Power supply unit and ablation system

Abstract

A power supply device (8) for performing ablation using an irreversible electroporation method includes a power supply section (26) electrically connected to a catheter (4) having a plurality of electrodes and a counter electrode plate (6) and applying a voltage to the plurality of electrodes and the counter electrode plate (6), and a control section (28) that controls the power supply section (26) in a manner that combines monopolar mode application of applying a voltage between the electrodes and the counter electrode plate (6) and bipolar mode application of applying a voltage between the electrodes.

Description

Technical Field

[0001] This disclosure relates to power supply devices and ablation systems. Background Technology

[0002] Patent Document 1 discloses an ablation system comprising an ablation catheter and a pulse waveform generator for delivering voltage pulses to the ablation catheter.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Publication No. 2019-500170 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Through repeated and in-depth research, the inventors came up with a novel technology related to catheter ablation.

[0008] This disclosure was made in view of the following circumstances, and its purpose is to provide a novel technique related to catheter ablation.

[0009] Solution for solving the problem

[0010] One aspect of this disclosure is a power supply device for performing ablation using irreversible electroporation. The power supply device includes: a power supply unit electrically connected to a conduit having multiple electrodes and a counter plate, applying voltage to the multiple electrodes and the counter plate; and a control unit that controls the power supply unit in a manner that combines applying voltage in a unipolar manner between the electrodes and the counter plate with applying voltage between the electrodes themselves.

[0011] Another aspect of this disclosure is an ablation system for performing ablation using irreversible electroporation. This ablation system includes: a catheter having multiple electrodes; a counter electrode; and a power supply device as described above.

[0012] Any combination of the above-mentioned constituent elements, or any scheme transformed from the expression of this disclosure into methods, apparatus, systems, etc., shall also be valid as a scheme of this disclosure.

[0013] Invention Effects

[0014] According to this disclosure, a novel technique related to catheter ablation can be provided. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the ablation system implemented in this way.

[0016] Figure 2 This is a 3D view of the electrode assembly.

[0017] Figure 3 (A) and Figure 3 (B) is a schematic diagram used to illustrate the first application mode.

[0018] Figure 4 (A) and Figure 4 (B) is a schematic diagram used to illustrate the second application mode.

[0019] Figure 5 (A) and Figure 5 (B) is a schematic diagram illustrating the switching control of the application method corresponding to the state of the rib. Detailed Implementation

[0020] Hereinafter, the present disclosure will be described based on preferred embodiments with reference to the accompanying drawings. These embodiments are not intended to limit the present disclosure but are illustrative; not all features described in the embodiments, or combinations thereof, are necessarily essential features of the present disclosure. Identical or equivalent constituent elements, components, and processes shown in the various drawings are labeled with the same reference numerals, and repeated descriptions are omitted where appropriate. Furthermore, for ease of explanation, the scales and shapes of the parts shown in the figures are set in a convenient manner and are not to be interpreted limitingly unless specifically mentioned. In addition, when terms such as "first" or "second" are used in this specification or claims, unless specifically mentioned, these terms are used to distinguish one component from others and do not indicate any order or importance. Furthermore, in the various drawings, based on the description of the embodiments, parts of less important components are omitted.

[0021] Figure 1 This is a schematic diagram of the ablation system 1 according to the implementation method. Figure 1 In this document, a portion of the constituent elements of the ablation system 1 are described as functional blocks. At least a portion of these functional blocks can be implemented as hardware components using elements and circuits, such as a computer's CPU (Central Processing Unit) and memory, or as software components using computer programs, etc. Those skilled in the art will understand that these functional blocks can be implemented in various forms through a combination of hardware and software.

[0022] The ablation system 1 ablates the affected area 2 of the patient. Examples of the affected area 2 include organs that cause arrhythmias. It should be noted that the ablation system 1 can also be used to ablate other affected areas 2. The ablation system 1 includes a catheter 4, a counter electrode 6, and a power supply 8.

[0023] As an example, catheter 4 has a shaft 10, an electrode assembly 12, and a handle 14. The shaft 10 is a flexible tubular body, with at least its tip side for insertion into the patient's body. The shaft 10 is made of a known flexible material containing resins such as polyolefins, polytetrafluoroethylene, polyether block amides, and polyamides. The shaft 10 may, for example, employ a multi-lumen structure with multiple lumens. The lumens are for various fine wires (not shown) such as lead wires, manipulation wires, and the inner tube 22 described later (see reference). Figure 2 (etc.)

[0024] The electrode assembly 12 is located on the top end side of the shaft 10. Figure 2 This is a perspective view of electrode assembly 12. Electrode assembly 12 has multiple ribs 16 and multiple electrodes 18. It should be noted that... Figure 1 The middle image shows the state of rib 16 after folding. Figure 2 The middle image shows the state of rib 16 after it has been unfolded.

[0025] Each stiffener 16 is a linear body extending axially along the shaft 10 and is made of the same flexible material as the shaft 10. As an example, Figure 2 The electrode assembly 12 shown has a first rib 16a, a second rib 16b, a third rib 16c, a fourth rib 16d, a fifth rib 16e, and a sixth rib 16f. However, the number of ribs 16 is not limited to six; any number is acceptable. In this disclosure, when it is not necessary to distinguish between the first rib 16a to the sixth rib 16f, they are sometimes simply referred to as "rib 16".

[0026] The ribs 16 are arranged at intervals around the shaft 10. The top end of each rib 16 is connected to the top tip 20. The base end of each rib 16 is inserted into the shaft 10 from the top end and fixed to the shaft 10. The top end of the inner tube 22 is connected to the top tip 20. The inner tube 22 passes through the cavity of the shaft 10, and its base end is connected to the handle 14. The inner tube 22 can be moved forward and backward towards the top end and base end of the shaft 10 by operating the handle 14.

[0027] Multiple ribs 16 can switch between a folded state and an unfolded state. When the inner tube 22 is pulled toward the base end of the shaft 10 in the folded state, that is, when the ribs 16 are extending in a straight line, the tip 20 displaces toward the base end of the shaft 10. As a result, each rib 16 bends outward in an unfolded state. In the unfolded state, the electrode assembly 12 becomes a basket shape. When the inner tube 22 is squeezed toward the tip of the shaft 10 in the unfolded state, the tip 20 displaces in a direction away from the base end of the shaft 10. As a result, each rib 16 is folded. It should be noted that the "basket shape" is derived from the fact that the shape of the multiple ribs 16 in the unfolded state is similar to the curved pattern on the surface of a basketball.

[0028] Each rib 16 is provided with a plurality of electrodes 18. The electrodes 18 are arranged at predetermined intervals along the longitudinal direction of the rib 16. Each electrode 18 is annular and is made of a highly conductive metal such as platinum, gold, silver, copper, aluminum, or stainless steel, or an alloy thereof. As an example, Figure 2 The electrode assembly 12 shown has a first electrode 18a, a second electrode 18b, a third electrode 18c, and a fourth electrode 18d on each rib 16. However, the number of electrodes 18 is not limited to four, as long as there is at least one. In this disclosure, when it is not necessary to distinguish between the first electrode 18a to the fourth electrode 18d, they are sometimes simply referred to as "electrode 18".

[0029] At the top end of each electrode 18, a wire (not shown) is connected. The wire passes through the cavity of the shaft 10, and the base end is connected to... Figure 1 The connector (not shown) of the handle 14 is connected. The power supply 8 is electrically connected to each wire via the connector of the handle 14. Therefore, each electrode 18 is electrically connected to the power supply 8 via wires and connectors. Details will be described later regarding the supply of ablation power to the multiple electrodes 18 via the power supply 8.

[0030] return Figure 1 A handle 14 is located at the base end of the shaft 10 and is positioned externally during use of the catheter 4 for the operator to grasp or operate. The handle 14 has a main body for the operator to grasp and an operating part for advancing and retracting the inner tube 22. By operating the operating part, the inner tube 22 can be displaced relative to the shaft 10 towards the base end. This unfolds the electrode assembly 12 in a direction intersecting the axis of the shaft 10. Furthermore, by operating the operating part, the inner tube 22 can be displaced relative to the shaft 10 towards the tip. This folds the electrode assembly 12 in its unfolded state. A connector is located in the main body. It should be noted that the catheter 4 may also have an infusion mechanism for spraying infusion fluids such as saline solution from the tip side during ablation.

[0031] The counter electrode 6 is worn on the patient's body surface during ablation. Furthermore, the counter electrode 6 is electrically connected to the power supply device 8. Details will be described later; the power supply device 8 supplies ablation power to the counter electrode 6.

[0032] The power supply unit 8 includes an input unit 24, a power supply unit 26, a control unit 28, and a display unit 30. The input unit 24, for example, consists of a dial, buttons, or a touch panel, and is operated by the operator of the ablation system 1. The operator can input various setting values ​​and signals indicating actions into the power supply unit 8 via the input unit 24. It should be noted that various setting values ​​can also be preset at the factory and stored in the power supply unit 8. Signals indicating setting values, etc., are sent from the input unit 24 to the control unit 28.

[0033] The power supply unit 26 applies an ablation voltage V to the plurality of electrodes 18 and the counter plate 6 according to the control signal CTL sent from the control unit 28. out The power supply unit 26 is configured, for example, by a power circuit such as a switching regulator. The control unit 28 controls the overall operation of the power supply device 8 and performs prescribed calculations. The control unit 28 is configured, for example, by a microcomputer. The control unit 28 controls the application of voltage Vout to the electrode 18 and the plate 6 by sending a control signal CTL to the power supply unit 26. The display unit 30 displays various information to the outside. The display unit 30 is configured as a liquid crystal display, a CRT (Cathode Ray Tube) display, an organic EL (Electroluminescence) display, etc.

[0034] Next, the control functions performed by the control unit 28 will be explained. In this embodiment, the ablation system 1 and power supply unit 8 use irreversible electroporation (IRE) to ablate the affected area 2. IRE is non-thermal, thus suppressing damage to surrounding tissues and nerves of the affected area 2. For example, in the case of performing pulmonary vein dissection to treat atrial fibrillation, it can suppress damage to the esophagus and diaphragm nerves surrounding the affected area, and can suppress complications such as esophageal fistula and diaphragm nerve paralysis.

[0035] In IRE, pulsed electric field ablation (PFA) is performed. PFA is an ablation technique that uses a pulsed electric field generated by applying a high voltage between each electrode 18 and the counter plate 6, and between the electrodes 18 themselves, to cause cell death, that is, to form an ablation lesion in the affected area 2. The electric field tends to reflect at the boundaries between tissues. Therefore, when cauterizing the affected area, damage to adjacent tissues can be suppressed.

[0036] With the electrode assembly 12 inserted into the patient's body via a blood vessel or the like and positioned on the affected area 2, the control unit 28 controls the power supply unit 26 to apply voltage to each electrode 18 and the counter plate 6 according to the rules described below. That is, the control unit 28 controls the power supply unit 26 to perform a combination of monopolar (also called unipolar) and bipolar application. In monopolar application, a voltage is applied between the electrode 18 and the counter plate 6. In bipolar application, a voltage is applied between the electrodes 18 and each other. Therefore, with monopolar application, it is easier to form an ablation foci deep within the tissue than with bipolar application. On the other hand, with bipolar application, it is easier to form a large-scale ablation foci in the surface direction (i.e., the direction of surface expansion) of the tissue than with monopolar application. As an example, the control unit 28 can perform at least a first application mode and a second application mode.

[0037] (First application mode)

[0038] Figure 3 (A) and Figure 3 (B) is a schematic diagram for explaining the first application mode. In the first application mode, the control unit 28 controls the power supply unit 26 to perform a predetermined bipolar application after performing a predetermined unipolar application. Furthermore, the combination of unipolar application and bipolar application is set as a group, and the control unit 28 performs more than one group of voltage applications in one ablation treatment.

[0039] like Figure 3 As shown in (A), in the unipolar application of the first application mode, each rib 16 is sequentially designated as the object to which voltage is applied, and a voltage is applied between the first electrode 18a to the third electrode 18c on the rib 16 that is the object to which voltage is applied and the counter plate 6. That is, voltages are applied to the first electrode 18a to the third electrode 18c simultaneously. In this disclosure, "simultaneous application" means that the states of applying voltages to each electrode 18 at least temporarily overlap.

[0040] As an example, firstly, a voltage is applied between the first electrode 18a to the third electrode 18c of the first rib 16a and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the second rib 16b and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the third rib 16c and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the fourth rib 16d and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the fifth rib 16e and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the sixth rib 16f and the counter electrode 6. Thus, the unipolar voltage application is completed.

[0041] like Figure 3 As shown in (B), in the subsequent bipolar application, a voltage is applied between the electrode 18 located on a given rib 16 and the electrode 18 located on a rib 16 adjacent to that rib 16. In this embodiment, a voltage is applied between the first electrode 18a in a group of two adjacent ribs 16, then between the second electrode 18b, and then between the third electrode 18c. The same voltage application is then performed on another group of ribs 16.

[0042] As an example, firstly, a voltage is applied between the first electrode 18a of the first rib 16a and the first electrode 18a of the second rib 16b. Next, a voltage is applied between the second electrodes 18b of the first rib 16a and the second electrodes 18b of the second rib 16b. Then, a voltage is applied between the third electrode 18c of the first rib 16a and the third electrode 18c of the second rib 16b.

[0043] When the voltage application in the group of first rib 16a and second rib 16b ends, the same voltage application is performed in the group of second rib 16b and third rib 16c. Next, the same voltage application is performed in the group of third rib 16c and fourth rib 16d. Next, the same voltage application is performed in the group of fourth rib 16d and fifth rib 16e. Next, the same voltage application is performed in the group of fifth rib 16e and sixth rib 16f. Next, the same voltage application is performed in the group of sixth rib 16f and first rib 16a. Thus, the bipolar voltage application ends.

[0044] (Second application mode)

[0045] Figure 4 (A) and Figure 4 (B) is a schematic diagram for explaining the second application mode. In the second application mode, the control unit 28 controls the power supply unit 26 to perform a predetermined bipolar application after performing a predetermined unipolar application. Furthermore, the combination of this unipolar application and bipolar application is set as a group, and the control unit 28 performs more than one group of voltage applications in a single ablation treatment.

[0046] like Figure 4 As shown in (A), in the unipolar application of the second application mode, similar to the first application mode, each rib 16 is sequentially set as the object of voltage application, and a voltage is applied between the first electrode 18a to the third electrode 18c on the rib 16 that is the object of application and the counter plate 6. That is, a voltage is applied to the first electrode 18a to the third electrode 18c simultaneously.

[0047] As an example, firstly, a voltage is applied between the first electrode 18a to the third electrode 18c of the first rib 16a and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the second rib 16b and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the third rib 16c and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the fourth rib 16d and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the fifth rib 16e and the counter electrode 6. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the sixth rib 16f and the counter electrode 6. Thus, the unipolar voltage application is completed.

[0048] like Figure 4 As shown in (B), in the subsequent bipolar application, a voltage is applied between the electrode 18 provided on the designated rib 16 and the electrode 18 provided on the rib 16 adjacent to the designated rib 16. In this embodiment, the first electrode 18a to the third electrode 18c in two adjacent groups of ribs 16 are applied to each other. That is, the first electrode 18a to the third electrode 18c are applied simultaneously. Then, the same voltage application is performed on another group of ribs 16. As a result, compared to the case where the first electrode 18a to the third electrode 18c are applied sequentially as in the bipolar application of the first application mode, the time spent until the end of the bipolar application can be shortened.

[0049] As an example, firstly, a voltage is applied between the first electrodes 18a to 18c of the first rib 16a and the first electrodes 18a to 18c of the second rib 16b. Next, a voltage is applied between the first electrodes 18a to 18c of the second rib 16b and the first electrodes 18a to 18c of the third rib 16c. Next, a voltage is applied between the first electrodes 18a to 18c of the third rib 16c and the first electrodes 18a to 18c of the fourth rib 16d. Next, a voltage is applied between the first electrodes 18a to 18c of the fourth rib 16d and the first electrodes 18a to 18c of the fifth rib 16e. Finally, a voltage is applied between the first electrodes 18a to 18c of the fifth rib 16e and the first electrodes 18a to 18c of the sixth rib 16f. Next, a voltage is applied between the first electrode 18a to the third electrode 18c of the sixth rib 16f and the first electrode 18a to the third electrode 18c of the first rib 16a. This completes the bipolar voltage application.

[0050] In this embodiment, the fourth electrode 18d on each rib 16 is excluded from the application of voltage. The fourth electrode 18d is set up for potentiometer measurement or as a backup in cases where the ablation range is large. That is to say, not all electrodes 18 of the catheter 4 are the application targets of ablation voltage. It should be noted that the fourth electrode 18d may also be omitted.

[0051] In this embodiment, the power supply unit 26 applies voltage to each electrode 18 and the counter plate 6 by generating biphase pulses (bipolar pulses). Therefore, positive and negative voltage phase pulses are applied to each electrode 18 and the counter plate 6, and the polarity of each electrode 18 and the counter plate 6 alternates. The voltage amplitude Am is, for example, 1000V or more and 4000V or less. The pulse width Δp is, for example, 0.1μs or more and 100μs or less.

[0052] In the unipolar application of each application mode, voltage is not applied simultaneously to all electrodes 18 located in the conduit 4 that are the targets of voltage application. Instead, the voltage is applied to each rib individually, thereby increasing the ablation foci that can be formed by unipolar application. This is believed to be because if voltage is applied to all electrodes 18 that are the targets of voltage application at the same time, the current flows dispersedly, and therefore the current density decreases. However, if voltage is applied sequentially to each of the ribs 16, the current is concentrated and the current density increases.

[0053] Furthermore, in the aforementioned unipolar application method, ablation foci tend to form more easily along the straight line connecting each rib 16 to the counter plate 6, while it is difficult to form ablation foci between adjacent ribs 16. Therefore, gaps may occur within the ablation foci. To address this, by applying voltage between adjacent ribs 16 using a bipolar application method, ablation foci can also be formed between adjacent ribs 16, thus filling the gaps between ablation foci. Therefore, by combining unipolar and bipolar application methods, uniform ablation foci can be easily formed over a large area.

[0054] Furthermore, in the unipolar application mode and the bipolar application mode of each application mode, the voltage application target is switched on a per-rib basis. This simplifies the power supply circuit for switching the voltage application target. Therefore, miniaturization of the power supply device 8 is possible. Furthermore, electrodes 18 can be easily added.

[0055] The voltage application scheme in both unipolar and bipolar application modes can be appropriately set based on the designer's experience or through experiments and simulations. For example, in unipolar application, the order of the ribs 16 to which voltage is applied is not limited to the order described above. Furthermore, some ribs 16 can be excluded from the power supply. Additionally, the combination of electrodes to which voltage is applied simultaneously is not limited to each rib; it can be any combination of two or more electrodes 18, or it can be all electrodes 18 that are the objects of voltage application. Furthermore, voltage can be applied to each electrode 18 sequentially. The power supply sequence to each electrode 18 can be appropriately set.

[0056] Furthermore, in the unipolar application of each application mode, the multiple ribs 16 can be divided into multiple groups, fewer than the number of ribs 16, and the voltage application target can be switched on a group basis. As an example, the first rib 16a, the third rib 16c, and the fifth rib 16e are designated as the first group, and the second rib 16b, the fourth rib 16d, and the sixth rib 16f are designated as the second group. After applying voltage between one or more electrodes 18 on the ribs 16 belonging to the first group and the counter plate 6, voltage is then applied between one or more electrodes 18 on the ribs 16 belonging to the second group and the counter plate 6. It should be noted that there can be a group to which only one rib 16 belongs, or the same rib 16 can be assigned to two or more different groups.

[0057] In bipolar application of voltage in each application mode, the number, combination, and order of voltage application of the electrodes being simultaneously applied are not limited to the above-described cases. For example, the electrodes 18 on each rib 16 can be divided into multiple groups, and the voltage application targets can be switched on a group basis. As an example, the first electrode 18a and the second electrode 18b on each rib 16 are designated as the first group, and the second electrode 18b and the third electrode 18c on each rib 16 are designated as the second group. Furthermore, voltage can be applied between the first groups of adjacent ribs 16 and then between the second groups. It should be noted that there can be a group to which only one electrode 18 belongs, or the same electrode 18 can be assigned to two or more different groups.

[0058] Furthermore, in bipolar application of each application mode, voltage may be applied between two electrodes 18 on the same rib 16. However, when performing bipolar application to fill gaps in ablation foci that may occur in unipolar application, it is preferable to apply voltage between the electrodes 18 on the respective ribs 16 that tend to be far apart from each other. Alternatively, instead of applying voltage between the electrodes 18 on adjacent ribs 16, it is also possible to apply voltage between the electrodes 18 on two ribs 16 arranged in a manner that sandwiches one or more ribs 16 in between. However, to more reliably fill gaps in ablation foci that may occur in unipolar application, it is preferable to apply voltage between the electrodes 18 on adjacent ribs 16.

[0059] Furthermore, in both unipolar and bipolar application modes, the application target can be switched after a single voltage application, or it can be switched after applying voltage to the same application target multiple times consecutively. By continuously applying voltage to the same electrode 18, the number of application target switching times can be reduced compared to the case where the application target is switched after each voltage application. Therefore, the control performed by the control unit 28 can be simplified. In this disclosure, "continuously applying voltage" means applying biphasic pulses to the same electrode 18 multiple times without interruption to applying voltage to other electrodes 18. Continuously applying voltage to each electrode 18 multiple times consecutively can be confirmed, for example, by connecting an oscilloscope to each electrode 18.

[0060] Furthermore, in each application mode, a unipolar application may be performed after a bipolar application. Also, in each application mode, the number of unipolar and bipolar applications included in a group is not limited to once each. For example, a group may consist of one or more consecutive unipolar applications and one or more consecutive bipolar applications. Furthermore, multiple groups with different contents may be combined in a single ablation treatment.

[0061] In the first application mode described above, voltages are sequentially applied to the first electrode 18a through the third electrode 18c in a bipolar application. Conversely, in the second application mode, voltages are applied simultaneously to the first electrode 18a through the third electrode 18c in a bipolar application. Therefore, the execution time of the bipolar application differs between the first and second application modes. Consequently, the ratio of the execution time of the unipolar application to the execution time of the bipolar application differs between the cases where ablation is performed in the first application mode and the cases where ablation is performed in the second application mode.

[0062] In other words, the control unit 28 of this embodiment can execute multiple application modes with different ratios of execution time for unipolar and bipolar application in a single ablation procedure. In this way, multiple application modes can be selected for execution, thereby enabling ablation suitable for the affected area 2. Therefore, the ease of use of the ablation system 1 can be improved. It should be noted that the control unit 28 can also execute an application scheme for at least one of the voltages in unipolar and bipolar application, in other words, an nth application mode (n is a natural number of 3 or more) where the ratio of the aforementioned execution time differs from the first and second application modes.

[0063] In addition, the control unit 28 can switch the application method according to the degree of bending of each rib 16. Figure 5 (A) and Figure 5 (B) is a schematic diagram illustrating the switching control of the application method corresponding to the state of stiffener 16. It should be noted that, in Figure 5 (A) and Figure 5 In (B), as an example, an electrode assembly 12 with eight ribs 16 is shown.

[0064] That is, such as Figure 5 As shown in (A), the control unit 28 controls the power supply unit 26 to apply power in a unipolar manner when each rib 16 is in a first unfolded state with a predetermined degree of bending. Furthermore, as... Figure 5 As shown in (B), the control unit 28 controls the power supply unit 26 to apply power in a bipolar manner when each rib 16 is in a second unfolded state where the bending is more abrupt than in the first unfolded state. Each rib 16 bends more gently in the first unfolded state than in the second unfolded state, and bends more abruptly in the second unfolded state than in the first unfolded state. The second unfolded state refers to the state in which each rib 16 has a portion with a greater curvature than in the first unfolded state. That is, the curvature of the portion with the greatest curvature in the second unfolded state is greater than the curvature of the portion with the greatest curvature in the first unfolded state.

[0065] When the multiple ribs 16 are in the first unfolded state, the electrodes 18 can be arranged over a large area. Therefore, by applying voltage in a unipolar manner when the multiple ribs 16 are in the first unfolded state, an ablation zone can be formed over a large area. Furthermore, when the multiple ribs 16 transition from the first unfolded state to the second unfolded state with a more abrupt bend, they tend to displace along the axis of the shaft 10. Therefore, the spacing between the electrodes 18 to which voltage is applied can be narrowed. Therefore, by applying voltage in a bipolar manner when the multiple ribs 16 are in the second unfolded state, the gaps in the ablation zone can be filled more reliably. The degree of bending of each rib 16 in the first and second unfolded states, in other words, the amount of pull on the inner tube 22, can be appropriately set based on the designer's experience or through experiments and simulations.

[0066] Furthermore, the configuration of the conduit 4 and the power supply device 8 can be appropriately modified. For example, the conduit 4 can also be bent in one or more directions by operating the handle 14. The control unit 28 can control the power supply unit 26 through hardware (circuit) or software (program). In the case of software implementation, the software consists of a group of programs for executing various functions via a computer. Each program can be pre-installed on the computer or installed on the computer from a network or recording medium.

[0067] Furthermore, the shape and number of the ribs 16 and electrodes 18 are not limited. Alternatively, the conduit 4 may not have ribs 16 at the top of the shaft 10, and the electrodes 18 may be disposed on the shaft 10. Alternatively, the electrodes 18 may be disposed on a balloon located at the top of the shaft 10. Furthermore, the power supply unit 26 may apply voltage to each electrode 18 in a manner that generates single-phase pulses.

[0068] Whether to apply the ablation voltage using a unipolar or bipolar method can be determined based on the impedance measurement results of the electrode 18, which is the target of the ablation voltage. Hereinafter, the electrode 18, which is the target of the ablation voltage, will be referred to as the target electrode 18x. That is, when the electrode assembly 12 is inserted into the patient's body via a blood vessel or the like, the objects contacted by the electrode 18 can include biological tissues such as the affected area 2 and blood. Furthermore, when physiological saline is sprayed from the tip of the catheter 4, the objects contacted by the electrode 18 also include physiological saline.

[0069] The conductivity of biological tissue is much lower than that of blood and saline solution. Therefore, the impedance Z generated when a voltage is applied between the electrode 6 and the target electrode 18x is relatively higher when the target electrode 18x is in contact with the biological tissue, and relatively lower when the target electrode 18x is not in contact with the biological tissue. Therefore, it is possible to determine whether the target electrode 18x is in contact with the biological tissue by measuring the impedance Z.

[0070] Therefore, the control unit 28 sends a control signal CTL to the power supply unit 26 to control the power supply unit 26 by applying a voltage for impedance measurement between the target electrode 18x and the counter plate 6. Then, the control unit 28 acquires information including the voltage value and current value obtained by applying this voltage via the power supply unit 26. Thus, the control unit 28 can measure the impedance Z between the target electrode 18x and the counter plate 6. Then, when the difference ΔZ between the measured impedance Z and the predetermined reference impedance Z0 is greater than or equal to a predetermined threshold Zth, the control unit 28 controls the power supply unit 26 to perform bipolar application using the target electrode 18x. Furthermore, when the difference ΔZ is less than the threshold Zth, the control unit 28 controls the power supply unit 26 to perform unipolar application using the target electrode 18x.

[0071] The reference impedance Z0 serves as the reference point, or zero point, for determining when the target electrode 18x contacts biological tissue. As an example, the reference impedance Z0 can be measured by applying an impedance measurement voltage between the two electrodes 18, ensuring that the electrode assembly 12 is inserted into the patient's body and that the target electrode 18x and the other electrodes 18 are not in contact with biological tissue. Alternatively, two dedicated reference electrodes for measuring the reference impedance Z0 can be placed in the electrode assembly 12 at locations where contact with biological tissue is ensured, and these two reference electrodes can be used to measure the reference impedance Z0. The reference impedance Z0 is pre-measured within the control unit 28 within the patient's body. Furthermore, the threshold Zth can be pre-set and maintained within the control unit 28, based on the designer's experience or through experiments, simulations, etc.

[0072] When the difference Δ is above the threshold Zth, it can be determined that the target electrode 18x is in contact with the biological tissue. When the target electrode 18x is in contact with the biological tissue, an electric field can be reliably generated in the biological tissue by applying it in a bipolar manner compared to the case where there is no contact. Therefore, when the difference Δ is above the threshold Zth, the control unit 28 controls the power supply unit 26 to perform bipolar application using the target electrode 18x. It should be noted that contact determination based on impedance Z is also performed on the electrode 18 that is the counterpart to the target electrode 18x when performing this bipolar application, thereby enabling bipolar application to be performed using only the electrode 18 that ensures contact with the biological tissue.

[0073] On the other hand, when the difference Δ is less than the threshold Zth, it can be determined that the target electrode 18x is not in contact with the biological tissue. In bipolar application when the target electrode 18x is not in contact with the biological tissue, a large amount of current flows in the blood or saline solution, making it difficult to generate an electric field in the biological tissue. Therefore, when the difference Δ is greater than or equal to the threshold Zth, the control unit 28 controls the power supply unit 26 to perform unipolar application using the target electrode 18x. With unipolar application, even if the target electrode 18x is not in contact with the biological tissue, an electric field can be generated in the biological tissue more reliably compared to bipolar application.

[0074] Furthermore, the impedance Z generated when a voltage is applied between the other electrodes 18 in contact with the biological tissue and the target electrode 18x is relatively higher when the target electrode 18x is in contact with the biological tissue, and relatively lower when the target electrode 18x is not in contact with the biological tissue. Therefore, the control unit 28 can also control the power supply unit 26 by applying a voltage for impedance measurement between the target electrode 18x and the other electrodes 18. In this case, it is preferable that the other electrodes 18, which are the counterparts to the target electrode 18x, are in contact with the biological tissue. As a result, it is possible to determine more accurately whether the target electrode 18x is in contact with the biological tissue.

[0075] Alternatively, the other electrodes 18 can also be electrodes used for bipolar application, namely, target electrodes 18x. In this case, if the difference Δ between the impedance Z between the two target electrodes 18x and the reference impedance Z0 is greater than or equal to the threshold Zth, it can be determined that the two target electrodes 18x are in contact with the biological tissue. Therefore, the control unit 28 controls the power supply unit 26 to perform bipolar application using these target electrodes 18x. On the other hand, if the difference Δ is less than the threshold Zth, it can be determined that at least one target electrode 18x is not in contact with the biological tissue. In this case, for example, the control unit 28 controls the power supply unit 26 to perform unipolar application regardless of which target electrode 18x is used.

[0076] Furthermore, whether to perform unipolar or bipolar application can be determined based on the pressure P applied to the target electrode 18x. That is, when the pressure P applied to the target electrode 18x is above a predetermined threshold Pth, it can be determined that the target electrode 18x is in contact with the biological tissue. Therefore, when the pressure P is above the threshold Pth, the control unit 28 controls the power supply unit 26 to perform bipolar application using the target electrode 18x. It should be noted that contact determination based on pressure P is also performed on the electrode 18 that is the counterpart to the target electrode 18x when performing this bipolar application, thereby enabling bipolar application to be performed using only the electrode 18 that ensures contact with the biological tissue.

[0077] On the other hand, when the pressure P is less than the threshold Pth, it can be determined that the target electrode 18x is not in contact with the biological tissue. Therefore, when the pressure P is less than the threshold Pth, the control unit 28 controls the power supply unit 26 to perform unipolar application using the target electrode 18x. The pressure P applied to the electrode 18 can be measured using known measurement methods. For example, by providing a known pressure sensor to the electrode 18, the pressure P can be measured. The threshold Pth can be preset and maintained within the control unit 28 based on the designer's experience or by setting appropriate settings such as experiments or simulations.

[0078] It should be noted that when multiple electrodes 18 are divided into multiple groups and unipolar and bipolar applications are performed on a group-by-group basis, contact determination of the target electrode 18x based on the aforementioned impedance Z and pressure P can also be performed on a group-by-group basis. Furthermore, contact determination based on impedance Z and contact determination based on pressure P can be combined. Additionally, contact determination can be performed periodically during ablation, and the unipolar and bipolar application methods can be switched based on the determination results. Furthermore, the application method can be selected or switched based on the number of times voltage is applied to the target electrode 18x, the duration, the temperature of the target electrode 18x, etc.

[0079] The embodiments of this disclosure have been described in detail above. These embodiments are merely examples illustrating specific practices of this disclosure. The content of the embodiments does not limit the technical scope of this disclosure, and various design changes, such as alterations, additions, and deletions of constituent elements, can be made without departing from the spirit of this disclosure as defined in the claims. New embodiments with applied design changes possess the effects of both combined embodiments and variations. In the embodiments, the phrases "in this embodiment" and "in this embodiment" are used to emphasize the possibility of such design changes, but design changes are permitted even without such phrases. Any combination of constituent elements included in each embodiment is valid as a solution of this disclosure. The shading lines in the cross-sectional drawings do not limit the material of the objects marked with shading lines.

[0080] The implementation method can also be determined by the items described below.

[0081] [Item 1]

[0082] A power supply device (8) for performing ablation using irreversible electroporation, the power supply device (8) comprising:

[0083] The power supply unit (26) is electrically connected to a conduit (4) having multiple electrodes (18) and a counter plate (6), and applies voltage to the multiple electrodes (18) and the counter plate (6); and

[0084] The control unit (28) controls the power supply unit (26) by combining the application of voltage between the electrode (18) and the counter plate (6) in a unipolar manner and the application of voltage between the electrodes (18) and each other in a bipolar manner.

[0085] [Item 2]

[0086] According to the power supply device (8) described in item 1, wherein,

[0087] The control unit (28) controls the power supply unit (26) in such a way that it applies the power in a unipolar manner after applying it in a bipolar manner.

[0088] [Item 3]

[0089] According to the power supply device (8) described in item 1 or item 2, wherein,

[0090] The control unit (28) can execute multiple application modes with different ratios of execution time for unipolar and bipolar ablation treatments.

[0091] [Item 4]

[0092] The power supply device (8) according to any one of items 1 to 3, wherein,

[0093] The conduit (4) has a shaft (10) and a plurality of ribs (16) arranged in the axial direction of the shaft (10).

[0094] At least one electrode (18) is provided in each rib (16).

[0095] In bipolar application, the control unit (28) controls the power supply unit (26) by applying voltage between the electrode (18) provided on the specified rib (16) and the electrode (18) provided on the rib (16) adjacent to the rib (16).

[0096] [Item 5]

[0097] The power supply device (8) according to any one of items 1 to 4, wherein,

[0098] The conduit (4) has a shaft (10) and a plurality of ribs (16) arranged in the axial direction of the shaft (10).

[0099] At least one electrode (18) is provided in each rib (16).

[0100] Multiple ribs (16) can switch between a first unfolded state with a specified degree of bending and a second unfolded state with a more rapid bending than the first unfolded state.

[0101] The control unit (28) controls the power supply unit (26) in a manner that applies the power in a unipolar manner when the multiple ribs (16) are in a first unfolded state and applies the power in a bipolar manner when the multiple ribs (16) are in a second unfolded state.

[0102] [Item 6]

[0103] The power supply device (8) according to any one of items 1 to 5, wherein,

[0104] The control unit (28) controls the power supply unit (26) in the following manner: an impedance measuring voltage is applied between the target electrode (18x), which is the target of the ablation voltage, and the counter plate (6), or between the target electrode (18x) and other electrodes (18) to measure the impedance (Z). When the difference (ΔZ) between the measured impedance (Z) and the reference impedance (Z0), which serves as the reference point for determining when the target electrode (18x) is in contact with biological tissue, is above a predetermined threshold (Zth), the target electrode (18x) is used to perform bipolar application. When the difference (ΔZ) is less than the threshold (Zth), the target electrode (18x) is used to perform unipolar application.

[0105] [Item 7]

[0106] The power supply device (8) according to any one of items 1 to 6, wherein,

[0107] The control unit (28) controls the power supply unit (26) in the following manner: when the pressure (P) applied to the target electrode (18x) which is the target of the ablation voltage among the multiple electrodes (18) is above a predetermined threshold (Pth), the target electrode (18x) is used to perform bipolar application; when the pressure (P) is less than the threshold (Pth), the target electrode (18x) is used to perform unipolar application.

[0108] [Item 8]

[0109] An ablation system (1) for performing ablation using irreversible electroporation, the ablation system (1) comprising:

[0110] The catheter (4) has multiple electrodes (18);

[0111] For the electrode plate (6); and

[0112] The power supply device (8) according to any one of items 1 to 7.

[0113] Industrial availability

[0114] This disclosure can be applied to power supply devices and ablation systems.

[0115] Explanation of reference numerals in the attached figures

[0116] 1: Ablation system; 4: Catheter; 6: Counter plate; 8: Power supply unit; 10: Shaft; 16: Rib; 18: Electrode; 26: Power supply unit; 28: Control unit.

Claims

1. A power supply device for performing ablation using irreversible electroporation, the power supply device comprising: The power supply section is electrically connected to a conduit having multiple electrodes and a counter plate, and applies voltage to the multiple electrodes and the counter plate; and The control unit controls the power supply unit by combining the application of voltage between the electrode and the counter plate in a unipolar manner and the application of voltage between the electrodes.

2. The power supply device according to claim 1, wherein, The control unit controls the power supply unit in such a way that the unipolar mode is applied after the bipolar mode is applied.

3. The power supply device according to claim 1 or 2, wherein, The control unit can execute multiple application modes in a single ablation procedure, with different ratios of the execution time applied in the unipolar mode to the execution time applied in the bipolar mode.

4. The power supply device according to claim 1 or 2, wherein, The conduit has a shaft and a plurality of ribs arranged around the shaft in the axial direction. At least one of the electrodes is provided in each rib. In the bipolar application, the control unit controls the power supply unit by applying a voltage between the electrode provided on a specified rib and the electrode provided on a rib adjacent to the specified rib.

5. The power supply device according to claim 1 or 2, wherein, The conduit has a shaft and a plurality of ribs arranged around the shaft in the axial direction. At least one of the electrodes is provided in each rib. The plurality of ribs can switch between a first unfolded state with a specified degree of bending and a second unfolded state with a more rapid bending than the first unfolded state. The control unit controls the power supply unit to apply the power in a unipolar manner when the plurality of ribs are in the first unfolded state, and to apply the power in a bipolar manner when the plurality of ribs are in the second unfolded state.

6. The power supply device according to claim 1, wherein, The control unit controls the power supply unit in the following manner: an impedance measurement voltage is applied between the target electrode (the object to which the ablation voltage is applied) and the counter electrode, or between the target electrode and other electrodes, to measure impedance; when the difference between the measured impedance and the reference impedance (which serves as a reference point for determining when the target electrode is in contact with biological tissue) is above a predetermined threshold, the target electrode is used to perform the bipolar application; when the difference is less than the threshold, the target electrode is used to perform the unipolar application.

7. The power supply device according to claim 1, wherein, The control unit controls the power supply unit in the following manner: when the pressure applied to the target electrode, which is the object of the ablation voltage among the plurality of electrodes, is above a predetermined threshold, the target electrode is used to perform the bipolar application; when the pressure is below the threshold, the target electrode is used to perform the unipolar application.

8. An ablation system for performing ablation using irreversible electroporation, the ablation system comprising: The catheter has multiple electrodes; For the plates; and The power supply device according to claim 1 or 2.

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