Electroporation ablation voltage control method and system for cardiovascular balloon

Abstract

The invention discloses an electroporation ablation voltage control method and system for a cardiovascular balloon. The method comprises the steps that original electric signals are collected for a balloon electrode, complex impedance information of each frequency point is extracted, and an impedance spectrum is obtained; converting the impedance spectrum into an equivalent conductivity tensor for describing anisotropic conductivity characteristics of the tissue; on the basis of the equivalent conductivity tensor, a corrected Poisson equation is adopted, and three-dimensional electric field distribution around the balloon is obtained and used for electric field prediction; based on an electric field prediction result and a feedback result in the impedance spectrum, a nonlinear dynamic regulation and control formula is established, and dynamic voltage output is controlled; and multi-physics field coupling is carried out to verify that the voltage output meets the safety and performance requirements. The system comprises a signal acquisition and impedance measurement module, an equivalent conductivity calculation and electric field prediction module, a voltage regulation and control and pulse generation module and a multi-mode feedback control module. Accurate voltage control in the electroporation ablation process can be achieved, and the uniformity and controllability of electric field distribution are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electroporation ablation voltage control, and in particular to an electroporation ablation voltage control method and system for a cardiovascular balloon. Background Art

[0002] At present, devices based on the principle of electroporation are mainly concentrated in the fields of tumor ablation, gene transfection and local drug delivery. Some studies have tried to combine electroporation with drug-coated balloons to improve the retention rate and penetration depth of drugs in the lesion area. However, the voltage control and safety of electroporation are still important factors affecting its clinical application.

[0003] With the development of digital control technology, computer modeling and high-precision electric field prediction methods, the application mode of electroporation technology is evolving from a single high-voltage pulse application mode to an intelligent, adaptive dynamic control mode. Especially in the field of interventional therapy, accurate prediction of electric field distribution and dynamic voltage control are the key to improving the safety and effectiveness of treatment. Therefore, the development of a control system that can adjust voltage in real time based on feedback from tissue electrical properties is an important direction of current research.

[0004] Although electroporation technology has potential advantages in the field of cardiovascular intervention, the existing technology still has the following problems:

[0005] (1) Uneven electric field distribution leads to the risk of local overheating or damage. Due to the anisotropy of the electrical conductivity of cardiovascular tissue, the traditional fixed voltage mode may cause the local electric field to be too strong, thereby causing uncontrollable thermal effects or tissue damage;

[0006] (2) There is a lack of adaptive control mechanisms based on tissue electrical properties. Existing electroporation systems mostly use preset fixed pulse parameters, but fail to fully consider the dynamic changes of tissue impedance, resulting in the inability of voltage output to match the conductivity characteristics of different parts in real time;

[0007] (3) The electrode-tissue interface effect affects the voltage control accuracy. The electrode geometry, material properties, and wall adhesion state will affect the local electric field distribution, making it difficult for the pulse voltage control method with fixed parameters to maintain a stable electroporation effect in a complex vascular environment.

[0008] (4) The accuracy of the computational model is limited, making it difficult to achieve efficient three-dimensional electric field prediction. Existing electric field calculation methods mostly use simplified homogeneous medium assumptions and fail to fully consider anisotropic conductive properties, resulting in limited computational accuracy. In addition, insufficient computational efficiency may affect the response speed of real-time feedback control. Summary of the invention

[0009] In view of this, the purpose of the embodiments of the present invention is to provide an electroporation ablation voltage control method and system for a cardiovascular balloon, which can achieve precise voltage control during the electroporation ablation process, improve the uniformity and controllability of the electric field distribution, optimize the electrode wall adhesion state, improve the voltage regulation accuracy, and control temperature safety.

[0010] The embodiment of the present invention is achieved as follows:

[0011] A method for controlling the voltage of electroporation ablation of a cardiovascular balloon, comprising:

[0012] The original electrical signal of the balloon electrode is collected, the complex impedance information of each frequency point is extracted, and the impedance spectrum of the specified frequency band is obtained.

[0013] The impedance spectrum is converted into an equivalent conductivity tensor that describes the anisotropic conductive properties of the tissue.

[0014] Based on the equivalent conductivity tensor, the modified Poisson's equation is used to obtain the three-dimensional electric field distribution around the balloon for electric field prediction.

[0015] Based on the electric field prediction result and the feedback result in the impedance spectrum, a nonlinear dynamic control formula is established to control the dynamic voltage output.

[0016] Perform multi-physics field coupling to verify that the voltage output meets safety and performance requirements.

[0017] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the steps of collecting the original electrical signal from the balloon electrode, extracting the complex impedance information of each frequency point, and obtaining the impedance spectrum of the specified frequency band include:

[0018] A high-frequency alternating current is applied by a sinusoidal excitation current source to collect the original electrical signal from the balloon electrode, thereby obtaining the voltage signal V[n] at the nth sampling moment and the current signal I[n] at the nth sampling moment.

[0019] Using discrete Fourier transform, the complex impedance information of the kth frequency point is extracted from the sampled signal Among them, Z k is the complex impedance at the kth frequency point, including impedance amplitude and phase information, N is the number of sampling points per cycle, I * [n] is the conjugate of the current signal, and K is the total number of discrete frequency points.

[0020] Output the impedance data of the specified frequency band and obtain the impedance spectrum {Z k}.

[0021] Its technical effects are: by applying high-frequency alternating current using a sinusoidal excitation current source, the stability and controllability of the excitation signal are ensured, and high-quality voltage and current signals are obtained; by combining discrete Fourier transform and performing frequency domain analysis on the sampled signal, the complex impedance information of each frequency point, including amplitude and phase, can be effectively extracted, and the electrical parameters such as the conductivity and dielectric properties of the tissue can be accurately characterized. By covering a wide frequency band of impedance measurement, the characterization capability of the anisotropic conductive properties of biological tissues is improved, and the differences in electrical properties of different tissue types (such as vascular walls, surrounding soft tissues, etc.) can be effectively characterized.

[0022] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the step of converting the impedance spectrum into an equivalent conductivity tensor describing the anisotropic conductive properties of tissue comprises:

[0023] The impedance spectrum is preprocessed to remove high-frequency noise and complete the missing frequency points to make the spectrum smooth and continuous, and the processed smooth impedance spectrum Z is obtained. smooth (f).

[0024] Based on the smooth impedance spectrum Z smooth (f), Calculate the equivalent conductivity tensor used to describe the anisotropic conductive properties of the tissue Among them, L i is the electrode spacing in the i-th direction, A i is the electrode-tissue contact area, Re(Z i (t)) is the real part of the smooth impedance spectrum in the i-th direction, e i are local coordinate basis vectors.

[0025] Its technical effects are: using high-frequency noise removal technology such as wavelet denoising and filtering algorithms to effectively reduce measurement errors; filling missing frequency points through interpolation or regression methods to ensure that impedance spectrum data is smooth and continuous in the full frequency range; the pre-processed smooth impedance spectrum can accurately reflect the true electrical characteristics of the tissue and improve the reliability of impedance data; based on the direction, spacing, electrode-tissue contact area and other parameters of the balloon electrode, a more realistic equivalent conductivity tensor calculation method is established to achieve personalized electrical modeling for different patients' vascular anatomical structures, improve the adaptability and accuracy of the ablation electric field, and realize individualized anisotropic conductivity calculation. The equivalent conductivity tensor can accurately characterize the local conductivity distribution by combining the real part information of the impedance spectrum, optimize the electroporation pulse parameters, prevent excessive concentration or uneven distribution of the electric field, and improve the safety and effectiveness of treatment. Through more accurate conductivity calculation, the nonlinear dynamic control formula can be optimized, making the adjustment of the pulse voltage more accurate and avoiding ablation failure caused by local overheating or insufficient field strength.

[0026] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the three-dimensional electric field distribution around the balloon is obtained based on the equivalent conductivity tensor and the modified Poisson equation is used for electric field prediction, which includes:

[0027] Based on the equivalent conductivity tensor, the Poisson equation describing the steady-state electric field distribution is established. eff ▽Φ)=-ρ, where ▽ is the vector differential operator, Φ is the potential distribution to be solved, σ eff is the equivalent conductivity tensor, and ρ is the charge density.

[0028] Setting the boundary conditions of the balloon electrode for the Poisson equation After correction, we get the modified Poisson equation, where Φ(r)| 电极表面 =V input The voltage applied by the balloon electrode is V input ,Φ(r)| 远场 →0 means that the potential in the area far away from the electrode is asymptotically zero.

[0029] The modified Poisson equation is converted into a linear algebraic equation system AΦ=b by using the finite element discretization method, where A is the equivalent conductivity tensor σ eff The calculated stiffness matrix, Φ is the potential distribution to be calculated, and b is the source term.

[0030] The conjugate gradient method or multigrid method is used to quickly solve the three-dimensional potential distribution Φ(x,y,z).

[0031] Perform gradient calculation to obtain the three-dimensional electric field distribution around the balloon E(x, y, z) = -▽Φ.

[0032] Its technical effects are: boundary correction of Poisson's equation, accurate description of the voltage applied by the balloon electrode, ensuring the physical rationality of the potential distribution, introducing zero asymptotic boundary conditions, ensuring the natural attenuation of the potential, avoiding the influence of boundary truncation errors on the calculation accuracy, improving the electric field resolution near the electrode, making the calculation results more consistent with the actual physical environment, and optimizing the electric field control in the ablation area. The finite element discretization method is used to improve the numerical stability of the electric field calculation, avoid the errors of the traditional differential method in complex geometric structures, and is suitable for complex vascular morphology and non-uniform tissue environments. The conjugate gradient method (CG) or the multigrid method (MG) is used to accelerate the solution process, improve the calculation efficiency, and ensure that the electric field prediction can be completed in a short time. Through gradient calculation, the electric field distribution is accurately obtained and the electroporation parameters are optimized.

[0033] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the nonlinear dynamic control formula is established based on the electric field prediction result and the feedback result in the impedance spectrum to control the dynamic voltage output, which includes:

[0034] The impedance change rate is extracted from the impedance spectrum and exponentially decayed integrated to obtain the exponential decay integral I Z (t).

[0035] The accumulated energy of the applied voltage is monitored, and the energy constraint term F is obtained using the hyperbolic secant function. E (t).

[0036] Combined with the exponential decay integral I Z (t) and the energy constraint term F E (t), construct a nonlinear dynamic control formula V for controlling the dynamic voltage output out (t) = V base ·[1+γ·I Z (t)]·F E (t), where V out (t) is the output voltage at time t, V base is the initially set stable output voltage, and γ is the impedance feedback gain coefficient.

[0037] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the impedance change rate is extracted from the impedance spectrum and exponential decay integral is performed to obtain the exponential decay integral I Z (t) include:

[0038] Extract the impedance change rate per unit time from the impedance spectrum

[0039] Calculate the exponential decay integral Among them, α is the memory decay factor and τ is the integral variable.

[0040] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the energy of the applied voltage is monitored, and the energy constraint term F is obtained by using the hyperbolic secant function. E (t) include:

[0041] Based on the three-dimensional electric field distribution around the balloon, the cumulative energy of the applied voltage is monitored and the cumulative energy density is calculated. Among them, V n is the voltage value of the nth pulse, t p is the pulse width and D is the duty cycle.

[0042] Using the hyperbolic secant function to obtain the energy constraint term Among them, sech(x) is the hyperbolic secant function, β is the adjustment factor, E th is the safety threshold energy density.

[0043] Its technical effect is that by extracting the impedance change rate per unit time, the dynamic changes of tissue electrical properties can be reflected in real time, such as the state of cell membrane electroporation, the increase or decrease of tissue conductivity, etc., which reduces the impact of short-term impedance fluctuations on voltage regulation, avoids drastic voltage fluctuations, and improves the stability and adaptability of the system. By calculating the cumulative energy density of the applied voltage, the energy constraint term is constructed using a hyperbolic secant function to ensure that when the cumulative energy approaches the safety threshold, the energy constraint term drops rapidly, reducing the voltage output and avoiding thermal damage or excessive ablation. Through the nonlinear dynamic control formula, the voltage control is dynamically adjusted with the tissue state to achieve precise voltage control.

[0044] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the multi-physical field coupling and verification that the voltage output meets the safety and performance requirements include:

[0045] Based on the three-dimensional electric field distribution around the balloon, the maximum electric field value is extracted. Where Ω is the computational domain, E(r) is the electric field at point r, and the electric field safety constraint E is established. max ≤1500V / cm.

[0046] Conduct electrothermal coupling analysis and use the biological heat conduction equation Where ρ is tissue density, C p is the tissue specific heat capacity, is the partial derivative of temperature with respect to time, ▽ is the gradient operator, k is the thermal conductivity of the tissue, ▽T is the temperature gradient, Q = σE 2 is the electric heat source term, and the temperature distribution T(r,t) is obtained by solving it, and the maximum temperature rise of the tissue is calculated Among them, T 0 is the initial temperature, and establishes the temperature safety constraint ΔT max ≤6℃.

[0047] Analysis shows that the current density J satisfies the charge conservation law ▽·J=0, and the integrated current flux on the electrode boundary should satisfy Among them, ∮ is the surface integral, is the closed boundary surrounding the computational domain Ω, J = σE is the current density, dA is the boundary microelement area, TH is the safety threshold, and the charge conservation verification constraint is established.

[0048] If E max >1500V / cm, then adjust the output voltage Vout (t) and / or optimize balloon electrode design.

[0049] If ΔT max >6℃, then reduce the output voltage V out (t) and / or use pulsed voltage application, reduce continuous heating, and / or increase cooling measures.

[0050] like The electrode structure is adjusted to reduce the uneven electric field and / or the balloon fit is adjusted to reduce the boundary leakage current.

[0051] Its technical effects are: extracting the maximum value of the electric field based on the three-dimensional electric field distribution around the balloon, avoiding excessive enhancement of the local electric field, preventing irreversible damage to cells in non-target areas, and ensuring that the tissue is within the appropriate electric field strength range by improving the uniformity of electroporation. The biological heat conduction equation is used to calculate the temperature distribution of the tissue to prevent irreversible thermal damage caused by excessive tissue temperature, ensuring that ablation only occurs in the target tissue, and optimizing thermal management and improving safety by reducing the output voltage, applying pulsed voltage, and increasing cooling measures. Based on the current density to meet the law of conservation of charge, avoid excessive leakage current at the balloon electrode boundary, ensure that the current flows to the target area, and reduce excessive current concentration by adjusting the balloon electrode structure, improve current uniformity, prevent excessive heating or uneven perforation of local tissues, optimize the fit of the balloon, and reduce current leakage caused by poor tissue contact.

[0052] An electroporation ablation voltage control system for a cardiovascular balloon, comprising:

[0053] The signal acquisition and impedance measurement module is used to collect the original electrical signal of the balloon electrode, extract the complex impedance information of each frequency point, and obtain the impedance spectrum of the specified frequency band. k}.

[0054] Equivalent conductivity calculation and electric field prediction module, used to calculate the equivalent conductivity tensor σ eff , solve the Poisson equation and obtain the three-dimensional electric field distribution E(x, y, z) around the balloon.

[0055] The voltage control and pulse generation module is used to establish a nonlinear dynamic control formula based on the electric field prediction result and the feedback result in the impedance spectrum to control the dynamic voltage output V out (t).

[0056] Multimodal feedback control module is used to optimize control parameters based on multi-physics field coupling.

[0057] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control system for cardiovascular balloon, the voltage regulation and pulse generation module includes a gradient pulse generator and a voltage dynamic regulator.

[0058] The gradient pulse generator adopts a segmented Marx high-voltage generator, including several levels of high-voltage units, and each level of the high-voltage unit includes an energy storage capacitor and a SiC MOSFET high-speed switch.

[0059] The voltage dynamic regulator is based on the nonlinear dynamic regulation formula V out (t) = V base ·[1+γ·I Z (t)]·F E (t), the control pulse voltage is adjusted within the safety threshold, where V out (t) is the output voltage at time t, V base is the initial stable output voltage, γ is the impedance feedback gain coefficient, I Z (t) is the exponential decay integral, F E (t) is the energy constraint term.

[0060] Its technical effects are: the use of gradient pulse generator can accurately adjust the pulse voltage to meet the electroporation requirements of different cardiovascular tissues; the use of SiC MOSFET high-speed switch can achieve nanosecond-level fast switching, improve the stability of pulse signals, reduce pulse distortion, and improve energy transmission efficiency; the use of segmented Marx high-voltage generator can accurately control the output voltage amplitude by gradually superimposing high-voltage units, improve the voltage regulation accuracy, and make the electric field distribution more uniform; it has variable pulse width regulation capabilities to ensure that different tissue types can obtain the best electroporation effect, while reducing heat accumulation and reducing the risk of tissue damage. The use of voltage dynamic regulators can achieve adaptive voltage regulation and enhance electric field uniformity.

[0061] The beneficial effects of the embodiments of the present invention are:

[0062] The present invention uses a sinusoidal excitation current source combined with a discrete Fourier transform (DFT) to extract complex impedance information at multiple frequency points, thereby obtaining a high-resolution impedance spectrum. By calculating the equivalent conductivity tensor, the anisotropic conductivity of the tissue can be accurately described to ensure the accuracy of the electric field distribution calculation. It overcomes the problems of traditional impedance measurement being greatly affected by noise and unstable frequency response, and provides a more accurate analysis of the conductive characteristics of biological tissues. It is suitable for changes in the electrical characteristics of different biological tissues and improves the personalized adaptability of the ablation process.

[0063] The present invention adopts the modified Poisson equation and combines the finite element method to solve the three-dimensional potential distribution around the balloon to ensure high accuracy of electric field prediction. The conjugate gradient method or the multi-grid method is used to quickly solve the problem, thereby improving the calculation efficiency. The calculation errors of the traditional method under complex geometric structures are avoided, and the uniformity of the electric field in the ablation area is improved. The range of tissue affected by the electric field is accurately predicted, and the electric field exposure of non-target tissues is reduced, thereby reducing side effects.

[0064] This maze constructs a nonlinear dynamic control formula through impedance feedback gain coefficient, exponential decay integral and energy constraint term to achieve real-time dynamic adjustment of voltage. The segmented Marx high-voltage generator can provide an adjustable pulse voltage of 0-1200V and support precise control of pulse width of 1-100μs. The voltage is automatically adjusted based on impedance feedback to prevent excessive voltage from causing tissue overheating or uneven electroporation. The applied voltage is optimized through energy constraint to reduce unnecessary energy loss and improve electroporation efficiency.

[0065] The present invention combines electric field distribution, electrothermal effect and current density analysis to establish multi-level safety constraints: through electric field safety constraints, ensure that the maximum value of the electric field does not exceed the safety threshold to avoid tissue damage; through temperature safety constraints, the biological heat conduction equation calculates the temperature distribution of the tissue to prevent local overheating; through charge conservation constraints, ensure that the current density meets safety regulations to avoid abnormal charge accumulation. Multiple safety mechanisms ensure that the ablation process is controllable and reduce side effects caused by excessive current or increased temperature. Provide more precise electric field control to make the ablation effect more stable and predictable.

[0066] The present invention adopts SiC MOSFET high-speed switch and segmented Marx high-voltage generator to provide efficient and stable pulse control. Each level of energy storage capacitor ensures accurate voltage regulation. The on-resistance of SiC MOSFET is as low as 5mΩ, which improves the switching response speed and reduces energy loss. Compared with the traditional discharge circuit, it can more accurately control the voltage waveform and improve the uniformity of electroporation. SiC MOSFET has the characteristics of high withstand voltage and low loss, which improves the overall life and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0068] Figure 1 The present invention is a flow chart of the electroporation ablation voltage control method for cardiovascular balloon. DETAILED DESCRIPTION

[0069] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0070] Please refer to Figure 1 The first embodiment of the present invention provides a method for controlling the electroporation ablation voltage of a cardiovascular balloon, which includes: collecting the original electrical signal of the balloon electrode, extracting the complex impedance information of each frequency point, and obtaining the impedance spectrum of the specified frequency band; converting the impedance spectrum into an equivalent conductivity tensor that describes the anisotropic conductive properties of the tissue; based on the equivalent conductivity tensor, using the modified Poisson's equation, obtaining the three-dimensional electric field distribution around the balloon for electric field prediction; based on the electric field prediction results and the feedback results in the impedance spectrum, establishing a nonlinear dynamic control formula to control the dynamic voltage output; performing multi-physical field coupling to verify that the voltage output meets the safety and performance requirements.

[0071] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloons, the acquisition of original electrical signals from the balloon electrodes, extraction of complex impedance information at each frequency point, and acquisition of impedance spectrum at a specified frequency band include: applying a high-frequency alternating current of about 1 MHz using a sinusoidal excitation current source, acquiring original electrical signals from the balloon electrodes, and obtaining a voltage signal V[n] at the nth sampling moment and a current signal I[n] at the nth sampling moment; and extracting complex impedance information at the kth frequency point from the sampled signals using a discrete Fourier transform. Among them, Z k is the complex impedance at the kth frequency point, including impedance amplitude and phase information, N is the number of sampling points per cycle, 1024 points are taken, I * [n] is the conjugate of the current signal, K is the total number of discrete frequency points; output impedance data in the specified frequency band from 0.1MHz to 10MHz, and obtain the impedance spectrum {Z k}, which reflects the electrical properties of the tissue surrounding the balloon and serves as the input for the subsequent equivalent conductivity tensor calculation, affecting the calculation of the electric field distribution and the dynamic regulation of voltage.

[0072] Its technical effects are: by applying high-frequency alternating current using a sinusoidal excitation current source, the stability and controllability of the excitation signal are ensured, and high-quality voltage and current signals are obtained; by combining discrete Fourier transform and performing frequency domain analysis on the sampled signal, the complex impedance information of each frequency point, including amplitude and phase, can be effectively extracted, and the electrical parameters such as the conductivity and dielectric properties of the tissue can be accurately characterized. By covering a wide frequency band of impedance measurement, the characterization capability of the anisotropic conductive properties of biological tissues is improved, and the differences in electrical properties of different tissue types (such as vascular walls, surrounding soft tissues, etc.) can be effectively characterized.

[0073] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the said converting the said impedance spectrum into an equivalent conductivity tensor describing the anisotropic conductive properties of tissues comprises: preprocessing the said impedance spectrum, removing high-frequency noise, completing the missing frequency points, making the spectrum smooth and continuous, and obtaining the processed smooth impedance spectrum Z smooth (f); Based on the smooth impedance spectrum Z smooth (f), Calculate the equivalent conductivity tensor used to describe the anisotropic conductive properties of the tissue Among them, L i is the electrode spacing in the i-th direction, A i is the electrode-tissue contact area, Re(Z i (t)) is the real part of the smooth impedance spectrum in the i-th direction, e i This process not only considers the contact geometry parameters of each electrode direction, but also reflects the local electrical characteristics in the tissue, providing accurate dielectric parameters for electric field calculation.

[0074] Its technical effects are: using high-frequency noise removal technology such as wavelet denoising and filtering algorithms to effectively reduce measurement errors; filling missing frequency points through interpolation or regression methods to ensure that impedance spectrum data is smooth and continuous in the full frequency range; the pre-processed smooth impedance spectrum can accurately reflect the true electrical characteristics of the tissue and improve the reliability of impedance data; based on the direction, spacing, electrode-tissue contact area and other parameters of the balloon electrode, a more realistic equivalent conductivity tensor calculation method is established to achieve personalized electrical modeling for different patients' vascular anatomical structures, improve the adaptability and accuracy of the ablation electric field, and realize individualized anisotropic conductivity calculation. The equivalent conductivity tensor can accurately characterize the local conductivity distribution by combining the real part information of the impedance spectrum, optimize the electroporation pulse parameters, prevent excessive concentration or uneven distribution of the electric field, and improve the safety and effectiveness of treatment. Through more accurate conductivity calculation, the nonlinear dynamic control formula can be optimized, making the adjustment of the pulse voltage more accurate and avoiding ablation failure caused by local overheating or insufficient field strength.

[0075] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the three-dimensional electric field distribution around the balloon is obtained based on the equivalent conductivity tensor and the modified Poisson equation is used for electric field prediction, which includes: based on the equivalent conductivity tensor, establishing the Poisson equation describing the steady-state electric field distribution ▽·(σ eff ▽Φ)=-ρ, where ▽ is the vector differential operator, Φ is the potential distribution to be solved, σ eff is the equivalent conductivity tensor, ρ is the charge density; the boundary conditions of the balloon electrode are set for the Poisson equation After correction, we get the modified Poisson equation, where Φ(r)| 电极表面 =V input The voltage applied by the balloon electrode is V input ,Φ(r)| 远场 →0 means that the potential far from the electrode area is asymptotically zero; the finite element discretization method is used to transform the modified Poisson equation into a linear algebraic equation system AΦ=b, where A is the equivalent conductivity tensor σ eff The calculated stiffness matrix, Φ is the potential distribution to be calculated, and b is the source term; the conjugate gradient method or the multi-grid method is used to quickly solve and obtain the three-dimensional potential distribution Φ(x, y, z); the gradient operation is performed to obtain the three-dimensional electric field distribution around the balloon E(x, y, z) = -▽Φ.

[0076] Its technical effects are: boundary correction of Poisson's equation, accurate description of the voltage applied by the balloon electrode, ensuring the physical rationality of the potential distribution, introducing zero asymptotic boundary conditions, ensuring the natural attenuation of the potential, avoiding the influence of boundary truncation errors on the calculation accuracy, improving the electric field resolution near the electrode, making the calculation results more consistent with the actual physical environment, and optimizing the electric field control in the ablation area. The finite element discretization method is used to improve the numerical stability of the electric field calculation, avoid the errors of the traditional differential method in complex geometric structures, and is suitable for complex vascular morphology and non-uniform tissue environments. The conjugate gradient method (CG) or the multigrid method (MG) is used to accelerate the solution process, improve the calculation efficiency, and ensure that the electric field prediction can be completed in a short time. Through gradient calculation, the electric field distribution is accurately obtained and the electroporation parameters are optimized.

[0077] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the nonlinear dynamic control formula is established based on the electric field prediction result and the feedback result in the impedance spectrum, and the dynamic voltage output is controlled by: extracting the impedance change rate from the impedance spectrum and performing exponential decay integration to obtain the exponential decay integral I Z (t); monitor the accumulated energy of the applied voltage and use the hyperbolic secant function to obtain the energy constraint term F E (t); combined with the exponential decay integral IZ (t) and the energy constraint term F E (t), construct a nonlinear dynamic control formula V for controlling the dynamic voltage output out (t) = V base ·[1+γ·I Z (t)]·F E (t), where V out (t) is the output voltage at time t, V base is the initially set stable output voltage, and γ is the impedance feedback gain coefficient, which is used to amplify or attenuate the effect of impedance change on voltage.

[0078] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the impedance change rate is extracted from the impedance spectrum and exponential decay integral is performed to obtain the exponential decay integral I Z (t) comprising: extracting the impedance change rate per unit time from the impedance spectrum The impedance change rate It reflects the dynamic changes of the electrical properties of the tissue interface during the ablation process, such as the increase or decrease of tissue conductivity, which in turn affects the local electric field distribution; the exponential decay integral is calculated Where α is the memory decay factor, τ is the integral variable, and the exponential decay integral I Z (t) Provides a dynamic correction based on changes in tissue electrical properties for subsequent adjustments.

[0079] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the energy of the applied voltage is monitored, and the energy constraint term F is obtained by using the hyperbolic secant function. E (t) comprising: monitoring the cumulative energy of the applied voltage based on the three-dimensional electric field distribution around the balloon, and calculating the cumulative energy density Among them, V n is the voltage value of the nth pulse, t p is the pulse width, D is the duty cycle; the energy constraint term is obtained using the hyperbolic secant function Among them, sech(x) is the hyperbolic secant function, which is used for nonlinear compression of values ​​to ensure that when E cum (t) Close to E th When F E (t) decreases rapidly, β is the regulating factor, which controls the intensity of energy constraint, E th The safety threshold energy density indicates the highest cumulative energy that the tissue can withstand. Exceeding this value may cause irreversible damage.

[0080] Its technical effect is that by extracting the impedance change rate per unit time, the dynamic changes of tissue electrical properties can be reflected in real time, such as the state of cell membrane electroporation, the increase or decrease of tissue conductivity, etc., which reduces the impact of short-term impedance fluctuations on voltage regulation, avoids drastic voltage fluctuations, and improves the stability and adaptability of the system. By calculating the cumulative energy density of the applied voltage, the energy constraint term is constructed using a hyperbolic secant function to ensure that when the cumulative energy approaches the safety threshold, the energy constraint term drops rapidly, reducing the voltage output and avoiding thermal damage or excessive ablation. Through the nonlinear dynamic control formula, the voltage control is dynamically adjusted with the tissue state to achieve precise voltage control.

[0081] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control method for cardiovascular balloon, the multi-physical field coupling to verify that the voltage output meets the safety and performance requirements includes: extracting the maximum value of the electric field based on the three-dimensional electric field distribution around the balloon Where Ω is the computational domain, E(r) is the electric field at point r, and the electric field safety constraint E is established. max ≤1500V / cm; Conduct electrothermal coupling analysis, through the biological heat conduction equation Where ρ is tissue density, C p is the tissue specific heat capacity, is the partial derivative of temperature with respect to time, ▽ is the gradient operator, k is the thermal conductivity of the tissue, ▽T is the temperature gradient, Q = σE 2 is the electric heat source term, and the temperature distribution T(r,t) is obtained by solving it, and the maximum temperature rise of the tissue is calculated Among them, T 0 is the initial temperature, and establishes the temperature safety constraint ΔT max ≤6℃; the current density J satisfies the charge conservation law ▽·J=0, and the integrated current flux on the electrode boundary should satisfy Among them, ∮ is the surface integral, is the closed boundary surrounding the computational domain Ω, J = σE is the current density, dA is the boundary microelement area, TH is the safety threshold, and the charge conservation verification constraint is established. If E max >1500V / cm, then adjust the output voltage V out (t) and / or optimize balloon electrode design; if ΔT max >6℃, then reduce the output voltage V out (t) and / or use pulsed voltage application, reduce continuous heating, and / or increase cooling measures; if The electrode structure is adjusted to reduce the uneven electric field and / or the balloon fit is adjusted to reduce the boundary leakage current.

[0082] Its technical effects are: extracting the maximum value of the electric field based on the three-dimensional electric field distribution around the balloon, avoiding excessive enhancement of the local electric field, preventing irreversible damage to cells in non-target areas, and ensuring that the tissue is within the appropriate electric field strength range by improving the uniformity of electroporation. The biological heat conduction equation is used to calculate the temperature distribution of the tissue to prevent irreversible thermal damage caused by excessive tissue temperature, ensuring that ablation only occurs in the target tissue, and optimizing thermal management and improving safety by reducing the output voltage, applying pulsed voltage, and increasing cooling measures. Based on the current density to meet the law of conservation of charge, avoid excessive leakage current at the balloon electrode boundary, ensure that the current flows to the target area, and reduce excessive current concentration by adjusting the balloon electrode structure, improve current uniformity, prevent excessive heating or uneven perforation of local tissues, optimize the fit of the balloon, and reduce current leakage caused by poor tissue contact.

[0083] The second embodiment of the present invention provides an electroporation ablation voltage control system for cardiovascular balloons, which includes: a signal acquisition and impedance measurement module, which is used to collect original electrical signals from balloon electrodes, extract complex impedance information at each frequency point, and obtain an impedance spectrum of a specified frequency band. k}; Equivalent conductivity calculation and electric field prediction module, used to calculate the equivalent conductivity tensor σ eff , solve the Poisson equation to obtain the three-dimensional electric field distribution E(x, y, z) around the balloon; a voltage control and pulse generation module is used to establish a nonlinear dynamic control formula based on the electric field prediction result and the feedback result in the impedance spectrum to control the dynamic voltage output V out (t); Multi-modal feedback control module, used to optimize control parameters based on multi-physical field coupling.

[0084] In a preferred embodiment of the present invention, in the electroporation ablation voltage control system for cardiovascular balloons, the signal acquisition and impedance measurement module includes a balloon electrode array and an impedance measurement unit; the balloon electrode array uses a shape memory alloy NiTiNol substrate, adjusts its shape under the action of Joule heat, adapts to different blood vessel diameters, and is coated with a TiN titanium nitride microporous coating on the surface to optimize the current distribution at the electrode-tissue interface and reduce the risk of excessive local field concentration; the impedance measurement unit includes a high-precision impedance analysis chip AD5933 and a multi-frequency signal generator to perform multi-frequency AC impedance measurement in the frequency range of 1kHz-1MHz. Among them, the equivalent conductivity calculation and electric field prediction module uses the NVIDIA CUDA architecture for GPU parallel computing.

[0085] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control system for cardiovascular balloon, the voltage control and pulse generation module includes a gradient pulse generator and a voltage dynamic regulator; the gradient pulse generator adopts a segmented Marx high-voltage generator, including several levels of high-voltage units, each level of the high-voltage unit includes a 10nF, 1kV withstand voltage energy storage capacitor and a SiC MOSFET high-speed switch with an on-resistance of 5mΩ, the output pulse voltage is 0-1200V, and the adjustable pulse width is 1-100μs; the voltage dynamic regulator is based on the nonlinear dynamic control formula V out (t) = V base ·[1+γ·I Z (t)]·F E (t), the control pulse voltage is adjusted within the safety threshold, and the maximum field strength E max ≤1500V / cm, where V out (t) is the output voltage at time t, V base is the initial stable output voltage, γ is the impedance feedback gain coefficient, I Z (t) is the exponential decay integral, F E (t) is the energy constraint term.

[0086] In a preferred embodiment of the present invention, in the above-mentioned electroporation ablation voltage control system for cardiovascular balloons, the multimodal feedback control module includes an optical coherence detection unit, an acoustic resonance analysis unit and a temperature sensor; the optical coherence detection unit uses a 1310nm OCT probe with an axial resolution of 10μm to monitor the wall adhesion state of the balloon electrode, and automatically adjusts the balloon filling pressure when the wall adhesion gap is >200μm; the acoustic resonance analysis unit uses a piezoelectric transducer array with a center frequency of 5MHz and a bandwidth of ±2MHz to evaluate tissue stiffness through the rate of change of the speed of sound and optimize voltage regulation; the temperature sensor uses a miniature thermocouple with a temperature measurement accuracy of ±0.1℃ to ensure that the tissue temperature rise ΔT≤6℃ to prevent thermal damage.

[0087] Its technical effects are: the use of gradient pulse generator can accurately adjust the pulse voltage to meet the electroporation requirements of different cardiovascular tissues; the use of SiC MOSFET high-speed switch can achieve nanosecond-level fast switching, improve the stability of pulse signals, reduce pulse distortion, and improve energy transmission efficiency; the use of segmented Marx high-voltage generator can accurately control the output voltage amplitude by gradually superimposing high-voltage units, improve the voltage regulation accuracy, and make the electric field distribution more uniform; it has variable pulse width regulation capabilities to ensure that different tissue types can obtain the best electroporation effect, while reducing heat accumulation and reducing the risk of tissue damage. The use of voltage dynamic regulators can achieve adaptive voltage regulation and enhance electric field uniformity.

[0088] The computer program product of the electroporation ablation voltage control method and device for cardiovascular balloon provided in the embodiments of the present invention includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods in the previous method embodiments. The specific implementation can be found in the method embodiments, which will not be repeated here.

[0089] Specifically, the storage medium can be a general storage medium, such as a mobile disk, a hard disk, etc. When the computer program on the storage medium is run, it can execute the above-mentioned electroporation ablation voltage control method for cardiovascular balloons, thereby achieving precise voltage control of the electroporation ablation process and improving the uniformity and controllability of the electric field distribution.

[0090] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0091] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for controlling the electroporation ablation voltage of a cardiovascular balloon, characterized in that: include: Collect the original electrical signal of the balloon electrode, extract the complex impedance information of each frequency point, and obtain the impedance spectrum of the specified frequency band; converting the impedance spectrum into an equivalent conductivity tensor describing the anisotropic conductive properties of the tissue; Based on the equivalent conductivity tensor, a modified Poisson equation is used to obtain the three-dimensional electric field distribution around the balloon for electric field prediction; Based on the electric field prediction result and the feedback result in the impedance spectrum, a nonlinear dynamic control formula is established to control the dynamic voltage output; Perform multi-physics field coupling to verify that the voltage output meets safety and performance requirements.

2. The electroporation ablation voltage control method for cardiovascular balloon according to claim 1, characterized in that: The collecting of the original electrical signal from the balloon electrode, extracting the complex impedance information of each frequency point, and obtaining the impedance spectrum of the specified frequency band includes: A high-frequency alternating current is applied by a sinusoidal excitation current source to collect the original electrical signal of the balloon electrode, and the voltage signal V[n] at the nth sampling moment and the current signal I[n] at the nth sampling moment are obtained; Using discrete Fourier transform, the complex impedance information of the kth frequency point is extracted from the sampled signal k=0,1,...,K-1, where Z k is the complex impedance at the kth frequency point, including impedance amplitude and phase information, N is the number of sampling points per cycle, I * [n] is the conjugate of the current signal, K is the total number of discrete frequency points; Output the impedance data of the specified frequency band and obtain the impedance spectrum {Z k }.

3. The electroporation ablation voltage control method for cardiovascular balloon according to claim 1, characterized in that: The step of converting the impedance spectrum into an equivalent conductivity tensor describing the anisotropic conductive properties of the tissue comprises: The impedance spectrum is preprocessed to remove high-frequency noise and complete the missing frequency points to make the spectrum smooth and continuous, and the processed smooth impedance spectrum Z is obtained. smooth (f); Based on the smooth impedance spectrum Z smooth (f), Calculate the equivalent conductivity tensor used to describe the anisotropic conductive properties of the tissue Among them, L i is the electrode spacing in the i-th direction, A i is the electrode-tissue contact area, Re(Z i (t)) is the real part of the smooth impedance spectrum in the i-th direction, e i are local coordinate basis vectors.

4. The electroporation ablation voltage control method for cardiovascular balloon according to claim 1, characterized in that: The method of obtaining the three-dimensional electric field distribution around the balloon based on the equivalent conductivity tensor and using the modified Poisson equation for electric field prediction includes: Based on the equivalent conductivity tensor, the Poisson equation describing the steady-state electric field distribution is established: in, is the vector differential operator, Φ is the potential distribution to be solved, σ eff is the equivalent conductivity tensor, ρ is the charge density; Setting the boundary conditions of the balloon electrode for the Poisson equation After correction, we get the modified Poisson equation, where Φ(r)| 电极表面 =V input The voltage applied by the balloon electrode is V input ,Φ(r)| 远场 →0 means that the potential in the area far from the electrode is asymptotically zero; The modified Poisson equation is converted into a linear algebraic equation system AΦ=b by using the finite element discretization method, where A is the equivalent conductivity tensor σ eff The calculated stiffness matrix, Φ is the potential distribution to be calculated, and b is the source term; The conjugate gradient method or multigrid method is used to quickly solve and obtain the three-dimensional potential distribution Φ(x,y,z); Perform gradient calculation to obtain the three-dimensional electric field distribution around the balloon 5. The electroporation ablation voltage control method for cardiovascular balloon according to claim 1, characterized in that: The establishing of a nonlinear dynamic regulation formula based on the electric field prediction result and the feedback result in the impedance spectrum to control the dynamic voltage output comprises: The impedance change rate is extracted from the impedance spectrum and exponentially decayed integrated to obtain the exponential decay integral I Z (t); The accumulated energy of the applied voltage is monitored, and the energy constraint term F is obtained using the hyperbolic secant function. E (t); Combined with the exponential decay integral I Z (t) and the energy constraint term F E (t), construct a nonlinear dynamic control formula V for controlling the dynamic voltage output out (t) = V base ·[1+γ·I Z (t)]·F E (t), where V out (t) is the output voltage at time t, V base is the initially set stable output voltage, and γ is the impedance feedback gain coefficient.

6. The electroporation ablation voltage control method for cardiovascular balloon according to claim 5, characterized in that: The impedance change rate is extracted from the impedance spectrum and exponentially decayed integral is performed to obtain the exponential decay integral I Z (t) include: Extract the impedance change rate per unit time from the impedance spectrum Calculate the exponential decay integral Among them, α is the memory decay factor and τ is the integral variable.

7. The electroporation ablation voltage control method for cardiovascular balloon according to claim 5, characterized in that: The accumulated energy of the applied voltage is monitored, and the energy constraint term F is obtained by using the hyperbolic secant function. E (t) include: Based on the three-dimensional electric field distribution around the balloon, the cumulative energy of the applied voltage is monitored and the cumulative energy density is calculated. Among them, V n is the voltage value of the nth pulse, t p is the pulse width, D is the duty cycle; Using the hyperbolic secant function to obtain the energy constraint term Among them, sech(x) is the hyperbolic secant function, β is the adjustment factor, E th is the safety threshold energy density.

8. The electroporation ablation voltage control method for cardiovascular balloon according to claim 1, characterized in that: The multi-physics field coupling and verification that the voltage output meets the safety and performance requirements include: Based on the three-dimensional electric field distribution around the balloon, the maximum electric field value is extracted. Where Ω is the computational domain, E(r) is the electric field at point r, and the electric field safety constraint E is established. max ≤1500V / cm; Conduct electrothermal coupling analysis and use the biological heat conduction equation Where ρ is tissue density, C p is the tissue specific heat capacity, is the partial derivative of temperature with respect to time, is the gradient operator, k is the thermal conductivity of the tissue, is the temperature gradient, Q = σE 2 is the electric heat source term, and the temperature distribution T(r,t) is obtained by solving it, and the maximum temperature rise of the tissue is calculated Among them, T0 is the initial temperature, and the temperature safety constraint ΔT is established max ≤6℃; Analysis shows that the current density J satisfies the charge conservation law ▽·J=0, and the integrated current flux on the electrode boundary should satisfy Among them, ∮ is the surface integral, is the closed boundary surrounding the computational domain Ω, J = σE is the current density, dA is the boundary microelement area, TH is the safety threshold, and the charge conservation verification constraint is established. If E max >1500V / cm, then adjust the output voltage V out (t) and / or optimizing balloon electrode design; If ΔT max >6℃, then reduce the output voltage V out (t) and / or use pulsed voltage application, reduce continuous heating, and / or increase cooling measures; like The electrode structure is adjusted to reduce the uneven electric field and / or the balloon fit is adjusted to reduce the boundary leakage current.

9. An electroporation ablation voltage control system for a cardiovascular balloon, characterized in that: include: The signal acquisition and impedance measurement module is used to collect the original electrical signal of the balloon electrode, extract the complex impedance information of each frequency point, and obtain the impedance spectrum of the specified frequency band. k }; Equivalent conductivity calculation and electric field prediction module, used to calculate the equivalent conductivity tensor σ eff , solve Poisson's equation and obtain the three-dimensional electric field distribution E(x,y,z) around the balloon; The voltage control and pulse generation module is used to establish a nonlinear dynamic control formula based on the electric field prediction result and the feedback result in the impedance spectrum to control the dynamic voltage output V out (t); Multimodal feedback control module is used to optimize control parameters based on multi-physics field coupling.

10. The electroporation ablation voltage control system for cardiovascular balloon according to claim 9, characterized in that: The voltage control and pulse generation module includes a gradient pulse generator and a voltage dynamic regulator; The gradient pulse generator adopts a segmented Marx high-voltage generator, including several levels of high-voltage units, each level of the high-voltage unit includes an energy storage capacitor and a SiC MOSFET high-speed switch; The voltage dynamic regulator is based on the nonlinear dynamic regulation formula V out (t) = V base ·[1+γ·I Z (t)]·F E (t), the control pulse voltage is adjusted within the safety threshold, where V out (t) is the output voltage at time t, V base is the initial stable output voltage, γ is the impedance feedback gain coefficient, I Z (t) is the exponential decay integral, F E (t) is the energy constraint term.

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