Method, System, Electronic Device, and Storage Medium for Obtaining Pulse Ablation Parameters

Abstract

The present invention discloses a method, a system, an electronic device, and a storage medium for obtaining pulse ablation parameters. The method includes obtaining set pulse parameters; determining the electric pulse field strength threshold of the ablation tissue under the set pulse parameters; obtaining the electrode parameters corresponding to the ablation electrodes in the ablation catheter, where the ablation electrodes are attached to the surface of the ablation tissue; constructing a tissue ablation numerical model based on the set pulse parameters and the electrode parameters; obtaining the field strength distribution information corresponding to the ablation tissue according to the tissue ablation numerical model; and obtaining the predicted ablation depth corresponding to the ablation tissue and / or the predicted ablation area on the surface of the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold. The present invention can effectively improve the prediction accuracy and efficiency of ablation parameters, provide reasonable guidance for pulse parameter setting for surgeons, achieve a better ablation effect, and effectively improve the treatment experience of patients.

Description

Technical Field

[0001] The present invention relates to the technical field of data processing, and particularly relates to a method, a system, an electronic device, and a storage medium for obtaining pulse ablation parameters. Background Art

[0002] Atrial fibrillation (AF) is one of the most common arrhythmias clinically. Currently, radiofrequency ablation and cryoablation are the main methods for treating atrial fibrillation and arrhythmias clinically. Treating arrhythmias mainly depends on the quality and effectiveness of one or more lesions generated during the operation, and the lesion can divide abnormal pathways and interfere with or isolate the conduction of abnormal electrical signals in myocardial tissue. During treatment, the selected ablation energy is applied to the tissue cells causing arrhythmias without affecting the surrounding organs or tissues.

[0003] Specifically, radiofrequency (RF) energy and cryogenic energy can meet the above requirements. Radiofrequency ablation is usually a point-to-point mode, which causes necrosis of tissue target cells by heating, and then achieves tissue electrical signal isolation. It is suitable for arrhythmias such as atrial fibrillation and atrial flutter formed by pulmonary veins or pulmonary veins. Its limitations are: when radiofrequency energy is applied to the predicted tissue site, it has an impact on non-predicted tissues. For example, when radiofrequency energy is applied to atrial wall tissue, it can cause damage to the esophagus or phrenic nerve near the heart. Moreover, the treatment time of radiofrequency ablation is relatively long, which further increases the possibility of damage to non-predicted tissues or the risk of tissue scarring, and further increases the possibility of embolism. Cryoablation uses the endothermic vaporization of liquefied refrigerant to greatly reduce the surrounding temperature. Currently, cryoballoon ablation can form a continuous and complete circular ablation lesion due to the good apposition between the balloon and the pulmonary vein ostium, and the conduction of tissue signals can be isolated by one or multiple ablations, shortening the treatment time; however, the incidence of damage to the phrenic nerve in cryoballoon ablation is relatively high, and there is a certain risk of esophageal injury and pulmonary vein stenosis. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects that the ablation techniques for treating atrial fibrillation in the prior art all have an impact on or even damage non-predicted tissues. The purpose is to provide a method, a system, an electronic device, and a storage medium for obtaining pulse ablation parameters.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] The present invention provides a method for obtaining pulse ablation parameters, and the obtaining method includes:

[0007] Obtain set pulse parameters;

[0008] Determine the electric pulse field strength threshold of the ablation tissue under the set pulse parameters;

[0009] Obtain the electrode parameters corresponding to the ablation electrode in the ablation catheter, and the ablation electrode is abutted against the surface of the ablation tissue;

[0010] Construct a tissue ablation numerical model based on the set pulse parameters and the electrode parameters;

[0011] Obtain the field strength distribution information corresponding to the ablation tissue according to the tissue ablation numerical model;

[0012] Based on the field strength distribution information and the electric pulse field strength threshold, obtain the predicted ablation parameters corresponding to the ablation tissue under the set pulse parameters;

[0013] Wherein, the predicted ablation parameters include predicted ablation depth and / or predicted ablation area.

[0014] Preferably, the step of obtaining the predicted ablation parameters corresponding to the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold includes:

[0015] Process the field strength distribution information with the electric pulse field strength threshold, draw field strength contour lines, and use the area enclosed by the field strength contour lines as the predicted ablation boundary;

[0016] Based on the field strength distribution information and the electric pulse field strength threshold, obtain the predicted ablation parameters corresponding to the predicted ablation boundary of the ablation tissue under the set pulse parameters.

[0017] Preferably, the step of obtaining the predicted ablation parameters corresponding to the predicted ablation boundary of the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold includes:

[0018] Obtain the first tissue cross-section of the ablation tissue along the tissue depth direction corresponding to different electrodes in the ablation electrode;

[0019] Based on the field strength distribution information corresponding to the first tissue cross-section, obtain the field strength values corresponding to different tissue depth information;

[0020] Establish a first fitting function between different tissue depth information and the corresponding field strength values;

[0021] According to the first fitting function and the electric pulse field strength threshold, respectively obtain the intermediate ablation depths in the depth direction at different electrode positions in the ablation electrode, and calculate the predicted ablation depth in the depth direction of the tissue surface of the ablation tissue under the set pulse parameters according to the different intermediate ablation depths.

[0022] Preferably, when the ablation electrode includes a pair of electrodes, the positions of different electrodes in the ablation electrode respectively correspond to the positions directly below the two electrodes in the pair of electrodes and the positions in the middle between two adjacent electrodes; or,

[0023] when the ablation electrode includes multiple pairs of electrodes, the positions of different electrodes in the ablation electrode respectively correspond to the positions directly below each electrode in each pair of electrodes and the positions in the middle between two adjacent electrodes in each pair of electrodes.

[0024] Preferably, the potential at the positive electrode in the ablation electrode is consistent with the pulse voltage and pulse structure of the pulse generator; and / or,

[0025] the positions of the positive and negative electrodes in the ablation electrode correspond to the pulse discharge form;

[0026] wherein, in the bipolar discharge form, the polarities of adjacent electrodes are opposite; in the monopolar discharge form, all the electrodes in the ablation catheter are positive electrodes, and the back plate is a negative electrode.

[0027] Preferably, when the set pulse parameters include a set pulse width, the number of set intra-burst pulses in a pulse train, and the number of set pulse trains, the step of determining the electric pulse field strength threshold of the ablation tissue under the set pulse parameters includes:

[0028] Inputting the set pulse width, the number of set intra-burst pulses, and the number of set pulse trains into a second fitting function to calculate the electric pulse field strength threshold corresponding to the ablation tissue.

[0029] Preferably, the calculation formula corresponding to the step of inputting the set pulse width, the number of set intra-burst pulses, and the number of set pulse trains into a second fitting function to calculate the electric pulse field strength threshold corresponding to the ablation tissue is as follows:

[0030]

[0031] wherein, E th represents the electric pulse field strength threshold, E 0 represents the critical field strength of irreversible electroporation when both the pulse width and the pulse dose are in a saturated state, τ represents the set pulse width, T is the total pulse release time, T = τ * n * N, n represents the number of set intra-burst pulses, N represents the number of set pulse trains, A 1 , B 1 , C 1 , A 2 , B 2 , C 2 are all fitting coefficients.

[0032] Preferably, the calculation formula corresponding to the step of establishing the first fitting function between different tissue depth information and corresponding field strength values is as follows:

[0033]

[0034] Where E 1 is the field strength value of the ablated tissue at the electrode at tissue depth information x, and E 2 is the field strength value of the ablated tissue at the middle of the two electrodes at tissue depth information x. k 1 U, k 3 U respectively represent the fitting values of the maximum field strength values at the position directly below the electrode on the surface of the ablated tissue and at the middle position between adjacent positive and negative electrodes. U represents the pulsed voltage applied to the ablated tissue. k 1 , k 2 , k 3 , k 4 are all fitting coefficients. The fitting coefficients of the first fitting function are associated with different pulsed discharge forms. x represents the tissue depth information;

[0035] The steps of respectively obtaining the intermediate ablation depths in the depth direction at different positions on the surface of the ablated tissue according to the first fitting function and the electric pulse field strength threshold, and calculating the predicted ablation depth in the depth direction of the tissue surface of the ablated tissue under the set pulse parameters according to different intermediate ablation depths have the following corresponding calculation formula:

[0036]

[0037] Where depth represents the predicted ablation depth, and E th represents the electric pulse field strength threshold. The tissue depth information x at the surface of the ablated tissue takes a value of 0.

[0038] Preferably, the electrode parameters include electrode geometric parameters, electrode material property parameters, and material property information of the insulating part between the electrodes; among them, the electrode geometric parameters include electrode diameter information, electrode length information, and electrode spacing information; and / or,

[0039] The boundary of the tissue ablation numerical model is set to be electrically insulated;

[0040] Where J·n = 0, J represents the current density inside the model, and n represents the normal vector of the tissue boundary.

[0041] Preferably, the obtaining method further includes:

[0042] Obtaining a plurality of groups of historical strength values corresponding to the ablated tissue and historical electrical conductivities corresponding to the historical strength values;

[0043] Based on the historical electric field intensity values and the historical conductivity of each group, plot the conductivity values at different electric field strengths, and perform function fitting on the curve of conductivity varying with electric field intensity to construct a dynamic conductivity model of conductivity varying with field strength;

[0044] Among them, adaptively adjust the model fitting parameters of the dynamic conductivity model according to different ablated tissues. The adjustable model fitting parameters of the dynamic conductivity model include the initial conductivity and the model fitting coefficient

[0045] The dynamic conductivity model is used to output the conductivity corresponding to the ablated tissue.

[0046] Preferably, the calculation formula corresponding to the step of constructing the dynamic conductivity model of conductivity varying with field strength by plotting the conductivity values at different electric field strengths based on the historical electric field intensity values and the historical conductivity of each group and performing function fitting on the curve of conductivity varying with electric field intensity is as follows:

[0047]

[0048] Among them, σ 0 represents the initial conductivity of the ablated tissue, σ max represents the maximum conductivity when all of the ablated tissue undergoes electroporation, σ max = C 3 *σ 0 A3, B3, and C 3 are respectively model fitting parameters, E del represents the field strength value corresponding to the center point of the transition region from the start of conductivity change to the development to the stable value, and E represents the field strength value corresponding to the field strength distribution information.

[0049] Preferably, the step of obtaining the field strength distribution information corresponding to the ablated tissue according to the tissue ablation numerical model includes:

[0050] Obtain the potential information inside the tissue ablation numerical model;

[0051] Based on the potential information and conductivity, calculate the field strength distribution information corresponding to the ablated tissue.

[0052] Preferably, the calculation formula corresponding to the step of calculating the field strength distribution information corresponding to the ablated tissue based on the potential information and the conductivity is as follows:

[0053]

[0054] Among them, E represents the field strength distribution information, represents the potential information, σ is the conductivity of the ablated tissue, and ε 0 is the vacuum permittivity, and ε r is the relative permittivity of the ablated tissue.

[0055] Preferably, the step of obtaining the predicted ablation parameters corresponding to the predicted ablation boundary of the ablated tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold includes:

[0056] Obtaining a first tissue cross-section of the ablated tissue along the tissue width direction corresponding to different electrodes in the ablation electrode;

[0057] Based on the field strength distribution information corresponding to the first tissue cross-section, obtaining field strength values corresponding to different tissue width information;

[0058] Establishing a third fitting function between different tissue width information and the corresponding field strength values;

[0059] According to the third fitting function and the electric pulse field strength threshold, respectively obtaining intermediate ablation regions corresponding to different electrodes in the ablation electrode, and calculating a predicted ablation region corresponding to the surface of the ablated tissue under the set pulse parameters based on different intermediate ablation regions.

[0060] Preferably, the calculation formula corresponding to the step of establishing the third fitting function between different tissue width information and the corresponding field strength values is as follows:

[0061]

[0062] where E 3 represents the field strength value of the ablated tissue at the electrode in the width displacement, E 4 represents the field strength value of the ablated tissue in the width displacement at the middle between two adjacent electrodes, w represents the displacement magnitude, U represents the pulse voltage, and p1 to p8 all represent fitting coefficients;

[0063] The calculation formula corresponding to the step of respectively obtaining intermediate ablation regions corresponding to different electrodes in the ablation electrode according to the third fitting function and the electric pulse field strength threshold, and calculating a predicted ablation region corresponding to the surface of the ablated tissue under the set pulse parameters is as follows:

[0064]

[0065]

[0066] where wide 1 and wide2 respectively represent different ones of the intermediate ablation regions, wide represents the predicted ablation region, E th represents the electric pulse field strength threshold.

[0067] Preferably, the obtaining method further includes:

[0068] Based on the predicted ablation region and the predicted ablation depth corresponding to the predicted ablation boundary, constructing a three-dimensional ablation model corresponding to the predicted ablation boundary.

[0069] Preferably, the obtaining method further includes:

[0070] Based on the predicted ablation depth and the target ablation depth under the set pulse parameters, using a genetic algorithm to calculate the fitness value corresponding to the predicted ablation depth;

[0071] When the fitness value does not meet the preset condition, then perform selection, crossover, and mutation processing in sequence to generate a new pulse parameter combination;

[0072] When the fitness value corresponding to the pulse parameter combination meets the preset condition, then update the set pulse parameters with the pulse parameter combination.

[0073] The present invention also provides a system for obtaining pulse ablation parameters, the obtaining system includes:

[0074] A pulse parameter obtaining module, configured to obtain set pulse parameters;

[0075] An electric pulse field strength threshold determination module, configured to determine the electric pulse field strength threshold of the ablation tissue under the set pulse parameters;

[0076] An electrode parameter obtaining module, configured to obtain the electrode parameters corresponding to the ablation electrodes in the ablation catheter, and the ablation electrodes are abutted against the surface of the ablation tissue;

[0077] An ablation model construction module, configured to construct a tissue ablation numerical model based on the set pulse parameters and the electrode parameters;

[0078] A field strength distribution information obtaining module, configured to obtain the field strength distribution information corresponding to the ablation tissue according to the tissue ablation numerical model;

[0079] A predicted ablation parameter obtaining module, configured to obtain the predicted ablation parameters corresponding to the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold;

[0080] Wherein, the predicted ablation parameters include a predicted ablation depth and / or a predicted ablation region.

[0081] Preferably, the predicted ablation parameter acquisition module includes:

[0082] An ablation boundary prediction unit, configured to process the field strength distribution information by using the electric pulse field strength threshold, draw field strength contour lines, and use the area enclosed by the field strength contour lines as the predicted ablation boundary;

[0083] A predicted ablation parameter calculation unit, configured to obtain the predicted ablation parameters corresponding to the predicted ablation boundary of the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold.

[0084] Preferably, the predicted ablation parameter calculation unit includes:

[0085] A tissue cross-section acquisition subunit, configured to obtain a first tissue cross-section of the ablation tissue along the tissue depth direction corresponding to different electrodes in the ablation electrode;

[0086] A depth field strength value acquisition subunit, configured to obtain field strength values corresponding to different tissue depth information based on the field strength distribution information corresponding to the first tissue cross-section;

[0087] A first fitting function establishment subunit, configured to establish a first fitting function between different tissue depth information and the corresponding field strength values;

[0088] An intermediate ablation depth acquisition subunit, configured to respectively obtain intermediate ablation depths in the depth direction at different electrode positions in the ablation electrode according to the first fitting function and the electric pulse field strength threshold;

[0089] A predicted ablation depth calculation subunit, configured to calculate the predicted ablation depth in the depth direction along the tissue surface of the ablation tissue under the set pulse parameters according to different intermediate ablation depths.

[0090] Preferably, when the ablation electrode includes a pair of electrodes, the positions of different electrodes in the ablation electrode respectively correspond to the positions directly below the two electrodes in the pair of electrodes and the positions in the middle between two adjacent electrodes; or,

[0091] When the ablation electrode includes multiple pairs of electrodes, the positions of different electrodes in the ablation electrode respectively correspond to the positions directly below each electrode in each pair of electrodes and the positions in the middle between two adjacent electrodes in each pair of electrodes.

[0092] Preferably, the electric potential at the positive electrode in the ablation electrode is consistent with the pulse voltage and pulse structure of the pulse generator; and / or,

[0093] The positions of the positive and negative electrodes in the ablation electrode correspond to the pulse discharge form;

[0094] Among them, in the bipolar discharge mode, the polarities of adjacent electrodes are opposite; in the monopolar discharge mode, all electrodes in the ablation catheter are positive electrodes, and the back plate is a negative electrode.

[0095] Preferably, when the set pulse parameters include a set pulse width, the number of set intra-burst pulses in a pulse train, and the number of set pulse trains, the electric pulse field strength threshold determination module is configured to input the set pulse width, the number of set intra-burst pulses, and the number of set pulse trains into a second fitting function to calculate the electric pulse field strength threshold corresponding to the ablated tissue.

[0096] Preferably, the calculation formula corresponding to the step of the electric pulse field strength threshold determination module determining the electric pulse field strength threshold is as follows:

[0097]

[0098] Among them, E th represents the electric pulse field strength threshold, E 0 represents the critical field strength of irreversible electroporation when both the pulse width and the pulse dose are in a saturated state, τ represents the set pulse width, T is the total pulse release time, T = τ * n * N, n represents the number of set intra-burst pulses, N represents the number of set pulse trains, A 1 , B 1 , V 1 , A 2 , B 2 , C 2 are all fitting coefficients.

[0099] Preferably, the calculation formula corresponding to the first fitting function establishing subunit for establishing the first fitting function is as follows:

[0100]

[0101] Among them, E 1 is the field strength value of the ablated tissue at the electrode at the tissue depth information x, E 2 is the field strength value of the ablated tissue at the middle of two electrodes at the tissue depth information x, k 1 U, k 3 U respectively represent the fitting values of the maximum field strength values at the position directly below the electrode on the surface of the ablated tissue and at the middle position between adjacent positive and negative electrodes, U represents the pulse voltage applied to the ablated tissue

[0102] , k 1 , k 2 , k 3 , k 4are all fitting coefficients. The fitting coefficients of the first fitting function are associated with different pulsed discharge forms, and x represents the tissue depth information;

[0103] The predicted ablation depth calculation subunit calculates the corresponding calculation formula for the predicted ablation depth as follows:

[0104]

[0105] where depth represents the predicted ablation depth, and E th represents the electric pulse field strength threshold, and the tissue depth information x at the surface of the ablated tissue takes a value of 0.

[0106] Preferably, the electrode parameters include electrode geometric parameters, electrode material property parameters, and material property information of the insulating part between the electrodes; among them, the electrode geometric parameters include electrode diameter information, electrode length information, and electrode spacing information; and / or,

[0107] The boundary of the tissue ablation numerical model is set to be electrically insulated;

[0108] where J·n = 0, J represents the current density inside the model, and n represents the tissue boundary normal vector.

[0109] Preferably, the acquisition system further includes:

[0110] A historical data acquisition module for acquiring a plurality of groups of historical intensity values corresponding to the ablated tissue and the historical conductivity corresponding to the historical intensity values;

[0111] A conductivity model construction module for plotting the conductivity values under different electric field strengths according to each group of the historical electric field intensity values and the historical conductivity, and performing function fitting on the curve of the conductivity varying with the electric field intensity to construct a dynamic conductivity model of the conductivity varying with the field strength;

[0112] Among them, according to different ablated tissues, the model fitting parameters of the dynamic conductivity model are adaptively adjusted. The adjustable model fitting parameters of the dynamic conductivity model include the initial conductivity and the model fitting coefficients;

[0113] The dynamic conductivity model is used to output the conductivity corresponding to the ablated tissue.

[0114] Preferably, the calculation formula corresponding to the steps of the conductivity model construction module for constructing the dynamic conductivity model is as follows:

[0115]

[0116] where σ 0 represents the initial conductivity of the ablated tissue, and σmax represents the maximum conductivity, σ, when all of the ablated tissue undergoes electroporation max = C 3 *σ 0 , A3, B3, C 3 are respectively model fitting parameters, and E del represents the field strength value corresponding to the center point of the transition region from the start of the change in conductivity to the stable value, and E represents the field strength value corresponding to the field strength distribution information

[0117] Preferably, the field strength distribution information acquisition module includes:

[0118] a potential information acquisition unit for acquiring the potential information inside the tissue ablation numerical model;

[0119] a field strength distribution information calculation unit for calculating the field strength distribution information corresponding to the ablated tissue based on the potential information and the conductivity

[0120] Preferably, the calculation formula corresponding to the steps of the field strength distribution information calculation unit for calculating the field strength distribution information corresponding to the ablated tissue is as follows:

[0121]

[0122] wherein, E represents the field strength distribution information, represents the potential information, σ is the conductivity of the ablated tissue, and ε 0 is the vacuum permittivity, and ε r is the relative permittivity of the ablated tissue

[0123] Preferably, the predicted ablation parameter calculation unit includes:

[0124] a tissue cross-section acquisition subunit for acquiring a first tissue cross-section along the tissue width direction corresponding to the positions of different electrodes in the ablation electrode;

[0125] a width field strength value acquisition subunit for acquiring the field strength values corresponding to different tissue width information based on the field strength distribution information corresponding to the first tissue cross-section;

[0126] a third fitting function establishment subunit for establishing a third fitting function between different tissue width information and the corresponding field strength values;

[0127] an intermediate ablation region acquisition subunit for respectively acquiring the intermediate ablation regions corresponding to the positions of different electrodes in the ablation electrode according to the third fitting function and the electric pulse field strength threshold;

[0128] A predicted ablation area calculation subunit, configured to calculate a predicted ablation area corresponding to the surface of the ablated tissue under the set pulse parameters according to different intermediate ablation areas.

[0129] Preferably, the third fitting function establishing subunit establishes the following calculation formula corresponding to the third fitting function:

[0130]

[0131]

[0132] Among them, E 3 represents the field strength value of the ablated tissue at the electrode in the width displacement direction, E 4 represents the field strength value of the ablated tissue at the middle between two adjacent electrodes in the width displacement direction, w represents the displacement magnitude, and p1 to p8 all represent fitting coefficients;

[0133] The calculation formula corresponding to the predicted ablation area calculated by the predicted ablation area calculation subunit is as follows:

[0134]

[0135] Among them, wide 1 and wide 2 respectively represent different intermediate ablation areas, wide represents the predicted ablation area, and E th represents the electric pulse field strength threshold.

[0136] Preferably, the acquisition system further includes:

[0137] A three-dimensional model construction module, configured to construct a three-dimensional ablation model corresponding to the predicted ablation boundary based on the predicted ablation area and the predicted ablation depth corresponding to the predicted ablation boundary.

[0138] Preferably, the acquisition system further includes:

[0139] A fitness value calculation module, configured to calculate a fitness value corresponding to the predicted ablation depth by using a genetic algorithm based on the predicted ablation depth and the target ablation depth under the set pulse parameters;

[0140] A pulse parameter combination generation module, configured to perform selection, crossover, and mutation processing in sequence to generate a new pulse parameter combination when the fitness value does not meet a preset condition;

[0141] A pulse parameter update module, configured to update the set pulse parameters with the pulse parameter combination when the fitness value corresponding to the pulse parameter combination meets the preset condition.

[0142] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method for obtaining pulse ablation parameters is implemented.

[0143] The present invention also provides a computer-readable storage medium, on which a computer program is stored. The computer program, when executed by a processor, implements the above-mentioned method for obtaining pulse ablation parameters.

[0144] On the basis of conforming to the common knowledge in the art, the above preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0145] The positive and progressive effects of the present invention are as follows:

[0146] In the present invention, the electric pulse field strength threshold at the pulse parameter is calculated based on the set pulse parameter and the fitting function of the electric pulse field strength threshold; an ablation numerical model is constructed based on the ablation electrode parameters in the ablation catheter to obtain the field strength distribution information corresponding to the ablation tissue in the tissue depth direction and the tissue width direction; the electric pulse field strength threshold is used to draw the field strength contour line to predict the ablation boundary; based on the field strength distribution information in the tissue depth direction and the electric pulse field strength threshold, the predicted ablation depth under the predicted ablation boundary is finally obtained, and based on the field strength distribution information in the tissue width direction and the electric pulse field strength threshold, the predicted ablation area under the predicted ablation boundary is finally obtained, effectively improving the prediction accuracy and efficiency of the ablation parameters corresponding to the pulse parameters, being applicable to single-pole and bipolar ablation methods, providing reasonable guidance for pulse parameter setting for surgeons, making the pulse energy corresponding to the pulse parameters match the electrical characteristics of myocardial tissue, thereby achieving the purpose of improving the ablation effect; a three-dimensional ablation model corresponding to the predicted ablation boundary is constructed based on the predicted ablation depth and the predicted ablation area, which can visually present the three-dimensional shape corresponding to the ablation area, facilitating doctors or patients to view and understand, and effectively improving the treatment experience of patients. BRIEF DESCRIPTION OF THE DRAWINGS

[0147] Figure 1 It is a flowchart of the method for obtaining pulse ablation parameters in Embodiment 1 of the present invention.

[0148] Figure 2 It is a schematic diagram of the bidirectional pulse structure output by the pulse generator in Embodiment 1 of the present invention.

[0149] Figure 3a It is a schematic diagram of the relationship between the pulse width and the field strength threshold in Embodiment 2 of the present invention.

[0150] Figure 3b It is a schematic diagram of the relationship between the pulse duration and the field strength threshold in Embodiment 2 of the present invention.

[0151] Figure 4It is the first flowchart of the method for obtaining pulse ablation parameters in Embodiment 2 of the present invention.

[0152] Figure 5 It is the schematic structural diagram of the annular ablation electrode in Embodiment 2 of the present invention.

[0153] Figure 6 It is the schematic diagram corresponding to the tissue ablation numerical model in Embodiment 2 of the present invention.

[0154] Figure 7 It is the fitting curve graph of the conductivity changing with the field strength in Embodiment 2 of the present invention.

[0155] Figure 8 It is the schematic diagram of the isogram of the electric pulse field strength threshold under the annular electrode in Embodiment 2 of the present invention.

[0156] Figure 9 It is the second flowchart of the method for obtaining pulse ablation parameters in Embodiment 2 of the present invention.

[0157] Figure 10 It is the schematic diagram of the relationship between the displacement in the tissue depth direction and the voltage distribution in Embodiment 2 of the present invention.

[0158] Figure 11 It is the schematic diagram of the relationship between the depth information at the tissue cross-section and the field strength in Embodiment 2 of the present invention.

[0159] Figure 12 It is the schematic diagram for comparing the predicted ablation depth and the historical ablation depth in Embodiment 2 of the present invention.

[0160] Figure 13 It is the schematic diagram of the field strength distribution in the ablation width direction in Embodiment 3 of the present invention.

[0161] Figure 14 It is the flowchart of the method for obtaining pulse ablation parameters in Embodiment 3 of the present invention.

[0162] Figure 15 It is the schematic diagram of the ablation area corresponding to the ablation area in Embodiment 3 of the present invention.

[0163] Figure 16 It is the first three-dimensional ablation model schematic diagram corresponding to the ablation area in Embodiment 3 of the present invention.

[0164] Figure 17 It is the second three-dimensional ablation model schematic diagram corresponding to the ablation area in Embodiment 3 of the present invention.

[0165] Figure 18 It is the flowchart of optimizing pulse parameters based on the genetic algorithm in Embodiment 3 of the present invention.

[0166] Figure 19Schematic diagram of the module of the system for obtaining pulse ablation parameters in Embodiment 4 of the present invention.

[0167] Figure 20 Schematic diagram of the module of the system for obtaining pulse ablation parameters in Embodiment 5 of the present invention.

[0168] Figure 21 Schematic diagram of the module of the system for obtaining pulse ablation parameters in Embodiment 6 of the present invention.

[0169] Figure 22 Schematic diagram of the structure of the electronic device for implementing the method for obtaining pulse ablation parameters in Embodiment 7 of the present invention. Detailed implementation manners

[0170] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the embodiments accordingly.

[0171] Embodiment 1

[0172] As Figure 1 shown, the method for obtaining pulse ablation parameters in this embodiment includes:

[0173] S101. Obtain set pulse parameters;

[0174] Among them, the set pulse parameters include but are not limited to set pulse width, the number of set intra-burst pulses in a pulse train, the number of set pulse trains, pulse voltage, and pulse duty cycle.

[0175] The set pulse parameters are input through the operation interface of pulse output devices such as pulse generators. Taking a pulse generator as an example, the pulse structure can be set to a single-phase structure and a bipolar structure; the discharge form can also be switched, and the discharge form is divided into bipolar discharge and monopolar discharge. In the bipolar discharge mode, there are both positive and negative electrodes in the ablation electrode (also known as the catheter electrode), and an electrical circuit is formed between the positive and negative electrodes; in the monopolar discharge mode: the ablation electrode is connected to the positive, and the back plate attached to the back is connected to the negative, and an electrical circuit is formed by the electrode and the back plate. Taking the bipolar pulse structure as an example, as Figure 2 shown, it is the output pulse structure of the pulse generator, where the horizontal axis represents time t (unit: second s), and the vertical axis represents voltage v(t).

[0176] Among them, the potential at the positive electrode of the ablation electrode is consistent with the pulse voltage and pulse structure of the pulse generator. As Figure 2 shown, U + = v(t), the negative electrode is in a grounded state, and U - = 0.

[0177] The setting positions of the positive and negative electrodes in the ablation electrode correspond to the pulse discharge form; in the bipolar discharge form, the polarities of adjacent electrodes are opposite; in the monopolar discharge form, all the electrodes in the ablation catheter are positive electrodes, and the back plate is the negative electrode.

[0178] S102. Determine the electric pulse field strength threshold of the ablation tissue under the set pulse parameters;

[0179] S103. Obtain the electrode parameters corresponding to the ablation electrodes in the ablation catheter, and the ablation electrodes are abutted against the surface of the ablation tissue;

[0180] S104. Construct a tissue ablation numerical model based on the set pulse parameters and electrode parameters;

[0181] S105. Obtain the field strength distribution information corresponding to the ablation tissue according to the tissue ablation numerical model;

[0182] S106. Based on the field strength distribution information and the electric pulse field strength threshold, obtain the predicted ablation parameters corresponding to the ablation tissue under the set pulse parameters;

[0183] Among them, the predicted ablation parameters include the predicted ablation depth and / or the predicted ablation area.

[0184] The pulsed electric field energy is different from the existing traditional RF energy, cryogenic energy, ultrasonic energy, etc. Pulsed irreversible electroporation ablation is that the pulsed electric field energy forms irreversible micropores on the cell membrane through instantaneous discharge, causing apoptosis of cells and achieving non-thermal ablation. Since different tissue cells have different voltage thresholds, pulsed ablation can selectively ablate the target tissue cells without affecting other non-target tissue cells, that is, it can avoid the complications caused by radiofrequency ablation, cryoablation, etc. when treating atrial fibrillation, and has no effect on other non-target tissue cells such as the esophagus, diaphragm, blood vessels, etc.

[0185] Atrial tissues vary from person to person, and there are differences in size, thickness, etc. The set pulse parameters may not be applicable to all atrial tissues, and doctors may need to adjust the pulse parameters appropriately according to the situation; however, it is difficult to set reasonable and effective parameter values relying on the doctor's own experience; even experienced doctors need to spend a lot of time debugging and demonstrating, which is time-consuming and laborious and it is difficult to ensure that the settings are reasonable and effective each time. In order to achieve an ideal ablation effect, a tissue ablation numerical model is established to predict the ablation effect of the electric field on the pulmonary veins during the action of electric pulses, and thus formulate a treatment plan for irreversible electroporation ablation.

[0186] Since pulmonary vein isolation for treating atrial fibrillation has requirements for ablation depth, if the ablation depth is too small, the medical operation may not be very effective, or multiple ablations may be required, resulting in a longer ablation time; if the ablation depth is too deep, adjacent tissues may be inadvertently ablated, and in some cases, perforation of the heart wall may occur. Therefore, before actual treatment, simulating the ablation depth through a tissue ablation numerical model as a reference basis has certain guiding significance for clinicians to formulate clinical treatment plans before surgery.

[0187] In this embodiment, the electric pulse field strength threshold under the pulse parameter is calculated based on the set pulse parameter and the fitting function of the electric pulse field strength threshold; an ablation numerical model is constructed based on the ablation electrode parameters in the ablation catheter to obtain the field strength distribution information corresponding to the ablated tissue in the tissue depth direction and the tissue width direction; the electric pulse field strength threshold is used to draw the field strength contour line to predict the ablation boundary; based on the field strength distribution information in the tissue depth direction and the electric pulse field strength threshold, the predicted ablation depth under the predicted ablation boundary is finally obtained, and based on the field strength distribution information in the tissue width direction and the electric pulse field strength threshold, the predicted ablation area under the predicted ablation boundary is finally obtained, effectively improving the prediction accuracy and efficiency of the ablation parameters corresponding to the pulse parameters, providing guidance for surgeons to set reasonable pulse parameters, and improving the ablation effect.

[0188] Embodiment 2

[0189] The method for obtaining the pulse ablation parameters in this embodiment is a further improvement of Embodiment 1. Specifically:

[0190] Considering that the main factors affecting the electric field strength threshold include pulse width, the number of intra-burst pulses in a pulse train, and the number of pulse trains, the electric pulse field strength thresholds corresponding to different combinations of pulse width, intra-burst pulse number, and pulse train number are pre-stored in the database, and a data list is established according to the corresponding relationship between different parameter combinations and the electric pulse field strength threshold for use in establishing a fitting function, so that the electric pulse field strength threshold corresponding to any pulse parameter combination can be obtained by combining this fitting function.

[0191] Specifically, as Figure 3a shown, for the corresponding relationship between pulse width and electric pulse field strength threshold, the horizontal axis represents pulse width, unit log(t) / us, and the vertical axis represents field strength threshold, unit V / cm; as Figure 3b shown, the horizontal axis represents pulse duration, T / us, and the vertical axis represents field strength threshold, unit V / cm.

[0192] When the total duration T of the pulse action remains consistent, the threshold of the electric pulse field strength will show differences due to different pulse width values, and the threshold of the electric pulse field strength decreases as the pulse width τ increases; when the pulse width τ remains consistent, the threshold of the electric pulse field strength will change with the change of the pulse release time T, and the threshold of the electric pulse field strength decreases as the pulse duration increases.

[0193] It can be known that the changing trends of the threshold of the electric pulse field strength with the pulse width and the pulse release time are approximate, decreasing as the variable increases, and both will reach a saturation value, that is, when the variable increases to a certain value, the threshold of the electric pulse field strength remains basically unchanged. When the pulse width and the pulse release time respectively take the saturation values, the corresponding threshold of the electric pulse field strength is set as E 0 ; K 1 (τ) is the influence coefficient of the pulse width on the threshold of the electric pulse field strength when the pulse release time is in the saturation state; K 2 (n) is the influence coefficient of the pulse release time on the threshold when the pulse width is in the saturation state.

[0194] Specifically, as Figure 4 shown, step S102 includes:

[0195] S1021. Input the set pulse width, the number of pulses in the set string, and the number of pulse strings into the second fitting function to calculate the threshold of the electric pulse field strength corresponding to the ablated tissue.

[0196] Specifically, the calculation formula corresponding to the step of inputting the set pulse width, the number of pulses in the set string, and the number of pulse strings into the second fitting function to calculate the threshold of the electric pulse field strength corresponding to the ablated tissue is as follows:

[0197]

[0198] Among them, E th represents the threshold of the electric pulse field strength, E 0 represents the critical field strength of irreversible electroporation when both the pulse width and the pulse dose are in the saturation state. For myocardial tissue, the value of E 0 is taken as 300 - 500 V / cm; τ represents the set pulse width, with a value range of 0.1 - 50 us; T is the total pulse release time, T = τ * n * N, n represents the number of pulses in the set string, N represents the number of pulse strings, A 1 , B 1 , C 1 , A 2 , B 2 , C 2 are all fitting coefficients. Specifically, A 1 , B 1 , C 1 , A 2, B 2 , C 2 are all fitting parameters determined according to the fitting accuracy coefficient R 2 > 0.95.

[0199] For example, the ablation threshold of cardiomyocytes during traditional irreversible electroporation is 400 V / cm. In this embodiment, the critical field strength value E 0 = 400 V / cm; read the corresponding array S1 of different pulse widths τ and field strength thresholds stored in the previous database, plot the influence function curve of the pulse width on the irreversible electroporation field strength threshold, and fit the curve to obtain the expression of K 1 (τ), Read the corresponding array S2 of different total pulse release times T and field strength thresholds stored in the previous database, plot the influence function curve of the total pulse release time on the irreversible electroporation field strength threshold, and fit the curve to obtain the expression of K 1 (τ),

[0200] Based on the above fitting function, the calculation formula for the field strength ablation threshold is obtained:

[0201] E th = F(τ, n, N) = E 0 * K 1 (τ) * K 2 (T)

[0202] = 400 * (0.43 × τ -0.48 + 0.95) * (1.04 × 10 5 × T -1.66 + 1.01)

[0203] After obtaining the functional expression of the field strength threshold with respect to the pulse width τ and the total pulse ablation time T, substitute the obtained pulse parameters to obtain the field strength threshold of irreversible electroporation under the set pulse parameters. For example: set a group of pulse parameters, where the pulse width τ = 5 μs, the number of pulses n = 20 in a pulse train, and the total number of ablation pulse trains N = 200. First, calculate the pulse ablation time T = τ * n * N = 5 * 20 * 200 = 20000 μs. Then, the field strength threshold under these pulse parameters is:

[0204] E th = E 0 * K 1 (τ) * K 2 (T) = 467.5 V / cm

[0205] In addition, the voltage value required for the pulse generator can be roughly calculated based on the product of the electrode spacing of the ablation electrodes in the ablation catheter and the electric pulse field strength threshold, and this voltage value is used as the pulse voltage of the pulse generator.

[0206] In the solution of an implementable embodiment, the electrode parameters include but are not limited to electrode geometric parameters, electrode material property parameters, and material property information of the insulating part between the electrodes; the electrode geometric parameters include but are not limited to electrode diameter information, electrode length information, and electrode spacing information.

[0207] Among them, for the ablation electrodes corresponding to different types of ablation catheters, the corresponding electrode parameters are all set fixed parameters. When using a certain ablation catheter, the corresponding electrode parameters can be directly obtained according to the product description information. The tissue ablation numerical model is used to simulate the actual ablation scenario corresponding to the ablation electrodes of the ablation catheter and the ablation tissue. As Figure 5 shown, taking the ablation electrode M1 as an annular electrode as an example, the geometric parameters include: the radius of the ablation electrode is 0.85 mm, the electrode length is 3 mm, and the distance between the two electrode end faces is 4 mm; the material properties include: the electrode material is platinum, and the middle of the electrode is an insulating material. A total of 9 electrodes are arranged (N represents the electrode in the figure), and the tissue ablation numerical model is constructed according to the geometric parameters and material properties of the annular electrode.

[0208] In the solution of an implementable embodiment, when the ablation electrodes include a pair of electrodes, the positions where different electrodes are located in the ablation electrodes respectively correspond to the positions directly below the two electrodes in the pair of electrodes and the positions in the middle between two adjacent electrodes.

[0209] In the solution of an implementable embodiment, when the ablation electrodes include multiple pairs of electrodes, the positions where different electrodes are located in the ablation electrodes respectively correspond to the positions directly below each electrode in each pair of electrodes and the positions in the middle between two adjacent electrodes in each pair of electrodes.

[0210] Specifically, as Figure 5 shown, the gray areas correspond to different electrodes, and the tissue below the electrode is the tissue directly below the electrode; the white area is the insulating gap between adjacent electrodes, and the tissue below the middle of the two electrodes is the tissue directly below the middle of the two electrodes.

[0211] When the ablation tissue is myocardial tissue, the ablation electrodes are placed in the blood and abutted against the myocardial tissue. As Figure 6 shown, corresponding to the tissue ablation numerical model of the myocardial tissue, where M1 represents the ablation electrode, M2 represents the blood, and M3 represents the myocardial tissue.

[0212] In addition, the boundary of the tissue ablation numerical model is set to be electrically insulated; among them, J·n = 0, where J represents the current density inside the model and n represents the normal vector of the tissue boundary.

[0213] The method for obtaining the pulse ablation parameters in this embodiment further includes:

[0214] Obtaining a plurality of groups of historical intensity values corresponding to the ablated tissue and the historical conductivity corresponding to the historical intensity values;

[0215] According to the historical electric field intensity value and historical conductivity of each group, plot the conductivity values under different electric field strengths, and perform function fitting on the curve of the conductivity changing with the electric field intensity to construct a dynamic conductivity model of the conductivity changing with the field strength;

[0216] Among them, according to different ablated tissues, adaptively adjust the model fitting parameters of the dynamic conductivity model. The adjustable model fitting parameters of the dynamic conductivity model include the initial conductivity and the model fitting coefficient;

[0217] The dynamic conductivity model is used to output the conductivity corresponding to the ablated tissue.

[0218] In an implementable case, since electroporation occurs in the tissue during the electro-pulse ablation process, the conductivity of the tissue will change with the continuation of the perforation process. Therefore, the conductivity of the tissue needs to be set as a dynamic parameter. Since in irreversible electroporation, the conductivity changes with the continuation of the perforation process, considering that during the ablation process, saline flushing will be carried out and the tissue temperature change is small, the conductivity change is mainly affected by the electric field strength; in order to improve the calculation efficiency, the influence of tissue temperature rise can be ignored, and a dynamic conductivity model changing with the electric field strength is constructed. As Figure 7 shown, the fitting curve representing the conductivity changing with the field strength, the horizontal axis represents the electric field strength (V / cm), and the vertical axis represents the conductivity (S / m). When the electric field strength is very small and not enough to cause tissue electroporation, the measured conductivity is the initial conductivity σ 0 , when the electric field strength is large enough and the pulsed electric field acts on the tissue, when the monitored current value tends to be stable, the measured conductivity at this time is the maximum conductivity σ max of the tissue.

[0219] Read the conductivity at different electric field strengths from the database, based on the existing historical experimental data, plot the conductivity at different electric field strengths, and perform fitting on the conductivity curve to obtain the dynamic conductivity model.

[0220] Specifically, the calculation formula corresponding to the step of constructing the dynamic conductivity model of the conductivity changing with the field strength by plotting the conductivity values under different electric field strengths according to the historical electric field intensity value and historical conductivity of each group and performing function fitting on the curve of the conductivity changing with the electric field intensity is as follows:

[0221]

[0222] Among them, σ 0 represents the initial conductivity of the ablated tissue, generally taken as 0.2 - 0.4 S / m, and σ max represents the maximum conductivity when all the ablated tissue undergoes electroporation. σ max = C 3 *σ 0 ; generally 3 - 4 times of σ 0 , E del represents the field strength value corresponding to the center point of the transition region from the start of conductivity change to the development to the stable value, generally taken as 500 - 700 V / cm, and E represents the field strength value corresponding to the field strength distribution information. A 3 , B 3 , C 3 are respectively model fitting parameters, and the specific selection of these parameters can be determined or adjusted according to the actual situation.

[0223] In an implementable case, considering that for different patients, there will be certain differences in the conductivity of atrial tissue. During actual application, after the catheter is in place, a test pulse is released, with the voltage around 20 - 80 V. Without causing electroporation, the voltage value U and the current value I are monitored. The monitored voltage value is used as the positive electrode voltage amplitude of the simulation model. Without electroporation, σ(E) = σ 0 , and the previous empirical value is used as the initial conductivity value and assigned to the material property of the ablated tissue, and the numerical calculation model is simulated; after the calculation is completed, the surface integral of the normal current density on the electrode surface is performed to obtain the numerically calculated current value, I s = ∫∫n·J; its value is compared and analyzed with the monitored and stored current value. If Is = I, it indicates that the preset initial conductivity can be used as the initial conductivity value of the ablated tissue; if Is ≠ I, the preset initial conductivity is adjusted according to a certain gradient until the calculated Is = I, and the corresponding conductivity value at this time is the initial conductivity σ 0 .

[0224] During the ablation process, the voltage value U and the current value I are continuously monitored. Under the action of high field strength, the tissue cells undergo electroporation, resulting in a change in tissue conductivity. The monitored voltage value is used as the positive electrode voltage amplitude of the simulation model, and the dynamic conductivity model obtained from empirical data is applied to the tissue material property of the simulation model, and the numerical calculation model is simulated; after the calculation is completed, the surface integral of the normal current density on the electrode surface is performed to obtain the numerically calculated current value, I s= ∫∫n·J, and compare its value with the monitored and stored current value for analysis. If Is = I, it indicates that the fitting coefficient in the above dynamic conductivity model is applicable to the ablation tissue. If Is ≠ I, adjust the fitting coefficient in the dynamic conductivity model according to a certain gradient until the calculated Is = I. At this time, the corresponding conductivity fitting coefficient is appropriate.

[0225] Step S105 includes:

[0226] S1051. Obtain the potential information inside the tissue ablation numerical model;

[0227] S1052. Based on the potential information and conductivity, calculate the field strength distribution information corresponding to the ablation tissue.

[0228] Specifically, the calculation formula corresponding to the step of calculating the field strength distribution information corresponding to the ablation tissue based on the potential information and conductivity is as follows:

[0229]

[0230] Among them, E represents the field strength distribution information, represents the potential information, σ is the conductivity of the ablation tissue, ε 0 is the vacuum permittivity, and ε r is the relative permittivity of the ablation tissue.

[0231] Among them, the field strength distribution is mainly determined by the voltage corresponding to the pulse parameters, the electrode spacing, the electrode size, and the discharge form, etc. In the actual application process, the ablation parameter prediction involved in this embodiment is used in cooperation with a finalized ablation catheter. For the same ablation catheter, its electrode spacing and electrode size are in a fixed state. Therefore, by pre-storing the electrode parameters of the catheter used in supporting, for different ablation electrodes, calculate the field strength distribution and predict the ablation parameters (including the ablation area and ablation depth) respectively.

[0232] Step S106 includes:

[0233] S1061. Process the field strength distribution information using the electric pulse field strength threshold, draw the field strength contour line, and use the area enclosed by the field strength contour line as the predicted ablation boundary;

[0234] Specifically, as Figure 8 shown, for the annular electrode, P represents the ablation catheter, N1 represents the positive electrode, N2 represents the negative electrode, N3 corresponds to the insulating material part between the positive and negative electrodes, and L1 represents the electric pulse field strength threshold contour line.

[0235] S1062. Based on the field strength distribution information and the electric pulse field strength threshold, obtain the predicted ablation parameters corresponding to the predicted ablation boundary of the ablation tissue under the set pulse parameters.

[0236] Specifically, as Figure 9 shown, step S1062 includes:

[0237] S106211. Obtain the first tissue cross-section of the ablated tissue corresponding to the positions of different electrodes in the ablation electrode along the tissue depth direction;

[0238] S106212. Based on the field strength distribution information corresponding to the first tissue cross-section, obtain the field strength values corresponding to different tissue depth information;

[0239] S106213. Establish a first fitting function between different tissue depth information and the corresponding field strength values;

[0240] After the calculation of the tissue ablation numerical model, i.e., the simulation model, is completed, the potential distribution (i.e., field strength distribution information) on any tissue cross-section in the tissue depth direction can be obtained. Among them, any tissue cross-section includes the tissue cross-section directly below the electrode and the tissue cross-section directly below the middle of the electrodes. In the tissue depth direction, the voltage shows a decreasing trend. As Figure 10 shown, draw a corresponding relationship diagram between the displacement (i.e., tissue depth information) in the tissue depth direction and the voltage distribution. The horizontal axis represents the displacement (mm) along the tissue depth direction, and the vertical axis represents the voltage value (V).

[0241] According to the above relationship formula between the field strength and the potential distribution, the field strength magnitude at the displacement can be calculated based on the potential distribution data, and its calculation formula is:

[0242]

[0243] U(n + 1) and U(n) respectively represent the voltage values at two positions, d(n + 1) and d(n) respectively represent the tissue depth information at two positions, and E(n) represents the field strength magnitude at the nth position.

[0244] According to the voltage distribution array obtained from the simulation calculation and the array in the tissue depth direction, the field strength magnitude array in the tissue depth direction can be obtained according to the above calculation formula.

[0245] In an implementable case, the system device for implementing the acquisition method of this embodiment can support multiple discharge modes of the catheter electrode (or ablation electrode), including bipolar discharge. For the annular electrode catheter type, the ablation depth prediction can be performed in the case of a pair of electrode discharges, and the depth prediction can also be performed in the case of multiple pairs of electrodes discharging simultaneously; it also supports the unipolar discharge form, with the catheter electrode connected to the positive and the back plate connected to the negative. In the tissue ablation numerical model, the distance between the catheter and the back plate can be adjusted according to the actual situation. In addition, when discharging unipolar, the number of catheter electrodes connected can be adjusted according to the user.

[0246] During the ablation process, the electric field strength is the largest at the surface of the electrode. Since the conductivity of the tissue is much smaller than that of the electrode, when the electric field passes through the tissue, the field strength decays exponentially. By comparing and analyzing different discharge forms, such as Figure 11 as shown, the field strength distribution at different cross-sections of the ablated tissue is described. The horizontal axis represents the depth information (mm) along the tissue cross-section, and the vertical axis represents the field strength magnitude (V / cm). Here, the tissue surface is used as the starting coordinate.

[0247] In an implementable case, the system device is used in conjunction with a circular electrode catheter with multiple electrodes. The electrode spacing of the electrode catheter is 4 mm. After establishing a three-dimensional model consistent with the ablation electrode parameters and selecting the discharge form (for example, bipolar discharge, one electrode is positive and one electrode is grounded), the applied voltage (300V - 3000V) is determined. Based on the distribution of different displacement magnitudes and field strength magnitudes at any tissue interface, the field strength magnitude is fitted according to the fitting function to obtain the first fitting function.

[0248] Specifically, the calculation formula corresponding to the step of establishing the first fitting function between different tissue depth information and the corresponding field strength values is as follows:

[0249]

[0250] where E 1 is the field strength value of the ablated tissue at the tissue depth information x at the electrode, E 2 is the field strength value of the ablated tissue at the tissue depth information x in the middle of the two electrodes, k 1 U, k 3 U respectively represent the fitting values of the maximum field strength values at the position directly below the electrode at the tissue surface and the position in the middle of two adjacent positive and negative electrodes. U represents the pulsed voltage applied to the ablated tissue, k 1 , k 2 , k 3 , k 4 are all fitting coefficients. The fitting coefficients of the first fitting function are associated with different pulsed discharge forms, and x represents the tissue depth information;

[0251] Under the same discharge form, in the above function expression of the tissue field strength, the fitting coefficient values of the tissue field strength at the electrode and in the middle of the electrodes will be different. Under different discharge forms, the fitting coefficients in the function relationship for calculating the field strength magnitude will be different.

[0252] For example, in the ablation tissue simulation calculation model, taking the bipolar discharge mode of a pair of electrodes as an example, the implementation process of the ablation depth prediction method is described:

[0253] Based on the above pulse parameters, the pulse width τ = 5 μs, the number of pulses in a pulse train n = 20, the total number of ablation pulse trains N = 200, and the field strength threshold calculated under these pulse parameters is 467.5 V / cm.

[0254] In the annular electrode, the electrode in sequence 1 is connected to the positive pole, the electrode in sequence 2 is connected to the negative pole, and bipolar discharge occurs between a pair of electrodes. The positive pole voltage value U is set + = 1200 V, the negative pole is in the grounded state, and U - = 0.

[0255] Combined with the boundary condition settings of the above simulation calculation, the numerical model is simulated. After the calculation is completed, the cross-section along the tissue depth direction directly below the electrode is obtained, and the electric field strength distribution curve along the depth direction displacement from the tissue surface is obtained. The distribution curve is fitted with a function to obtain the corresponding relationship between the depth displacement and the field strength magnitude.

[0256]

[0257] For the voltage value U = 1200 V, the corresponding fitting coefficient k 1 = 3.22; the fitting coefficient k 2 = 0.54.

[0258] Similarly, the cross-section along the tissue depth direction directly below the middle of the positive and negative electrodes is obtained, and the electric field strength distribution curve along the depth direction displacement from the tissue surface is obtained. The distribution curve is fitted with a function to obtain the corresponding relationship between the depth displacement and the field strength magnitude.

[0259]

[0260] For the voltage value U = 1200 V, the corresponding fitting coefficient k 3 = 1.22; the fitting coefficient k 4 = 0.31.

[0261] For the same ablation tissue object and the same discharge mode, if the pulse voltage changes, the fitting coefficients (k 1 , k 2 , k 3 , k 4 ) of the electric field strength distribution do not change accordingly. If the discharge form is changed, the fitting coefficients need to be refitted according to the field strength distribution results under the new discharge mode.

[0262] For different ablation individuals, due to the difference in conductivity values, for the same discharge mode as above, the fitting coefficients (k 1 , k 2 , k 3 , k 4 ) of the electric field strength distribution will also be different.

[0263] S106214. Obtain the intermediate ablation depths in the depth direction at the positions of different electrodes in the ablation electrode respectively according to the first fitting function and the electric pulse field strength threshold.

[0264] S106215. Calculate the predicted ablation depth in the depth direction of the tissue surface of the ablated tissue under the set pulse parameters according to the different intermediate ablation depths.

[0265] The field strength value is the largest at the electrode surface and smaller at the middle of the electrode. Therefore, the tissue field strength values at different positions are different, but their change trends along the tissue cross-section direction are the same. The field strength is the largest at the tissue surface, and then along the depth direction, the field strength magnitude decays exponentially. Take the ablation depth of the tissue below the electrode as the maximum value, take the ablation depth of the tissue at the middle of the electrode as the minimum value, and take the average of the two as the ablation depth of all tissues.

[0266] Specifically, according to the first fitting function and the electric pulse field strength threshold, obtain the intermediate ablation depths in the depth direction at different positions on the surface of the ablated tissue respectively, and the calculation formula corresponding to the step of calculating the predicted ablation depth in the depth direction of the tissue surface of the ablated tissue under the set pulse parameters according to the different intermediate ablation depths is as follows:

[0267]

[0268] Among them, depth represents the predicted ablation depth, and E th represents the electric pulse field strength threshold, and the tissue depth information x on the surface of the ablated tissue takes the value of 0. Of course, the tissue depth information x on the surface of the ablated tissue can also be other constants, which can be designed and adjusted according to actual needs.

[0269] For example: According to the fitting result of the field strength in the depth direction obtained above and the field strength threshold under the set pulse parameters, substitute the obtained fitting coefficients (k 1 、k 2 、k 3 、k 4 ) and E th into the depth calculation equation, that is

[0270]

[0271] Based on the above formula, determine the pulsed electric field ablation parameters, compare and analyze the predicted ablation depth with the historical ablation depth measured in the historical database, and draw a curve graph, as Figure 12 shown. In the figure, the function relationship of y = x is used for curve fitting, and the correlation coefficient R 2= 0.96, indicating that there is a good linear correlation between the predicted ablation depth value obtained by this prediction method and the experimentally measured value.

[0272] In an implementable case, to reduce the ablation time and improve efficiency, multiple pairs of electrodes are selected to discharge simultaneously; after establishing a three-dimensional model consistent with the catheter electrode parameters and selecting the discharge form (multiple pairs of electrodes discharge simultaneously, n / 2 electrodes are connected to the positive pole, n / 2 electrodes are connected to the negative pole, where n is the total number of electrodes; or, select the monopolar discharge mode, n electrodes are connected to the positive pole simultaneously, and the back plate is connected to the negative pole), determine the applied voltage (for example, 300V - 3000V), and then perform numerical calculation of the electric field strength distribution.

[0273] After the calculation is completed, since ablation regions are generated at multiple positions, that is, the tissue ablation depth under the above electrodes includes the tissue depths under 2 or more electrodes, and the tissue directly under the electrodes can include the positions of the positive and negative electrodes, and the tissue ablation depth at the middle of the above electrodes includes the tissue depths at the middle of 2 or more electrodes. For the phenomenon of multiple pairs of electrodes discharging simultaneously, the ablation depth value is the average of all values of the tissue ablation depths directly under the multiple electrodes and the tissue ablation depths at the middle of the multiple electrodes. The specific calculation principle is similar to that of the case of a pair of electrodes, so it will not be elaborated here.

[0274] In this embodiment, the electric pulse field strength threshold under this pulse parameter is calculated based on the set pulse parameters and the fitting function of the electric pulse field strength threshold; an ablation numerical model is constructed based on the ablation electrode parameters in the ablation catheter to obtain the field strength distribution information corresponding to the ablation tissue in the tissue depth direction and the tissue width direction; the electric pulse field strength threshold is used to draw the field strength isolines to predict the ablation boundary; based on the field strength distribution information in the tissue depth direction and the electric pulse field strength threshold, the predicted ablation depth under the predicted ablation boundary is finally obtained, and based on the field strength distribution information in the tissue width direction and the electric pulse field strength threshold, the predicted ablation region under the predicted ablation boundary is finally obtained, effectively improving the prediction accuracy and efficiency of the ablation parameters corresponding to the pulse parameters, being applicable to monopolar and bipolar ablation methods, providing reasonable guidance for pulse parameter settings for surgeons, and improving the ablation effect.

[0275] Example 3

[0276] The method for obtaining the pulse ablation parameters in this embodiment is a further improvement of Example 2. Specifically:

[0277] As Figure 13As shown in the figure, an electric field is formed around the electrodes, and the electric field radiates to the tissue. For the ablated tissue, the field strength at the tissue surface is the largest, and the ablation area at the tissue surface is taken as the ablation lesion surface area (i.e., the predicted ablation boundary). On the tissue surface, the field strength in contact with the electrode is relatively large, while the field strength in the tissue between the two electrodes is slightly weaker. Therefore, the electrode width is not completely uniform. The average of the ablation width directly below the electrode and the ablation width below the middle of the electrode is taken as the average width of the ablation lesion on the tissue surface.

[0278] The electric field strength at the electrode reaches its maximum value at the center of the electrode, and radiates outward from the center of the electrode. At the surface of the tissue, the electric field strength gradually weakens as the distance from the center of the electrode increases. The electric field strength in the middle of the electrode reaches its maximum value at the position closest to the edge of the electrode, and gradually weakens along the up and down width directions. According to the above-constructed numerical model of tissue ablation, the cross-section passing through the electrode and the cross-section passing through the middle of the electrode are drawn respectively, and the field strength distribution on this cross-section with the displacement size is obtained. Specifically, the field strength distribution in the ablation width direction is characterized, the horizontal axis represents the displacement in the width direction (mm), and the vertical axis represents the field strength (V / cm).

[0279] After obtaining the displacement in the width direction, the displacement at the maximum field strength (i.e., tissue width information) is obtained by solving the maximum value equation E(w_max)=max(E), and the displacement in the width direction is translated, w=w-w_max, so that the field strength corresponding to the origin of the displacement coordinate is the maximum, as shown in Figure 8 The negative coordinate on the horizontal axis represents the width of the maximum field strength point toward the center of the catheter, and the positive coordinate on the horizontal axis represents the width of the maximum field strength point in the opposite direction of the catheter center, and the predicted ablation area is the sum of the two.

[0280] After obtaining the field intensity distribution in the width direction, the field intensity is fitted according to the fitting function to obtain a third fitting function.

[0281] like Figure 14 As shown, step S1062 includes:

[0282] S106221, obtaining a first tissue section line of the ablated tissue corresponding to the positions of different electrodes in the ablation electrode along the tissue width direction;

[0283] S106222. Based on the field intensity distribution information corresponding to the first tissue section line, obtain field intensity values ​​corresponding to different tissue width information;

[0284] S106223, establishing a third fitting function between different tissue width information and corresponding field strength values;

[0285] Specifically, the calculation formula corresponding to the step of establishing the third fitting function between different tissue width information and the corresponding field strength values is as follows:

[0286]

[0287] Among them, E 3 represents the field strength value of the ablated tissue at the electrode in the width displacement, E 4 represents the field strength value of the ablated tissue in the width displacement at the middle between two adjacent electrodes, w represents the displacement magnitude, U represents the pulse voltage, and p1 to p8 all represent fitting coefficients.

[0288] Under the same discharge form, in the above function expression of the tissue field strength, the fitting coefficient values of the tissue field strength at the electrode and in the middle of the electrode will be different. The correlation coefficient between the fitting function and the original value needs to satisfy: R 2 ≥0.95.

[0289] S106224. Obtain the corresponding middle ablation regions at the positions of different electrodes in the ablation electrode according to the third fitting function and the electric pulse field strength threshold;

[0290] S106225. Calculate the predicted ablation region corresponding to the surface of the ablated tissue under the set pulse parameters according to different middle ablation regions.

[0291] For example, in the ablation tissue simulation calculation model, taking the bipolar discharge mode of a pair of electrodes as an example, describe the implementation process of the ablation tissue surface ablation width prediction method:

[0292] Based on the above pulse parameters, the pulse width τ = 5 μs, the number of pulses n in a pulse train = 20, the total number of ablation pulse trains N = 200, and the field strength threshold calculated under these pulse parameters is 467.5 V / cm.

[0293] In the annular electrode, the electrode in sequence 1 is connected to the positive pole, the electrode in sequence 2 is connected to the negative pole, and a pair of electrodes performs bipolar discharge. Set the positive pole voltage value U + = 1200 V, the negative pole is in the grounded state, and U - = 0.

[0294] Combined with the boundary condition settings of the above simulation calculation, perform simulation calculation on the numerical model. After the calculation is completed, obtain the cross-section of the tissue surface directly below the electrode, obtain the tissue surface electric field intensity distribution map, select a certain position point directly below the electrode, draw the intercept line passing through the center of the annular electrode and this point, obtain the field strength distribution curve of the tissue along this intercept line, perform function fitting on this electric field intensity curve, and obtain the corresponding relationship between the width displacement and the field strength magnitude:

[0295]

[0296] The voltage value U = 1200V, and the corresponding fitting coefficient p is obtained. 1 = 2.37; The fitting coefficient p 2 = 2.13×10 -10 ; The fitting coefficient p 3 = 2.66; The fitting coefficient p 4 = 168.4.

[0297] Similarly, take a position point directly below the middle of the positive and negative electrodes, draw a cross-section line passing through the center of the ring electrode and this point, obtain the field strength distribution curve of the tissue along this cross-section line, perform function fitting on this electric field strength curve, and obtain the corresponding relationship between the width displacement and the field strength magnitude:

[0298]

[0299] The voltage value U = 1200V, and the corresponding fitting coefficient p is obtained. 5 = 1.03; The fitting coefficient p 6 = 7.88×10 -9 ; The fitting coefficient p 7 = 3.9; The fitting coefficient p 8 = 77.94.

[0300] For the same ablation tissue object, in the same discharge mode, if the pulsed voltage changes, the fitting coefficients (p1 - p8) of the electric field strength distribution do not change accordingly. If the discharge form is changed, the fitting coefficients need to be refitted according to the field strength distribution results in the new discharge mode.

[0301] For different ablation individuals, due to the difference in conductivity values, in the above-mentioned same discharge mode, the fitting coefficients (p1 - p8) of the electric field strength distribution will also be different. Specifically, according to the third fitting function and the electric pulse field strength threshold, the corresponding intermediate ablation regions at different electrode positions in the ablation electrode are obtained respectively, and the calculation formula corresponding to the step of calculating the predicted ablation region corresponding to the surface of the ablation tissue under the set pulse parameters is as follows:

[0302]

[0303] Among them, wide 1 and wide 2 respectively represent different intermediate ablation regions, wide represents the predicted ablation region, and E th represents the electric pulse field strength threshold.

[0304] For example, according to the fitting results of the field strength in the width direction obtained above, and the field strength threshold under the set pulse parameters, the obtained fitting coefficients (p1 - p8) and Eth Substitute it into the depth calculation equation, that is

[0305]

[0306] In the solution of an embodiment, it is a multi-pair electric simultaneous discharge mode. After establishing a three-dimensional model consistent with the catheter electrode parameters and selecting the discharge form (multi-pair electrodes discharge simultaneously, n / 2 electrodes are connected to the positive, n / 2 electrodes are connected to the negative, where n is the total number of electrodes; or, select the monopolar discharge mode, n electrodes are connected to the positive simultaneously, and the back plate is connected to the negative), determine the applied voltage (for example, 300V to 3000V), and then perform numerical calculation of the field strength distribution.

[0307] After the calculation is completed, since ablation zones are generated at multiple positions, the ablation width on the tissue surface below the above electrodes includes the ablation widths below 2 or more electrodes. The ablation width directly below the electrodes can include the positive electrode and negative electrode positions. The ablation width on the tissue surface at the middle of the above electrodes includes the ablation widths at the middle of 2 or more electrodes. For the phenomenon of multi-pair electrodes discharging simultaneously, the ablation width value on the tissue surface is the average value of the sum of all ablation widths of the ablation widths below the positive electrodes of multiple electrodes and the ablation widths at the middle of multiple electrodes obtained.

[0308] Taking the center line of the catheter electrode as the baseline, draw the ablation area contour lines above and below the baseline according to the calculated ablation width, as Figure 15 shown. Given that the circular radius where the catheter electrode is located is r0, the circular radius of the outer contour is r0 + wide / 2; the circular radius of the inner contour is r0 - wide / 2. Then the ablation area on the tissue surface can be approximately calculated as:

[0309] S = ε·2π·r 0 ·wide = (r 0 ·θ + wide)·wide

[0310] where ε is the ratio of the arc length participating in the formation of the ablation area to the circumference of the circle where the electrode center is located, that is, ε = (r 0 ·θ + wide) / (2π·r 0 ), θ is the arc angle formed by all the electrodes participating in ablation in the circular electrode under the selected discharge mode, and it depends on the number of electrodes participating in ablation.

[0311] For example, for the circular electrode used in combination, the circular radius where the catheter electrode is located is 13mm, one pair of electrodes, and the formed arc angle is 45°. Substitute the ablation width value on the tissue surface obtained according to the above calculation into the calculation formula of the ablation area on the tissue surface ablation area, that is

[0312]

[0313] In the solution of an embodiment, the acquisition method in this embodiment further includes:

[0314] Based on the predicted ablation region and the predicted ablation depth corresponding to the predicted ablation boundary, a three-dimensional ablation model corresponding to the predicted ablation boundary is constructed.

[0315] As Figure 16 and 17 shown, according to the tissue surface ablation surface area S (predicted ablation region) and the predicted ablation depth calculated above, the volume of the entire ablation region can be approximately calculated as:

[0316]

[0317] For example, according to the ablation depth in the tissue depth direction and the ablation area on the tissue surface calculated above, substituting them into the calculation formula of the ablation region volume, that is

[0318]

[0319] It can intuitively present the three-dimensional shape corresponding to the ablation region, which is convenient for doctors or patients to view and understand, and effectively improves the treatment experience of patients.

[0320] In the solution of an embodiment, the acquisition method further includes:

[0321] Based on the predicted ablation depth and the target ablation depth under the set pulse parameters, the fitness value corresponding to the predicted ablation depth is calculated using the genetic algorithm;

[0322] When the fitness value does not meet the preset conditions, selection, crossover, and mutation processing are sequentially performed to generate a new pulse parameter combination;

[0323] When the fitness value corresponding to the pulse parameter combination meets the preset conditions, the set pulse parameters are updated using the pulse parameter combination.

[0324] Specifically, according to the ideal ablation depth value fed back externally, comparing it with the calculated predicted ablation depth, and based on the genetic algorithm, the set pulse parameters are optimized. The parameters to be optimized include pulse width τ, number of pulses n, number of pulse trains N, and pulse voltage U; among them, the objective function is f(X):

[0325]

[0326] Wherein, d is the predicted ablation depth, D is the ideal target ablation depth, the value range of the pulse width τ is 0.1 to 50 us; the value range of the number of pulses n in a string is 1 to 100; the number of pulse trains N ranges from 1 to 200; the voltage ranges from 200 to 2000 V, and the objective function value is required to be the smallest and greater than 0.

[0327] Fitness is an index to judge the quality of individuals in a population. The genetic algorithm selects individuals according to the magnitude of the individual fitness value, so as to realize the optimization of parameters. The determination of the fitness function lies in that when the function value is the largest, it is closest to the ideal target ablation depth, and its fitness function is:

[0328]

[0329] In the formula, when the predicted ablation depth is less than the ideal target ablation depth, the fitness function value is less than 1; when the predicted ablation depth is greater than the ideal target ablation depth, the fitness function value is greater than 1. In order to reduce the damage to other tissues, the predicted ablation depth should be greater than and as close as possible to the ideal target ablation depth. According to the above expression of the fitness function, the fitness value should be made as large as possible.

[0330] As Figure 18 shown, the process of optimizing pulse parameters based on the genetic algorithm generally includes:

[0331] S1. Obtain the initial random pulse parameter population (including pulse width, number of pulses, number of pulse trains, pulse voltage);

[0332] S2. Evaluate the fitness value of the current pulse parameter population using the fitness function;

[0333] S3. When the fitness value does not reach the expected value and / or the number of iterations does not reach the maximum value, perform selection, crossover, and mutation processing on the pulse parameter population in turn to generate a new pulse parameter combination, and return to step S2 until the fitness reaches the expected value or the number of iterations reaches the maximum value, output the current pulse parameter combination, and use this pulse parameter combination as the set pulse parameter corresponding to the pulse generator.

[0334] The set pulse parameters optimized by the genetic algorithm can ensure that the ablation area corresponding to the pulse energy output by the pulse generator using this pulse parameter combination is within the target ablation depth range, thus effectively improving the ablation effect and accuracy.

[0335] In addition, how to fuse the initial pulse parameters with the genetic algorithm to calculate the corresponding optimized pulse parameters belongs to the mature technology in this field, so it will not be elaborated here.

[0336] In the above genetic algorithm, the operating parameters include the population size Size, the total number of generations G of evolution, the crossover probability Pc, and the mutation probability Pm. The value range of the population size Size is 20 to 100; the value range of the number of generations G of evolution is 100 to 500; the value range of the crossover probability Pc is 0.4 to 0.99, and the value range of the mutation probability Pm is 0.0001 to 0.1. Of course, the values of the above parameters can be re-determined and adjusted according to the actual situation to be applicable to different actual application scenarios.

[0337] In this embodiment, the electric pulse field strength threshold under the pulse parameter is calculated based on the set pulse parameter and the fitting function of the electric pulse field strength threshold; an ablation numerical model is constructed based on the ablation electrode parameters in the ablation catheter to obtain the field strength distribution information corresponding to the ablation tissue in the tissue depth direction and the tissue width direction; the electric pulse field strength threshold is used to draw the field strength contour line to predict the ablation boundary; based on the field strength distribution information in the tissue depth direction and the electric pulse field strength threshold, the predicted ablation depth under the predicted ablation boundary is finally obtained, and based on the field strength distribution information in the tissue width direction and the electric pulse field strength threshold, the predicted ablation area under the predicted ablation boundary is finally obtained, effectively improving the prediction accuracy and efficiency of the ablation parameters corresponding to the pulse parameters, being applicable to the ablation methods of single and bipolar, providing reasonable guidance for pulse parameter setting for surgeons, and improving the ablation effect; a three-dimensional ablation model corresponding to the predicted ablation boundary is constructed based on the predicted ablation depth and the predicted ablation area, which can intuitively present the three-dimensional shape corresponding to the ablation area, facilitating doctors or patients to view and understand, and enhancing the user experience.

[0338] Embodiment 4

[0339] As Figure 19 shown, the acquisition system of the pulse ablation parameters in this embodiment includes:

[0340] A pulse parameter acquisition module 1 for acquiring set pulse parameters;

[0341] Among them, the set pulse parameters include but are not limited to the set pulse width, the set number of pulses in a pulse train, the set number of pulse trains, the pulse voltage, and the pulse duty cycle.

[0342] The set pulse parameters are input through the operation interface of pulse output devices such as pulse generators. Taking a pulse generator as an example, the pulse structure can be set to a single-phase structure and a bipolar structure; the discharge form can also be switched, and the discharge form is divided into bipolar discharge and monopolar discharge. In the bipolar discharge mode, there are both positive and negative electrodes in the ablation electrode (also called catheter electrode), and an electric circuit is formed between the positive and negative electrodes; in the monopolar discharge mode: the ablation electrode is connected to the positive, and the back plate attached to the back is connected to the negative, and an electric circuit is formed between the electrode and the back plate. Taking the bipolar pulse structure as an example, as Figure 2As shown, it is the output pulse structure of the pulse generator. The horizontal axis represents time t (unit: second s), and the vertical axis represents voltage v(t).

[0343] Among them, the electric potential at the positive electrode of the ablation electrode is consistent with the pulse voltage and pulse structure of the pulse generator. As Figure 2 shown, U + = v(t), the negative electrode is in a grounded state, and U - = 0.

[0344] The setting positions of the positive and negative electrodes in the ablation electrode correspond to the pulse discharge form; in the bipolar discharge form, the polarities of adjacent electrodes are opposite; in the monopolar discharge form, all electrodes in the ablation catheter are positive electrodes, and the back plate is the negative electrode.

[0345] The electric pulse field strength threshold determination module 2 is used to determine the electric pulse field strength threshold of the ablation tissue under the set pulse parameters;

[0346] The electrode parameter acquisition module 3 is used to acquire the electrode parameters corresponding to the ablation electrodes in the ablation catheter, and the ablation electrodes are attached to the surface of the ablation tissue;

[0347] The ablation model construction module 4 is used to construct a tissue ablation numerical model based on the set pulse parameters and electrode parameters;

[0348] The field strength distribution information acquisition module 5 is used to acquire the field strength distribution information corresponding to the ablation tissue according to the tissue ablation numerical model;

[0349] The predicted ablation parameter acquisition module 6 is used to acquire the predicted ablation parameters corresponding to the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold;

[0350] Among them, the predicted ablation parameters include the predicted ablation depth and / or the predicted ablation area.

[0351] In this embodiment, the electric pulse field strength threshold under the pulse parameters is calculated by fitting a function based on the set pulse parameters and the electric pulse field strength threshold; an ablation numerical model is constructed based on the ablation electrode parameters in the ablation catheter to obtain the field strength distribution information corresponding to the ablation tissue in the tissue depth direction and the tissue width direction; the electric pulse field strength threshold is used to draw field strength contour lines to predict the ablation boundary; based on the field strength distribution information in the tissue depth direction and the electric pulse field strength threshold, the predicted ablation depth under the predicted ablation boundary is finally obtained, and based on the field strength distribution information in the tissue width direction and the electric pulse field strength threshold, the predicted ablation area under the predicted ablation boundary is finally obtained, effectively improving the prediction accuracy and efficiency of the ablation parameters corresponding to the pulse parameters, providing reasonable guidance for the pulse parameter setting for the surgeon, and improving the ablation effect.

[0352] Embodiment 5

[0353] As Figure 20 shown, the acquisition system for pulse ablation parameters in this embodiment is a further improvement on Embodiment 4. Specifically:

[0354] Considering that the main factors affecting the electric field strength threshold include pulse width, the number of intra-burst pulses in a pulse train, and the number of pulse trains, different combinations of pulse width, the number of intra-burst pulses, and the number of pulse trains corresponding to the electric pulse field strength threshold are pre-stored in the database, and a data list is established according to the corresponding relationship between different parameter combinations and the electric pulse field strength threshold for use in establishing a fitting function, so that the electric pulse field strength threshold corresponding to any pulse parameter combination can be obtained in combination with this fitting function.

[0355] Specifically, as Figure 3a shown, for the corresponding relationship between pulse width and the electric pulse field strength threshold, the horizontal axis represents the pulse width, with the unit log(t) / us, and the vertical axis represents the field strength threshold, with the unit V / cm; as Figure 3b shown, the horizontal axis represents the pulse duration, T / us, and the vertical axis represents the field strength threshold, with the unit V / cm.

[0356] When the total duration T of the pulse action remains consistent, the electric pulse field strength threshold will show differences due to different pulse width values, and the electric pulse field strength threshold decreases as the pulse width τ increases; when the pulse width τ remains consistent, the electric pulse field strength threshold will change with the change of the pulse release time T, and the electric pulse field strength threshold decreases as the pulse duration increases.

[0357] It can be known that the change trends of the electric pulse field strength threshold with pulse width and pulse release time are approximate, decreasing with the increase of the variable, and both will reach a saturation value, that is, when the variable increases to a certain value, the electric pulse field strength threshold is basically unchanged. When the pulse width and pulse release time respectively take the saturation values, the corresponding electric pulse field strength threshold is set as E 0 ; K 1 (τ) is the influence coefficient of the pulse width on the electric pulse field strength threshold when the pulse release time is in the saturation state; K 2 (n) is the influence coefficient of the pulse release time on the threshold when the pulse width is in the saturation state.

[0358] Specifically, the calculation formula corresponding to the steps for the electric pulse field strength threshold determination module 2 to determine the electric pulse field strength threshold is as follows:

[0359]

[0360] Among them, E th represents the electric pulse field strength threshold, E 0Indicates the critical electric field strength of irreversible electroporation when both the pulse width and pulse dose are in the saturation state. τ represents the set pulse width, T is the total pulse release time, T = τ * n * N, n represents the number of pulses in the set train, N represents the number of set pulse trains, and A 1 、B 1 、C 1 、A 2 、B 2 、C 2 are all fitting coefficients. Specifically, A 1 、B 1 、C 1 、A 2 、B 2 、C 2 are all fitting parameters determined according to the fitting accuracy coefficient R 2 > 0.95.

[0361] In the solution of an implementable embodiment, the electrode parameters include but are not limited to electrode geometric parameters, electrode material property parameters, and material property information of the insulating part between the electrodes; the electrode geometric parameters include but are not limited to electrode diameter information, electrode length information, and electrode spacing information.

[0362] Among them, for the ablation electrodes corresponding to different types of ablation catheters, the corresponding electrode parameters are all set fixed parameters. When using a certain ablation catheter, the corresponding electrode parameters can be directly obtained according to the product description information.

[0363] The tissue ablation numerical model is used to simulate the actual ablation scenario corresponding to the ablation electrode of the ablation catheter and the ablation tissue. As Figure 5 shown, taking the ablation electrode M1 as a ring electrode as an example, the geometric parameters include: the radius of the ablation electrode is 0.85 mm, the electrode length is 3 mm, and the distance between the two electrode end faces is 4 mm; the material properties include: the electrode material is platinum, and the middle of the electrode is an insulating material. A total of 9 electrodes are arranged, and the tissue ablation numerical model is constructed according to the geometric parameters and material properties of the ring electrode.

[0364] In the solution of an implementable embodiment, when the ablation electrode includes a pair of electrodes, the positions where different electrodes are located in the ablation electrode respectively correspond to the positions directly below the two electrodes in the pair of electrodes and the positions in the middle between two adjacent electrodes.

[0365] In the solution of an implementable embodiment, when the ablation electrode includes multiple pairs of electrodes, the positions where different electrodes are located in the ablation electrode respectively correspond to the positions directly below each electrode in each pair of electrodes and the positions in the middle between two adjacent electrodes in each pair of electrodes.

[0366] Specifically, as Figure 5As shown, the gray areas correspond to different electrodes, and the tissue below the electrode is the tissue directly below the electrode; the white areas are the insulating gaps between adjacent electrodes, and the tissue directly below the middle of the two electrodes is the tissue directly below the middle of the two electrodes.

[0367] When the tissue to be ablated is myocardial tissue, the ablation electrode is placed in the blood and abuts against the myocardial tissue. As Figure 6 shown, the corresponding tissue ablation numerical model for the myocardial tissue, where M1 represents the ablation electrode, M2 represents the blood, and M3 represents the myocardial tissue.

[0368] In addition, the boundary of the tissue ablation numerical model is set to be electrically insulated; where J·n = 0, J represents the current density inside the model, and n represents the normal vector of the tissue boundary.

[0369] The acquisition system of this embodiment further includes:

[0370] A historical data acquisition module 7 for acquiring a plurality of groups of historical intensity values corresponding to the ablated tissue and the historical conductivity corresponding to the historical intensity values;

[0371] A conductivity model construction module 8 for plotting the conductivity values under different electric field strengths according to each group of historical electric field intensity values and historical conductivity, and performing function fitting on the curve of the conductivity changing with the electric field intensity to construct a dynamic conductivity model of the conductivity changing with the field strength;

[0372] Among them, the model fitting parameters of the dynamic conductivity model are adaptively adjusted according to different ablated tissues. The adjustable model fitting parameters of the dynamic conductivity model include the initial conductivity and the model fitting coefficient;

[0373] The dynamic conductivity model is used to output the conductivity corresponding to the ablated tissue.

[0374] In an implementable case, since electroporation occurs in the tissue during the electro-pulse ablation process, the conductivity of the tissue will change as the perforation process continues. Therefore, the conductivity of the tissue needs to be set as a dynamic parameter. Since in irreversible electroporation, the conductivity changes as the perforation process continues, considering that during the ablation process, saline flushing will be carried out and the tissue temperature change is small, and the conductivity change is mainly affected by the electric field strength; in order to improve the calculation efficiency, the influence of tissue temperature rise can be ignored, and a dynamic conductivity model changing with the electric field strength can be constructed. As Figure 7 shown, the fitting curve representing the conductivity changing with the field strength, the horizontal axis represents the electric field strength (V / cm), and the vertical axis represents the conductivity (S / m). When the electric field strength is very small and not enough to cause tissue electroporation, the measured conductivity is the initial conductivity σ 0, when the electric field strength is large enough, the pulsed electric field acts on the tissue. When the measured current value tends to be stable, the conductivity measured at this time is the maximum conductivity σ of the tissue max .

[0375] Read the conductivity at different electric field strengths from the database. Based on the existing historical experimental data, plot the conductivity at different electric field strengths and fit the conductivity curve to obtain the dynamic conductivity model.

[0376] Specifically, the calculation formula corresponding to the steps of the conductivity model construction module 8 for constructing the dynamic conductivity model is as follows:

[0377]

[0378] Among them, σ 0 represents the initial conductivity of the ablated tissue, generally taken as 0.2 - 0.4 S / m, and σ max represents the maximum conductivity when all of the ablated tissue undergoes electroporation. σ max = C 3 * σ 0 ; generally 3 - 4 times of σ 0 , E del represents the field strength value corresponding to the center point of the transition region from the start of the change in conductivity to the stable value, generally taken as 500 - 700 V / cm, and E represents the field strength value corresponding to the field strength distribution information. A 3 , B 3 , C 3 are respectively model fitting parameters, and the specific selection of these parameters can be determined or adjusted according to the actual situation.

[0379] The field strength distribution information acquisition module 5 of this embodiment includes:

[0380] The potential information acquisition unit 9 is used to acquire the potential information inside the tissue ablation numerical model;

[0381] The field strength distribution information calculation unit 10 is used to calculate the field strength distribution information corresponding to the ablated tissue based on the potential information and the conductivity.

[0382] Specifically, the calculation formula corresponding to the steps of the field strength distribution information calculation unit 10 for calculating the field strength distribution information corresponding to the ablated tissue is as follows:

[0383]

[0384] Among them, E represents the field strength distribution information, represents the potential information, σ is the conductivity of the ablated tissue, and ε 0 is the vacuum permittivity, and ε r is the relative permittivity of the ablated tissue.

[0385] Among them, the electric field strength distribution is mainly determined by the voltage corresponding to the pulse parameters, the electrode spacing, the electrode size, the discharge form, etc. During the actual application process, the ablation parameter prediction involved in this embodiment is used in cooperation with a finalized ablation catheter. For the same ablation catheter, its electrode spacing and electrode size are in a fixed state. Therefore, by pre-storing the electrode parameters of the catheter used in supporting, for different ablation electrodes, the calculation of the electric field strength distribution and the prediction of ablation parameters (including the ablation area and ablation depth) are carried out respectively.

[0386] The prediction ablation parameter acquisition module 6 of this embodiment includes:

[0387] An ablation boundary prediction unit 11, configured to process the electric field strength distribution information by using an electric pulse field strength threshold, draw an electric field strength contour line, and use the area enclosed by the electric field strength contour line as the predicted ablation boundary;

[0388] Specifically, as Figure 8 shown, for the annular electrode, P represents the ablation catheter, N1 represents the positive electrode, N2 represents the negative electrode, N3 corresponds to the insulating material part between the positive and negative electrodes, and L1 represents the electric pulse field strength threshold contour line.

[0389] A prediction ablation parameter calculation unit 12, configured to obtain the predicted ablation parameters corresponding to the predicted ablation boundary of the ablation tissue under the set pulse parameters based on the electric field strength distribution information and the electric pulse field strength threshold.

[0390] Specifically, the prediction ablation parameter calculation unit 12 of this embodiment includes:

[0391] A tissue cross-section acquisition subunit, configured to acquire a first tissue cross-section of the ablation tissue corresponding to different electrode positions in the ablation electrode along the tissue depth direction;

[0392] A depth electric field strength value acquisition subunit, configured to acquire the electric field strength values corresponding to different tissue depth information based on the electric field strength distribution information corresponding to the first tissue cross-section;

[0393] A first fitting function establishment subunit, configured to establish a first fitting function between different tissue depth information and the corresponding electric field strength values;

[0394] After the calculation of the tissue ablation numerical model, that is, the simulation model, is completed, the potential distribution situation (i.e., the electric field strength distribution information) on any tissue cross-section in the tissue depth direction can be obtained. Among them, any tissue cross-section includes the tissue cross-section directly below the electrode and the tissue cross-section directly below the middle of the electrodes. The voltage shows a decreasing trend in the tissue depth direction, as Figure 10As shown, a corresponding relationship diagram between the displacement in the tissue depth direction (i.e., tissue depth information) and the voltage distribution is drawn. The horizontal axis represents the displacement (mm) along the tissue depth direction, and the vertical axis represents the voltage value (V).

[0395] According to the above relationship formula between the field strength and the potential distribution, the magnitude of the field strength at the displacement can be calculated based on the potential distribution data, and its calculation formula is:

[0396]

[0397] U(n + 1) and U(n) respectively represent the voltage values at two positions, d(n + 1) and d(n) respectively represent the tissue depth information at two positions, and E(n) represents the magnitude of the field strength at the n position.

[0398] According to the voltage distribution array obtained by simulation calculation and the array in the tissue depth direction, the array of the magnitude of the field strength in the tissue depth direction is obtained according to the above calculation formula.

[0399] In an implementable case, the system device for implementing the acquisition method of this embodiment can support multiple discharge modes of the catheter electrode (or ablation electrode), including bipolar discharge. For the annular electrode catheter type, the ablation depth prediction can be performed in the case of a pair of electrode discharges, and the depth prediction can also be performed in the case of multiple pairs of electrodes discharging simultaneously; it also supports the monopolar discharge form, with the catheter electrode connected to the positive and the back plate connected to the negative. In the tissue ablation numerical model, the distance between the catheter and the back plate can be adjusted according to the actual situation. In addition, when discharging monopolarly, the number of catheter electrodes connected can be adjusted according to the user.

[0400] During the ablation process, the electric field strength at the electrode surface is the largest. Since the conductivity of the tissue is much smaller than that of the electrode, when the electric field passes through the tissue, the magnitude of the field strength decays exponentially. By comparing and analyzing different discharge forms, as Figure 11 shown, the field strength distribution at different cross-sections of the ablated tissue is shown. The horizontal axis represents the depth information (mm) at the tissue cross-section, and the vertical axis represents the magnitude of the field strength (V / cm), where the tissue surface is used as the starting coordinate.

[0401] In an implementable case, the system device is used in combination with a circular electrode catheter with multiple electrodes. The electrode spacing of the electrode catheter is 4 mm. After establishing a three-dimensional model consistent with the ablation electrode parameters and selecting the discharge form (for example, bipolar discharge, one electrode connected to the positive and one electrode grounded), the applied voltage (300 V - 3000 V) is determined, and the magnitude of the field strength is fitted based on the distribution of different displacement magnitudes and field strength magnitudes at any tissue interface according to the fitting function to obtain the first fitting function.

[0402] Specifically, the calculation formula corresponding to the first fitting function established by the first fitting function establishment subunit is as follows:

[0403]

[0404] Among them, E 1 is the field strength value of the ablated tissue at the electrode at the tissue depth information x, and E 2 is the field strength value of the ablated tissue in the middle of the two electrodes at the tissue depth information x, and k 1 U, k 3 U respectively represent the fitting values of the maximum field strength values at the positions directly below the electrodes on the surface of the ablated tissue and at the middle positions between adjacent positive and negative electrodes. U represents the pulsed voltage applied to the ablated tissue, and k 1 , k 2 , k 3 , k 4 are all fitting coefficients. The fitting coefficients of the first fitting function are associated with different pulsed discharge forms, and x represents the tissue depth information;

[0405] Under the same discharge form, in the function expression of the above tissue field strength, the fitting coefficient values of the tissue field strength at the electrode and in the middle of the electrodes will be different. Under different discharge forms, the fitting coefficients in the function relationship for calculating the field strength magnitude will be different.

[0406] The middle ablation depth acquisition subunit is configured to respectively acquire the middle ablation depths in the depth direction at the positions of different electrodes in the ablation electrodes according to the first fitting function and the electric pulse field strength threshold;

[0407] The predicted ablation depth calculation subunit is configured to calculate the predicted ablation depth in the depth direction along the tissue surface of the ablated tissue under the set pulse parameters according to different middle ablation depths.

[0408] The field strength value is the largest at the electrode surface and smaller in the middle of the electrodes. Therefore, the tissue field strength values at different positions are different, but their change trends along the tissue cross-section direction are the same. The field strength is the largest at the tissue surface, and then along the depth direction, the field strength magnitude decays exponentially. Take the tissue ablation depth below the electrode as the maximum value, take the tissue ablation depth in the middle of the electrodes as the minimum value, and take the average of the two as the ablation depth of all tissues.

[0409] Specifically, the calculation formula corresponding to the predicted ablation depth calculated by the predicted ablation depth calculation subunit is as follows:

[0410]

[0411] Among them, depth represents the predicted ablation depth, and E thDenote the threshold value of the electric pulse field strength, and the tissue depth information x at the surface of the ablated tissue takes the value of 0. Of course, the tissue depth information x at the surface of the ablated tissue can also be other constants, which can be designed and adjusted according to actual needs.

[0412] Based on the above formula, determine the pulsed electric field ablation parameters, compare and analyze the predicted ablation depth with the historical ablation depth measured in the historical database, and draw a curve graph, as Figure 12 shown. In the figure, the curve is fitted with the functional relationship of y = x, and the correlation coefficient R 2 = 0.96, which indicates that there is a good linear correlation between the predicted value of the pre-ablation lesion depth obtained by this prediction method and the experimental measurement value.

[0413] In an implementable case, to reduce the ablation time and improve the efficiency, multiple pairs of electrodes are selected to discharge simultaneously; after establishing a three-dimensional model consistent with the catheter electrode parameters and selecting the discharge form (multiple pairs of electrodes discharge simultaneously, n / 2 electrodes are connected to the positive, and n / 2 electrodes are connected to the negative, where n is the total number of electrodes; or, select the monopolar discharge mode, n electrodes are connected to the positive simultaneously, and the back plate is connected to the negative), determine the applied voltage (for example, 300V - 3000V), and then perform numerical calculation of the field strength distribution.

[0414] After the calculation is completed, since ablation regions are generated at multiple positions, that is, the tissue ablation depth under the above electrodes includes the tissue depth under 2 or more electrodes. The tissue depth directly under the electrodes can include the positions of the positive and negative electrodes. The tissue ablation depth at the middle of the above electrodes includes the tissue depth at the middle of 2 or more electrodes. For the phenomenon of multiple pairs of electrodes discharging simultaneously, the ablation depth value is the average value of all values of the tissue ablation depth directly under multiple electrodes and the tissue ablation depth at the middle of multiple electrodes. The specific calculation principle is similar to that of the case of a pair of electrodes, so it will not be elaborated here.

[0415] In this embodiment, based on the set pulse parameters and the fitting function of the electric pulse field strength threshold, calculate the electric pulse field strength threshold under this pulse parameter; based on the ablation electrode parameters in the ablation catheter, construct an ablation numerical model to obtain the field strength distribution information corresponding to the ablated tissue in the tissue depth direction and the tissue width direction; use the electric pulse field strength threshold to draw the field strength isolines to predict the ablation boundary; finally obtain the predicted ablation depth under the predicted ablation boundary based on the field strength distribution information in the tissue depth direction and the electric pulse field strength threshold, and finally obtain the predicted ablation area under the predicted ablation boundary based on the field strength distribution information in the tissue width direction and the electric pulse field strength threshold, effectively improving the prediction accuracy and efficiency of the ablation parameters corresponding to the pulse parameters, being applicable to single and bipolar ablation methods, providing reasonable guidance for pulse parameter setting for surgeons, and improving the ablation effect.

[0416] Example 6

[0417] The pulse ablation parameter acquisition system of this embodiment is a further improvement of Embodiment 5. Specifically:

[0418] like Figure 12 As shown in the figure, an electric field is formed around the electrodes, and the electric field radiates to the tissue. For the ablated tissue, the field strength at the tissue surface is the largest, and the ablation area at the tissue surface is taken as the ablation lesion surface area (i.e., the predicted ablation boundary). On the tissue surface, the field strength in contact with the electrode is relatively large, while the field strength in the tissue between the two electrodes is slightly weaker. Therefore, the electrode width is not completely uniform. The average of the ablation width directly below the electrode and the ablation width below the middle of the electrode is taken as the average width of the ablation lesion on the tissue surface.

[0419] The electric field strength at the electrode reaches its maximum value at the center of the electrode, and radiates outward from the center of the electrode. At the surface of the tissue, the electric field strength gradually weakens as the distance from the center of the electrode increases. The electric field strength in the middle of the electrode reaches its maximum value at the position closest to the edge of the electrode, and gradually weakens along the vertical width direction. According to the above-constructed numerical model of tissue ablation, the cross-section passing through the electrode and the cross-section passing through the middle of the electrode are drawn respectively, and the field strength distribution on this cross-section with the displacement size is obtained. Specifically, if Figure 13 As shown, it represents the field intensity distribution in the ablation width direction, the horizontal axis represents the displacement in the width direction (mm), and the vertical axis represents the field intensity (V / cm).

[0420] After obtaining the displacement in the width direction, the displacement at the maximum field strength (i.e., tissue width information) is obtained by solving the maximum value equation E(w_max)=max(E), and the displacement in the width direction is translated, w=w-w_max, so that the field strength corresponding to the origin of the displacement coordinate is the maximum, as shown in Figure 8 The negative coordinate on the horizontal axis represents the width of the maximum field strength point toward the center of the catheter, and the positive coordinate on the horizontal axis represents the width of the maximum field strength point in the opposite direction of the catheter center, and the predicted ablation area is the sum of the two.

[0421] After obtaining the field intensity distribution in the width direction, the field intensity is fitted according to the fitting function to obtain a third fitting function.

[0422] The predicted ablation parameter calculation unit 12 of this embodiment includes:

[0423] A tissue section line acquisition subunit, used for acquiring a first tissue section line of the ablated tissue corresponding to the positions of different electrodes in the ablation electrodes along the tissue width direction;

[0424] A width field strength value acquisition subunit, configured to acquire field strength values ​​corresponding to different tissue width information based on the field strength distribution information corresponding to the first tissue section line;

[0425] The third fitting function establishing subunit is configured to establish a third fitting function between different tissue width information and corresponding field strength values;

[0426] Specifically, the calculation formula corresponding to the third fitting function established by the third fitting function establishing subunit is as follows:

[0427]

[0428] Among them, E 3 represents the field strength value of the ablated tissue at the electrode in the width displacement, E 4 represents the field strength value of the ablated tissue in the width displacement at the middle between two adjacent electrodes, w represents the displacement magnitude, U represents the pulse voltage, and p1 to p8 all represent fitting coefficients.

[0429] Under the same discharge form, in the above function expression of the tissue field strength, the fitting coefficient values of the tissue field strength at the electrode and in the middle of the electrodes will be different, and the correlation coefficient between the fitting function and the original value needs to satisfy: R 2 ≥0.95.

[0430] The middle ablation region obtaining subunit is configured to respectively obtain the corresponding middle ablation regions at the positions of different electrodes in the ablation electrodes according to the third fitting function and the electric pulse field strength threshold;

[0431] The predicted ablation region calculating subunit is configured to calculate the predicted ablation region corresponding to the surface of the ablated tissue under the set pulse parameters according to different middle ablation regions.

[0432] Specifically, the calculation formula corresponding to the predicted ablation region calculated by the predicted ablation region calculating subunit is as follows:

[0433]

[0434] Among them, wide 1 and wide 2 respectively represent different middle ablation regions, wide represents the predicted ablation region, and E th represents the electric pulse field strength threshold.

[0435] In an implementable embodiment of the solution, for the multi-pair electric simultaneous discharge mode, after establishing a three-dimensional model consistent with the catheter electrode parameters and selecting the discharge form (simultaneous discharge of multiple pairs of electrodes, n / 2 electrodes are connected to the positive, n / 2 electrodes are connected to the negative, where n is the total number of electrodes; or, selecting the monopolar discharge mode, n electrodes are simultaneously connected to the positive and the backplane is connected to the negative), determining the applied voltage (such as 300V to 3000V), and then performing numerical calculation of the field strength distribution.

[0436] After the calculation is completed, since ablation zones are generated at multiple positions, the ablation width on the tissue surface under the above-mentioned electrodes includes the ablation widths under two or more electrodes. The positions directly under the electrodes may include the positions of the positive and negative electrodes. The ablation width on the tissue surface at the middle of the above-mentioned electrodes includes the ablation widths at the middle of two or more electrodes. For the phenomenon of simultaneous discharge of multiple pairs of electrodes, the ablation width value on the tissue surface is the average value of the sum of all ablation widths of the ablation widths under the positive sides of multiple electrodes and the ablation widths at the middle of multiple electrodes obtained.

[0437] Taking the center line of the catheter electrode as the baseline, draw the ablation area contour lines above and below the baseline according to the ablation width calculated above, as Figure 15 shown. Given that the radius of the circle where the catheter electrode is located is r0, the radius of the outer contour circle is r0 + wide / 2; the radius of the inner contour circle is r0 - wide / 2. Then the ablation area on the tissue surface can be approximately calculated as:

[0438] S = ε·2π·r 0 ·wide = (r 0 ·θ + wide)·wide

[0439] where ε is the ratio of the arc length participating in the formation of the ablation area to the circumference of the circle where the electrode center is located, that is, ε = (r 0 ·θ + wide) / (2π·r 0 ), θ is the arc angle formed by all the electrodes participating in ablation in the circular electrode under the selected discharge mode, and it depends on the number of electrodes participating in ablation.

[0440] In the solution of an implementable embodiment, as Figure 21 shown, the acquisition system of this embodiment further includes:

[0441] A three-dimensional model construction module 13, configured to construct a three-dimensional ablation model corresponding to the predicted ablation boundary based on the predicted ablation area and the predicted ablation depth corresponding to the predicted ablation boundary.

[0442] As Figure 16 and 17 shown, according to the ablation surface area S (predicted ablation area) and the predicted ablation depth depth of the tissue surface calculated above, the volume of the entire ablation area can be approximately calculated as:

[0443]

[0444] It can intuitively present the three-dimensional shape corresponding to the ablation area, facilitating doctors or patients to view and understand, and effectively improving the treatment experience of patients.

[0445] In the solution of an implementable embodiment, the acquisition system of this embodiment further includes:

[0446] The fitness value calculation module 14 is used to calculate the fitness value corresponding to the predicted ablation depth based on the predicted ablation depth and the target ablation depth under the set pulse parameters by using the genetic algorithm;

[0447] The pulse parameter combination generation module 15 is used to perform selection, crossover, and mutation processing in sequence to generate a new pulse parameter combination when the fitness value does not meet the preset conditions;

[0448] The pulse parameter update module 16 is used to update the set pulse parameters with the pulse parameter combination when the fitness value corresponding to the pulse parameter combination meets the preset conditions.

[0449] Specifically, according to the ideal ablation depth value fed back externally, it is compared and analyzed with the calculated predicted ablation depth, and the set pulse parameters are optimized based on the genetic algorithm. The parameters to be optimized include pulse width τ, number of pulses n, number of pulse trains N, and pulse voltage U; among them, the objective function is f(X):

[0450]

[0451] Among them, d is the predicted ablation depth, D is the ideal target ablation depth, the value range of the pulse width τ is 0.1 - 50 us; the value range of the number of pulses n within a train is 1 - 100; the value range of the number of pulse trains N is 1 - 200; the voltage value range is 200 - 2000 V, and the objective function value is required to be the smallest and greater than 0.

[0452] Fitness is an index to judge the quality of individuals in a population. The genetic algorithm selects individuals according to the size of the individual fitness value, so as to realize the optimization of parameters. The determination of the fitness function lies in that when the function value is the largest, it is closest to the ideal target ablation depth, and its fitness function is:

[0453]

[0454] In the formula, when the predicted ablation depth is less than the ideal target ablation depth, the fitness function value is less than 1; when the predicted ablation depth is greater than the ideal target ablation depth, the fitness function value is greater than 1. In order to reduce the damage to other tissues, the predicted ablation depth should be greater than and as close as possible to the ideal target ablation depth. According to the above expression of the fitness function, the fitness value should be made as large as possible.

[0455] Such as Figure 18 shown, the process of optimizing pulse parameters based on the genetic algorithm generally includes:

[0456] S1. Obtain the initial generation of random pulse parameter populations (including pulse width, number of pulses, number of pulse trains, pulse voltage);

[0457] S2. Evaluate the fitness values of the current pulse parameter population using a fitness function;

[0458] S3. When the fitness value does not reach the expected value and / or the number of iterations does not reach the maximum value, perform selection, crossover, and mutation operations on the pulse parameter population in sequence to generate new pulse parameter combinations, and return to step S2. When the fitness reaches the expected value or the number of iterations reaches the maximum value, output the current pulse parameter combination, and use this pulse parameter combination as the set pulse parameters corresponding to the pulse generator.

[0459] The set pulse parameters optimized by the genetic algorithm can ensure that the ablation area corresponding to the pulse energy output by the pulse generator using this pulse parameter combination is within the target ablation depth range, thus effectively improving the ablation effect and accuracy.

[0460] In addition, how to fuse the initial pulse parameters with the genetic algorithm to calculate the corresponding optimized pulse parameters belongs to the mature technology in this field, so it will not be elaborated here.

[0461] In the above genetic algorithm, the operating parameters include the population size Size, the total number of generations G of evolution, the crossover probability Pc, and the mutation probability Pm. The value range of the population size Size is 20 - 100; the value range of the number of generations of evolution G is 100 - 500; the value range of the crossover probability Pc is 0.4 - 0.99, and the value range of the mutation probability Pm is 0.0001 - 0.1. Of course, the values of the above parameters can be re-determined and adjusted according to the actual situation to be applicable to different actual application scenarios.

[0462] In this embodiment, the electric pulse field strength threshold under this pulse parameter is calculated based on the set pulse parameters and the electric pulse field strength threshold fitting function; an ablation numerical model is constructed based on the ablation electrode parameters in the ablation catheter to obtain the field strength distribution information corresponding to the ablation tissue in the tissue depth direction and the tissue width direction; the electric pulse field strength threshold is used to draw the field strength contour lines to predict the ablation boundary; based on the field strength distribution information in the tissue depth direction and the electric pulse field strength threshold, the predicted ablation depth under the predicted ablation boundary is finally obtained, and based on the field strength distribution information in the tissue width direction and the electric pulse field strength threshold, the predicted ablation area under the predicted ablation boundary is finally obtained, effectively improving the prediction accuracy and efficiency of the ablation parameters corresponding to the pulse parameters, being applicable to single - and bipolar ablation methods, providing reasonable guidance on pulse parameter settings for surgeons, and improving the ablation effect; a three - dimensional ablation model corresponding to this predicted ablation boundary is constructed based on the predicted ablation depth and the predicted ablation area, which can visually present the three - dimensional shape of the ablation area, facilitating doctors or patients to view and understand, and enhancing the user experience.

[0463] Example 7

[0464] Figure 22 This is a schematic structural diagram of an electronic device provided in Embodiment 7 of the present invention. The electronic device includes a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the method for obtaining pulse ablation parameters in any one of Embodiments 1-3. Figure 22 The displayed electronic device 30 is merely an example and should not impose any limitations on the functions and usage scope of the embodiments of the present invention.

[0465] As Figure 22 shown, the electronic device 30 may be presented in the form of a general-purpose computing device, for example, it may be a server device. The components of the electronic device 30 may include, but are not limited to: the at least one processor 31 mentioned above, the at least one memory 32 mentioned above, and a bus 33 connecting different system components (including the memory 32 and the processor 31).

[0466] The bus 33 includes a data bus, an address bus, and a control bus.

[0467] The memory 32 may include volatile memory, such as a random access memory (RAM) 321 and / or a cache memory 322, and may further include a read-only memory (ROM) 323.

[0468] The memory 32 may further include a program / utilities 325 having a set (at least one) of program modules 324. Such program modules 324 include, but are not limited to: an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include the implementation of a network environment.

[0469] The processor 31 executes various functional applications and data processing by running the computer program stored in the memory 32, such as the method for obtaining pulse ablation parameters in any one of Embodiments 1-3 of the present invention.

[0470] The electronic device 30 may also communicate with one or more external devices 34 (such as a keyboard, a pointing device, etc.). Such communication may be carried out through an input / output (I / O) interface 35. And, the electronically generated device 30 may also communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through a network adapter 36. As Figure 22As shown, network adapter 36 communicates with other modules of the electronic device 30 that generates the model via bus 33. It should be understood that, although not shown in the figures, other hardware and / or software modules may be used in conjunction with the electronic device 30 that generates the model, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (redundant array of independent disks) systems, tape drives, and data backup storage systems, etc.

[0471] It should be noted that, although several units / modules or sub-units / modules of the electronic device are mentioned in the above detailed description, this division is merely exemplary and not mandatory. In fact, according to the embodiments of the present invention, the features and functions of two or more of the above-described units / modules may be embodied in one unit / module. Conversely, the features and functions of one unit / module described above may be further divided and embodied by multiple units / modules.

[0472] Embodiment 8

[0473] This embodiment provides a computer-readable storage medium having a computer program stored thereon, and when the program is executed by a processor, it implements the steps in the method for obtaining pulse ablation parameters in any one of Embodiments 1-3.

[0474] Among them, more specifically, the readable storage medium may include but is not limited to: portable disks, hard disks, random access memories, read-only memories, erasable programmable read-only memories, optical storage devices, magnetic storage devices, or any suitable combination of the above.

[0475] In a possible implementation manner, the present invention may also be implemented in the form of a program product, which includes program code. When the program product runs on a terminal device, the program code is used to cause the terminal device to execute the steps in the method for obtaining pulse ablation parameters in any one of Embodiments 1-3.

[0476] Among them, the program code for executing the present invention may be written in any combination of one or more programming languages, and the program code may be executed entirely on the user device, partially on the user device, executed as an independent software package, partially on the user device and partially on a remote device, or entirely on a remote device.

[0477] Although the specific implementation manners of the present invention are described above, those skilled in the art should understand that this is only an example, and the protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art may make various changes or modifications to these implementation manners, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A method for obtaining pulse ablation parameters, characterized in that, the obtaining method includes: Obtaining set pulse parameters; Determining the electric pulse field strength threshold of the ablation tissue under the set pulse parameters; Obtaining the electrode parameters corresponding to the ablation electrode in the ablation catheter, and the ablation electrode is attached to the surface of the ablation tissue; Constructing a tissue ablation numerical model based on the set pulse parameters and the electrode parameters; wherein, the ablation electrode includes a ring electrode, and the tissue ablation numerical model is constructed according to the electrode geometric parameters of the ring electrode, the electrode material property parameters and the material property information of the insulating part between the electrodes; Obtaining the field strength distribution information corresponding to the ablation tissue according to the tissue ablation numerical model; Based on the field strength distribution information and the electric pulse field strength threshold, obtaining the predicted ablation parameters corresponding to the ablation tissue under the set pulse parameters; wherein, the predicted ablation parameters include predicted ablation depth and / or predicted ablation area; The step of obtaining the predicted ablation parameters corresponding to the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold includes: Processing the field strength distribution information with the electric pulse field strength threshold, drawing field strength contour lines, and taking the area enclosed by the field strength contour lines as the predicted ablation boundary; Based on the field strength distribution information and the electric pulse field strength threshold, obtaining the predicted ablation parameters corresponding to the predicted ablation boundary of the ablation tissue under the set pulse parameters; The step of obtaining the predicted ablation parameters corresponding to the predicted ablation boundary of the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold includes: Obtaining a first tissue cross-section of the ablation tissue along the tissue depth direction corresponding to different electrodes in the ablation electrode; Based on the field strength distribution information corresponding to the first tissue cross-section, obtaining the field strength values corresponding to different tissue depth information; Establishing a first fitting function between different tissue depth information and the corresponding field strength values; According to the first fitting function and the electric pulse field strength threshold, respectively obtaining the intermediate ablation depths in the depth direction at different electrode positions in the ablation electrode, and calculating the predicted ablation depth in the depth direction of the tissue surface of the ablation tissue under the set pulse parameters according to different intermediate ablation depths; The calculation formula corresponding to the step of establishing the first fitting function between different tissue depth information and the corresponding field strength values is as follows: Among them, E 1 is the field strength value of the ablated tissue at the electrode at the tissue depth information x, and E 2 is the field strength value of the ablated tissue at the middle of the two electrodes at the tissue depth information x, and k 1 U, k 3 U respectively represent the fitting values of the maximum field strength values at the position directly below the electrode on the surface of the ablated tissue and at the middle position between two adjacent positive and negative electrodes. U represents the pulsed voltage applied to the ablated tissue, and k 1 , k 2 , k 3 , k 4 are all fitting coefficients. The fitting coefficients of the first fitting function are associated with different pulsed discharge forms, and x represents the tissue depth information; The calculation formula corresponding to the step of respectively obtaining the intermediate ablation depths in the depth direction at different positions on the surface of the ablation tissue according to the first fitting function and the electric pulse field strength threshold, and calculating the predicted ablation depth in the depth direction of the tissue surface of the ablation tissue under the set pulse parameters is as follows: where depth represents the predicted ablation depth, and E th represents the electric pulse field strength threshold, and the tissue depth information x on the surface of the ablated tissue takes a value of 0.

2. The method for obtaining pulse ablation parameters according to claim 1, characterized in that, When the ablation electrode includes a pair of electrodes, the positions where different electrodes are located in the ablation electrode respectively correspond to the positions directly below the two electrodes in the pair of electrodes and the positions in the middle between two adjacent electrodes; or, When the ablation electrode includes multiple pairs of electrodes, the positions where different electrodes are located in the ablation electrode respectively correspond to the positions directly below each electrode in each pair of electrodes and the positions in the middle between two adjacent electrodes in each pair of electrodes.

3. The method for obtaining pulse ablation parameters according to claim 2, characterized in that the electric potential at the positive electrode in the ablation electrode is consistent with the pulse voltage and pulse structure of the pulse generator; and / or, the setting positions of the positive and negative electrodes in the ablation electrode correspond to the pulse discharge form; wherein, in the bipolar discharge form, the polarities of adjacent electrodes are opposite; in the monopolar discharge form, all the electrodes in the ablation catheter are positive electrodes, and the back plate is a negative electrode.

4. The method for obtaining pulse ablation parameters according to claim 3, characterized in that when the set pulse parameters include a set pulse width, the set number of pulses in a pulse train, and the set number of pulse trains, the step of determining the electric pulse field strength threshold of the ablation tissue under the set pulse parameters includes: inputting the set pulse width, the set number of pulses in a pulse train, and the set number of pulse trains into a second fitting function to calculate the electric pulse field strength threshold corresponding to the ablation tissue.

5. The method for obtaining pulse ablation parameters according to claim 4, characterized in that the calculation formula corresponding to the step of inputting the set pulse width, the set number of pulses in a pulse train, and the set number of pulse trains into a second fitting function to calculate the electric pulse field strength threshold corresponding to the ablation tissue is as follows: Among them, E th represents the electric pulse field strength threshold, and E 0 represents the irreversible electroporation critical field strength when the pulse width and pulse dose are both in the saturated state. τ represents the set pulse width, T is the total pulse release time, T = τ * n * N, n represents the number of pulses in the set pulse train, N represents the number of set pulse trains, A 1 , B 1 , C 1 , A 2 , B 2 , C 2 are all fitting coefficients.

6. The method for obtaining pulse ablation parameters according to claim 1, characterized in that the electrode parameters include electrode geometric parameters, electrode material property parameters, and material property information of the insulating part between electrodes; wherein, the electrode geometric parameters include electrode diameter information, electrode length information, and electrode spacing information; and / or, the boundary of the tissue ablation numerical model is set to be electrically insulated; wherein, J·n = 0, J represents the current density inside the model, and n represents the tissue boundary normal vector.

7. The method for obtaining pulse ablation parameters according to claim 2, characterized in that the obtaining method further includes: obtaining a plurality of groups of historical electric field strength values corresponding to the ablation tissue and the historical conductivity corresponding to the historical electric field strength values; drawing the conductivity values under different electric field strengths according to each group of the historical electric field strength values and the historical conductivity, and performing function fitting on the curve of the conductivity varying with the electric field strength to construct a dynamic conductivity model of the conductivity varying with the field strength; wherein, according to different ablation tissues, the model fitting parameters of the dynamic conductivity model are adaptively adjusted, and the adjustable model fitting parameters of the dynamic conductivity model include the initial conductivity and the model fitting coefficient; the dynamic conductivity model is used to output the conductivity corresponding to the ablation tissue.

8. The method for obtaining pulse ablation parameters according to claim 7, characterized in that The calculation formula corresponding to the step of plotting the conductivity values at different electric field strengths based on the historical electric field strength values and the historical conductivity of each group, and performing function fitting on the curve of conductivity varying with electric field strength to construct a dynamic conductivity model of conductivity varying with field strength is as follows: where σ 0 represents the initial conductivity of the ablated tissue, and σ max represents the maximum conductivity when all of the ablated tissue has undergone electroporation. σ max = C 3 * σ 0 , A 3 , B 3 , and C 3 are respectively model fitting parameters, and E del represents the field strength value corresponding to the center point of the transition region from the start of the change in conductivity to the development to the stable value. E represents the field strength value corresponding to the field strength distribution information.

9. The method for obtaining pulse ablation parameters according to claim 8, wherein, the step of obtaining the field strength distribution information corresponding to the ablated tissue according to the tissue ablation numerical model includes: obtaining the potential information inside the tissue ablation numerical model; calculating the field strength distribution information corresponding to the ablated tissue based on the potential information and the conductivity.

10. The method for obtaining pulse ablation parameters according to claim 9, wherein, the calculation formula corresponding to the step of calculating the field strength distribution information corresponding to the ablated tissue based on the potential information and the conductivity is as follows: where E represents the field strength distribution information, represents the potential information, σ is the conductivity of the ablated tissue, ε 0 is the vacuum permittivity, ε r is the relative permittivity of the ablated tissue.

11. The method for obtaining pulse ablation parameters according to claim 2, wherein, the step of obtaining the predicted ablation parameters corresponding to the predicted ablation boundary of the ablated tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold includes: obtaining a first tissue cross-section of the ablated tissue along the tissue width direction corresponding to different electrodes in the ablation electrode; obtaining the field strength values corresponding to different tissue width information based on the field strength distribution information corresponding to the first tissue cross-section; establishing a third fitting function between different tissue width information and the corresponding field strength values; respectively obtaining intermediate ablation regions corresponding to different electrodes in the ablation electrode according to the third fitting function and the electric pulse field strength threshold, and calculating the predicted ablation region corresponding to the surface of the ablated tissue under the set pulse parameters according to different intermediate ablation regions.

12. The method for obtaining pulse ablation parameters according to claim 11, wherein, the calculation formula corresponding to the step of establishing a third fitting function between different tissue width information and the corresponding field strength values is as follows: Among them, E 3 represents the field strength value of the ablated tissue at the electrode in the width displacement, E 4 represents the field strength value of the ablated tissue in the width displacement at the middle between two adjacent electrodes, w represents the displacement magnitude, U represents the pulse voltage, and p1 to p8 all represent fitting coefficients; The calculation formula corresponding to the step of respectively obtaining intermediate ablation regions corresponding to different electrodes in the ablation electrode according to the third fitting function and the electric pulse field strength threshold, and calculating the predicted ablation region corresponding to the surface of the ablated tissue under the set pulse parameters according to different intermediate ablation regions is as follows: Among them, wide 1 and wide 2 respectively represent different ones of the said intermediate ablation regions, wide represents the said predicted ablation region, and E th represents the said electric pulse field strength threshold.

13. The method for obtaining pulse ablation parameters according to claim 11 or 12, wherein, the obtaining method further includes: constructing a three-dimensional ablation model corresponding to the predicted ablation boundary based on the predicted ablation region and the predicted ablation depth corresponding to the predicted ablation boundary.

14. The method for obtaining pulse ablation parameters according to claim 1, wherein, the obtaining method further includes: calculating the fitness value corresponding to the predicted ablation depth by using a genetic algorithm based on the predicted ablation depth and the target ablation depth under the set pulse parameters; When the fitness value does not meet the preset conditions, selection, crossover, and mutation processes are sequentially performed to generate a new pulse parameter combination; When the fitness value corresponding to the pulse parameter combination meets the preset conditions, the set pulse parameters are updated using the pulse parameter combination.

15. A system for obtaining pulse ablation parameters, characterized in that, the obtaining system includes: a pulse parameter obtaining module, configured to obtain set pulse parameters; an electric pulse field strength threshold determination module, configured to determine the electric pulse field strength threshold of the ablation tissue under the set pulse parameters; an electrode parameter obtaining module, configured to obtain the electrode parameters corresponding to the ablation electrodes in the ablation catheter, and the ablation electrodes are abutted against the surface of the ablation tissue; an ablation model construction module, configured to construct a tissue ablation numerical model based on the set pulse parameters and the electrode parameters; wherein, the ablation electrode includes a ring electrode, and the tissue ablation numerical model is constructed according to the electrode geometric parameters of the ring electrode, the electrode material property parameters, and the material property information of the insulating part between the electrodes; a field strength distribution information obtaining module, configured to obtain the field strength distribution information corresponding to the ablation tissue according to the tissue ablation numerical model; a predicted ablation parameter obtaining module, configured to obtain the predicted ablation parameters corresponding to the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold; wherein, the predicted ablation parameters include predicted ablation depth and / or predicted ablation area; the predicted ablation parameter obtaining module includes: an ablation boundary prediction unit, configured to process the field strength distribution information using the electric pulse field strength threshold, draw field strength contour lines, and use the area enclosed by the field strength contour lines as the predicted ablation boundary; a predicted ablation parameter calculation unit, configured to obtain the predicted ablation parameters corresponding to the predicted ablation boundary of the ablation tissue under the set pulse parameters based on the field strength distribution information and the electric pulse field strength threshold; the predicted ablation parameter calculation unit includes: a tissue cross-section obtaining subunit, configured to obtain a first tissue cross-section of the ablation tissue along the tissue depth direction corresponding to different electrodes in the ablation electrode; a depth field strength value obtaining subunit, configured to obtain the field strength values corresponding to different tissue depth information based on the field strength distribution information corresponding to the first tissue cross-section; a first fitting function establishing subunit, configured to establish a first fitting function between different tissue depth information and the corresponding field strength values; an intermediate ablation depth obtaining subunit, configured to respectively obtain the intermediate ablation depths in the depth direction at different electrode positions in the ablation electrode according to the first fitting function and the electric pulse field strength threshold; a predicted ablation depth calculation subunit, configured to calculate the predicted ablation depth of the ablation tissue along the depth direction from the tissue surface under the set pulse parameters according to different intermediate ablation depths; the formula corresponding to the first fitting function established by the first fitting function establishing subunit is as follows: Among them, E 1 is the field strength value of the ablated tissue at the electrode at the tissue depth information x, and E 2 is the field strength value of the ablated tissue in the middle of the two electrodes at the tissue depth information x. k 1 U, k 3 U respectively represent the fitting values of the maximum field strength values at the position directly below the electrode on the surface of the ablated tissue and at the position in the middle of two adjacent positive and negative electrodes. U represents the pulsed voltage applied to the ablated tissue. k 1 , k 2 , k 3 , k 4 are all fitting coefficients. The fitting coefficients of the first fitting function are associated with different pulsed discharge forms, and x represents the tissue depth information; the formula corresponding to the predicted ablation depth calculated by the predicted ablation depth calculation subunit is as follows: where depth represents the predicted ablation depth, and E th represents the electric pulse field strength threshold, and the tissue depth information x on the surface of the ablated tissue takes a value of 0.

16. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, when the processor executes the computer program, the method for obtaining pulse ablation parameters according to any one of claims 1-14 is implemented.

17. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the computer program is executed by a processor, the method for obtaining pulse ablation parameters according to any one of claims 1-14 is implemented.

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