8, propagates from the skin surface through the atmosphere, and is detected by the magnetic sensor. It is the sum of the depth d1 to d3 of the conductive paths 50a to 50c from the skin surface and the distance ds from the skin surface of the magnetic sensor that measures the magnetic field intensity. Specifically, using the example of FIG. 2, when the sensor s23 measures the magnetic field strength due to the current flowing through the conduction path 50a, the distance D is the depth d1 from the skin surface of the conduction path 50a and the magnetic sensor s23. It is summed with the distance ds3 from the skin surface (ie D=d1+ds3). It can be generally assumed that the inside of the living body 8 and the atmosphere in which the sensor device 20 (sensors s11 to s33) is provided have substantially the same magnetic permeability. Also, as shown in FIG. 5, the conductive paths 50a and 50b contain capacitor components C1 and C2, respectively, and when a DC current is applied to the conductive paths 50a and 50b, the capacitor components C1 and C2 will However, the relationship shown in FIG. 6 is for each conduction path 50a and for the current through 50b.

Specifically, the depth evaluation unit 40 uses the magnetic field strengths of a plurality of sensors having different distances from the conduction path 50x among the magnetic field strengths of the sensors S11 to S33 calculated by the magnetic field strength calculation unit 38. , evaluate the depth of the conduction path 50x. In the following description, the conductive path 50x refers to at least one of the conductive paths 50a to 50c through which the applied intervention current actually flows.

In this embodiment, as shown in FIG. 2, the position and attitude of the magnetic sensor 20 are determined so that the conduction path 50x is perpendicular to the sensor surface 21 on which the sensors S11 to S33 of the magnetic sensor device 20 are provided. be done. This is because when a pair of electrodes 18a and 18b are attached to positions corresponding to adjacent meridians of the subject 8, assuming that the conduction paths 50a to 50c exist on a straight line connecting the pair of meridians, magnetic The sensor surface 21 of the sensor device 20 is arranged so as to be perpendicular to a pair of meridians, that is, a straight line (line segment) connecting the pair of electrodes 18a and 18b, and perpendicular to the skin surface.

In this arrangement, the sensors S21, S22 and S23 in the magnetic sensor device 20 are located directly above the conduction paths 50a to 50c as shown in FIG. When the magnetic field strength of each of the sensors S21, S22, and S23 measured by the magnetic field strength calculation unit 38 is obtained, the depth evaluation unit 40 calculates the measured magnetic field strength values and the pre-stored distance from the conduction path. Based on the relationship between D and the magnetic field strength M, the depth of the conduction path is estimated.

FIG. 7 is a diagram for explaining the process of evaluating the depth of the conduction path by the depth evaluation unit 40, and is an enlarged view of a part of the relationship between the distance ds from the conduction path and the magnetic field strength M shown in FIG. It is a diagram for explaining. In FIG. 7, two relationships, a relationship La corresponding to the conducting path 50a and a relationship Lb corresponding to the conducting path 50b, are shown as examples. When the magnetic field strengths of the sensors S21, S22, and S23 measured by the magnetic field strength calculation unit 38 are obtained as M1, M2, and M3(T), respectively, the depth evaluation unit 40 determines that the conduction path 50x through which the current actually flowed is For each of the transmission paths 50a and 50b, the distance between each sensor and the transmission path 50x is calculated from the relationships La and Lb shown in FIG.

When the magnetic field intensities detected by the sensors S21, S22, S23 are respectively M1, M2, M3(T), according to the relationship La in FIG. are D1a, D2a, D3a, while according to the relation Lb, the distances between the conduction path 50a and the sensors S21, S22, S23, respectively, are D1b, D2b, D3b. Here, as shown in FIG. 2, when the sensor device 20 is arranged so that the sensors S21, S22, and S23 are on the same straight line as the conduction path 50x through which current actually flows, the distance from the conduction path 50x to the sensor S21 is The difference D2-D1 between the distance D1 and the distance D2 from the transmission path 50x to the sensor S22 is the distance between the sensors S21 and S22, and the distance D2 from the transmission path 50x to the sensor S22 and from the transmission path 50x to the sensor S23. The difference D3-D2 from the distance D3 is the distance between the sensor S22 and the sensor S23.

The depth evaluation unit 40 calculates the difference D2-D1 between the distance D1 from the conduction path 50x to the sensor S21 and the distance D2 from the conduction path 50x to the sensor S22, the distance D2 from the conduction path 50x to the sensor S22, and the distance D2 from the conduction path 50x. A difference D3-D2 from the distance D3 to the sensor S23 is calculated based on the relationships La and Lb, respectively. That is, based on the relationship La, the difference D2-D1 between the distance D1 from the transmission path 50x to the sensor S21 and the distance D2 from the transmission path 50x to the sensor S22 is D2a-D1a, and based on the relationship Lb, D2b- D1b. Similarly, the difference D3-D2 between the distance D2 from the path 50x to the sensor S22 and the distance D3 from the path 50x to the sensor S23 is D3a-D2a based on the relationship Lb, and D3b based on the relationship Lb. - D2b.

Here, the mutual positional relationship between the sensors S21, S22, and S23 is known in terms of design, and as shown in FIG. -ds2. With respect to the difference D2-D1, the depth evaluation unit 40 determines which of D2a-D1a obtained based on the relationship La and D2b-D1b obtained based on the relationship Lb is the actual value ds2-ds1 and whether it is within a predetermined error range. Similarly, for the difference D3-D2, the depth evaluation unit 40 determines which of D3a-D2a obtained based on the relationship La and D3b-D2b obtained based on the relationship Lb is the actual value. It is determined whether or not ds3-ds2 is within a predetermined error range.

Of the value obtained based on the relationship La and the value obtained based on the relationship Lb, both the value of the difference D2-D1 and the value of the difference D3-D2 are the actual value and the predetermined value. If it is determined to be within the margin of error, the depth evaluator 40 evaluates that the relationship used to obtain the value is the conduction path 50x through which the current actually flowed. For example, if the value of the difference D2-D1 obtained based on the relationship La is the distance between the actual sensors S21 and S22 is within a predetermined error of ds2-ds1, and the value of the difference D3-D2 is the actual sensor S22 and S22. If the distance between S23 is within a predetermined error of ds3-ds2, it is evaluated that the conduction path 50a corresponding to the relationship La is the conduction path 50x through which the current actually flows. In other words, the position of the pathway 50a is evaluated as the depth of the pathway. Further, the depth evaluation unit 40 causes the display unit 16 to display information about the evaluation result as necessary.

In addition, application of an intervention current by the electrical intervention unit 32, measurement of the magnetic field strength in each magnetic sensor by the magnetic sensor drive unit 34, the signal detection unit 36, and the magnetic field strength calculation unit 38, and determination of the conduction path by the depth evaluation unit 40 The series of operations for evaluation was performed only once in the above description, but is not limited to this, and the series of operations may be repeated multiple times. is performed a predetermined number of times or more, the evaluation may be finalized.

FIG. 8 is an example of a flow chart for explaining the outline of the control operation of the driveway evaluation device 10 of the present invention. In step ST (hereinafter, the word “step” will be omitted as appropriate) 10 corresponding to the electrical intervention unit 32, the power supply circuit 14 generates an intervention current having a predetermined current magnitude, and the skin of the subject 8 is The intervening current is applied through a pair of electrodes 18 attached to the .

In ST20 corresponding to the magnetic sensor driving section 34, the signal detecting section 36, the magnetic field strength calculating section 38, etc., the magnetic sensor device 20 is driven, and the magnetic field strength M is measured by the sensors S11 to S33 in the magnetic sensor device 20. done.

In ST30 corresponding to the depth evaluation unit 40, the value of the magnetic field intensity in each sensor obtained in ST20, the relationship between the distance ds from the skin surface to the sensor and the magnetic field intensity M stored in advance in the storage unit 42, is used to evaluate the pathway through which the intervention current actually flowed.

In ST40 corresponding to the depth evaluation unit 40, it is determined whether or not the series of operations from ST10 to ST30 have been repeated a predetermined number of times. This is to prevent erroneous evaluation based on the fact that the same evaluation was repeatedly obtained in ST30 for a predetermined number of times.

According to the above-described embodiment, the conduction path evaluation device 10 includes the electrical intervention unit 32 that applies an intervention current to the living body of the subject 8, and the magnetic field change when the intervention current is applied by the electrical intervention unit 32. A magnetic sensor device 20 that detects outside the subject 8, a magnetic sensor drive unit 34 that drives the magnetic sensor device 20, a signal detection unit 36, and a magnetic field strength calculation unit 38, and the magnetic field strength calculation unit 38 detects Since it has the depth evaluation part 40 which evaluates the conduction state in the subject 8 based on the information about a magnetic field, the conduction state of the intervention current in the body of the subject 8 can be evaluated.

Further, according to the above-described embodiment, the intervention current applied by the electrical intervention section 32 is a current having a rectangular waveform. In this way, an electrical intervention can be applied, such as said rectangular waveform, for example a current rise, fall, DC component, etc., or a repetition thereof.

Further, according to the above-described embodiment, the depth evaluation unit 40 performs evaluation based on the steady-state magnetic field intensity detected by the magnetic field intensity calculation unit 38 . In this way, the conduction state of the intervention current in the body of the subject 8 can be evaluated based on the magnetic field intensity M that varies depending on the position of the conduction path 50x through which the intervention current flows, particularly the depth from the skin surface. Also, by being based on the magnetic field strength M in the steady state, it is possible to reduce the influence of elements that generate frequency components.

Further, according to the above-described embodiment, the evaluation of the conduction state in the body of the subject 8 is the evaluation of the position in the body of the subject 8 of the conduction path 50x through which the intervention current flows, particularly the depth from the skin surface. In this way, it is possible to evaluate in what route or depth the interventional current is conducted inside the body of the subject 8 .

Preferably, the application of the intervention current by the electrical intervention unit 32 and the detection of the magnetic field by the magnetic sensor drive unit 34, the signal detection unit 36, and the magnetic field intensity calculation unit 38 are executed in synchronism. be. In this way, magnetic field changes outside the body of the subject 8 caused by the intervention current can be appropriately detected.

Preferably, the electrical intervention unit 32 applies an intervention current via electrodes 18a and 18b provided at positions corresponding to the meridians of the subject's 8 body. In this way, it is possible to evaluate the conduction paths carrying interventional currents between said meridians.

Also preferably, the electrical intervention IE applied by the electrical intervention unit 32 flows unidirectionally through a path in the body and is not accompanied by a return current at the cellular level. In other words, the conduction path unidirectionally conducts the electrical intervention IE in order to conduct electricity from the outside of the body to the body. If so, the living cells themselves do not respond to the current applied again, and the living cells themselves do not excite, and there is no return current path inside the living body. In this way, the magnetic field generated when the electrical intervention IE is conducted inside the living body can be efficiently measured by the magnetic sensor device 20 existing at a distance from the conduction path that is the source of the magnetic field. .

Preferably, the application of the electrical intervention IE by the electrical intervention section 32 and the detection of the magnetic field by the detection section 36 are executed synchronously. In this way, the detection unit 36 can efficiently and appropriately detect the extracorporeal magnetic field change caused by the electrical intervention IE.

Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention is also applicable to other aspects.

In the conduction path evaluation apparatus 10 of the present embodiment, the depth evaluation unit 40 uses the outputs of the three sensors S21, S22, and S23 to determine which of the conduction paths 50a and 50b corresponding to the relationships La and Lb the intervention current flows. However, it is not limited to such an aspect. For example, a similar evaluation may be performed using only two of the three sensors described above.

Although the conduction path evaluation device 10 of the present embodiment includes the display device 16 that displays the operation thereof, it is not limited to such a mode. For example, instead of or in addition to the display device 16, one or more display lamps or a buzzer that emits a buzzing sound may be provided. Here, the indicator lamp and the buzzer indicate information regarding the operation of the conduction path evaluation device 10 by means of light emission or operation sound. Specifically, for example, the intensity of the light emitted from the lamp, the blinking interval, the number of lamps that emit light, or the volume and frequency of the buzzer sound can be varied according to the depth from the skin surface of the subject 8 to the conduction path. can be replaced with the display on the display device 16 .

Although the electrode 18 of this embodiment is assumed to be a gel electrode, it is not limited to such a mode. For example, a needle-like electrode may be used and the electrical intervention applied by pointing the tip portion to the subject 8 .

In the above-described embodiment, the magnetic sensor device 20 is provided with the magnetic sensor SR for reference and is differentially connected to each of the magnetic sensors S11 to S33, but is not limited to this. That is, the reference magnetic sensor SR is not necessarily essential, and the reference magnetic sensor SR may not be provided and the measured values of the magnetic sensors S11 to S33 may be used as they are.

In addition, application of an intervention current by the electrical intervention unit 32, measurement of the magnetic field strength in each magnetic sensor by the magnetic sensor drive unit 34, the signal detection unit 36, and the magnetic field strength calculation unit 38, and determination of the conduction path by the depth evaluation unit 40 A series of evaluation operations may be repeated multiple times, but is not limited to such a mode. For example, the application of an intervention current by the electrical intervention unit 32, the operation of measuring the magnetic field strength in each magnetic sensor by the magnetic sensor drive unit 34, the signal detection unit 36, and the magnetic field strength calculation unit 38 are repeatedly performed, and the magnetic field of each sensor After obtaining the average value of the strength measurements, the depth estimator 40 may evaluate the conduction path only once.

In the above-described embodiment, as shown in FIG. 2, the sensor device 20 has three locations in the vertical direction, i.e., the direction away from the conduction path, and three locations in the horizontal direction, which is the direction perpendicular to the vertical direction. Although the nine magnetic sensors S11 to S33 are provided, the present invention is not limited to such an aspect. For example, when the intervention current is applied repeatedly, instead of the three magnetic sensors S21, S22, S23 used by the depth estimator 40 in the previous embodiment, one sensor S is , the measurement may be repeatedly performed at the positions of the three magnetic sensors S21, S22, and S23. In this case, the magnetic sensor device 20 may be attached to a manipulator or a robot arm so that the position of the magnetic sensor device 20 can be moved through the plurality of measurement positions and temporarily held at each measurement position. Alternatively, the sensor device 20 may consist only of the three magnetic sensors S21, S22, S23 used by the depth evaluation unit 40. FIG.

Further, in the above embodiment, the sensor device 20 has nine magnetic sensors S11 to S33 provided on one plane, but the present invention is not limited to this. For example, in addition to these nine magnetic sensors, a pair of sensors S41 and S42 may be provided on a straight line orthogonal to the plane so that the distances from the plane are equal. In this way, by arranging the sensor device 20 so that the outputs of the pair of sensors S41 and S42 are equal, the pair of sensors S41 and S42 are arranged parallel to the conduction path 50x, in other words, , the sensor device 20 can be arranged so that a plane orthogonal to a straight line connecting the pair of sensors S41 and S42 is orthogonal to the transmission path 50x.

In the above-described embodiment, the relationship between the distance ds from the skin surface of the subject 8 to the sensor and the magnetic field strength M to be measured is, for example, the relationships La, Lb, and Lc illustrated in FIGS. However, it is not limited to such a mode. For example, instead of the relationships La, Lb, and Lc, a relational expression (mathematical formula) with the distance ds and the magnetic field strength M as variables and the depth D as a parameter may be used. In this case, the depth evaluation unit 40 evaluates the depth by specifying a relational expression that satisfies the magnetic field intensity M measured by each of the sensors S21, S22, and S23, specifically, by specifying parameters in the expression. may In particular, when the conduction paths 50x through which the intervention current actually flows are a plurality of the conduction paths 50a, 50b, and 50c, each of the plurality of conduction paths generates a magnetic field according to the magnitude of the current flowing. Therefore, the relational expression corresponding to one conduction path (eg 50a) and the relational expression corresponding to another conduction path (eg 50b) are weighted according to the magnitude of the flowing current. A plurality of conduction paths 50x can be identified by simultaneously solving with . In this case, the number of sensors S in the magnetic sensor device 20 is preferably equal to or greater than the number of conductive paths 50x through which current flows.

Also, in the above-described embodiment, a pulsed current is applied as the intervention current IE, but the present invention is not limited to this. That is, the intervening current may be not only a continuous step pulse with the same amplitude, but also a current obtained by synthesizing a plurality of pulses having different frequencies. Further, pulses of a plurality of frequencies in a predetermined frequency band may be used as the pulses having a plurality of different frequencies.

In the above-described embodiment, a pulsed current, that is, an intermittent DC current is used as the intervention current, and the power supply circuit 14 is used as the electrical intervention unit 32 for generating the intervention current. is not limited to a specific form. That is, as described above, various forms of current can be used as the intervention current, so various electrical intervention units 32 that realize such currents are appropriately used. That is, a configuration such as a programmable electrical waveform generator driven by a current amplifier and a timer is conceivable. In this way, the electrically excitable cell group existing in the conduction path inside the living body to which the intervention current is applied does not generate an activity current by itself and form another current closed circuit inside the living body. Since the current can be applied again during the refractory period after being excited by the lower energization or the current application once, it is easy to estimate the unidirectional current conduction path in the body. Furthermore, the response magnetic field to the required frequency current can be measured in a short period of time, and if the response waveform itself is recorded in the storage unit, the response to complex changes in the biomagnetic field can be evaluated even off-line.

Further, in the case of sequentially outputting currents having a plurality of different frequencies as intervention currents, an oscillator capable of dynamically changing the frequencies of the currents may be used. When currents having a plurality of different frequencies are sequentially applied as intervention currents, when intervention currents flow through a plurality of conduction paths (for example, 50a and 50b) shown in FIG. By sweeping the frequency of the oscillator, the amount of current flowing through each conduction path can be changed, so the position of the conduction path 50 can be evaluated even if the number of sensors S included in the magnetic sensor device 20 is reduced. can.

In addition, although not listed individually, the present invention can be implemented in aspects with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and such embodiments are the aspects of the present invention. Needless to say, all are included within the scope of the present invention as long as they do not deviate from the spirit.

For example, in the above embodiment, a magnetic impedance sensor (MI sensor) was used as the magnetic sensor 20, but it is not limited to this. That is, when the intervention current IE is applied to the subject 8, any other type of magnetic sensor can be used as long as it has the accuracy and resolution to detect the magnetic field fluctuation caused by the intervention current IE. Specifically, for example, it is possible to use a fluxgate sensor or the like. Also, the magnetic sensor 20 in the present invention may have relatively low sensitivity. That is, even when the magnetic impedance sensor or the iPA sensor described above is used as the magnetic sensor 20 in this embodiment, the sensor element made of an amorphous-like metal does not have to have a sufficiently high sensitivity. Here, "sufficiently high sensitivity" means, for example, high sensitivity to the extent that the resolution of a superconducting quantum interference device or an optically pumped atomic magnetometer has.

A so-called programmable electrical waveform generator can also be used as the electrical intervention unit 32 . This programmable electric waveform generator has, for example, a current amplifier and a timer, and can generate a current with an arbitrary waveform by driving the current amplifier based on a time signal generated by the timer. is. In this way, the electrically excitable cell group existing in the conduction path inside the living body to which the intervention current is applied does not generate an activity current by itself and form another current closed circuit inside the living body. Since the intervening current can be applied again during the refractory period after being excited by the lower energization or the current application once, it is easy to estimate the unidirectional current conduction path in the body. Preferably, the programmable electric waveform generator continuously measures the magnetic field response in the signal detector 36 while synthesizing electric waveforms containing DC and various AC frequencies for a certain period of time, and immediately calculates the results. Instead, it may be stored in the storage unit 42 . By doing so, responses to complex biomagnetic field changes can be evaluated even off-line.

In the above-described embodiment, the magnitude of the intervention current set by the electrical intervention unit 32 is set so that the excitable cells through which the current flows are not in an excited state, but the present invention is not limited to such a mode. For example, it is conceivable to apply a current exceeding the aforementioned threshold prior to the application of the intervention current, intentionally bring the excitable cells into an excited state, and then apply the intervention current within the predetermined time period immediately thereafter. In this way, when an excitable cell is in an excited state, it will not be in an excited state any more within a predetermined period of time and will not generate a return current. can flow unidirectionally. Note that the above-described predetermined time is obtained in advance through experiments or the like.

8: test subject, 10: conduction path evaluation device, 12: electronic control device, 14: power supply circuit (electrical intervention unit), 16: display device, 18a, 18b: electrodes, 20: magnetic sensor device (detection unit), 30 : timer, 32: electrical intervention unit, 34: magnetic sensor drive unit, 36: signal detection unit, 38: magnetic field intensity calculation unit, 40: depth evaluation unit, 42: storage unit, 50a to 50c, 50x: conduction path

Claims (6)

A conduction path evaluation device for evaluating a current conduction state by electrical intervention from the outside to the inside of a living body using a pair of electrodes attached to the living body,
an electrical intervention unit that applies a direct current as the electrical intervention to the living body;
a detection unit that detects, outside the living body, a magnetic field change that occurs when the electrical intervention is applied by the electrical intervention;
an evaluation unit that calculates the depth of the conduction path as an evaluation of the conduction state between the pair of electrodes in the living body based on the information about the magnetic field strength detected by the detection unit and the previously obtained relationship; have
The evaluation unit evaluates the conduction state according to the position on the skin surface to which the electrical intervention is applied in the living body,
wherein the electrical intervention propagates through a plurality of conduction pathways within the organism;
The relationship obtained in advance represents a relationship between information about the magnetic field strength detected by the detection unit and the depth of the conduction path through which the electrical intervention propagates,
The evaluation unit evaluates the depth of the conduction path through which the electrical intervention propagates among the plurality of conduction paths;
A conduction path evaluation device characterized by: A conduction path evaluation device for evaluating a current conduction state by electrical intervention from the outside to the inside of a living body using a pair of electrodes attached to the living body,
an electrical intervention unit that applies a direct current as the electrical intervention to the living body;
a detection unit that detects, outside the living body, a magnetic field change that occurs when the electrical intervention is applied by the electrical intervention;
an evaluation unit that calculates the depth of the conduction path as an evaluation of the conduction state between the pair of electrodes in the living body based on the information about the magnetic field strength detected by the detection unit and the previously obtained relationship; have
The relationship obtained in advance represents a relationship between information about the magnetic field strength detected by the detection unit and the depth of the conduction path through which the electrical intervention propagates,
The electrical intervention unit applies electrical intervention to locations on the skin surface corresponding to the meridians of the living body;
A conduction path evaluation device characterized by: the electrical intervention performed by the electrical intervention unit is application of a current having a rectangular waveform;
The conduction path evaluation device according to claim 1 or 2, characterized by: The evaluation unit evaluates the depth of the conduction path based on information about the magnetic field strength detected by the detection unit at two or more positions on the skin surface ;
The conduction path evaluation device according to claim 1, characterized by: The application of the electrical intervention by the electrical intervention unit and the detection of the magnetic field by the detection unit are executed synchronously;
The conduction path evaluation apparatus according to any one of claims 1 to 4, characterized by: the electrical intervention applied by the electrical intervention unit flows unidirectionally through a conduction path in the body and is not accompanied by a return current at the cellular level;
The conduction path evaluation device according to any one of claims 1 to 5, characterized by:

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