A multiphase radio frequency treatment system and method of heating electrically conductive matter using the same

Abstract

The present application relates to the technical field of medical equipment, and particularly relates to a multi-phase radio frequency treatment system and a method for heating conductive substances using the same. The multi-phase radio frequency treatment system comprises a multi-phase radio frequency generator and a microneedle electrode array. The multi-phase radio frequency generator is configured to output M-phase radio frequency signals, wherein M=3 or 4, and each phase signal has the same frequency and the same amplitude. The phase difference between the M-phase signals output by the multi-phase radio frequency generator is greater than 360° / M-30° and less than 360° / M+30°. The microneedle electrode array comprises a plurality of microneedles. The plurality of microneedles are divided into M phase groups. The microneedles in each phase group are electrically connected. The distribution of the phase groups of the plurality of microneedles satisfies the following condition: in any local area formed by adjacent microneedles, at least one microneedle of each phase group is contained. The microneedles of the M phase groups of the microneedle electrode array are in corresponding communication with M phase output ends of the multi-phase radio frequency generator. The rotating electric field in the area surrounded by microneedles of different phases realizes "intrinsic uniform" heating.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to a multiphase radiofrequency therapy system and a method for heating conductive materials using the same. Background Technology

[0002] Radiofrequency (RF) technology is widely used in skin treatments, primarily by heating dermal collagen fibers with high-frequency current to induce their contraction and regeneration. Current RF treatment devices typically use a single-phase RF power supply, coupled with monopolar or bipolar electrodes. Regardless of the electrode arrangement, because they are connected to a single-phase RF source, the electric field distribution characteristics result in energy concentration near the electrodes, leading to independent hotspots around each needle tip, while the inter-needle area receives insufficient heating. This uneven energy distribution directly affects the controllability and consistency of the treatment effect.

[0003] To address the aforementioned issues, the applicant explored solutions from two directions: "energy source" and "energy application end."

[0004] On the one hand, the applicant has developed a multiphase active phased radio frequency generator that can output multiphase radio frequency signals with adjustable phase differences, providing a signal source basis for constructing diverse thermal fields. However, multiphase signals themselves do not directly equate to uniform heating—if the electrodes used in conjunction with them still adopt the traditional monopole or bipole layout, the potential of multiphase signals cannot be fully realized, and energy may still be concentrated in local areas.

[0005] On the other hand, the applicant has developed a microneedle electrode array for multiphase radiofrequency therapy. By arranging the microneedles in a cyclic sequence such as ABC, all phases of the microneedles are contained within any local area, providing a physical carrier for uniform energy distribution. However, if the electrode array is still driven by a traditional monophase radiofrequency source, a phase difference cannot be formed between the electrodes, and the advantages of this layout cannot be realized—the needles remain in phase, and the energy remains concentrated at the needle tip.

[0006] Therefore, the multiphase radio frequency generator and the phase-layout electrodes are not simply a "1+1" combination, but rather a mutually dependent and indispensable synergistic relationship: the multiphase signal provided by the generator is the "source" for exciting the rotating electric field, while the phase layout of the electrode array is the "carrier" that enables the formation of the rotating electric field. The two must be precisely matched to truly excite the rotating electric field in subcutaneous tissue and achieve intrinsically uniform heating. Current technology lacks a systematic solution that designs the two as an organic whole.

[0007] Therefore, providing a complete system consisting of a multiphase radio frequency generator and phase layout electrodes that can synergistically excite a rotating electric field has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] The present invention aims to provide a multiphase radiofrequency therapy system and its heating method. The multiphase radiofrequency therapy system organically combines a multiphase radiofrequency generator with a microneedle electrode array with a specific phase layout, so that the two work synergistically to directly excite a rotating electric field in the subcutaneous tissue, thereby achieving intrinsic uniform heating and fundamentally solving the problem of uneven energy distribution.

[0009] To achieve the above objectives, in a first aspect, the present invention provides a multiphase radiofrequency ablation system, employing the following technical solution:

[0010] A multiphase radiofrequency therapy system includes a multiphase radiofrequency generator and a microneedle electrode array.

[0011] A multiphase radio frequency generator is configured to output M-phase radio frequency signals, where M=3 or 4, and each phase signal has the same frequency and amplitude. The phase difference of the M-phase signals output by the multiphase radio frequency generator is greater than 360° / M-30° and less than 360° / M+30°.

[0012] The microneedle electrode array includes multiple microneedles, which are divided into M phase groups. The microneedles in each phase group are electrically connected, and the phase group distribution of the multiple microneedles satisfies the following condition: in any local area composed of adjacent microneedles, there is at least one microneedle containing each phase group.

[0013] The microneedles of the M phase groups of the microneedle electrode array are connected to the M phase output terminals of the multiphase radio frequency generator.

[0014] By employing the above technical solution, a multiphase radio frequency generator is organically combined with a phase-layout electrode array, enabling the two to work synergistically: the generator provides multiphase signals with equal amplitude and precise phase difference, while the phase layout of the electrode array ensures the correct spatial distribution of each phase signal. After matching, a rotating electric field is synthesized within the region enclosed by adjacent microneedles of different phases, driving charged particles to undergo eddy current motion. This ensures that energy is uniformly distributed at the electric field level within the region enclosed by the multiple microneedles, rather than concentrated around the needle tip, achieving "intrinsically uniform" heating.

[0015] Preferably, when M=3 and the microneedles are arranged in a rectangular pattern, in any 3*3 local area composed of adjacent microneedles, each row and each column contains one microneedle of each of the three phases.

[0016] By adopting the above technical solution, any group of four adjacent microneedles includes three microneedles with different phases and one microneedle with the same phase as the diagonal microneedle. Therefore, two sets of three-phase local regions are formed. The triangular regions enclosed by the different three-phase microneedles are synthesized into an electric field vector by the three signals. The amplitude of this vector is constant, and its direction rotates uniformly in the plane with time. Compared with other arrangements such as rhombuses and hexagons, the rectangular arrangement makes it easier to form a complete, non-overlapping, and heat-free skin treatment effect when applying needles to the user. At the same time, in the isosceles right-angled triangular splicing array, the triangle type of the entire array is consistent, the rotation field shape is uniform (all are in the same elliptical direction), the average heating power density of the entire array is equal everywhere, and the temperature rise rate is consistent, forming a macroscopically uniform thermal field. If rhomboid or regular hexagonal honeycomb arrays are used for rectangular treatment surfaces, the equilateral triangular structure at the boundary must be changed (compressed or stretched), resulting in a circular rotating field in the center of the array and an elliptical rotating field at the boundary. The rotating field morphology of each region is different, and the average heating power density varies. After heating for a certain period of time, temperature differences are generated in different regions, and the uniformity of the macroscopic thermal field decreases.

[0017] Preferably, when M=3 and the microneedles are arranged in a hexagonal pattern, any three adjacent microneedles that form a triangle when connected by a line are each one of the three phases.

[0018] By adopting the above technical solution, any three adjacent microneedles can form a three-phase local region, forming a "circular rotating electric field", and the electric field arrangement is more dense.

[0019] Preferably, when M=3, the three microneedles in the local area form a triangle, and each of the three phases has one microneedle.

[0020] By adopting the above technical solution, the three signals are synthesized into a circular rotating electric field within the triangular area enclosed by the three-phase microneedles. When the three-phase microneedles are equilateral triangles, a circular rotating electric field is formed; when they are isosceles triangles, an elliptical rotating electric field is formed.

[0021] Preferably, when M=4, the four microneedles in the local area form a quadrilateral, and each of the four phases is represented by one microneedle.

[0022] By employing the above technical solution, four signals are synthesized into a circular rotating electric field within the quadrilateral region enclosed by the four-phase microneedles. Compared to a three-phase system, the rotating electric field of the four-phase system is smoother and has higher spatial symmetry.

[0023] Preferably, the multiphase RF generator includes a programmable logic control unit and a programmable multiphase phase modulation module. The programmable multiphase phase modulation module is configured to adjust the phase difference within a range greater than 360° / M-30° and less than 360° / M+30° according to the instructions of the programmable logic control unit.

[0024] Preferably, the programmable multiphase phase modulation module is implemented using direct digital frequency synthesis technology, and its internal components include a phase accumulator and a phase control word register.

[0025] Preferably, during the output of the radio frequency signal, the phase control word register enters a locked state, and in the locked state, the phase control word register does not respond to write operation commands from external systems or internal modules.

[0026] By adopting the above technical solution, the phase control word register is locked during the output of the radio frequency signal. This hardware locking mechanism forces the target phase difference of each phase to be maintained at the written value during the radio frequency output process, without responding to any internal or external dynamic adjustment commands, thus providing the necessary signal source foundation for constructing a stable rotating electric field with a defined trajectory.

[0027] Secondly, the present invention provides a method for heating conductive materials using the above-mentioned multiphase radiofrequency therapy system, employing the following technical solution:

[0028] A method for heating a conductive material using the above-described multiphase radiofrequency therapy system includes the following steps:

[0029] S1: Attach the microneedle electrode array to the prepared area of ​​the conductive material, and insert the microneedles into the conductive material to a preset depth;

[0030] S2: Set the operating parameters of the multiphase RF generator;

[0031] S3: Start the multiphase RF generator and output multiphase RF signals with a set phase difference. The signals of each phase have the same frequency and amplitude.

[0032] S4: Within the region enclosed by adjacent microneedles of different phases, a rotating electric field synthesized by multiphase signals drives charged particles in the subcutaneous tissue to undergo eddy current motion.

[0033] By adopting the above technical solution, when using a multiphase radiofrequency therapy system with a defined number of phases, after setting the microneedle electrode array to be attached to the preparatory area of ​​the conductive material, the working parameters of the multiphase radiofrequency generator are adjusted, and multiphase radiofrequency signals with a set phase difference are output to synthesize a rotating electric field, which drives charged particles in the subcutaneous tissue to perform eddy current motion for uniform heating.

[0034] A method for heating conductive materials using the aforementioned multiphase radiofrequency therapy system.

[0035] S1: Connect the M phase groups of the microneedle electrode array to the corresponding phase output terminals of the multiphase radio frequency generator;

[0036] S2: Attach the microneedle electrode array to the prepared area of ​​the conductive material, and insert the microneedles into the conductive material to a preset depth;

[0037] S3: Set the operating parameters of the multiphase RF generator, including setting the number of output phases and phase difference;

[0038] S4: Start the multiphase RF generator and output M-phase RF signals with a set phase difference. The signals of each phase have the same frequency and amplitude.

[0039] S5: Within the area enclosed by adjacent microneedles of different phases, a rotating electric field is synthesized by the M-phase signal, driving charged particles to perform eddy current motion, generating uniform Joule heating, and achieving intrinsic uniform heating of the skin tissue.

[0040] By adopting the above technical solution, when using the multiphase radiofrequency therapy system with adjustable phase number, after connecting the microneedles of the microneedle electrode array to the output terminal of the multiphase radiofrequency generator according to the phase, the microneedle electrode array is attached to the preparation area of ​​the conductive material, the working parameters of the multiphase radiofrequency generator are adjusted, and the multiphase radiofrequency signals with a set phase difference are output to synthesize a rotating electric field, which drives the charged particles in the subcutaneous tissue to perform eddy current motion for uniform heating.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] 1. This invention organically combines a multiphase radio frequency generator with a phase-layout electrode array, enabling the two to work synergistically: the generator provides multiphase signals with equal amplitude and precise phase differences, while the phase layout of the electrode array ensures the correct spatial distribution of each phase signal. After matching, a rotating electric field is synthesized within the region enclosed by adjacent microneedles of different phases, driving charged particles to undergo eddy current motion. This ensures that energy is uniformly distributed at the electric field level within the region enclosed by the multiple microneedles, rather than concentrated around the needle tip. This "intrinsically uniform" heating method fundamentally solves the problem of uneven energy distribution in traditional single-phase systems.

[0043] 2. The multiphase radio frequency generator of the present invention adopts a multiphase output architecture, which can achieve efficient energy deposition with only a low DC bus voltage (5-90V), thereby reducing patient pain and improving the treatment experience from the source.

[0044] 3. The multiphase radio frequency generator of this invention can flexibly adjust the phase difference within the range of 360° / M ± 30° according to the number of output phases M. When set to 360° / M (e.g., 120° when M=3, 90° when M=4), the system operates in rotating electric field mode, achieving intrinsically uniform heating; when set to other phase differences, it can be used to achieve different thermal field distributions (e.g., linear superposition, local focusing, etc.) to meet diverse clinical needs. When the three-phase microneedles are arranged in a rectangular array within any 3*3 local area composed of adjacent microneedles, with each row and column containing one microneedle from each of the three phases, the rectangular treatment area is completely covered without overlap and without any omissions in the skin treatment effect. At the same time, in the isosceles right-angled triangle splicing array, the entire array has a consistent triangle type, a uniform rotating field shape, and the average heating power density is equal everywhere, with a consistent temperature rise rate, forming a macroscopically uniform thermal field. Attached Figure Description

[0045] Figure 1 The overall module composition diagram of the multiphase active phase-controlled radio frequency generator of the present invention shows the connection relationship between the programmable logic control unit, the multiphase modulation module, and the multi-channel power module.

[0046] Figure 2 A schematic diagram of a single RF power channel, showing the sequential connection relationship of the half-bridge MOSFET driver module, RF conversion module, RF power transformer and impedance matching module;

[0047] Figure 3 : A schematic diagram of the output of a multiphase RF generator in three-phase output mode, showing that the phase difference between the three-phase signals A, B, and C is 120°;

[0048] Figure 4 : Output diagram of a multiphase RF generator in four-phase output mode, showing that the four-phase signals A, B, C, and D are 90° out of phase;

[0049] Figure 5A The schematic diagram of the phase layout of the 25-pin three-phase microneedle electrode array in Embodiment 1 of the present invention shows the three-phase cyclic arrangement rule in the 5*5 matrix;

[0050] Figure 5B The schematic diagram of the phase layout of the 25-pin three-phase microneedle electrode array in Embodiment 1 of the present invention shows the three-phase cyclic arrangement rule in the 5*5 rhomboid array;

[0051] Figure 6 The schematic diagram of the phase layout of the 49-needle three-phase microneedle electrode array in Embodiment 2 of the present invention shows the three-phase cyclic arrangement rule in the 7*7 matrix;

[0052] Figure 7The schematic diagram of the phase layout of the 19-needle three-phase microneedle electrode array in Embodiment 3 of the present invention illustrates the three-phase cyclic arrangement rule in the hexagonal matrix;

[0053] Figure 8 The schematic diagram of the phase layout of the 16-pin four-phase microneedle electrode array in Embodiment 4 of the present invention shows the four-phase cyclic arrangement rule in the 4*4 matrix;

[0054] Figure 9 The schematic diagram (three-phase) of the principle of the rotating electric field formed in the subcutaneous tissue during the operation of the system of the present invention shows the trajectory of the end of the synthesized vector within the triangular region enclosed by adjacent A, B, and C electrodes;

[0055] Figure 10 The schematic diagram (four phases) of the rotating electric field formed in the subcutaneous tissue during the operation of the system of this invention shows the eddy current thermal field in the quadrilateral region enclosed by adjacent electrodes A, B, C, and D.

[0056] Figure 11A-11E The graph shows a comparison of the temperature rise curves of ex vivo pigskin in 1MHz mode (corresponding to the 120° phase difference of this invention) for electrodes of different specifications (3-needle, 10-needle, 25-needle, and 49-needle). It includes control electrodes (3-needle and 10-needle) and electrodes of this invention (25-needle and 49-needle). Figure 11A It has 3-pin electrodes. Figure 11B It has 10 electrodes. Figure 11C It has 25 electrodes. Figure 11D It has 49 electrodes. Figure 11E The reference sample is a 49-pin bipolar mode.

[0057] Figures 12A-12C Immediate postoperative thermal damage comparison photos (HE staining, left side 10x magnification, right side 400x magnification), among which... Figure 12A This invention relates to a 25-pin tri-phase array intervention. Figure 12B This invention relates to a 49-pin tri-phase array intervention. Figure 12C The reference sample is shown in the 49-needle bipolar mode intervention. The red arrow points to the tissue coagulation point, demonstrating that the focal coagulation point generated by the system of this invention has a clear boundary and no deep tissue damage.

[0058] Figures 13A-13C Tissue repair photos taken 1 month post-surgery (HE staining, left side 10x magnification, right side 400x magnification), among which... Figure 13A This invention relates to a 25-pin tri-phase array intervention. Figure 13B This invention relates to a 49-pin tri-phase array intervention. Figure 13C The 49-needle bipolar intervention for the reference product demonstrated the integrity of the epidermal structure and the orderly arrangement of dermal collagen fibers in the intervention area.

[0059] Figures 14A-14DComparison photos of collagen regeneration one month post-surgery (Masson staining, left side 10x magnification, right side 400x magnification, collagen fibers appear blue). Figure 14A This invention relates to a 25-pin tri-phase array intervention. Figure 14B This invention relates to a 49-pin tri-phase array intervention. Figure 14C For reference, 49 needles were used for bipolar mode intervention. Figure 14D The control group is shown to have significantly higher collagen density after intervention by the system of the present invention compared to the control group and the reference product.

[0060] Figure 15 : A schematic diagram of the multiphase radiofrequency therapy system of the present invention, showing the connection between the multiphase radiofrequency generator and the microneedle electrode array;

[0061] Figure 16 Flowchart of heating conductive materials using a multiphase radiofrequency therapy system with a fixed number of phases;

[0062] Figure 17 Flowchart of heating conductive materials using a multiphase radiofrequency therapy system with adjustable phase number;

[0063] Figure 18 Schematic diagram of a single-phase radio frequency source and bipolar electrodes;

[0064] Figure 19 : Schematic diagram of current density distribution in subcutaneous tissue using bipolar microneedles, showing that energy is concentrated around the needle tip. Detailed Implementation

[0065] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0066] In existing technologies, monopolar electrodes require the use of an external negative electrode plate, resulting in a deep but uncontrollable current penetration path. For example... Figure 18 As shown, although bipolar or multipolar electrodes concentrate the electrodes in the treatment head, the current path is limited to between the positive and negative electrodes. However, as... Figure 19 As shown, regardless of the electrode arrangement, since all electrodes are connected to a single-phase radio frequency source, the electric field distribution characteristics determine that the energy is most concentrated in the area near the electrodes. In microneedling therapy, this results in an independent hot spot around each needle tip, while the heating in the inter-needle area is relatively insufficient. The non-uniformity of energy distribution directly affects the controllability and consistency of the treatment effect, and differences in heating intensity may occur within the treatment area, affecting the overall treatment quality and aesthetics.

[0067] Ultimately, the problem stems from the fact that the electric field generated by a single-phase power supply and a combination of monopolar / bipolar electrodes can only vibrate in one direction in space, failing to create uniform volumetric heating. Although there are electrodes on the market that arrange microneedles into a matrix, they are essentially simple replicas of multiple monopolar or bipolar units, without changing the physical characteristic that energy is concentrated near the needle tip, and thus cannot fundamentally solve the problem of uneven heating.

[0068] Example 1: Tri-phase radiofrequency ablation system (25 needles)

[0069] This embodiment provides a triphase radiofrequency therapy system, including a triphase active phased radiofrequency generator and a 25-needle triphase microneedle electrode array.

[0070] 1. System Composition

[0071] (1) Multiphase radio frequency generator

[0072] The three-phase active phase-controlled radio frequency generator used in this embodiment has the following core architecture: Figure 1 As shown, it includes:

[0073] Programmable Logic Control Unit (CPLD): As the core control component, it employs a CPLD programmable gate array device and is responsible for top-level control logic, parameter configuration, and status monitoring. The CPLD, together with the auxiliary power supply module and the RF detection module, forms a closed loop. Based on the RF electrical parameters fed back by the RF detection module, it adjusts the amplitude of the adjustable DC bus voltage output by the auxiliary power supply module to maintain the consistency of output power in each phase and the stability of the total output power when the load changes.

[0074] Radio frequency bus voltage generation module (DC / DC): Connected to a programmable logic control unit, it provides an adjustable DC bus voltage (VBUS) according to control commands, with a voltage range of DC5-90V;

[0075] Programmable Frequency Signal Module (DDS): Uses a crystal oscillator as the clock source and internally employs frequency multiplication and phase-locked loop technology and a high-precision frequency divider circuit to generate an RF reference frequency. The programmable logic control unit writes the frequency division coefficients to it through the IIC interface to generate the required reference RF frequency signal (preferably 1MHz in this embodiment).

[0076] Programmable multiphase phase modulation module: Connected to the programmable logic control unit and the programmable frequency signal module. This module is the core of this generator, used to receive a reference RF frequency signal and generate M sets (M=3 in this embodiment) of independent, phase-adjustable complementary control signals. In this embodiment, this module is specifically implemented using digital logic circuits based on DDS (Direct Digital Synthesis) technology. Internally, it includes a phase accumulator, a phase control word register, and a multi-channel waveform generator. The programmable logic control unit writes a phase control word representing the target phase difference to the phase control word register via an internal bus. The phase difference adjustment accuracy can reach within 1°, and the adjustment range is 0° to 180° (for example, to achieve a 120° phase difference, a control word corresponding to 120.0° is written). The phase accumulator uses a reference clock as a reference and generates an address with a corresponding phase offset based on the phase control word, driving the multi-channel waveform generator to simultaneously output M sets of precisely phased complementary control signals. When this embodiment operates in three-phase mode, as... Figure 3 As shown, the programmable multiphase phase modulation module outputs three sets of complementary control signals, corresponding to phases A, B, and C, with a phase difference of 120° (i.e., phase A 0°, phase B 120°, and phase C 240°). The programmable logic control unit can send a latch enable signal to the phase control word register, placing the phase control word register in a locked state. In the locked state, the phase control word register is configured to block write operation commands to its stored contents. This write operation blocking function is coupled to the latch enable signal—that is, the register only resumes its response to write operation commands after the latch enable signal is released. Once the phase control word is written to the phase control word register and locked, it remains constant throughout the entire RF output process, and the phase difference cannot be dynamically adjusted. However, when it is necessary to reset the phase control word between different treatments or different usage scenarios, the RF output must be stopped first, the locked state of the register must be released, and a new phase control word must be written and locked again before the next RF output.

[0077] Multiple RF power channels: This includes M (M=3 in this embodiment) independent and structurally identical RF power channels, labeled as phase A, phase B, and phase C power modules, respectively. Each RF power channel is uniquely connected to a set of complementary control signals of a programmable multiphase phase modulation module, used to independently convert the input DC bus voltage into the corresponding phase of RF power output.

[0078] like Figure 2 As shown, each RF power channel contains, in sequence:

[0079] ① Half-bridge MOS transistor driver module: Receives a pair of complementary drive signals from the programmable multiphase phase modulation module to drive the subsequent RF conversion module.

[0080] ②RF conversion module: It adopts a half-bridge LCC resonant circuit to convert the input rectangular square wave into a sine wave energy output of the same frequency.

[0081] ③ Radio frequency power transformer and impedance matching module: Increases the output voltage, improves the radio frequency power output, and provides electrical isolation between the secondary circuit and the patient application circuit, thereby increasing safety.

[0082] ④ Impedance matching module: Composed of an RC network and controlled by a programmable logic control unit, it is used to match the dynamic impedance of human skin (usually tens to hundreds of ohms) so that radio frequency energy can be input into the skin to generate Joule heat to the maximum extent.

[0083] Auxiliary power supply module: connected to the bus voltage input terminal of the programmable logic control unit and each RF power channel, used to uniformly supply power to N RF power channels under an adjustable DC bus voltage (in this embodiment, the voltage range is DC 5-90V, preferably 50V).

[0084] The radio frequency (RF) detection module includes an RF voltage detection module, an RF current detection module, a skin impedance detection module, and an RF energy integration module. It uses high-precision current and voltage transformers to sample the RF voltage and current signals output from each phase channel in real time. The sampled signals are rectified and converted into digital quantities by an ADC, then fed back to the main control module via an SPI interface for software-level PID closed-loop control, energy accumulation calculation, and system operation status monitoring.

[0085] Communication interface module: Connects to the programmable logic control unit and is used for data exchange with external systems.

[0086] The workflow of a multiphase RF generator includes:

[0087] Initialization: Power on the main control module, configure the programmable clock module, and set the RF base frequency to 1MHz.

[0088] Parameter settings: The main control module writes parameters such as working mode (three-phase) and target phase difference (120°) to the CPLD.

[0089] Energy preparation: The main control module is equipped with an auxiliary power supply module, and the DC bus voltage is set to 50V.

[0090] Synchronous output: The CPLD generates three pairs of complementary drive signals with a phase difference of 120°, which are sent to the three power channels respectively.

[0091] Power conversion: The three channels operate independently, outputting a 1MHz high-voltage sine wave with a phase difference of 120°.

[0092] Real-time monitoring and closed-loop control: The RF detection module provides real-time feedback on the parameters of each channel, and the main control module uses this feedback to perform closed-loop adjustment of the total output voltage of the auxiliary power module to maintain the system's set output power.

[0093] The parameters of the multiphase RF generator are set using the following steps:

[0094] Step S1: Determine the output parameters

[0095] Based on treatment needs, determine the target frequency f, number of output phases M, and maximum output power P_max of the radio frequency output.

[0096] Step S2: Configure the programmable frequency signal module

[0097] The programmable logic control unit calculates the division factor of the programmable frequency signal module based on the target frequency f: division factor = base frequency / f. For example, if the base frequency is 100MHz and the target frequency is 1MHz, then the division factor is 100.

[0098] Step S3: Configure the programmable multiphase phase modulation module

[0099] The programmable logic control unit determines the number of half-bridge drive groups to be activated and the phase difference based on the target number of phases M, and sets the phase difference according to the treatment requirements. For example, when M=3, three sets of complementary drive signals are activated with a phase difference of 120° to construct a rotating electric field.

[0100] The phase difference adjustment for different phase numbers follows a 360° / M rule. For example, when M=3, the phase difference adjustment is 360° / 3=120°; when M=4, the phase difference adjustment is 360° / 4=90°. Those skilled in the art can determine the phase difference for other phase numbers based on this rule without any inventive effort.

[0101] Step S4: Configure RF bus voltage

[0102] The programmable logic control unit calculates the required RF bus voltage V_bus based on the target maximum output power P_max and the load impedance range. Simultaneously, based on V_bus and the maximum output power, it ensures that the power devices (MOSFETs, transformers, resonant capacitors) of the RF converter module operate within safe limits.

[0103] Step S5: Configure the detection module range

[0104] The programmable logic control unit calculates the maximum output current I_max and the maximum output voltage V_max based on P_max and the load impedance range, and configures the range of the RF voltage detection module and the RF current detection module to ensure detection accuracy.

[0105] Step S6: Start output

[0106] After completing the above configuration, the multiphase RF generator begins operation according to the set parameters. The programmable logic control unit performs closed-loop control of the output voltage of the auxiliary power module based on the feedback signal to maintain the stability of the output power of each phase.

[0107] (2) Microneedle electrode array

[0108] The 25-pin three-phase microneedle electrode array used in this embodiment, such as Figure 5A As shown, the array includes an insulating substrate made of PC-HP2NR material with a thickness of 2mm and an overall size of 11mm*11mm.

[0109] Twenty-five microneedles are fixedly arranged in a 5x5 matrix on an insulating substrate. Each microneedle is made of conductive metal, with a diameter of 0.15 mm, a height protruding from the substrate of 0.4–6 mm, and a center-to-center distance of 1.95 mm between adjacent microneedles.

[0110] The 25 microneedles are divided into three phase groups, A, B, and C, and are arranged in a cyclical sequence of "ABC", periodically distributed in both row and column directions, as shown in Table 1.

[0111] Table 1: Schematic diagram of the phase layout of a 25-needle three-phase microneedle electrode array (and...) Figure 5A correspond)

[0112] Line 1 B C A B C Line 2 A B C A B Line 3 C A B C A line 4 B C A B C Line 5 A B C A B

[0113] With this layout, in any 3x3 local area composed of adjacent microneedles, each row and each column contains one microneedle of each of the three phases. (Alternatively, it can be done...) Figure 5B (Arrangement of the rhomboid array)

[0114] All microneedles marked as phase A are electrically connected to a common phase A input terminal via internal wires. Similarly, phase B and phase C microneedles are connected to their respective phase B and phase C input terminals. These three input terminals (A, B, and C) are the external interfaces of this microneedle electrode array, used to connect one-to-one with the three phase output terminals of an external multiphase RF generator.

[0115] 2. System Connection and Collaborative Working Principle

[0116] like Figure 15As shown, the three input terminals (A, B, C) are connected one-to-one to the three phase output terminals of a three-phase active phase-controlled RF generator via a multi-pin connector (e.g., an FPC connector). The RF generator operates in three-phase mode with a phase difference set to 120°. This method allows the multiphase signals output by the generator to be precisely distributed to the corresponding microneedles according to the phase layout of the electrode array.

[0117] When the system is operating, the three-phase RF generator outputs three-phase signals with a frequency of 1MHz, equal amplitude, and a phase difference of 120°. These signals are transmitted to the corresponding phase groups of the microneedle electrode array via connecting lines. Due to the regular phase layout of the electrode array, adjacent A, B, and C phase microneedles are arranged in a triangular pattern in space.

[0118] like Figure 9 As shown, within the triangular region enclosed by adjacent A, B, and C phase microneedles, the three signals synthesize into an electric field vector. This vector has a constant amplitude and rotates uniformly in the plane with time. For the local region formed by the three microneedles with different phases, the trajectory is circular when the electrodes are distributed in an equilateral triangle, and elliptical in an isosceles triangular layout.

[0119] Heating of biological tissues (Joule heating) depends on the square of the electric field strength (E). 2 (Time average)

[0120] Inside the three-phase microneedle unit A, B, and C: the rotational field amplitude is constant at E0, and the time-averaged power is... .

[0121] In a rectangular array, adjacent triangular units are joined in a mirror image manner, with their internal rotating electric fields rotating in opposite directions. Therefore, at the shared boundary, the horizontal components of the two electric fields cancel each other out, while their vertical components superimpose. The resulting field becomes... .

[0122] Calculate the time-averaged power:

[0123] Therefore, when multiple triangles are joined together, the time-averaged heating power at the boundary is exactly equal to the heating power inside the unit. In terms of the average heating efficiency per unit time, the heating efficiency at the boundary is consistent with that inside the unit, and there is no energy abrupt change caused by the joining. The heat generation at the electric field boundary is consistent with the heat generation in other regions.

[0124] When tri-phase microneedles are arranged in a rectangular array within any 3x3 local area composed of adjacent microneedles, with each row and column containing one microneedle from each of the three phases, compared to other arrangements such as rhombuses and hexagons, it is easier to achieve a complete, non-overlapping, and thorough heating effect on the rectangular treatment area during acupuncture. Furthermore, in an isosceles right-angled triangular array, the entire array has a consistent triangle type and a uniform rotational field shape (all in the same elliptical direction), resulting in a uniform average heating power density and consistent temperature rise rate, forming a macroscopically uniform thermal field. In contrast, if rhombus or regular hexagonal honeycomb arrays are used on a rectangular treatment surface, the equilateral triangular structure at the boundaries must be altered (by compression or stretching), resulting in a circular rotational field at the center and an elliptical rotational field at the boundaries. This leads to different rotational field shapes in different areas, resulting in variations in average heating power density. After a certain heating time, temperature differences arise in different areas, reducing the uniformity of the macroscopic thermal field.

[0125] From a signal flow perspective, the generator's programmable multiphase phase modulation module first generates three pairs of complementary drive signals based on the phase control word set by the programmable logic control unit (corresponding to a 120° phase difference). These three pairs of signals are independently amplified by three structurally identical RF power channels and then transmitted to the A, B, and C phase input terminals of the electrode array via FPC connectors. Since the three power channels share the same adjustable DC bus voltage and have identical structures, the amplitudes of the three output signals naturally remain consistent, requiring no additional amplitude calibration. The phase layout of the electrode array (ABC cyclic arrangement) causes adjacent A, B, and C phase microneedles to be triangularly distributed, matching the 120° time phase difference of the generator output.

[0126] The rotating electric field drives charged particles in the skin tissue to move in eddy currents, generating uniform Joule heating in the area between the microneedles, forming a "radiofrequency eddy current region". The entire treatment surface is seamlessly connected by multiple such microscopic eddy current regions, achieving macroscopically uniform heating.

[0127] 3. System Advantages

[0128] This embodiment achieves the following technical effects through the synergistic effect of the generator and electrodes:

[0129] Intrinsic uniform heating: energy is evenly distributed within the triangular region at the electric field level, rather than concentrated around the needle tip, fundamentally solving the problem of uneven heating in traditional single-phase systems;

[0130] Low voltage, high efficiency: The generator adopts a multi-phase output architecture, which can achieve efficient energy deposition with only low voltage;

[0131] Heating consistency: Figure 11C and Figure 11DThe temperature rise curves show that, under the same experimental parameters (e.g., 32W), the heating rates (curve slopes) and heat accumulation patterns of the 25-pin and 49-pin electrodes exhibit extremely high similarity. This demonstrates that the heating rates and heat accumulation patterns of electrodes of different specifications are highly consistent under the same operating parameters, proving that the heating mechanism and energy deposition efficiency of the system of this invention are stable and consistent across electrodes of different specifications.

[0132] Example 2: Tri-phase radiofrequency ablation system (49 needles)

[0133] This embodiment provides another tri-phase radiofrequency therapy system, whose multi-phase radiofrequency generator is the same as that in Embodiment 1, except that it uses a 49-pin tri-phase microneedle electrode array.

[0134] 1. Microneedle electrode array

[0135] The 49-pin three-phase microneedle electrode array used in this embodiment, such as Figure 6 As shown, the array includes an insulating substrate made of PC-HP2NR material with a thickness of 2mm and an overall size of 11mm*11mm.

[0136] Forty-nine microneedles are fixedly arranged in a 7x7 matrix on an insulating substrate. Each microneedle is made of a conductive metal (such as stainless steel, titanium alloy, or gold-plated copper alloy), with a needle diameter of 0.15 mm, a height protruding from the substrate of 0.4–6 mm, and a center-to-center distance of 1.25 mm between adjacent microneedles.

[0137] The 49 microneedles are divided into three phase groups, A, B, and C, and are arranged in a cyclical sequence of "ABC", periodically distributed in both row and column directions, as shown in Table 2.

[0138] Table 2: Schematic diagram of the phase layout of the 49-needle three-phase microneedle electrode array

[0139] Line 1 B C A B C A B Line 2 A B C A B C A Line 3 C A B C A B C line 4 B C A B C A B Line 5 A B C A B C A Line 6 C A B C A B C Line 7 B C A B C A B

[0140] With this layout, in any 3*3 local area composed of adjacent microneedles, each row and each column contains one microneedle of each of the three phases.

[0141] 2. System Connection and Collaborative Working Principle

[0142] Connect the A, B, and C phase input terminals of the 49-pin electrode array to the A, B, and C phase output terminals of the three-phase RF generator, respectively. When the system is working, the generator outputs a 1MHz, 120° phase difference three-phase signal, which excites a rotating electric field in the triangular region formed by the adjacent A, B, and C phase microneedles.

[0143] Compared to a 25-pin array, a 49-pin array creates a denser micro-vortex region, further enhancing the precision of heating. Figure 11C and 11D The temperature rise curves show that, under the same operating parameters, the temperature rise characteristics of the 25-pin and 49-pin electrodes are highly consistent, proving that the phase layout rules of the system of the present invention ensure the heating consistency between electrodes of different specifications.

[0144] Example 3: Tri-phase radiofrequency ablation system (19 needles)

[0145] This embodiment provides another tri-phase radiofrequency therapy system, whose multi-phase radiofrequency generator is the same as that in Embodiment 1, except that it uses a 19-pin tri-phase microneedle electrode array.

[0146] 1. Microneedle electrode array

[0147] The 19-pin three-phase microneedle electrode array used in this embodiment, such as Figure 7 As shown, the array includes an insulating substrate made of PC-HP2NR material with a thickness of 2mm and an overall size of 11mm*11mm.

[0148] Nineteen microneedles are fixedly arranged in a hexagonal array on an insulating substrate. Each microneedle is made of a conductive metal (such as stainless steel, titanium alloy, or gold-plated copper alloy), with a needle diameter of 0.15 mm, a height protruding from the substrate of 0.4–6 mm, and a center-to-center distance of 1.25 mm between adjacent microneedles.

[0149] The 19 microneedles are divided into three phase groups, A, B, and C, and their arrangement follows an ABC cyclic sequence, periodically distributed in both row and column directions, as shown in the diagram. Figure 7 As shown:

[0150] With this layout, any three adjacent microneedles that form a triangle when connected by a line are each one of the three phases A, B, and C.

[0151] 2. System Connection and Collaborative Working Principle

[0152] Connect the A, B, and C phase input terminals of the 19-pin electrode array to the A, B, and C phase output terminals of the three-phase RF generator, respectively. When the system is working, the generator outputs a 1MHz, 120° phase difference three-phase signal, which excites a rotating electric field in the triangular region formed by the adjacent A, B, and C phase microneedles.

[0153] Example 4: Quadrature Radiofrequency Therapy System

[0154] This embodiment provides a quadriphase radiofrequency therapy system, including a quadriphase active phased radiofrequency generator and a 16-needle quadriphase microneedle electrode array.

[0155] 1. System Composition

[0156] (1) Multiphase radio frequency generator

[0157] The four-phase active phase-controlled radio frequency generator used in this embodiment has a similar architecture to that in Embodiment 1. The difference lies in that the programmable multiphase phase modulation module is configured in four-phase mode, generating four sets of complementary control signals. The phase difference can be adjusted within the range of 0° to 180°. In this embodiment, it is preferably set to 90° (i.e., phase A 0°, phase B 90°, phase C 180°, and phase D 270°). Figure 4 As shown, the four outputs have equal amplitudes and a phase difference of 90°.

[0158] (2) Microneedle electrode array

[0159] The 16-pin four-phase microneedle electrode array used in this embodiment, such as Figure 8 As shown, the array includes an insulating substrate made of PC-HP2NR material, with a thickness of 2mm and an overall size of 9mm*9mm.

[0160] Sixteen microneedles are fixedly arranged in a 4x4 matrix on an insulating substrate. Each microneedle is made of a conductive metal (such as stainless steel, titanium alloy, or gold-plated copper alloy), with a needle diameter of 0.15 mm, a height protruding from the substrate of 0.4–6 mm, and a center-to-center distance of 1.95 mm between adjacent microneedles.

[0161] The 16 microneedles are divided into four phase groups: A, B, C, and D. Their arrangement follows a cyclical sequence of "ABCD" and uses periodic repeating units. Each 2*2 basic unit contains one of each of the four phases A, B, C, and D. The specific distribution is shown in Table 3.

[0162] Table 3: Phase Distribution of 16-Needle Four-Phase Microneedle Electrode Array

[0163] Line 1 A B A B Line 2 D C D C Line 3 A B A B line 4 D C D C

[0164] With this layout, any four adjacent microneedles that form a quadrilateral when connected by lines are each one of the four phases A, B, C, and D, making the distribution of the rotating electric field more compact and uniform.

[0165] 2. System Connection and Collaborative Working Principle

[0166] Connect the A, B, C, and D phase input terminals of the microneedle electrode array to the A, B, C, and D phase output terminals of the four-phase RF generator, respectively. When the system is working, the generator outputs four-phase signals with the same frequency, equal amplitude, and a 90° phase difference.

[0167] like Figure 10As shown, within the quadrilateral region enclosed by the adjacent A, B, C, and D phase microneedles, the four signals synthesize into a circular rotating electric field. Compared to the three-phase system, the rotating electric field of the four-phase system is smoother and has higher spatial symmetry, making it suitable for treatment scenarios requiring extremely high heating uniformity.

[0168] Example 5:

[0169] This embodiment provides a method for heating conductive materials using a multiphase radiofrequency therapy system with a fixed number of phases, such as... Figure 16 As shown, it includes the following steps:

[0170] S1: Attach the microneedle electrode array to the prepared area of ​​the conductive material, and insert the microneedles into the conductive material to a preset depth.

[0171] The insertion depth of microneedles is typically 0.5 mm to 3.0 mm.

[0172] S2: Set the operating parameters of the multiphase RF generator.

[0173] Operators can set the output phase number M and phase difference through the generator's control interface. Output frequency f, output power P, and duration t.

[0174] S3: Start the multiphase RF generator and output multiphase RF signals with a set phase difference. The signals of each phase have the same frequency and amplitude.

[0175] S4: Within the region enclosed by adjacent microneedles of different phases, a rotating electric field synthesized by multiphase signals drives charged particles in the subcutaneous tissue to undergo eddy current motion.

[0176] Example 6:

[0177] This embodiment provides a method for heating conductive materials using a multiphase radiofrequency therapy system with adjustable phase number, such as... Figure 17 As shown, it includes the following steps:

[0178] S1: Connect the M phase groups of the microneedle electrode array to the M phase output terminals of the multiphase radio frequency generator respectively.

[0179] For a three-phase system, connect the A, B, and C phase input terminals of the electrode array to the A, B, and C phase output terminals of the generator, respectively; for a four-phase system, connect the A, B, C, and D phase input terminals accordingly.

[0180] S2: Attach the microneedle electrode array to the prepared area of ​​the conductive material, and insert the microneedles into the conductive material to a preset depth.

[0181] The insertion depth of microneedles is typically 0.5 mm to 3.0 mm.

[0182] S3: Set the operating parameters of the multiphase RF generator, including setting the number of output phases and phase difference.

[0183] Operators can set the output phase number M and phase difference through the generator's control interface. The output frequency f, output power P, and duration t are selected. For example, for a three-phase output, the following parameters can be selected: For four-phase output, you can select... The frequency can be selected from 0.1MHz to 10MHz, the power can be selected from 1W to 50W, and the single-action time can be selected from 100ms to 2000ms.

[0184] S4: Start the multiphase RF generator and output M-phase RF signals with a set phase difference. The signals of each phase have the same frequency and amplitude.

[0185] For a three-phase system, a phase difference of 120° is preferred; for a four-phase system, a phase difference of 90° is preferred.

[0186] S5: Within the area enclosed by adjacent microneedles of different phases, a rotating electric field is synthesized by the M-phase signal, driving charged particles to perform eddy current motion, generating uniform Joule heating, and achieving intrinsic uniform heating of the skin tissue.

[0187] This method may also include dynamically adjusting the set phase difference based on the impedance detected in real time to further optimize the heating effect.

[0188] Experiment Example 1: In vitro temperature gradient experiment (to verify the heating consistency of a rotating electric field)

[0189] To verify the heating consistency and heat conduction efficiency of the system of the present invention (multiphase generator + phase layout electrode) when a rotating electric field is excited, the applicant conducted an in vitro pigskin temperature gradient experiment.

[0190] 1. Experimental Materials and Methods

[0191] Radio frequency signal source: The three-phase radio frequency generator of Embodiment 1 of the present invention (capable of outputting 1MHz / 120°);

[0192] Treatment electrodes: The 25-needle and 49-needle tri-phase microneedle electrode arrays of this invention, as well as 3-needle and 10-needle electrodes, are used as controls;

[0193] Reference device: Commercially available bipolar radiofrequency microneedle system (Jesus Medical INTRACel Tip1011 electrode + INTRACel main unit), operating in bipolar mode;

[0194] Ex vivo tissue: Fresh porcine skin tissue (including dermis, subcutaneous fat and superficial muscle).

[0195] Temperature measuring equipment: thermocouple thermometer, with the thermocouple electrodes placed at the tip of the needle and 2mm below the tissue;

[0196] Experimental parameters: needle depth 2mm, 4mm; power settings 12W, 32W, 50W; action time 70 seconds.

[0197] 2. Experimental Results

[0198] (1) Verification of heating consistency of rotating electric field

[0199] like Figure 11A-11E As shown, under the same experimental parameters (1MHz / 120°C, 32W), the heating rate (curve slope) and heat accumulation law of the 25-pin and 49-pin electrodes of this invention exhibit extremely high similarity. Both can achieve continuous, stable, and linear heating within a 70-second treatment cycle, effectively avoiding the limitations of traditional bipolar radiofrequency devices (such as...). Figure 11E (As shown) Thermal saturation and host current limiting problems caused by the surge in tissue impedance under high power. This proves that even with different needle counts and needle spacings, the system of this invention can still stably excite a rotating electric field and achieve highly consistent heating performance. This "intrinsically uniform" heating characteristic is not possessed by traditional radio frequency microneedle systems.

[0200] Under the same experimental parameters, the temperature rise rate of 3-pin and 10-pin electrodes was lower than that of the 25-pin and 49-pin full arrays. Analysis suggests this is primarily due to the smaller number of electrodes in the 3-pin and 10-pin arrays; their parallel branch count and total contact area are significantly smaller than those of the 25-pin and 49-pin arrays, resulting in a significantly higher overall impedance. At higher impedance, the efficiency of radio frequency energy transmission to tissue decreases, and the device's own impedance protection mechanism is more easily triggered, thus limiting the deposition of effective energy.

[0201] (2) Targeting of rotating electric fields

[0202] In 1MHz / 120° mode, the temperature rise of non-target tissue below the needle tip is less than 5°C, while the temperature rise of tissue at the target depth is rapid, confirming that the rotating electric field energy is precisely concentrated in the dermis.

[0203] (3) Comparison with bipolar technology

[0204] Taking a 49-pin electrode as an example, the endpoint temperature in 1MHz / 120° mode at 32W setting is 31.2℃, while the reference temperature is 16.5℃.

[0205] Analyze the temperature rise curve of the reference sample ( Figure 11E As can be seen, the heating efficiency of bipolar mode is limited by the local overheating problem caused by its electrode structure: when the power is high, the energy is concentrated at the needle tip, the local temperature of the tissue rises rapidly, the moisture vaporizes, the equivalent impedance increases, the equipment output is limited, and the heating tends to be slow.

[0206] Specifically, at level 5, the initial heating is relatively fast, but as the local temperature of the needle tip increases and the equivalent impedance gradually rises, the output of the equipment is limited, and the heating slows down in the middle and later stages. The overall curve is an arc that is "steep at first and then slows down".

[0207] At power level 7, due to the higher power, the surge in equivalent impedance occurs in the very early stages of heating (within seconds), and the main unit's output is immediately clamped. Subsequently, the entire heating process operates at a lower, constrained power, resulting in a temperature rise curve that is a straight line with a constant slope. Furthermore, the error bars from multiple experiments are extremely small, indicating that this power level is forcibly clamped to a consistent low output level from the initial startup. As a result, although power level 7 is higher, the final heating effect is actually less than expected.

[0208] In contrast, the system of this invention, due to the rotating electric field, distributes energy evenly in the eddy current region between the microneedles, eliminating the drastic fluctuations in equivalent impedance caused by localized overheating at the needle tip, and maintaining a stable linear increase in temperature rise even at high power. Figure 11C , 11D This enables continuous and efficient energy deposition.

[0209] At the 12W setting, due to the lower power, the bipolar mode reference did not cause the moisture in the tissue to vaporize, so the heating effect was similar.

[0210] This demonstrates that the system of the present invention achieves higher heating efficiency through a rotating electric field. Typical results are shown in the table below:

[0211] 49 stitches 1MHz (120°) 32W 31.2 Reference Bipolar (1MHz) 5 gears (32W) 16.5 49 stitches 1MHz (120°) 12W 4.8 Reference Bipolar (1MHz) 2nd gear (12W) 4.6

[0212] 3. Experimental Conclusions

[0213] In vitro experiments have confirmed that the system of the present invention can generate a stable rotating electric field in 1MHz / 120° mode. This electric field makes the heating characteristics of electrodes with different numbers of needles highly consistent, and achieves precise targeted delivery and efficient heating.

[0214] Experimental Example 2: Verification of safety and efficacy in living tissue (intrinsic uniform heating effect of rotating electric field)

[0215] 2.1 Experimental Objective:

[0216] To verify whether the rotating electric field generated by the system of the present invention in living tissue achieves intrinsic uniform heating, and the resulting safety and collagen regeneration effect, the applicant conducted an intervention experiment on the back skin of Bama pigs.

[0217] 2.2. Experimental Materials and Methods

[0218] Experimental animals: 6 female Bama pigs, weighing 15±5 kg.

[0219] Experimental setup: a three-phase radio frequency generator (1MHz / 120° mode) according to Embodiment 1 of the present invention + a 25-pin and 49-pin three-phase microneedle electrode array.

[0220] Reference device: Commercially available bipolar radiofrequency microneedle system (Jesus Medical INTRACel Tip1011 electrode + INTRACel main unit), operating in bipolar mode.

[0221] Experimental parameters: needle depth 2mm, 4mm; power settings 12W (recommended) and 32W (higher power); action time 70 seconds.

[0222] Observation time points: immediately after surgery and 1 month after surgery.

[0223] Detection indicators: thermal damage area (HE staining), histological score, collagen fiber area ratio (Masson staining).

[0224] 2.3 Experimental Results

[0225] (1) Uniform thermal damage from rotating electric field (immediately after surgery, HE staining)

[0226] like Figures 12A-12C As shown in Table 4, at the 1MHz / 32W setting, the focal coagulation point areas generated by the 25-pin and 49-pin electrodes were 0.57±0.06mm² and 0.57±0.08mm², respectively, with no statistically significant difference. This indicates that, because the basic heating unit of the rotating electric field in this invention is based on independent three-phase microneedle local regions, even with different numbers of macroscopic electrode needles (25-pin and 49-pin), the instantaneous thermal damage per unit target area is highly consistent, overcoming the problem that the more needles a traditional radio frequency electrode has, the more difficult it is to control the thermal field.

[0227] Furthermore, the focal coagulation point areas generated by the 25-needle and 49-needle electrodes of this invention are slightly smaller than those of the reference product (0.62±0.07mm²). The reference product has a slightly larger damage area precisely because its energy is concentrated around the needle tip, resulting in a larger but isolated thermal coagulation point at each needle tip. In contrast, the damage area of ​​this invention is smaller, and the thermal damage area has clear boundaries, a regular shape, and no discrete hot spots. This confirms that the rotating electric field uniformly disperses energy in the area surrounded by multiple microneedles, rather than concentrating it around the needle tip, achieving a smaller single-point damage area while providing comprehensive and uniform heating of the inter-needle area. This is precisely the embodiment of "intrinsic uniformity".

[0228] Table 4: Summary of immediate postoperative thermal injury area:

[0229] Test subject - 25 needles 1MHz (120°) 2mm 0.57±0.06 Test subject - 49 needles 1MHz (120°) 2mm 0.57±0.08 Reference-49 needles Bipolar (1MHz) 2mm 0.62±0.07

[0230] 2) Safety of tissue repair under rotating electric fields (1 month post-surgery, HE staining)

[0231] like Figures 13A-13C As shown, one month after the operation, the skin tissue structure in all intervention areas returned to normal, the epidermis was intact, the dermal collagen fibers were arranged in an orderly manner, and no necrotic residue or chronic inflammatory cell infiltration was observed. There was no significant difference compared with the blank group and the reference group, which confirms that the controllable thermal damage generated by the rotating electric field has good long-term safety.

[0232] (3) Uniform collagen regeneration effect of rotating electric field (Masson staining 1 month after surgery)

[0233] Masson staining results showed (combined with) Figures 14A-14D (Table 5) At 1MHz / 32W, the collagen fiber area ratios after intervention with 25 and 49 electrodes reached 54.31±8.50% and 60.97±19.92%, respectively, significantly higher than the control group (22.66±6.48%, P<0.01). There was no significant difference in effect between the 25 and 49-needle groups, further demonstrating the uniformity of the rotating electric field across electrodes with different needle counts. This invention not only achieves consistency and controllability of in vitro heating at the physical level, but also a high degree of consistency in the range of thermal damage and the therapeutic effect of collagen regeneration at the biological in vivo level.

[0234] Table 5: Summary of collagen fiber area ratio 1 month post-surgery:

[0235] Test subject - 25 needles 1MHz (120°) higher-end 54.31±8.50 Test subject - 49 needles 1MHz (120°) higher-end 60.97±19.92 Reference-49 needles Bipolar (1MHz) higher-end 45.46±16.92 Blank group — — 22.66±6.48

[0236] 3. Experimental Conclusions

[0237] In vivo experiments have confirmed that the rotating electric field excited by the system of this invention achieves intrinsically uniform heating, resulting in uniform thermal damage, complete tissue repair, and consistent collagen regeneration. This result directly demonstrates the superiority of the synergistic effect between the generator and the electrodes.

[0238] The heating consistency and effect consistency of the system of this invention across electrodes of different specifications are not only reflected in the overlap of the detached physical temperature rise curves (e.g.) Figure 11C , 11D Furthermore, it has been fully cross-validated in in vivo histological reactions.

[0239] Experiment Example 3: Comparison of heating uniformity under different phase differences

[0240] 3.1 Experimental Objective

[0241] According to the rotating electric field theory of three-phase alternating current, when three alternating electric fields of equal amplitude, frequency, and phase difference of 120° act on three electrodes arranged in a triangular pattern in space, the resultant vector is a rotating electric field with a constant amplitude and a direction that rotates uniformly with time. When the electrodes are arranged in an equilateral triangle, the trajectory is circular; when they are arranged in an isosceles triangle, the trajectory is elliptical. When the phase difference deviates from 120°, the trajectory at the end of the resultant vector is distorted, and the uniformity of the electric field distribution decreases.

[0242] 3.2 Experimental Materials and Methods

[0243] Radio frequency signal source: The three-phase radio frequency generator of Embodiment 1 of the present invention can output three-phase signals with six phase differences of 0°, 60°, 90°, 120°, 150° and 180° (frequency 1MHz, amplitude the same).

[0244] Treatment electrode: The 25-needle tri-phase microneedle electrode array (5×5, A / B / C cyclic arrangement) described in Embodiment 1 of this invention.

[0245] Excised skin: Fresh excised pig skin (3-5mm thick) is moistened with physiological saline.

[0246] Temperature measurement equipment: FLIR T1030sc high-precision infrared thermal imager (thermal sensitivity <20mK, pixel 1024×768, emissivity set to 0.98), recording the temperature distribution of the treatment area.

[0247] Fixation device: Custom-made clamps ensure consistent contact pressure between the electrode and the skin (contact pressure 50g / cm²) to avoid the impact of poor contact on experimental results.

[0248] Evaluation indicators: hot spot temperature difference (highest temperature - lowest temperature), temperature variation coefficient (standard deviation of temperature measured at multiple points / average temperature × 100%).

[0249] 3.2 Experimental Results

[0250] Table 6: Measurement results of hotspot temperature difference under different phase differences

[0251] 0° 37.92 44.68 41.25 44.12 39.84 41.56 ± 2.55 6.76 ℃ 6.14% 60° 41.26 43.88 44.31 42.12 43.36 42.99 ± 1.18 3.05 ℃ 2.74% 90° 42.83 44.15 43.76 43.03 44.62 43.68 ± 0.81 1.79 ℃ 1.85% 120° 43.28 44.72 43.95 43.47 44.81 44.05 ± 0.63 1.53 ℃ 1.43% 150° 42.25 44.21 43.79 43.51 44.52 43.66 ± 0.92 2.27 ℃ 2.11% 180° 42.15 44.29 43.84 42.28 44.07 43.33 ± 1.07 2.14 ℃ 2.47%

[0252] In Table 6, the hotspot temperature difference = highest temperature - lowest temperature; the smaller the value, the more uniform the heating. The temperature variation coefficient = standard deviation / average of temperatures measured at multiple points * 100%; the smaller the value, the more uniform the heating. It can be seen that the heating uniformity is optimal at a 120° phase difference, with a hotspot temperature difference of only 1.53℃ and a temperature variation coefficient of 1.43%; while at 0°, single-phase input exhibits obvious point-like hot spots, with a hotspot temperature difference reaching 6.76℃. This result perfectly matches the theoretical prediction, confirming that 120° is the optimal operating point for exciting a circular rotating electric field. When the phase difference is between 90° and 150°, the temperature variation coefficient is small, and the rotating electric field achieves a more significant effect in achieving uniform regional heating.

[0253] 3.3 Experimental Conclusions

[0254] The comparative experiments with different phase differences directly proved the scientific basis for the selection of 120° as the optimal phase difference for the three phases in the system of this invention, and also showed that the formation of the rotating electric field is the key to achieving uniform heating.

[0255] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multiphase radiofrequency therapy system, comprising a multiphase radiofrequency generator and a microneedle electrode array, characterized in that, A multiphase radio frequency generator is configured to output M-phase radio frequency signals, where M=3 or 4, and each phase signal has the same frequency and amplitude. The phase difference of the M-phase signals output by the multiphase radio frequency generator is greater than (360° / M-30°) and less than (360° / M+30°). The microneedle electrode array includes multiple microneedles, which are divided into M phase groups. The microneedles in each phase group are electrically connected, and the phase group distribution of the multiple microneedles satisfies the following condition: in any local area composed of adjacent microneedles, there is at least one microneedle containing each phase group. The microneedles of the M phase groups of the microneedle electrode array are connected to the M phase output terminals of the multiphase radio frequency generator.

2. The multiphase radiofrequency ablation system according to claim 1, characterized in that, When M=3 and the microneedles are arranged in a rectangular pattern, in any 3*3 local area composed of adjacent microneedles, each row and each column contains one microneedle of each of the three phases.

3. The multiphase radiofrequency ablation system according to claim 1, characterized in that, When M=3 and the microneedles are arranged in a hexagonal pattern, any three adjacent microneedles that form a triangle when connected by a line are each one of the three phases.

4. The multiphase radiofrequency ablation system according to claim 1, characterized in that, When M=3, the three microneedles in the local area form a triangle, and each of the three phases has one microneedle.

5. The multiphase radiofrequency ablation system according to claim 1, characterized in that, When M=4, the four microneedles in the local area form a quadrilateral, and each of the four phases has one microneedle.

6. The multiphase radiofrequency ablation system according to claim 1, characterized in that, The multiphase RF generator includes a programmable logic control unit and a programmable multiphase phase modulation module. The programmable multiphase phase modulation module is configured to adjust the phase difference within a range greater than 360° / M-30° and less than 360° / M+30° according to the instructions of the programmable logic control unit.

7. The multiphase radiofrequency ablation system according to claim 6, characterized in that, The programmable multiphase phase modulation module is implemented using direct digital frequency synthesis technology and includes a phase accumulator and a phase control word register.

8. The multiphase radiofrequency ablation system according to claim 7, characterized in that, During the output of the radio frequency signal, the phase control word register enters a locked state. In the locked state, the phase control word register does not respond to write operation commands from external systems or internal modules.

9. A method for heating a conductive material using the multiphase radiofrequency therapy system according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1: Attach the microneedle electrode array to the prepared area of ​​the conductive material, and insert the microneedles into the conductive material to a preset depth; S2: Set the operating parameters of the multiphase RF generator; S3: Start the multiphase RF generator and output multiphase RF signals with a set phase difference. The signals of each phase have the same frequency and amplitude. S4: Within the region enclosed by adjacent microneedles of different phases, a rotating electric field synthesized by multiphase signals drives charged particles in the subcutaneous tissue to undergo eddy current motion.

10. A method for heating a conductive material using the multiphase radiofrequency therapy system according to any one of claims 1 to 8, characterized in that, S1: Connect the M phase groups of the microneedle electrode array to the corresponding phase output terminals of the multiphase radio frequency generator; S2: Attach the microneedle electrode array to the prepared area of ​​the conductive material, and insert the microneedles into the conductive material to a preset depth; S3: Set the operating parameters of the multiphase RF generator, including setting the number of output phases and phase difference; S4: Start the multiphase RF generator and output M-phase RF signals with a set phase difference. The signals of each phase have the same frequency and amplitude. S5: Within the area enclosed by adjacent microneedles of different phases, a rotating electric field is synthesized by the M-phase signal, driving charged particles to perform eddy current motion, generating uniform Joule heating, and achieving intrinsic uniform heating of the skin tissue.

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