CN114081614B - Pulsed electric field tissue ablation device - Google Patents
Pulsed electric field tissue ablation device Download PDFInfo
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- CN114081614B CN114081614B CN202110841605.3A CN202110841605A CN114081614B CN 114081614 B CN114081614 B CN 114081614B CN 202110841605 A CN202110841605 A CN 202110841605A CN 114081614 B CN114081614 B CN 114081614B
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- 238000002679 ablation Methods 0.000 title claims abstract description 34
- 230000005684 electric field Effects 0.000 title claims abstract description 27
- 238000002955 isolation Methods 0.000 claims abstract description 111
- 239000003990 capacitor Substances 0.000 claims abstract description 61
- 238000004146 energy storage Methods 0.000 claims abstract description 41
- 230000000087 stabilizing effect Effects 0.000 claims description 53
- 230000002457 bidirectional effect Effects 0.000 claims description 16
- 238000007599 discharging Methods 0.000 claims description 5
- 230000002051 biphasic effect Effects 0.000 claims 1
- 206010028980 Neoplasm Diseases 0.000 abstract description 4
- 210000001519 tissue Anatomy 0.000 description 35
- 238000010586 diagram Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 230000008859 change Effects 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 238000011282 treatment Methods 0.000 description 5
- 238000004520 electroporation Methods 0.000 description 4
- 230000009471 action Effects 0.000 description 3
- 230000002427 irreversible effect Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000006907 apoptotic process Effects 0.000 description 2
- 210000000170 cell membrane Anatomy 0.000 description 2
- 230000006641 stabilisation Effects 0.000 description 2
- 238000011105 stabilization Methods 0.000 description 2
- 238000011298 ablation treatment Methods 0.000 description 1
- 230000017531 blood circulation Effects 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 210000004027 cell Anatomy 0.000 description 1
- 230000030833 cell death Effects 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 210000005003 heart tissue Anatomy 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004118 muscle contraction Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
- A61B18/1206—Generators therefor
- A61B18/1233—Generators therefor with circuits for assuring patient safety
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B18/04—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
- A61B18/12—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
- A61B18/1206—Generators therefor
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00571—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body for achieving a particular surgical effect
- A61B2018/00577—Ablation
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B18/00—Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
- A61B2018/00636—Sensing and controlling the application of energy
- A61B2018/00696—Controlled or regulated parameters
- A61B2018/00767—Voltage
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- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Plasma & Fusion (AREA)
- Physics & Mathematics (AREA)
- Heart & Thoracic Surgery (AREA)
- Medical Informatics (AREA)
- Molecular Biology (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
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- Electrotherapy Devices (AREA)
Abstract
The invention belongs to the technical field of medical appliances, and particularly relates to an ablation device. A pulsed electric field tissue ablation device comprising: the pulse generator is provided with a direct-current power supply, an energy storage capacitor and a discharge switch circuit which are sequentially connected; a pair of electrodes; the pulse generator further includes: and the isolating transformer is arranged between the discharge switch circuit and the electrodes, the primary side of the isolating transformer is connected with the discharge switch circuit, and the secondary side of the isolating transformer is respectively connected with the pair of electrodes. The invention adopts the isolation transformer to isolate the voltage-transformation discharge between the energy storage capacitor and the electrode for the patient, reduces the leakage current of the patient of the equipment, improves the safety of the equipment, and is suitable for ablation of tissues such as heart, tumor and the like.
Description
Technical Field
The invention belongs to the technical field of medical appliances, and particularly relates to an ablation device.
Background
Ablation refers to the local destruction of target tissue by thermal or chemical means. Traditionally, these techniques can be divided into two categories: thermal ablation techniques and chemical ablation techniques. Thermal ablation techniques destroy tissue by heating or freezing the tissue; chemical ablation technology is to inject corrosive substances into target tissues to destroy the tissues.
Pulsed electric field tissue ablation is a non-thermal ablation technique that utilizes the irreversible electroporation principle to interfere with cell permeability to achieve a level of cell death. Because the pulse electric field has short action time and low deposition energy, the electric field strength is not influenced by blood flow, and the method is widely used for tumor tissue ablation and heart tissue ablation.
Existing pulsed electric field tissue ablation devices are typically composed of a pulse generator and electrodes. During treatment, the pulse generator outputs pulses with certain amplitude, and the pulses are applied to human tissues through the electrodes. The pulse electric field strength is proportional to the pulse amplitude and inversely proportional to the electrode spacing. Since the electrode spacing is fixed, the pulse amplitude must be stabilized in order to ensure the stable electric field strength. The pulse generator must provide sufficient current in order to maintain the voltage between the electrodes due to the presence of ions in the human tissue. Although the average pulse power is small, only tens of watts, the peak pulse power is large, up to hundreds of kilowatts. In order to output such high peak power, energy is typically stored in a capacitor. The high-energy capacitor and the patient are directly discharged through the switch, so that the electric safety risk is high, and the high-energy capacitor and the patient belong to a third type of medical equipment.
Disclosure of Invention
The invention aims at the technical problems that a high-energy capacitor and a patient are directly discharged through a switch, and the electrical safety risk is high, and aims to provide a pulsed electric field tissue ablation device.
A pulsed electric field tissue ablation device comprising:
the pulse generator is provided with a direct-current power supply, an energy storage capacitor and a discharge switch circuit which are sequentially connected;
A pair of electrodes;
the pulse generator further includes:
the isolating transformer is arranged between the discharge switch circuit and the electrodes, the primary side of the isolating transformer is connected with the discharge switch circuit, and the secondary side of the isolating transformer is respectively connected with a pair of electrodes.
The invention is used in a tissue ablation scene, and a pair of electrodes are arranged near the ablated tissue during treatment. The pulse generator outputs a pulse with a certain amplitude, so that a pulse electric field is formed between the two electrodes. Under the action of the pulsed electric field, irreversible electroporation is formed on the cell membranes of the tissue to be treated, resulting in apoptosis of the tissue. The purpose of tissue ablation is achieved. According to the invention, the isolation transformer is additionally arranged in the pulse generator, the electric field provided by the discharge of the energy storage capacitor is isolated by the isolation transformer, and the discharge is realized by the electrode, so that the leakage current of a patient of the device is reduced, the safety of the device is improved, and the device is suitable for ablation of tissues such as heart, tumor and the like.
The discharge switching circuit includes:
The drain electrode of the first MOS tube is connected with the positive electrode of the energy storage capacitor;
The source electrode of the second MOS tube is connected with the negative electrode of the energy storage capacitor, and the drain electrode of the second MOS tube is connected with the source electrode of the first MOS tube;
The drain electrode of the third MOS tube is connected with the positive electrode of the energy storage capacitor;
The source electrode of the fourth MOS tube is connected with the negative electrode of the energy storage capacitor, and the drain electrode of the fourth MOS tube is connected with the source electrode of the third MOS tube;
A common end between the source electrode of the first MOS tube and the drain electrode of the second MOS tube is connected with a primary side non-homonymous end of the isolation transformer;
and a common end between the source electrode of the third MOS tube and the drain electrode of the fourth MOS tube is connected with the primary side homonymous end of the isolation transformer.
The discharge switching circuit further includes:
the signal output end of the discharging switch control module is respectively connected with the grid electrode of the first MOS tube, the grid electrode of the second MOS tube, the grid electrode of the third MOS tube and the grid electrode of the fourth MOS tube and is used for controlling the on or off of the first MOS tube, the second MOS tube, the third MOS tube or the fourth MOS tube;
the control mode of the discharge switch circuit by the discharge switch control module adopts the following modes:
Let the discharge time of the energy storage capacitor be t0, the discharge periods of the energy storage capacitor be t1, t2, t3 and t4, and the discharge end time of the energy storage capacitor be t5, then:
at time t0, closing the fourth MOS tube, switching on the third MOS tube, connecting the primary homonymous end of the isolation transformer with the positive electrode of the energy storage capacitor, closing the first MOS tube, switching on the second MOS tube, connecting the primary non-homonymous end of the isolation transformer with the negative electrode of the energy storage capacitor, and generating positive pulse at the secondary homonymous end of the isolation transformer;
At time t1 to time t2, the second MOS tube and the fourth MOS tube are conducted, the first MOS tube and the third MOS tube are closed, two ends of the primary side of the isolation transformer are grounded, the primary side input voltage of the isolation transformer is zero, and the secondary side voltage of the isolation transformer is also zero;
At time t2 to time t3, closing the second MOS tube, conducting the first MOS tube, connecting a primary side non-homonymous end of the isolation transformer with a positive electrode of the energy storage capacitor, closing the third MOS tube, conducting the fourth MOS tube, connecting a primary side homonymous end of the isolation transformer with a negative electrode of the energy storage capacitor, and generating negative pulses at a secondary side homonymous end of the isolation transformer;
At time t3 to time t4, the second MOS tube and the fourth MOS tube are conducted, the first MOS tube and the third MOS tube are closed, the two ends of the primary side of the isolation transformer are grounded, the primary side input voltage of the isolation transformer is zero, and the secondary side voltage of the isolation transformer is also zero;
and repeating the control from the time t0 to the time t4 to form at least one pulse train until the pulse train ends at the time t 5.
The discharge switching circuit further includes:
And a second capacitor connected in parallel with the energy storage capacitor.
The pulse generator further includes:
And the amplitude stabilizing circuit is arranged between the secondary side of the isolation transformer and the pair of electrodes and is used for stabilizing the amplitude of alternating current pulses output by the isolation transformer.
The amplitude stabilizing circuit adopts a dual-phase amplitude stabilizing circuit, and the dual-phase amplitude stabilizing circuit comprises:
the grid electrode of the first IGBT tube is connected with the same-name end of the secondary side of the isolation transformer, the collector electrode of the first IGBT tube is connected with the same-name end of the secondary side of the isolation transformer, and the emitter electrode of the first IGBT tube is connected with one electrode;
One end of the first resistor is connected with the grid electrode of the first IGBT tube, and the other end of the first resistor is connected with the collector electrode of the first IGBT tube;
The grid electrode of the second IGBT tube is connected with the secondary side non-homonymous end of the isolation transformer, the collector electrode of the second IGBT tube is connected with the secondary side non-homonymous end of the isolation transformer, and the emitter electrode of the second IGBT tube is connected with the other electrode;
one end of the second resistor is connected with the grid electrode of the second IGBT tube, and the other end of the second resistor is connected with the collector electrode of the second IGBT tube;
at least one bidirectional voltage stabilizing tube is connected in series in sequence and then connected with the secondary side of the isolation transformer in parallel;
And at least one solid-state relay, the number of which is the same as that of the bidirectional voltage stabilizing tubes, wherein one solid-state relay is connected with one bidirectional voltage stabilizing tube in parallel.
The dual-phase amplitude stabilizing circuit further comprises:
The anode of the first diode is connected with the grid electrode of the first IGBT, and the cathode of the first diode is connected with the same-name end of the secondary side of the isolation transformer;
And the anode of the second diode is connected with the grid electrode of the second IGBT tube, and the cathode of the second diode is connected with the secondary side non-homonymous end of the isolation transformer.
The dual-phase amplitude stabilizing circuit further comprises:
The first protection diode is a bidirectional voltage stabilizing tube, one end of the first protection diode is connected with the grid electrode of the first IGBT tube, and the other end of the first protection diode is connected with the emitter electrode of the first IGBT tube;
And one end of the second protection diode is connected with the grid electrode of the second IGBT tube, and the other end of the second protection diode is connected with the emitter electrode of the second IGBT tube.
The secondary side of the isolation transformer comprises:
And each group of secondary coils is respectively connected with one path of amplitude stabilizing circuit, and the plurality of paths of amplitude stabilizing circuits are connected in series and then connected with one pair of electrodes.
The isolation transformers are multiple, primary sides of the isolation transformers are connected in parallel, secondary sides of the isolation transformers are respectively connected with one path of amplitude stabilizing circuit, and multiple paths of amplitude stabilizing circuits are connected with a pair of electrodes after being connected in series.
The isolation transformer adopts a step-up transformer, and the output pulse amplitude of the isolation transformer is higher than the preset output pulse amplitude of the electrode terminal.
The direct current power supply is a direct current power supply with adjustable output voltage.
The direct current power supply is internally provided with a discharge circuit, and the discharge circuit is preferably a rapid discharge circuit.
When the direct current power supply charges the energy storage capacitor, the setting amplitude of the latter pulse is lower than that of the former pulse.
The electrode adopts one of a flat electrode, a needle electrode or a catheter electrode.
The invention has the positive progress effects that: the invention has the following remarkable advantages:
1. the isolation transformer is adopted between the energy storage capacitor and the electrode for the patient to isolate the voltage-variable discharge, so that the leakage current of the patient of the device is reduced, the safety of the device is improved, and the device is suitable for ablation of tissues such as heart, tumor and the like;
2. After the transformer is isolated, a stable amplitude circuit is utilized, the circuit is simple, the reliability of equipment is improved, the pulse amplitude is constant, the treatment is accurate, the positive and negative amplitudes of each pulse train can be independently set, and the two-phase high-frequency pulse trains can reduce muscle contraction;
3. after the pulse trains with the amplitude are connected in series, the output pulse amplitude can be improved to be suitable for ablation of different tissues.
Drawings
FIG. 1 is a block diagram of the overall structure of the present invention;
FIG. 2 is a circuit diagram of a discharge switch circuit of the present invention;
FIG. 3 is a waveform diagram of the secondary side of the isolation transformer of the present invention;
FIG. 4 is a circuit diagram of a dual phase amplitude stabilizing circuit of the present invention;
Fig. 5 is a waveform diagram of the two ends of the load after stabilizing amplitude.
Detailed Description
In order that the manner in which the invention is practiced, as well as the features and objects and functions thereof, will be readily understood and appreciated, the invention will be further described in connection with the accompanying drawings.
Referring to fig. 1 to 5, a pulsed electric field tissue ablation device includes a pulse generator 100 and a pair of electrodes 200. The pulse generator 100 comprises a direct current power supply 101, a storage capacitor C+, a discharge switch circuit 102, an isolation transformer T1 and a amplitude stabilizing circuit 103 which are connected in sequence. The pair of electrodes 200 are an electrode 201 and an electrode 202, respectively. The electrode 200 is one of a flat electrode 200, a needle electrode 200 or a catheter electrode 200.
The dc power supply 101 is a dc power supply with an adjustable output voltage, so as to initially set the amplitude of the pulse. The direct current power supply 101 is internally provided with a discharge circuit, and the discharge circuit is preferably a rapid discharge circuit which is also used for discharging the residual energy in the energy storage capacitor C+ after the treatment is finished, so that the requirement of the general standard of medical electrical safety on the residual energy is further met. When the dc power supply 101 charges the storage capacitor c+, the amplitude of the subsequent pulse is lower than that of the previous pulse to ensure that the excess energy in the storage capacitor c+ is discharged before the subsequent pulse is delivered.
Referring to fig. 2, the discharge switch circuit 102 includes a first MOS transistor K1, a second MOS transistor K2, a third MOS transistor K3, a fourth MOS transistor K4, a discharge switch control module, and a second capacitor C2.
The drain electrode of the first MOS tube K1 is connected with the positive electrode of the energy storage capacitor C+. The source electrode of the second MOS tube K2 is connected with the negative electrode of the energy storage capacitor C+, and the drain electrode of the second MOS tube K2 is connected with the source electrode of the first MOS tube K1. The drain electrode of the third MOS tube K3 is connected with the positive electrode of the energy storage capacitor C+. The source electrode of the fourth MOS tube K4 is connected with the negative electrode of the energy storage capacitor C+, and the drain electrode of the fourth MOS tube K4 is connected with the source electrode of the third MOS tube K3. The common end between the source electrode of the first MOS tube K1 and the drain electrode of the second MOS tube K2 is connected with the primary side non-homonymous end of the isolation transformer T1. The common end between the source electrode of the third MOS tube K3 and the drain electrode of the fourth MOS tube K4 is connected with the primary side homonymous end of the isolation transformer T1.
The second capacitor C2 is connected in parallel with the storage capacitor c+.
The signal output end of the discharging switch control module is respectively connected with the grid electrode of the first MOS tube K1, the grid electrode of the second MOS tube K2, the grid electrode of the third MOS tube K3 and the grid electrode of the fourth MOS tube K4, and the discharging switch control module is used for controlling the conduction or the closing of the first MOS tube K1, the second MOS tube K2, the third MOS tube K3 or the fourth MOS tube K4. The control mode of the discharge switch control module for the discharge switch circuit 102 adopts the following manner: assuming that the discharge time of the storage capacitor c+ is t0, the discharge periods of the storage capacitor c+ are t1, t2, t3, and t4, and the discharge end time of the storage capacitor c+ is t5, then:
At time T0, the fourth MOS tube K4 is closed, the third MOS tube K3 is connected, the primary side homonymous end of the isolation transformer T1 is connected with the positive electrode of the energy storage capacitor C+, the first MOS tube K1 is closed, the second MOS tube K2 is connected, the primary side non-homonymous end of the isolation transformer T1 is connected with the negative electrode of the energy storage capacitor C+, and positive pulses are generated at the secondary side homonymous end of the isolation transformer T1;
At the time T1 to the time T2, the second MOS tube K2 and the fourth MOS tube K4 are conducted, the first MOS tube K1 and the third MOS tube K3 are closed, the two ends of the primary side of the isolation transformer T1 are grounded, the primary side input voltage of the isolation transformer T1 is zero, and the secondary side voltage of the isolation transformer T1 is also zero;
At time T2 to time T3, closing the second MOS tube K2, conducting the first MOS tube K1, connecting the primary side non-homonymous end of the isolation transformer T1 with the positive electrode of the energy storage capacitor C+, closing the third MOS tube K3, conducting the fourth MOS tube K4, connecting the primary side homonymous end of the isolation transformer T1 with the negative electrode of the energy storage capacitor C+, and generating negative pulses at the secondary side homonymous end of the isolation transformer T1;
At time t3 to time t4, the above-described process from time t1 to time t2 is repeated, namely: the second MOS tube K2 and the fourth MOS tube K4 are conducted, the first MOS tube K1 and the third MOS tube K3 are closed, the two ends of the primary side of the isolation transformer T1 are grounded, the primary side input voltage of the isolation transformer T1 is zero, and the secondary side voltage of the isolation transformer T1 is also zero;
The control from time T0 to time T4 is repeated, and as shown in fig. 3, a plurality of pulse trains are formed on the secondary side of the isolation transformer T1 until the end of the pulse train at time T5. Because of the short discharge time, only a small portion of the voltage of the storage capacitor C1 is discharged, and the secondary side output waveform of the isolation transformer T1 as shown in fig. 3 is a square wave showing a change in pulse amplitude due to a change in load impedance.
Referring to fig. 2, an isolation transformer T1 is disposed between the discharge switching circuit 102 and the electrodes 200, a primary side of the isolation transformer T1 is connected to the discharge switching circuit 102, a secondary side of the isolation transformer T1 is connected to the pair of electrodes 200, respectively, and as shown in fig. 2, the secondary side of the isolation transformer T1 is grounded at a non-identical name. The isolation transformer T1 is preferably a step-up transformer, and the output pulse amplitude of the isolation transformer T1 is higher than the preset output pulse amplitude of the electrode 200.
Since the electrical impedance of human tissue is constantly changing as electroporation progresses. The amplitude of the output pulse is continuously changed along with the electrical impedance of human tissues due to the output resistance of the isolation transformer T1, and the electric field intensity is continuously changed due to the fixed distance between the pair of electrodes 200. To stabilize the electric field strength, the amplitude of the output pulse must be stabilized. In order to reduce the complexity of the circuit and improve the reliability of the equipment, the invention utilizes the amplitude stabilizing circuit 103 to directly stabilize the amplitude of the alternating current pulse output by the isolation transformer T1.
Referring to fig. 4, a stabilizing circuit 103 is disposed between the secondary side of the isolation transformer T1 and the pair of electrodes 200, for stabilizing the ac pulse output from the isolation transformer T1. Wherein RX is the equivalent resistance of the treated human tissue.
The amplitude stabilizing circuit 103 adopts a dual-phase amplitude stabilizing circuit, and the dual-phase amplitude stabilizing circuit comprises a first IGBT Q+, a first resistor R+, a first diode D1, a first protection diode W+, a second IGBT Q-, a second resistor R-, a second diode D2, a second protection diode W-, at least one bidirectional voltage stabilizing tube and at least one solid-state relay.
The gate of the first IGBT q+ is connected to the same-name end of the secondary side of the isolation transformer T1, the collector of the first IGBT q+ is connected to the same-name end of the secondary side of the isolation transformer T1, and the emitter of the first IGBT q+ is connected to one electrode 201 (not shown in fig. 4). One end of the first resistor R+ is connected with the grid electrode of the first IGBT tube Q+, and the other end of the first resistor R+ is connected with the collector electrode of the first IGBT tube Q+. The positive pole of first diode D1 is connected with the grid of first IGBT pipe Q+, and the negative pole of first diode D1 is connected with isolation transformer T1's vice limit homonymy end. The first protection diode W+ is a bidirectional voltage stabilizing tube, one end of the first protection diode W+ is connected with the grid electrode of the first IGBT tube Q+, and the other end of the first protection diode W+ is connected with the emitter electrode of the first IGBT tube Q+.
The gate of the second IGBT Q-is connected to the secondary non-identical terminal of the isolation transformer T1, the collector of the second IGBT Q-is connected to the secondary non-identical terminal of the isolation transformer T1, and the emitter of the second IGBT Q-is connected to the other electrode 202 (not shown in fig. 4). One end of the second resistor R-is connected with the grid electrode of the second IGBT tube Q-and the other end of the second resistor R-is connected with the collector electrode of the second IGBT tube Q-. The positive pole of the second diode D2 is connected with the grid electrode of the second IGBT tube Q-, and the negative pole of the second diode D2 is connected with the non-homonymous end of the secondary side of the isolation transformer T1. The second protection diode W-is a bidirectional voltage stabilizing tube, one end of the second protection diode W-is connected with the grid electrode of the second IGBT tube Q-and the other end of the second protection diode W-is connected with the emitter electrode of the second IGBT tube Q-.
The number of the bidirectional voltage stabilizing tubes can be one or more according to the requirement, namely Z1 and Z2 … … ZN respectively, and the one or more bidirectional voltage stabilizing tubes are connected in series in sequence and then connected with the secondary side of the isolation transformer T1 in parallel.
One or more solid-state relays can be arranged according to requirements, the number of the solid-state relays is the same as that of the bidirectional voltage stabilizing tubes, and one solid-state relay is connected with one bidirectional voltage stabilizing tube in parallel. The input end of each solid state relay, namely the LED1 and the LED2 … … LEDN end, can be connected with a relay controller for controlling the switch state of the solid state relay.
The working principle of the dual-phase amplitude stabilizing circuit is as follows:
Firstly, the output pulse amplitude of the isolation transformer T1 is higher than the expected output pulse amplitude of the preset electrode 200 end, and the higher amplitude can be set according to the actual scene requirement. The electrode 200 acts on human tissue, as shown in fig. 4, let RX be the equivalent resistance of the treated human tissue, D+ be the body diode of the first IGBT Q+ and D-be the body diode of the second IGBT Q-.
When the pulse output by the same-name end of the secondary side of the isolation transformer T1 is positive, the first resistor R+ enables the first IGBT tube Q+ to be turned on. The first resistor r+, the bidirectional regulators Z1 to ZN, and the first diode D1 act together to generate a voltage vg+. Changing the switching states of the solid state relays OP1 to OPN can change vg+ and thus change the amplitude of the output pulse stabilization. When the first IGBT tube q+ is in the emitter follower state, the emitter voltage ve= (vg+) -V GE of the first IGBT tube q+. Since V GE is basically unchanged, VE is kept unchanged, and the positive pulse amplitude is ensured to be unchanged. The flow direction of the positive pulse current is the same name end of the isolation transformer T1, the first IGBT tube Q+, the equivalent resistor RX and the body diode D-, and the non-same name end of the isolation transformer T1.
Similarly, when the pulse output by the non-homonymous end of the secondary side of the isolation transformer T1 is positive, the second resistor R-enables the second IGBT tube Q-to be turned on. The second resistor R-, the regulators Z1 to ZN and the second diode D2 together generate a voltage Vg-. Changing the switching state of the solid state relays OP1 to OPN can change Vg-, thereby changing the amplitude of the output pulse stabilization. When the second IGBT tube Q-is in the emitter follower state, the emitter voltage ve= (Vg-) -V GE of the second IGBT tube Q-. Since V GE is essentially unchanged, VE remains unchanged. Ensuring that the negative pulse amplitude is unchanged. The flow direction of the negative pulse current is the non-homonymous end of the isolation transformer T1, the second IGBT tube Q-, the equivalent resistor RX, the body diode D+ and the homonymous end of the isolation transformer T1.
The invention can control the amplitude of each pulse train by changing the switching state of the solid state relay. If the positive or negative pulse amplitude is set to zero, a monophasic pulse can be output.
Referring to fig. 5, the waveform diagram is a waveform diagram of the equivalent resistor RX, that is, two ends of the load, and compared with fig. 3, the pulse output by the secondary side of the isolation transformer T1 is stabilized by the dual-phase amplitude stabilizing circuit of the present invention, and then the pulse amplitude output to the load is stable and reliable.
In order to improve the pulse amplitude, the secondary side of the isolation transformer T1 adopts a plurality of groups of secondary side coils, each group of secondary side coils is respectively connected with one path of amplitude stabilizing circuit 103, and the plurality of paths of amplitude stabilizing circuits 103 are connected in series and then connected with a pair of electrodes 200. The number of the isolation transformers T1 may be plural, the primary sides of the isolation transformers T1 may be connected in parallel, the secondary sides of the isolation transformers T1 may be connected to one path of the amplitude stabilizing circuit 103, and the multiple paths of the amplitude stabilizing circuits 103 may be connected in series and then connected to the pair of electrodes 200.
The invention is used in a tissue ablation scenario, referring to fig. 1, a dc power supply 101 charges a storage capacitor c+ and stores energy in the storage capacitor c+ prior to tissue ablation treatment. In treatment, a pair of electrodes 200 are placed adjacent to the body tissue 300 to be ablated. The discharge switching circuit 102 operates to transfer the energy in the storage capacitor c+ to the isolation transformer T1. The isolation transformer T1 increases the voltage on the storage capacitor c+ to a certain magnitude, and after stabilizing the amplitude by the amplitude stabilizing circuit 103, the voltage is applied to the human tissue 300 through the pair of electrodes 200. The voltage forms a pulsed electric field in the human tissue 300, and under the action of the pulsed electric field, irreversible electroporation is formed on the cell membrane of the tissue to be treated, so that the tissue apoptosis is caused, and the purpose of tissue ablation is achieved.
The foregoing has shown and described the basic principles and main features of the present invention and the advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (8)
1. A pulsed electric field tissue ablation device comprising:
the pulse generator is provided with a direct-current power supply, an energy storage capacitor and a discharge switch circuit which are sequentially connected;
A pair of electrodes;
characterized in that the pulse generator further comprises:
The isolating transformer is arranged between the discharge switch circuit and the electrode, the primary side of the isolating transformer is connected with the discharge switch circuit, and the secondary side of the isolating transformer is respectively connected with a pair of electrodes;
the discharge switching circuit includes:
The drain electrode of the first MOS tube is connected with the positive electrode of the energy storage capacitor;
The source electrode of the second MOS tube is connected with the negative electrode of the energy storage capacitor, and the drain electrode of the second MOS tube is connected with the source electrode of the first MOS tube;
The drain electrode of the third MOS tube is connected with the positive electrode of the energy storage capacitor;
The source electrode of the fourth MOS tube is connected with the negative electrode of the energy storage capacitor, and the drain electrode of the fourth MOS tube is connected with the source electrode of the third MOS tube;
A common end between the source electrode of the first MOS tube and the drain electrode of the second MOS tube is connected with a primary side non-homonymous end of the isolation transformer;
a common end between the source electrode of the third MOS tube and the drain electrode of the fourth MOS tube is connected with a primary side homonymous end of the isolation transformer;
The discharge switching circuit further includes:
the signal output end of the discharging switch control module is respectively connected with the grid electrode of the first MOS tube, the grid electrode of the second MOS tube, the grid electrode of the third MOS tube and the grid electrode of the fourth MOS tube and is used for controlling the on or off of the first MOS tube, the second MOS tube, the third MOS tube or the fourth MOS tube;
the control mode of the discharge switch circuit by the discharge switch control module adopts the following modes:
Let the discharge time of the energy storage capacitor be t0, the discharge periods of the energy storage capacitor be t1, t2, t3 and t4, and the discharge end time of the energy storage capacitor be t5, then:
at time t0, closing the fourth MOS tube, switching on the third MOS tube, connecting the primary homonymous end of the isolation transformer with the positive electrode of the energy storage capacitor, closing the first MOS tube, switching on the second MOS tube, connecting the primary non-homonymous end of the isolation transformer with the negative electrode of the energy storage capacitor, and generating positive pulse at the secondary homonymous end of the isolation transformer;
At time t1 to time t2, the second MOS tube and the fourth MOS tube are conducted, the first MOS tube and the third MOS tube are closed, two ends of the primary side of the isolation transformer are grounded, the primary side input voltage of the isolation transformer is zero, and the secondary side voltage of the isolation transformer is also zero;
At time t2 to time t3, closing the second MOS tube, conducting the first MOS tube, connecting a primary side non-homonymous end of the isolation transformer with a positive electrode of the energy storage capacitor, closing the third MOS tube, conducting the fourth MOS tube, connecting a primary side homonymous end of the isolation transformer with a negative electrode of the energy storage capacitor, and generating negative pulses at a secondary side homonymous end of the isolation transformer;
At time t3 to time t4, the second MOS tube and the fourth MOS tube are conducted, the first MOS tube and the third MOS tube are closed, the two ends of the primary side of the isolation transformer are grounded, the primary side input voltage of the isolation transformer is zero, and the secondary side voltage of the isolation transformer is also zero;
and repeating the control from the time t0 to the time t4 to form at least one pulse train until the pulse train ends at the time t 5.
2. The pulsed electric field tissue ablation device of claim 1 wherein the pulse generator further comprises:
And the amplitude stabilizing circuit is arranged between the secondary side of the isolation transformer and the pair of electrodes and is used for stabilizing the amplitude of alternating current pulses output by the isolation transformer.
3. The pulsed electric field tissue ablation device of claim 2 wherein the amplitude stabilizing circuit employs a biphasic amplitude stabilizing circuit comprising:
the grid electrode of the first IGBT tube is connected with the same-name end of the secondary side of the isolation transformer, the collector electrode of the first IGBT tube is connected with the same-name end of the secondary side of the isolation transformer, and the emitter electrode of the first IGBT tube is connected with one electrode;
One end of the first resistor is connected with the grid electrode of the first IGBT tube, and the other end of the first resistor is connected with the collector electrode of the first IGBT tube;
The grid electrode of the second IGBT tube is connected with the secondary side non-homonymous end of the isolation transformer, the collector electrode of the second IGBT tube is connected with the secondary side non-homonymous end of the isolation transformer, and the emitter electrode of the second IGBT tube is connected with the other electrode;
one end of the second resistor is connected with the grid electrode of the second IGBT tube, and the other end of the second resistor is connected with the collector electrode of the second IGBT tube;
at least one bidirectional voltage stabilizing tube is connected in series in sequence and then connected with the secondary side of the isolation transformer in parallel;
And at least one solid-state relay, the number of which is the same as that of the bidirectional voltage stabilizing tubes, wherein one solid-state relay is connected with one bidirectional voltage stabilizing tube in parallel.
4. The pulsed electric field tissue ablation device of claim 3 wherein the bi-phase amplitude stabilizing circuit further comprises:
The anode of the first diode is connected with the grid electrode of the first IGBT, and the cathode of the first diode is connected with the same-name end of the secondary side of the isolation transformer;
And the anode of the second diode is connected with the grid electrode of the second IGBT tube, and the cathode of the second diode is connected with the secondary side non-homonymous end of the isolation transformer.
5. The pulsed electric field tissue ablation device of claim 3 wherein the bi-phase amplitude stabilizing circuit further comprises:
The first protection diode is a bidirectional voltage stabilizing tube, one end of the first protection diode is connected with the grid electrode of the first IGBT tube, and the other end of the first protection diode is connected with the emitter electrode of the first IGBT tube;
And one end of the second protection diode is connected with the grid electrode of the second IGBT tube, and the other end of the second protection diode is connected with the emitter electrode of the second IGBT tube.
6. The pulsed electric field tissue ablation device of claim 2 wherein the secondary side of the isolation transformer comprises:
And each group of secondary coils is respectively connected with one path of amplitude stabilizing circuit, and the plurality of paths of amplitude stabilizing circuits are connected in series and then connected with one pair of electrodes.
7. The pulsed electric field tissue ablation device of claim 2 wherein the isolation transformers are a plurality, primary sides of the isolation transformers are connected in parallel, secondary sides of the isolation transformers are respectively connected with one of the amplitude stabilizing circuits, and the plurality of the amplitude stabilizing circuits are connected in series and then connected with a pair of the electrodes.
8. The pulsed electric field tissue ablation device of claim 1 wherein the discharge switching circuit further comprises:
A second capacitor connected in parallel with the energy storage capacitor;
the isolation transformer adopts a step-up transformer, and the output pulse amplitude of the isolation transformer is higher than the preset output pulse amplitude of the electrode terminal;
The direct current power supply is a direct current power supply with adjustable output voltage;
the direct current power supply is internally provided with a discharge circuit which is a rapid discharge circuit;
when the direct current power supply charges the energy storage capacitor, the setting amplitude of the latter pulse is lower than the setting amplitude of the former pulse;
The electrode adopts one of a flat electrode, a needle electrode or a catheter electrode.
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| CN106388929A (en) * | 2016-10-25 | 2017-02-15 | 上海健康医学院 | Isolated type square wave irreversible electroporation apparatus |
| CN108095820A (en) * | 2018-02-07 | 2018-06-01 | 上海健康医学院 | A kind of nano-knife tumour ablation control device and its control method |
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