A method and system for measuring in-vivo field strength during electrotherapy

Abstract

A method for measuring the in-vivo field strength during electrotherapy, comprising the following steps: (1) modeling the measurement target in finite element simulation software; (2) inserting differential electrodes with a spacing of L in the simulation model and simulating and calculating the electric potential on the differential electrodes, the peak field strength at the center of the endpoints of the differential electrodes, and the peak field strength at this position when the differential electrodes are not inserted; (3) calculating the potential difference on the differential electrodes and calculating the peak value of the average field strength; (4) determining the spacing of the differential electrodes during the actual measurement process; (5) inserting the differential electrodes with the required spacing into the body and using an oscilloscope to record the electric potential; (6) calculating the potential difference on the differential electrodes and calculating the peak value of the average field strength according to the actual spacing of the differential electrodes, as the actual field strength at the target position during electrotherapy. And a system for realizing the measurement of the in-vivo field strength during electrotherapy is provided. The present invention can effectively measure the actual applied dose of electrotherapy and verify the electric field strength in the simulation results.

Description

Technical Field

[0001] The present invention relates to the fields of electric field therapy and field strength measurement, and more particularly to a method and system for measuring in-vivo field strength during electric field therapy. Background Art

[0002] Tumor treating fields (TTFields) is a new non-invasive anti-mitotic technology for treating tumors. By applying an alternating electric field with a medium frequency (100 - 500 kHz) and a low intensity (1 - 3 V / cm) to tumor cells, its mitotic process is inhibited, achieving the effect of treating tumors. Currently, the clinical trial results at home and abroad have confirmed the therapeutic effect of tumor treating fields.

[0003] A main factor affecting the effect of electric field therapy is the electric field strength. Current research shows that in various in-vitro cancer cell lines, as the electric field strength increases, the inhibitory effect of electric field therapy on tumors is more significant.

[0004] There are some problems in current research. The most important one is the lack of methods and systems for actually measuring the electric field strength during electric field therapy. To solve this problem, some research directly uses the electric field strength in the simulation results of finite element software as the actual electric field strength during treatment, but this method lacks the verification of actual measurement results.

[0005] Therefore, it is necessary to construct a method and system for actually measuring the in-vivo electric field strength during electric field therapy. Summary of the Invention

[0006] To overcome the deficiencies of the prior art, the present invention provides a method and system for measuring in-vivo field strength during electric field therapy, which can effectively measure the actual applied dose of electric field therapy and verify the electric field strength in the simulation results.

[0007] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0008] A method for measuring in-vivo field strength during electric field therapy, comprising the following steps:

[0009] Step (1), modeling the measurement target in finite element simulation software;

[0010] Step (2), inserting differential electrodes with a spacing of L in the simulation model and obtaining the electric potential on the differential electrodes through simulation calculation and the peak field strength E at the center of the endpoints of the differential electrodes Peak1-Simul and the peak field strength E at this position when the differential electrodes are not inserted Peak0-Simul , where a 1-Simul and a 2-Simul are the amplitudes of the signals during simulation, ω is the signal angular frequency, and t is the time. and is the phase of the signal during simulation;

[0011] Step (3), calculate the potential difference V 21-Simul (t) on the differential electrode and calculate the peak value E of the average field strength according to the spacing L Avg-Simul , where

[0012]

[0013]

[0014] Step (4), continuously adjust L and re - simulate, compare E Peak1-Simul , E Peak0-Simul and E Avg-Simul , and take the range of L when the three are close as the spacing of the differential electrode during the actual measurement;

[0015] Step (5), insert the differential electrode meeting the above spacing requirements into the body and use an oscilloscope to record the potential and where a1 and a2 are the amplitudes of the signals during actual measurement, ω is the signal angular frequency, t is the time, and is the phase of the signal during actual measurement;

[0016] Step (6), calculate the potential difference V 21 (t) on the differential electrode and calculate the peak value E of the average field strength according to the actual spacing of the differential electrode Avg , and take E Avg as the actual field strength at the target position during the electric field treatment, where

[0017]

[0018]

[0019] Furthermore, the modeling parameters in step (1) include the output parameters of the electric field treatment system, the structure and size of the treatment electrode, the structure and size of the measurement target, and the conductivity and relative permittivity of the media in each structure.

[0020] Furthermore, the differential electrode structure used in step (2) is a conductive thin wire wrapped with an insulating material. During simulation, it is necessary to model the differential electrode. The modeling parameters include the size of the insulating material and the conductive thin wire, the conductivity and relative permittivity of the insulating material and the conductive thin wire, and the position of the differential electrode in the measurement target.

[0021] A system for measuring the in-vivo field strength during electrotherapy, comprising an electric field generator, a treatment electrode, a differential measurement electrode, and an oscilloscope. The electric field generator can generate a sine signal with a specified frequency and amplitude. It is characterized in that the system further comprises a field strength measurement module, which includes:

[0022] A modeling unit for modeling the measurement target in finite element simulation software;

[0023] A differential electrode parameter calculation unit for inserting differential electrodes with a spacing of L into the simulation model and obtaining the electric potential on the differential electrodes through simulation calculation and the peak field strength E at the center of the endpoints of the differential electrode Peak1-Simul and the peak field strength E at this position when no differential electrode is inserted Peak0-Simul , where a 1-Simul and a 2-Simul are the amplitudes of the signal during simulation, ω is the signal angular frequency, t is time, and are the phases of the signal during simulation;

[0024] An average field strength peak calculation unit for calculating the potential difference V 21-Simul (t) on the differential electrodes and calculating the peak E of the average field strength according to the spacing L Avg-Simul , where

[0025]

[0026]

[0027] A differential electrode spacing determination unit for continuously adjusting L and re-simulating, comparing E Peak1-Simul , E Peak0-Simul and E Avg-Simul , and taking the range of L when the three are close as the differential electrode spacing during the actual measurement;

[0028] An oscilloscope recording unit for inserting differential electrodes meeting the above spacing requirements into the body and using the oscilloscope to record the electric potential and where a1 and a2 are the amplitudes of the signal during actual measurement, ω is the signal angular frequency, t is time, and are the phases of the signal during actual measurement;

[0029] A field strength calculation unit for calculating the potential difference V 21 (t) on the differential electrodes and calculating the peak E of the average field strength according to the actual spacing of the differential electrodes Avg , and taking E Avg as the actual field strength at the target position during electrotherapy, where

[0030]

[0031]

[0032] Preferably, the treatment electrode is composed of a ceramic electrode with a relative dielectric constant greater than 10,000.

[0033] More preferably, only the tip of the differential measurement electrode is exposed, and the rest is wrapped by an insulating material.

[0034] The beneficial effects of the present invention are mainly manifested in: effectively measuring the actual applied dose of electric field treatment and verifying the electric field strength in the simulation results. Description of the Drawings

[0035] Figure 1 is a flowchart of the electric field strength measurement method of the present invention.

[0036] Figure 2 is a diagram of the electric field strength measurement system of the present invention.

[0037] Figure 3 is a measurement schematic diagram of the first embodiment of the present invention.

[0038] Figure 4 is a simplified equivalent circuit diagram of the first embodiment of the present invention.

[0039] Figure 5 is an equivalent circuit diagram of the first embodiment of the present invention.

[0040] Figure 6 is the structure of the differential electrode in the second embodiment of the present invention.

[0041] Figure 7 is a test model of the second embodiment of the present invention.

[0042] Figure 8 is the peak electric field strength E without inserting the differential electrode in the simulation result at point C in the test model of the second embodiment of the present invention Peak0-Simul , the peak electric field strength E after inserting the differential electrode Peak1-Simul and the peak E of the calculated average electric field strength Avg-Simul .

[0043] Figure 9 is the peak E of the average electric field strength obtained by simulation calculation on the axis in the test model of the second embodiment of the present invention Avg-Simul and the measured results E at five points A, B, C, D, and E Avg . Detailed Embodiments

[0044] The present invention will be further described below with reference to the drawings.

[0045] Example 1

[0046] Example 1 of the present invention provides a method and system for field strength measurement. Figure 1 It is a flowchart of the in-vivo field strength measurement method during the electric field treatment process. Figure 2 It is a diagram of the field strength measurement system in the present invention. Figure 3 It is a measurement schematic diagram of the first embodiment of the present invention, including differential electrodes 1, treatment electrodes 2, an oscilloscope 3, an electric field generator 4, and a measurement target 5. The treatment electrode 2 is divided into a high relative permittivity ceramic 22 and a medical conductive paste 21. The oscilloscope 3 is used to measure the electric potential, the electric field generator 4 is used to generate an electric field treatment signal, and the measurement target 5 is the target of the electric field action. Figure 4 is Figure 3 the corresponding simplified equivalent circuit diagram, where C1 and C2 are the equivalent capacitances of the treatment electrode 2, and R total is the equivalent resistance of the measurement target 5, and V ac is generated by the electric field generator 4. Figure 5 is the equivalent circuit diagram after splitting R total . After inserting the differential electrodes 1, the measurement target 5 is split into three equivalent resistances R1, R2, and R3. The oscilloscope 3 is used to measure the electric potentials of the two electrodes on the differential electrodes 1 and where a1 and a2 are the amplitudes of the signals during actual measurement, t is the time, and are the phases of the signals during actual measurement. Calculate the potential difference V 21 (t) on the differential electrodes 1 and calculate the peak value E Avg of the average field strength according to the actual spacing of the differential electrodes 1. Take E Avg as the actual field strength at the target position during the electric field treatment process, where

[0047]

[0048]

[0049] Example 2

[0050] Example 2 of the present invention provides a method and system for field strength measurement. Figure 6 It is the structure of the differential electrodes in the second embodiment of the present invention, including conductive thin wires 11 and an insulating layer 12. Figure 7 It is the test model of the second embodiment of the present invention, including differential electrodes 1, a medical conductive paste 21, a high relative permittivity ceramic 22, an oscilloscope 3, an electric field generator 4, and a cylindrical agar 6.

[0051] In the test model, the conductivity and relative permittivity of the thin wire 11 are 6e7 S / m and 1e6, those of the insulating layer 12 are 3 S / m and 1e-14, those of the medical conductive paste 21 are 70 S / m and 5, those of the high relative permittivity ceramic 22 are 70 S / m and 0.15, and those of the cylindrical agar 6 are 0.15 S / m and 70. The conductivity of the cylindrical agar 6 is similar to that of some biological tissues (0.164 S / m for the large intestine, 0.164 S / m for the stomach, and 0.17 S / m for the skin). Moreover, under the condition of electric field therapy (200 kHz), the displacement current in both the agar model and biological tissues is much smaller than the conduction current. Therefore, the measurement results of the agar model can be used to approximate the measurement results of some biological tissues.

[0052] In the test model, the diameter of the conductive thin wire 11 in the differential electrode 1 is 0.21 mm, and the thickness of the insulating layer 12 is 0.01 mm. The upper bottom diameter of the medical conductive paste 21 is 9.57 mm, the lower bottom diameter is 12 mm, and the height is 2 mm. The diameter of the high relative permittivity ceramic 22 is 9.57 mm, and the height is 1.78 mm. The bottom diameter of the cylindrical agar 6 is 36 mm, and the height is 50 mm. The oscilloscope 3 is of the Keysight DSOX3054T model. The electric field generator 4 applies a sine signal with an amplitude of 5 V and a frequency of 200 kHz to the two high relative permittivity ceramics 22 on both sides.

[0053] The test model is modeled and simulated in the finite element simulation software COMSOL Multiphysics, and the spacing L is continuously adjusted to obtain the results as Figure 8 shown. The difference between E Peak1-Simul and E Peak0-Simul represents the influence of inserting the differential electrode 1 on the electric field strength in the cylindrical agar 6. Generally, as L increases, this influence decreases significantly. When L is greater than 0.69 mm, the deviation between E Peak1-Simul and E Peak0-Simul is less than 3%. The difference between E Avg-Simul and E Peak0-Simul represents the difference between the result of measuring the potential difference and calculating the average electric field strength and the electric field strength in the cylindrical agar 6. When the electrode pair spacing is greater than 0.69 mm, the deviation between E Avg-Simul and E Peak0-Simul is less than 2.5%. Therefore, L greater than 0.69 mm is selected for the actual measurement.

[0054] Use the oscilloscope 5 to measure the potential of each electrode in each pair of differential electrodes 1 inserted into the cylindrical agar 6, and calculate the actual measurement results E at five points A, B, C, D, and E AvgDuring simulation and actual measurement, the parameters output by the electric field generator 4 are the same. However, during actual measurement, there are contact resistances between the medical conductive paste 21 and the high relative permittivity ceramic 22, and also between the medical conductive paste 21 and the cylindrical agar 6. While in simulation, the interface is ideal without contact resistance, which leads to a deviation between the measured result and the simulation result. To verify the accuracy of the measurement result, it is necessary to correct the result, and the corrected measurement result E Avg-Ecorrection is compared with the simulation calculation result. The peak potential difference ΔV at both ends of the cylindrical agar 6 is recorded through the simulation result in the finite element simulation software ref0 , and the peak potential difference ΔV at both ends of the cylindrical agar 6 is obtained through actual measurement ref1 . Through the formula , the corrected result E of the measured result is calculated Avg-Ecorrection . The peak value E of the average field strength obtained by simulation calculation on the central axis of the cylindrical agar 6 Avg-Simul and the corrected results E of the measured results at five points A, B, C, D, and E Avg-Ecorrection are as shown in Figure 9 . The results show that the deviation between E Avg-Simul and E Avg-Ecorrection at each point is less than 5%. Therefore, this method and system for measuring the in-vivo field strength during electrotherapy have high accuracy.

[0055] The content described in the embodiments of this specification is only an enumeration of the implementation forms of the inventive concept and is only for illustrative purposes. The protection scope of the present invention should not be regarded as limited to the specific forms stated in this embodiment. The protection scope of the present invention also extends to equivalent technical means that can be thought of by those of ordinary skill in the art based on the inventive concept of the present invention.

Claims

1. A method for measuring the in-vivo field strength during electrotherapy, characterized in that, The method includes the following steps: Step (1), modeling the measurement target in a finite element simulation software; Step (2): Insert differential electrodes with a spacing of L in the simulation model and obtain the electric potential on the differential electrodes through simulation calculations and the peak field strength E at the center of the endpoints of the differential electrodes Peak1-Simul and the peak field strength E at this position when the differential electrodes are not inserted Peak0-Simul , where a 1-Simul and a 2-Simul are the amplitudes of the signals during simulation, ω is the signal angular frequency, t is the time, and are the phases of the signals during simulation; Step (3), calculate the potential difference V on the differential electrode 21-Simul (t) and calculate the peak value E of the average field strength according to the spacing L Avg-Simul , where Step (4), continuously adjust L and re - simulate, and compare Es under different Ls Peak1-Simul , E Peak0-Simul and E Avg-Simul , and take the range of L when the three are close as the differential electrode spacing during the actual measurement; Step (5), insert the differential electrodes that meet the above spacing requirements into the body and use an oscilloscope to record the electric potential and where a1 and a2 are the amplitudes of the signals during actual measurement, ω is the signal angular frequency, and t is time and is the phase of the signal during actual measurement; Step (6), calculate the potential difference V on the differential electrode 21 (t) and calculate the peak value E of the average field strength according to the actual distance between the differential electrodes Avg , and use E Avg as the actual field strength at the target position during the electrotherapy process, where 2. The method for measuring the in-vivo field strength during the electric field treatment according to claim 1, characterized in that, The modeling parameters in step (1) of the method include the output parameters of the electric field treatment system, the structure and dimensions of the treatment electrode, the structure and dimensions of the measurement target, and the conductivity and relative permittivity of the media in each structure.

3. A method for measuring the in-vivo field strength during electrotherapy according to claim 1 or 2, characterized in that, The differential electrode structure used in step (2) is a conductive thin wire wrapped with an insulating material. During simulation, it is necessary to model the differential electrode. The modeling parameters include the dimensions of the insulating material and the conductive thin wire, the conductivity and relative permittivity of the insulating material and the conductive thin wire, and the position of the differential electrode in the measurement target.

4. A system for implementing the method for measuring in-vivo field strength during electrotherapy as claimed in claim 1, characterized in that, The system includes an electric field generator, a treatment electrode, a differential measurement electrode, and an oscilloscope. The electric field generator can generate a sine signal with a specified frequency and amplitude. It is characterized in that the system further includes a field strength measurement module, and the field strength measurement module includes: A modeling unit for modeling the measurement target in a finite element simulation software; A differential electrode parameter calculation unit is configured to insert differential electrodes with a spacing of L into the simulation model and obtain the electric potential on the differential electrodes through simulation calculations. and the peak field strength E at the center of the endpoints of the differential electrodes Peak1-Simul and the peak field strength E at this position when the differential electrodes are not inserted Peak0-Simul , where a 1-Simul and a 2-Simul are the amplitudes of the signals during simulation, ω is the signal angular frequency, t is the time, and are the phases of the signals during simulation; Peak calculation unit of average field strength, which is used to calculate the potential difference V 21-Simul (t) on the differential electrode and calculate the peak value E of the average field strength according to the spacing L Avg-Simul , where Differential electrode spacing determination unit, which is used to continuously adjust L and re-simulate, and compare Es under different Ls Peak1-Simul , E Peak0-Simul and E Avg-Simul , and take the range of L when the three are close as the differential electrode spacing during the actual measurement; An oscilloscope recording unit for inserting differential electrodes that meet the above spacing requirements into the body and using an oscilloscope to record the electric potential and where a1 and a2 are the amplitudes of the signal during actual measurement, ω is the signal angular frequency, t is the time, and is the phase of the signal during actual measurement; The electric field strength calculation unit calculates the potential difference V 21 (t) on the differential electrodes and calculates the peak value E of the average electric field strength according to the actual distance between the differential electrodes Avg , and takes E Avg as the actual electric field strength at the target position during the electrotherapy process, where 5. The system according to claim 4, characterized in that, The treatment electrode is composed of a ceramic electrode with a relative permittivity greater than 10,000.

6. The system according to claim 4 or 5, characterized in that, Only the tip of the differential measurement electrode is exposed, and the rest is wrapped with an insulating material.

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