Impedance detection method and device for bioelectrical impedance tomography

Abstract

The present invention belongs to the field of medical devices, and discloses an impedance detection method for bioelectrical impedance tomography, which can effectively and accurately quantify the subtle changes in the impedance information of tissues and organs. First, a detection electrode pair is set on the human body surface of the same cross section of the human body, and the two electrodes of the detection electrode pair and the impedance detection part through which the connection passes constitute a detection branch. Then, a variable capacitor connected in parallel with the detection branch is set, and the variable capacitor includes a fixed capacitor plate and a movable capacitor plate; then, an induced transparent light cavity is set with the movable capacitor plate as a side cavity wall; an induced transparent light cavity control laser is set to be injected into the outer side of the cavity wall of the self-induced transparent light cavity, and a control laser is set; finally, after a predetermined current pulse is input to the detection branch, the impedance of the impedance detection part is obtained according to the waveform of the transmission spectrum formed by the transmission light intensity of the incident laser. The present invention also discloses an impedance detection device for implementing the above method.

Description

Technical Field

[0001] The present invention belongs to the field of medical devices, and in particular relates to an impedance detection method and device for bioelectrical impedance tomography. Background Art

[0002] Medical research shows that biological tissues are composed of a large number of fluids between cells of different shapes, and cells are composed of cell membranes and cytoplasm. Different tissues and organs have different impedance characteristics, that is, the tissues and organs of the human body make the human body have anisotropic impedance characteristics. Bioelectrical impedance tomography (EIT) technology is a new type of medical auxiliary imaging technology developed based on this anisotropic impedance anisotropy inside the human body. The internal impedance distribution characteristics of the human body obtained by it are used as basic data for judging the physiological activity status of the human body.

[0003] At present, the specific practice of EIT is: it is necessary to accurately extract the electrical characteristic information related to the functional changes of tissues and organs, and reconstruct the image of the impedance of biological tissues that carry rich physiological and pathological information. Specifically, a certain number of electrodes are arranged on the surface of the object to be tested, and a certain safety voltage is applied. Then, the voltage distribution of each tissue and organ inside the object to be tested under the action of the voltage field is measured through different electrodes. Because the impedance changes before and after the lesion, the voltage division size will also change accordingly. The current electrical impedance imaging uses this direct measurement of electrical signals to achieve the reconstruction imaging of organs.

[0004] However, in many cases, such changes are very subtle, and it is difficult to effectively quantify such subtle changes by directly measuring general electrical signals. In addition, this makes the impedance characteristic reconstruction algorithm very complicated, making the related algorithm design very difficult. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides an impedance detection method and device for bioelectrical impedance tomography, which reflects the measured slight changes in electrical signals through changes in the number of photons, thereby being able to effectively and accurately quantify the slight changes in impedance information of tissues and organs, thereby greatly reducing the design complexity of related algorithms.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An impedance detection method for bioelectrical impedance tomography comprises the following steps:

[0008] Step S1: setting a detection electrode pair on the human body surface at the same cross section of the human body, wherein the two electrodes of the detection electrode pair and the part of the tissue and organ through which the connection line passes constitute a detection branch, and the part of the tissue and organ is used as an impedance detection part;

[0009] Step S2: setting a variable capacitor connected in parallel with the detection branch, wherein the variable capacitor includes a fixed capacitor plate and a movable capacitor plate;

[0010] Step S3: setting an induced transparent optical cavity with the movable capacitor plate as one side of the cavity wall;

[0011] Step S4: setting a control laser to control the laser to vertically irradiate the induced transparent light cavity from the outer side of the cavity wall of the induced transparent light cavity;

[0012] Step S5: setting an incident laser to be incident on the induced transparent optical cavity;

[0013] Step S6: After a predetermined current pulse is input into the detection branch, the impedance of the impedance detection part is obtained according to the waveform of the transmission spectrum formed by the transmission light intensity of the incident laser.

[0014] Preferably, in step S6, the impedance of the impedance detection part is obtained according to the waveform amplitude of the transmission spectrum.

[0015] Preferably, the relationship between the frequency ωc of the controlled laser and the cavity length L of the induced transparent optical cavity is: ωc=nπC / L, n is an integer, and C is the speed of light.

[0016] Furthermore, the interior of the transparent optical cavity is induced to be vacuum, and the laser is controlled to be parallel to the direction of the incident laser.

[0017] Furthermore, the induced transparent optical cavity has an induced atomic ensemble inside, and the direction of the controlled laser intersects with the incident laser.

[0018] Furthermore, the induced atomic ensemble is any one of a rubidium atomic ensemble, a cesium atomic ensemble and a Rydberg atomic ensemble.

[0019] Furthermore, the direction of the incident laser light is perpendicular to the incident direction of the control laser light.

[0020] Preferably, an impedance detection device for implementing the above-mentioned impedance detection method for bioelectrical impedance tomography comprises: at least two detection electrodes for forming a detection electrode pair; a voltage output circuit comprising a predetermined current source, a pulse injection terminal and a variable capacitor, the predetermined current source being used to provide a predetermined current pulse to the pulse injection terminal, the pulse injection terminal being used to be detachably electrically coupled to the detection branch, and the variable capacitor being used to be connected in parallel with the detection branch; a spectral detection device comprising an induced transparent optical cavity, a control laser, an incident laser, a light detector and a spectral oscilloscope, the control laser being used to emit a control laser, the incident laser being used to emit an incident laser, the light detector being used to collect a transmission spectrum of the incident laser, and the spectral oscilloscope being electrically connected to the light detector.

[0021] Furthermore, there are multiple detection electrodes, and any two of the multiple detection electrodes form a detection electrode pair.

[0022] Furthermore, the voltage output circuit further includes a predetermined variable resistor, and the pulse injection terminal is electrically connected to a predetermined current source through the predetermined variable resistor.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The impedance detection method for bioelectrical impedance tomography of the present invention firstly sets a detection electrode pair on the human body surface of the same cross section of the human body, and the two electrodes of the detection electrode pair and the impedance detection part through which the connection passes constitute a detection branch. Then, a variable capacitor connected in parallel with the detection branch is set, and the variable capacitor includes a fixed capacitor plate and a movable capacitor plate that can be movably set; then, an induced transparent light cavity is set with the movable capacitor plate as a cavity wall on one side; a control laser is set to control the laser to vertically enter the induced transparent light cavity from the outer side of the cavity wall of the induced transparent light cavity; an incident laser is set to be incident on the induced transparent light cavity; finally, after a predetermined current pulse is input into the detection branch, the impedance of the impedance detection part is obtained according to the waveform of the transmission spectrum formed by the transmission light intensity of the incident laser. When the predetermined current pulse is not input, the incident laser and the control laser are in a quantum interference state in the induced transparent light cavity. The input of the predetermined current pulse causes a change in the impedance detection part to form a detection voltage, and the detection voltage causes the active capacitor plate to displace under the action of the Coulomb force, thereby changing the cavity length of the induced transparent optical cavity, thereby causing the control laser and the induced transparent optical cavity to resonate and detune, and then the transmission light intensity of the incident laser changes on the impedance detection part to form a transmission spectrum formed in the process of forming the detection voltage, that is, the waveform of the transmission spectrum reflects the change in the detection voltage. In summary, the impedance characteristics of the impedance detection part cause characteristic changes in the transmission spectrum of the incident laser, and then the impedance characteristics of the impedance detection part can be obtained by measuring the changes in the transmission spectrum. Therefore, the present invention reflects the subtle changes in the electrical signal measured on the impedance detection part through the change in the number of photons of the transmitted laser of the incident laser, so that the subtle changes in the impedance information of tissues and organs can be effectively and accurately quantified.

[0025] 2. Because the interior of the induced transparent optical cavity of the present invention is a vacuum, and the direction of the laser is controlled to be parallel to the incident laser, the photon energy level transition in the induced transparent optical cavity of the present invention is based on the phonon number state of the active capacitor plate. Therefore, there is no need to introduce and fix any inducing medium, thereby greatly reducing the setting complexity of the induced transparent optical cavity.

[0026] 3. Because the impedance detection device of the present invention is characterized in that it includes: detection electrodes for forming a detection electrode pair; a voltage output circuit including a predetermined current source, a pulse injection terminal and a variable capacitor, and a spectral detection device including an induced transparent optical cavity, a control laser, an incident laser, a light detector and a spectral oscilloscope, therefore, the present invention can better implement the impedance detection method for bioelectrical impedance tomography through a detection device for tissue and organ impedance measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the steps of an impedance detection method for bioelectrical impedance tomography according to an embodiment of the present invention;

[0028] Figure 2 It is a schematic diagram of an implementation of an impedance detection device according to the first embodiment of the present invention;

[0029] Figure 3 It is a schematic diagram of an implementation of an impedance detection device according to the second embodiment of the present invention.

[0030] In the figure: S100, impedance detection method for bioelectrical impedance tomography, 100, impedance detection device, A, human body surface, 10, detection electrode, 20, voltage output circuit, 21, predetermined current source, 22, predetermined variable resistor, 23, pulse injection end, 24, variable capacitor, 241, fixed capacitor plate, 242, movable capacitor plate, 30, spectrum detection device, 31, induced transparent optical cavity, 31A, control of incident cavity wall, 31a, cavity length of induced transparent optical cavity, 311 induced atomic ensemble, 32, control laser, 33, incident laser, 33a, transmitted light of incident laser, 34, light detector. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate an impedance detection method and device for bioelectrical impedance tomography of the present invention. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0032] <Example 1>

[0033] like Figure 1 As shown, an impedance detection method S100 for bioelectrical impedance tomography in this embodiment includes the following steps:

[0034] Step S1: a detection electrode pair is set on the human body surface in the same cross section, the connection line of the detection electrode pair passes through the tissues and organs of the human body, the two electrodes of the detection electrode pair and the part of the tissues and organs through which the connection line passes constitute a detection branch, and the tissue and organ part is used as the impedance detection part.

[0035] Specifically, since the tissues and organs of the human body have anisotropic impedance characteristics, detection electrode pairs are arranged at different positions on the surface of the tissues and organs, and the impedance characteristics of multiple impedance detection parts obtained are different from each other.

[0036] Step S2: A variable capacitor is arranged in parallel with the detection branch. The variable capacitor includes a fixed capacitor plate fixedly arranged and a movable capacitor plate movably arranged.

[0037] Specifically, the movable capacitor plate is a nano-mechanical oscillator.

[0038] Step S3: An electromagnetically induced transparency (EIT) optical cavity is arranged with the movable capacitor plate as one side wall of the cavity.

[0039] Specifically, the inside of the EIT optical cavity is a vacuum, and the other side wall opposite to the movable capacitor plate is used as the control incident cavity wall.

[0040] Step S4: A control laser is arranged, and the control laser is vertically incident into the EIT optical cavity from the outside of the control incident cavity wall of the EIT optical cavity.

[0041] Specifically, the relationship between the frequency ωc of the control laser and the cavity length L of the EIT optical cavity is: ωc = nπC / L, where n is an integer and C is the speed of light.

[0042] Step S5: An incident laser incident into the EIT optical cavity is arranged.

[0043] Specifically, the control laser and the incident laser are parallel in direction in the EIT optical cavity, that is, the incident laser is vertically incident into the EIT optical cavity from the outside of the control incident cavity wall of the EIT optical cavity.

[0044] Step S6: After a predetermined current pulse is input to the detection branch, the impedance of the impedance detection part is obtained according to the waveform of the transmission spectrum formed by the transmitted light intensity of the incident laser.

[0045] Specifically, the relationship between the period T of the predetermined current pulse and the movement duration t of the movable capacitor plate is: T >> t, that is, T is at least one order of magnitude larger than t. The short change of the predetermined current pulse before the voltage division on the impedance detection part stabilizes causes the movable capacitor plate to move relative to the fixed capacitor plate. The relationship between the distance r between the fixed capacitor plate and the movable capacitor plate and the movement amount q of the movable capacitor plate is: q << r, that is, r is at least one order of magnitude larger than q, and it satisfies the following expression:

[0046]

[0047] where U is the voltage division on the impedance detection part, m is the mass of the movable capacitor plate, ω mis the vibration frequency of the active capacitor plate, ε0 is the vacuum permittivity, and S is the area of ​​the variable capacitor plate.

[0048] When the control laser is detuned in the induced transparent optical cavity, the partial pressure U on the impedance detection part and the incident laser field intensity ε C and the transmitted field intensity ε of the incident laser T Satisfies the following expression:

[0049]

[0050] Where κ is the attenuation factor of the induced transparent cavity, G0 = ωc / L, γ m is the damping coefficient of the active capacitor plate.

[0051] According to the transmission field intensity ε of the incident laser T The waveform amplitude of the transmission spectrum is used to obtain the impedance of the impedance detection part.

[0052] like Figure 2 As shown, the detection device 100 for measuring tissue organ impedance is characterized by comprising at least two detection electrodes 10, a voltage output circuit 20 and a spectrum detection device 30.

[0053] At least two detection electrodes 10 are arranged on the human body surface A to form the above-mentioned detection electrode pair. Specifically, there are multiple detection electrodes 10, and any two of the multiple detection electrodes 10 form the above-mentioned detection electrode pair.

[0054] The voltage output circuit 20 includes a predetermined current source 21, a predetermined variable resistor 22, a pulse injection terminal 23 and the above-mentioned variable capacitor 24. The predetermined current source 21 is used to provide the above-mentioned predetermined current pulse to the pulse injection terminal 23. The pulse injection terminal 23 is used to be detachably electrically coupled with the above-mentioned detection branch. The above-mentioned variable capacitor 24 is used to be connected in parallel with the above-mentioned detection branch. The pulse injection terminal 23 is electrically connected to the predetermined current source 21 through the predetermined variable resistor 22, so as to adjust the intensity of the current passing through the above-mentioned detection branch.

[0055] The variable capacitor 24 is composed of the above-mentioned fixed capacitor plate 241 and movable capacitor plate 242.

[0056] The spectral detection device 30 includes an induced transparent optical cavity 31, a control laser (not marked in the drawing), an incident laser (not marked in the drawing), a light detector 34 and a spectral oscilloscope (not marked in the drawing). Specifically, the induced transparent optical cavity 31 is composed of a control incident cavity wall 31A and an active capacitor plate 242.

[0057] The control laser is used to emit the control laser 32, the incident laser is used to emit the incident laser 33, the light detector 34 is used to collect the spectrum of the transmitted light 33a of the incident laser, the spectrum oscilloscope is electrically connected to the light detector 34, and the control laser 32 is vertically transmitted and incident from the controlled incident cavity wall 31A along the cavity length 31a direction of the induced transparent optical cavity 31.

[0058] <Example 2>

[0059] In the second embodiment, the same symbols are given to the same structures as those in the first embodiment, and the same descriptions are omitted.

[0060] In the second embodiment, the structure of the detection device 100 for measuring tissue organ impedance is different from that of the first embodiment in that:

[0061] like Figure 3 As shown, the induced transparent optical cavity 31 has an induced atomic ensemble 311 inside, and the control laser 32 intersects the direction of the incident laser 33 perpendicularly.

[0062] The induced atomic ensemble is any one of the rubidium atomic ensemble, the cesium atomic ensemble and the Rydberg atomic ensemble, and the induced atomic ensemble 311 is a three-level system.

[0063] When the control laser 32 resonates and detunes in the induced transparent optical cavity 31, the partial pressure U on the impedance detection part and the incident field intensity ε of the incident laser C And the absorption rate Im(χ) of the incident laser 33 satisfies the following expression:

[0064]

[0065] in μ ba is the dipole transition momentum, N is the total number of atoms in the induced atomic ensemble 311, h is Planck's constant, ε0 is the vacuum permittivity, V is the volume of the induced atomic ensemble 311, γ is the decay rate of the upper energy level |a>, γ s is the decay rate between two metastable states and γ s <<γ.

[0066] The above-mentioned embodiments are preferred cases of the present invention and are not intended to limit the protection scope of the present invention. Various modifications or variations that can be made by ordinary technicians in the field without creative work within the scope of the attached claims are still within the protection scope of this patent.

[0067] For example, in practice, the induced atomic ensemble 311 can also use solid-state systems, defect states (NV color centers), semiconductor quantum dots, and superconducting systems.

[0068] For example, in practice, multiple pairs of detection electrodes may be pre-set on the human body surface, and multiple impedance characteristics of tissues and organs of the multiple detection electrode pairs may be simultaneously detected through relevant control circuits to facilitate comparative analysis.

Claims

1. An impedance detection method for bioelectrical impedance tomography, characterized in that: The following steps are involved: Step S1: setting a detection electrode pair on the human body surface of the same cross section of the human body, wherein the two electrodes of the detection electrode pair and the part of the tissue and organ through which the connection line passes constitute a detection branch, and the part of the tissue and organ is used as an impedance detection part; Step S2: setting a variable capacitor connected in parallel with the detection branch, the variable capacitor comprising a fixed capacitor plate and a movable capacitor plate; Step S3: setting an induced transparent optical cavity with the movable capacitor plate as a side cavity wall; Step S4: setting a control laser, wherein the control laser is vertically injected into the induced transparent light cavity from the outer side of the cavity wall of the induced transparent light cavity; Step S5: setting an incident laser to be incident on the induced transparent optical cavity; Step S6: After a predetermined current pulse is input into the detection branch, the impedance of the impedance detection part is obtained according to the waveform of the transmission spectrum formed by the transmission light intensity of the incident laser.

2. The impedance detection method for bioelectrical impedance tomography according to claim 1, characterized in that: in, In step S6, the impedance of the impedance detection part is obtained according to the waveform amplitude of the transmission spectrum.

3. The impedance detection method for bioelectrical impedance tomography according to claim 1, characterized in that: in, The relationship between the frequency ωc of the control laser and the cavity length L of the induced transparent optical cavity is: ωc=nπC / L, n is an integer, and C is the speed of light.

4. The impedance detection method for bioelectrical impedance tomography according to claim 3, characterized in that: in, The interior of the induced transparent optical cavity is vacuum, and the control laser is parallel to the direction of the incident laser.

5. The impedance detection method for bioelectrical impedance tomography according to claim 3, characterized in that: in, The induced transparent optical cavity has an induced atomic ensemble inside, and the control laser intersects with the direction of the incident laser.

6. The impedance detection method for bioelectrical impedance tomography according to claim 5, characterized in that: in, The induced atomic ensemble is any one of a rubidium atomic ensemble, a cesium atomic ensemble and a Rydberg atomic ensemble.

7. The impedance detection method for bioelectrical impedance tomography according to claim 5, characterized in that: in, The direction of the incident laser light is perpendicular to the incident direction of the control laser light.

8. An impedance detection device for implementing the impedance detection method for bioelectrical impedance tomography according to any one of claims 1 to 7, characterized in that: include: at least two of the detection electrodes, used to form the detection electrode pair; A voltage output circuit, comprising a predetermined current source, a pulse injection terminal and the variable capacitor, wherein the predetermined current source is used to provide the predetermined current pulse to the pulse injection terminal, the pulse injection terminal is used to be detachably electrically coupled to the detection branch, and the variable capacitor is used to be connected in parallel with the detection branch; The spectral detection device includes the induced transparent optical cavity, a control laser, an incident laser, a light detector and a spectrum oscilloscope, wherein the control laser is used to emit the control laser, the incident laser is used to emit the incident laser, the light detector is used to collect the transmission spectrum of the incident laser, and the spectrum oscilloscope is electrically connected to the light detector.

9. The impedance detection device according to claim 8, characterized in that: in, The number of the detection electrodes is plural, and any two of the plural detection electrodes form the detection electrode pair.

10. The impedance detection device according to claim 8, characterized in that: in, The voltage output circuit further includes a predetermined variable resistor, and the pulse injection terminal is electrically connected to the predetermined current source through the predetermined variable resistor.

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