Intelligent safety biopsy needle integrated with optical fiber pressure feedback obstacle avoidance function

Abstract

The application discloses an intelligent safety biopsy needle integrated with optical fiber pressure feedback obstacle avoidance function. The intelligent safety biopsy needle and a control method thereof comprise a puncture outer tube and a biopsy inner needle, an optical fiber is embedded in a micro groove in the side wall of the inner needle, the optical fiber is provided with a first grating which is rigidly bonded and a second grating which is suspended and isolated, a microprocessor is built in a control handle, and an electromagnetic release mechanism containing a reset compression spring is provided, the microprocessor calculates pure strain according to the wavelength drift of the two gratings and converts the pure strain into axial resistance, a real-time resistance change rate is obtained by time differentiation, the electromagnetic release mechanism is powered off when the resistance change rate is greater than a trigger threshold and the duration exceeds a set time limit, and the biopsy inner needle is forced to retract by the elastic force of the reset compression spring. The application can eliminate in-vivo temperature interference and artificial perception reaction delay, and can prevent blood vessel perforation by automatic needle retraction.

Description

Technical Field

[0001] This application relates to the field of medical device technology, and in particular to the International Patent Classification A61B, specifically to an intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function for thyroid and deep organ puncture biopsy scenarios. Background Technology

[0002] In the field of medical diagnostics, fine-needle aspiration biopsy is a core method for obtaining soft tissue pathological samples. In such procedures, the target lesion is often surrounded by a rich network of blood vessels and nerve bundles. Conventional techniques typically rely on two-dimensional ultrasound guidance and tactile feedback to control the needle depth. The goal is to accurately obtain the diseased tissue while strictly avoiding the surrounding blood vessel walls to prevent large-scale internal bleeding or severe nerve damage complications.

[0003] However, existing general-purpose technical solutions suffer from numerous insurmountable physical and physiological defects. Conventional two-dimensional ultrasound imaging systems objectively have spatial resolution blind spots, making it difficult to reflect microscopic tissue structure changes directly in front of the needle tip in real time, three-dimensionally, and with precision. Furthermore, although the elastic modulus of the blood vessel wall differs from that of surrounding normal fat or glandular tissue due to its smooth muscle structure, the axial resistance increment generated when the needle tip contacts the blood vessel wall is extremely small, typically only in the range of 0.1N to 0.5N. The combined delay of tactile transmission in the human nervous system and the braking delay of muscle control usually takes 200ms to 300ms. By the time the finger senses an abnormal increase in resistance and stops the hand muscles from advancing, the biopsy needle has often already punctured the highly elastic blood vessel wall due to the inertia of the hand movement. This lag in the human sensory response chain makes traditional biopsy procedures inherently risky for accidental injury.

[0004] Currently, it is difficult to fundamentally eliminate the negative impact of delayed physiological responses in the human body within the framework of existing purely mechanical biopsy needles or simple image-guided technologies. There is a lack of an integrated device capable of miniaturizing and increasing the frequency of resistance sensing, and automating the underlying hardware of obstacle avoidance actions. Summary of the Invention

[0005] This application addresses the technical problems of existing biopsy puncture techniques that rely excessively on touch, leading to delayed response and easy accidental damage to surrounding blood vessels due to inertia. It provides an intelligent and safe biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function and its control method.

[0006] The first aspect of this application provides an intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function, including...

[0007] The puncture assembly includes an outer puncture tube and a biopsy inner needle that is slidably sleeved inside the outer puncture tube. The side wall of the biopsy inner needle is provided with a microgroove, and an optical fiber is embedded in the microgroove. The optical fiber is provided with a first grating and a second grating along the axial direction. The first grating is rigidly bonded to the inner wall of the microgroove, and the second grating is sleeved with a microtube to make the local optical fiber in a suspended state.

[0008] The control handle is connected to the tail of the puncture assembly and contains a miniature light source, a spectral demodulation plate, a microprocessor, and an electromagnetic release mechanism. The miniature light source is connected to an optical fiber, and the electromagnetic release mechanism includes a moving iron core and a reset spring.

[0009] The tail end of the biopsy needle is connected to a moving iron core, which switches between the first position of extending out of the puncture tube and the second position of retracting into the inner cavity of the puncture tube under the action of the moving iron core.

[0010] The microprocessor is connected to the spectral demodulation board and the electromagnetic release mechanism respectively. It is configured to calculate the pure strain variable based on the wavelength drift of the first grating and the second grating and convert it into the axial resistance of the biopsy needle; perform time differentiation on the axial resistance to obtain the resistance change rate; when the resistance change rate is determined to be greater than the trigger threshold and the duration exceeds the set time limit, a power cut-off signal is sent to the electromagnetic release mechanism.

[0011] When the electromagnetic release mechanism is de-energized, the compressed reset spring pushes the moving iron core backward, causing the biopsy needle to switch from the first position to the second position.

[0012] Furthermore, the microprocessor is equipped with a high-frequency sampling module. The microprocessor obtains the data output by the spectral demodulation board through the high-frequency sampling module at a set high-frequency sampling rate, and performs time derivative calculation on the axial resistance to obtain the real-time resistance change rate.

[0013] Furthermore, the high-frequency sampling rate is configured to be greater than or equal to 2kHz; the discrimination logic within the microprocessor is configured such that the trigger threshold is set to 1.5N / s and the set time limit is set to 3ms; when the microprocessor calculates the time derivative of the axial resistance in real time and the value exceeds the trigger threshold, and the duration of the state exceeding the trigger threshold meets the set time limit condition, a power cut-off signal is sent to the electromagnetic release mechanism.

[0014] Furthermore, the first grating is a strain sensing grating, and the second grating is a temperature compensation reference grating; the fiber core segment containing the first grating is bonded to the inner wall of the microgroove with rigid adhesive; one end of the microtube is closed, and the other end is sealed to the inner wall of the microgroove, so that the second grating is isolated in the cavity.

[0015] Furthermore, the logic configuration within the microprocessor is as follows: to obtain the first center wavelength drift amount generated by the first grating and the second center wavelength drift amount generated by the second grating; to use the second center wavelength drift amount as an environmental temperature compensation term, to subtract the wavelength change component caused by the environmental temperature change from the first center wavelength drift amount, to calculate the pure strain variable, and to linearly convert the pure strain variable into axial resistance by combining the elastic modulus and cross-sectional area parameters of the biopsy needle.

[0016] Furthermore, the electromagnetic release mechanism also includes a stationary iron core and a housing, with the moving iron core coaxially sliding inside the housing; a reset spring is sleeved on the outside of the moving iron core, with one end abutting against the flange of the moving iron core and the other end abutting against the inner wall of the housing; when the electromagnetic release mechanism is energized, the stationary iron core generates electromagnetic attraction to overcome the elastic force of the reset spring and attract the moving iron core.

[0017] Furthermore, the reset spring is equipped with a set stiffness coefficient, so that when the electromagnetic release mechanism disconnects the power supply to make the stationary iron core lose its electromagnetic attraction, the reset spring releases the compression potential energy and forcibly pushes the biopsy needle backward and back to the second position of the puncture tube inner cavity within a physical rebound time of less than or equal to 10ms, and the retraction endpoint is in a state of concealment without sharp obtuse angles.

[0018] The second aspect of this application provides a control method for an intelligent safety biopsy needle that implements the aforementioned integrated fiber optic pressure feedback obstacle avoidance function, including...

[0019] The wavelength shift of the first and second gratings on the optical fiber in the microgroove on the side wall of the biopsy needle is obtained.

[0020] The pure strain variable is calculated based on the wavelength shift of the first and second gratings and converted into the axial resistance of the biopsy needle.

[0021] The rate of change of resistance is obtained by differentiating the axial resistance over time.

[0022] When the resistance change rate is determined to be greater than the trigger threshold and the duration exceeds the set time limit, a power cut-off signal is sent to the electromagnetic release mechanism to de-energize the electromagnetic release mechanism and drive the biopsy inner needle to retract into the inner lumen of the puncture outer tube through the reset spring.

[0023] Further, the step of calculating the pure strain variable based on the wavelength drift of the first grating and the second grating and converting it into the axial resistance of the biopsy needle includes: determining the wavelength drift of the second grating in a suspended state as a temperature compensation reference value; subtracting the temperature compensation reference value from the wavelength drift of the rigidly bonded first grating to extract the pure strain variable after peeling off the temperature interference; and multiplying the pure strain variable with the material elastic modulus and cross-sectional area of ​​the biopsy needle to obtain the axial resistance.

[0024] Furthermore, the axial resistance is differentiated over time to obtain the resistance change rate, and the subsequent judgment steps include: solving the derivative of the axial resistance with time in real time at a frequency set to 2kHz to generate a real-time resistance change rate; comparing the resistance change rate with a trigger threshold set to 1.5N / s; when the continuous comparison results show that the duration of the resistance change rate is greater than 1.5N / s exceeds a set time limit of 3ms, a high-level touch recognition signal is generated, and a power cut-off signal is sent to the electromagnetic release mechanism based on the touch recognition signal.

[0025] Based on the above scheme, this application decentralizes the safety identification task of biopsy obstacle avoidance to the calculus layer at the hardware level. By combining the rigid sensing grating in the fiber optic microgroove on the side wall of the biopsy needle with the suspended reference grating, the interference of internal temperature drift on the measurement of minute resistance is eliminated, providing a high signal-to-noise ratio data base for subsequent calculations. The microprocessor calculates the rate of change of resistance in real time at a set high frequency. Once a sudden change in the state representing the boundary of high elastic modulus is detected, it directly controls the electromagnetic release mechanism to cut off the power supply, and the inner needle is forced to retract by the mechanical force of the spring. The entire process eliminates the human brain reaction and muscle braking links, and physically eliminates the possibility of accidental injury caused by puncture. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function provided in the embodiments of this application.

[0027] Figure 2 This is a partial cross-sectional view of the fiber optic microgroove and grating structure provided in the embodiments of this application.

[0028] Figure 3 This is a logic flowchart of the intelligent safety biopsy needle control method provided in the embodiments of this application.

[0029] Explanation of reference numerals in the attached figures:

[0030] The puncture assembly 101, control handle 102, puncture outer tube 103, biopsy inner needle 104, miniature light source 105, spectral demodulation plate 106, microprocessor 107, electromagnetic release mechanism 108, stationary iron core 109, moving iron core 110, reset spring 111, microgroove 201, single-mode quartz optical fiber 202, first grating 203, epoxy resin rigid adhesive 204, second grating 205, polyimide microtube 206, and parylene biocompatible coating 207. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of protection of this application. Those skilled in the art, after reading the disclosure of this application, can achieve the technical objectives of this application by employing similar alternatives or reasonable variations.

[0032] In the description of this application, it should be understood that the terms "first," "second," etc., are used only to distinguish the objects of description and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0033] Example 1

[0034] like Figure 1 As shown in the figure, this application embodiment provides an intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function. Its overall physical architecture consists of two core components: a puncture assembly 101 and a control handle 102 coaxially fixedly connected to its tail end. The entire system achieves autonomous retraction when the biopsy needle encounters a high elastic modulus boundary through purely physical mechanical feedback and embedded low-level computation.

[0035] Specifically, the external form of the puncture assembly 101 is a hollow tubular structure. It includes an outer puncture tube 103 and a biopsy inner needle 104 slidably fitted inside the cavity of the outer puncture tube 103. In this embodiment, the outer puncture tube 103 is made of high-strength medical-grade 304 stainless steel to ensure rigid support under external tissue pressure. The outer diameter of the outer puncture tube 103 is set at 1.2 mm, and the wall thickness is controlled at 0.15 mm. The front end of the outer puncture tube 103 is formed with a beveled cutting edge for cutting through routine soft tissue during travel. The biopsy inner needle 104 is coaxially disposed inside the cavity of the outer puncture tube 103. The front end of the biopsy inner needle 104 is a solid conical needle tip, and a groove is formed on its proximal side for cutting the target tissue during the sampling stage.

[0036] In terms of the physical definition of the working state, the biopsy needle 104 can linearly slide between a first position and a second position under the constraint of the built-in mechanism of the control handle 102. When in the first position, the solid conical tip of the biopsy needle 104 extends completely beyond the beveled edge of the front end of the puncture tube 103, and is in a state of sharp protrusion and force sensing. When switching to the second position, the biopsy needle 104 is displaced backward and retracted into the inner cavity of the puncture tube 103, so that the front end of the entire puncture assembly 101 no longer has a sharp piercing capability and is in a hidden and safe state without sharp angles.

[0037] To obtain the microscopic resistance changes experienced by the biopsy needle 104 during axial travel, this embodiment integrates a fiber optic microelectromechanical structure on the sidewall of the biopsy needle 104. Please refer to... Figure 2 , Figure 2 The microscopic cross-sectional structure of the grating region in the puncture assembly is shown. A V-shaped microgroove 201 is formed on the axially extending sidewall of the biopsy needle 104. The width of the microgroove 201 is controlled to be 150 μm, and the depth is 120 μm. A single-mode silica optical fiber 202 with an outer diameter of 125 μm is seamlessly embedded inside the microgroove 201, thus not increasing the outer diameter of the biopsy needle 104.

[0038] Two independent fiber Bragg gratings (FBGs) are sequentially etched along the axial direction in the core region of the single-mode silica fiber 202. The first grating 203 is located at the leading edge closest to the solid conical needle tip and serves as the core strain sensor. To ensure that external axial resistance is transmitted to the grating without loss, the fiber segment containing the first grating 203 is filled with epoxy resin rigid adhesive 204 between itself and the inner wall of the microgroove 201. Through the rigid curing bonding of this high-modulus adhesive, the minute strain generated during the deformation of the biopsy needle 104 can be completely coupled to the first grating 203. It should be noted that the specific type of adhesive is only an example; those skilled in the art can achieve the purpose of this application by using other high-rigidity curing adhesives capable of synchronous strain transfer.

[0039] However, the inherent physical characteristics of fiber Bragg gratings determine that their center wavelength is not only sensitive to strain but also extremely sensitive to changes in ambient temperature. The temperature of deep human tissues fluctuates slightly, and without eliminating temperature interference, temperature drift can easily be misinterpreted as a sudden change in stress. Therefore, a second grating 205 is used as a temperature compensation reference in the system. The second grating 205 is physically located approximately 5 mm behind the first grating 203. The most critical structural difference lies in the fact that a polyimide microtube 206 is coaxially sleeved outside the fiber core segment containing the second grating 205. This polyimide microtube 206 has an inner diameter of 200 μm, and its outer wall is sealed to the inner wall of the microgroove 201, while a gap exists between the inner wall of the polyimide microtube 206 and the outer wall of the single-mode silica fiber 202. One end of the microtube is closed, and the other end is sealed, thus forming an isolation cavity inside the microtube. The second grating 205 is suspended and isolated within this cavity, in a completely free state. Based on this unique isolation and encapsulation architecture, when the biopsy needle 104 is subjected to axial stress and undergoes tensile or compressive deformation, the stress is absorbed or bypassed by the external polyimide microtube 206, while the internally suspended second grating 205 is not subjected to any axial stress tension and only undergoes wavelength drift with changes in ambient temperature. After the entire fiber optic encapsulation is completed, a parylene biocompatible coating 207 is applied to the surface of the microgroove 201 and the exterior of the biopsy needle 104. The coating thickness is controlled to be 10 μm, thereby filling the microgroove gaps to be flush with the tube wall, ensuring the smoothness requirements of medical device implantation.

[0040] Please return again. Figure 1 To support the aforementioned sensing and subsequent actions, the control handle 102 integrates a complete electrical and electromechanical actuation network. The control handle 102 contains, in sequence, a miniature light source 105, a spectrum demodulation board 106, a microprocessor 107, and an electromagnetic release mechanism 108. Additionally, the handle also contains general support modules not shown in the figures, such as a rechargeable battery pack to power the components, a crystal oscillator circuit to provide a reference clock for the microprocessor 107, and a system reset circuit.

[0041] A miniature light source 105 injects broadband ranging light into a single-mode silica fiber 202 via an optical fiber coupler. A spectral demodulation board 106, connected to the fiber's reflector, is responsible for high-speed scanning and demodulation of the narrowband light signals reflected from the first grating 203 and the second grating 205, outputting a digital value of the center wavelength. A microprocessor 107 (e.g., a processor chip with floating-point arithmetic capabilities) is connected to the spectral demodulation board 106 via a high-speed communication bus. The microprocessor 107 is internally configured with a high-frequency sampling module specifically for reading wavelength data at a set high-frequency sampling rate. In this embodiment, the high-frequency sampling rate is configured to be greater than or equal to 2 kHz. This high-frequency sampling characteristic is fundamental to ensuring the system can capture transient elastic changes.

[0042] After acquiring the underlying optical data, the microprocessor 107 must perform temperature decoupling and physical quantity mapping transformation. The logic framework of the microprocessor 107 includes dual-grating compensation and mapping formulas. Specifically, the system performs calculations to remove temperature interference. To remove temperature interference, the following physical-mathematical model is used to calculate the pure strain variables:

[0043]

[0044]

[0045] in, This represents the measured first center wavelength shift generated by the first grating; This represents the measured second center wavelength shift generated by the second grating; This indicates the inherent strain sensitivity coefficient of this type of fiber grating, which typically ranges to approximately 1.2 pm / με at room temperature in this field; K T This indicates the temperature sensitivity coefficient of the grating, typically around 10 pm / ℃; This represents the actual axial strain experienced by the tip of the biopsy needle; This represents the relative temperature change within the environment surrounding the needle tip. The formula for the pure strain variable after removing the temperature disturbance, extracted by the microprocessor 107, is as follows:

[0046]

[0047] Subsequently, using Hooke's Law from mechanics of materials, the microprocessor 107 linearly converts the pure strain variable into the axial resistance of the biopsy needle:

[0048]

[0049] Where F represents the real-time axial resistance experienced by the needle tip (unit: Newtons N); E represents the elastic modulus of the biopsy needle material, which is approximately 193 GPa for the 304 stainless steel used in this embodiment; A represents the effective cross-sectional area of ​​the biopsy needle, calculated in advance based on geometric parameters such as the needle diameter. It should be noted that the above formula is the core model for converting microscopic wavelength quantities into macroscopic physical forces. Those skilled in the art can use similar higher-order calibration polynomials containing nonlinear correction terms to replace it, without departing from the protective essence of this application.

[0050] To determine whether the needle tip has touched the blood vessel wall, the microprocessor 107 performs time-dimension differentiation on the axial resistance F calculated in real time to obtain the real-time rate of change of resistance. The elastic modulus of human soft tissue exhibits layered differences. The typical fat and glandular layers show low modulus characteristics, while upon encountering a blood vessel wall, the elastic modulus changes abruptly due to the dense smooth muscle structure. The microprocessor 107 incorporates discrimination logic with a trigger threshold of 1.5 N / s and a time limit of 3 ms. When the microprocessor 107 calculates the elastic modulus in real time... If the value exceeds the trigger threshold of 1.5 N / s, and the duration of this high slope state exceeding the threshold is equal to or exceeds 3 ms, the microprocessor 107 will determine that a dangerous boundary with a high elastic modulus has been encountered ahead.

[0051] At this point, the puncture kinetic energy must be cut off immediately. This embodiment does not employ the conventional motor reversal and needle withdrawal method because there is an inherent delay in motor acceleration and gear engagement. The microprocessor 107 responds by sending a power-off signal to the electromagnetic release mechanism 108. Specifically, the output pin of the microprocessor 107 is connected to the gate of the metal-oxide-semiconductor field-effect transistor switching circuit driving the electromagnetic coil, and by pulling the level low, directly cuts off the current in the main circuit.

[0052] The electromagnetic release mechanism 108 is specifically designed for transient response. It includes a stationary iron core 109 fixed inside the control handle 102 and a coaxial outer casing. A moving iron core 110 slides coaxially through the casing via a guide rod, and the tail end of the biopsy needle 104 is rigidly fixed directly to the moving iron core 110. A return spring 111 is sleeved around the moving iron core 110. One end of the return spring 111 abuts against the flange at the end of the moving iron core 110, and the other end abuts against the fixed end face of the stationary iron core 109 or the inner wall of the casing.

[0053] During the normal operation of the biopsy needle insertion, the coil of the stationary iron core 109 is energized, generating a strong electromagnetic attraction that draws in and firmly locks the moving iron core 110 in front. At this time, the reset spring 111 is passively in a deeply compressed, energy-storing state. The moving iron core 110 holds the biopsy inner needle 104 in the first position extending from the outer tube.

[0054] Once the microprocessor 107 determines that obstacle avoidance has been triggered and cuts off the power supply signal, the stationary iron core 109 loses current, and the electromagnetic attraction instantly collapses and disappears. At this time, without any external power source, the compressed return spring 111, based on its own set high stiffness coefficient, releases compressive potential energy to overcome the weak residual magnetism and sliding friction resistance between the iron cores, forcibly pushing the moving iron core 110 to move backward. Due to the direct rigid connection, the rebound force of the return spring 111 directly pulls the biopsy needle 104 backward rapidly. After verification of the mechanical system response characteristics, the entire physical rebound time of the biopsy needle 104 from the first position to the second position inside the puncture tube 103 is controlled within a range of less than or equal to 10ms. Adding the time for the microprocessor 107 to identify and send signals in the early stage, the entire system can automatically retract within 15ms after the needle tip contacts the blood vessel wall, physically isolating the insertion end.

[0055] The beneficial effect of this embodiment is that, through the dual-grating architecture combining rigid bonding and suspended microtubes, data drift caused by the deep body temperature environment is eliminated, ensuring that the system can stably capture resistance changes at the 0.1N level. Simultaneously, the complex obstacle avoidance control is handled by underlying calculus-based hard calculations and directly coupled to a spring-driven, purely physical retraction mechanism that retracts the needle upon power failure. This eliminates the reliance on a manual tactile feedback chain, compressing the needle retraction delay from hundreds of milliseconds to the 15ms level, thereby physically eliminating the risk of accidental puncture injury and massive bleeding.

[0056] Example 2

[0057] Based on the integrated fiber optic hardware architecture constructed in the above embodiments, this embodiment focuses on explaining how... Figure 3 The diagram illustrates the underlying algorithm logic flow for controlling the biopsy needle. This control method transforms minute deformations in the physical world into time derivative calculations in the digital world and uses this data to control the electromechanical device in a closed loop. This control method is primarily executed by a microprocessor located inside the control handle.

[0058] like Figure 3 As shown, the control method includes the following steps:

[0059] The wavelength shift S301 is obtained by acquiring the wavelength shift of the first and second gratings on the optical fiber within the microgroove on the sidewall of the biopsy needle. To ensure the smoothness of drag capture and prevent the loss of abrupt peaks in a very short time, the microprocessor strictly controls the spectral demodulation board to pull and update the transient wavelength dataset of the reflected light from the first and second gratings in parallel at a high frequency set to 2kHz.

[0060] The strain variable is calculated and converted into resistance S302. Based on the wavelength shift of the first and second gratings, the strain variable is calculated and converted into the axial resistance of the biopsy needle. Due to local differences and fluctuations in the body's ambient temperature, a baseline stripping step is first performed to extract the wavelength shift measured by the second grating in a suspended, stress-free state, which is then separately determined as the ambient temperature compensation baseline value. Subsequently, the wavelength shift of the rigidly bonded first grating, which is affected by both stress and temperature, is directly subtracted from the previously extracted temperature compensation baseline value, thereby offsetting the thermodynamic influence term in the equation and extracting the pure strain variable after stripping away the temperature interference. After obtaining the value of the pure strain variable, the microprocessor extracts pre-configured static parameters from the internal non-volatile memory and performs continuous multiplication operations on the pure strain variable, elastic modulus, and cross-sectional area to obtain the precise axial resistance value currently borne by the biopsy needle in real time.

[0061] The drag change rate S303 is obtained by differentiating the drag over time; the drag change rate is obtained by differentiating the axial drag over time. In discrete embedded systems, the microprocessor utilizes the small time interval corresponding to a set sampling frequency of 2kHz. The axial resistance F(n) at the current moment and the resistance at the previous moment are calculated in real time using a differential algorithm. The time-varying derivative. By solving this continuously sliding window derivative, a real-time rate of change of drag, characterizing the steepness of the drag change, is generated. sequence flow.

[0062] In the comparison and time limit determination step S304, after obtaining the resistance change rate, the microprocessor compares the absolute value of the resistance change rate with a set trigger threshold in each calculation cycle. In this embodiment, the trigger threshold is strictly anchored at 1.5 N / s. Exceeding the threshold only once is insufficient to trigger the protection mechanism to prevent interference caused by hand tremors. The microprocessor activates the timing accumulator to evaluate the time span of continuous exceedance states. When the continuous comparison results show that the duration of the resistance change rate greater than 1.5 N / s exceeds the set time limit of 3 ms, the system can eliminate accidental noise and confirm that the probe has encountered a high-modulus dense blood vessel wall.

[0063] Upon executing the obstacle avoidance and cutoff operation S305, once the combined triggering conditions of the comparison and time limit determination S304 are met, the microprocessor immediately generates a high-level internal touch recognition signal on its control bus and, based on this internal touch recognition signal, issues an execution command to the control circuit. A low-level pulse signal to cut off the power supply is sent to the power semiconductor switch connected to the electromagnetic release mechanism. As the current returns to zero, the magnetic field of the electromagnetic release mechanism instantly dissipates and loses power, unlocking the suppressed spring energy inside the mechanical system. The reset spring instantly expands, causing the biopsy needle fixed to it to rapidly retract into the harmless inner cavity of the puncture outer tube.

[0064] The beneficial effect of the control logic in this embodiment is that by filtering through three layers of logic—compensation, differential, and time-domain filtering—it ensures that the algorithm will not make misjudgments due to small displacements or body temperature fluctuations; by transforming the obstacle avoidance strategy into a pure digital game of physical parameters, it improves the objectivity and repeatability of the safety boundary of medical operations.

[0065] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in this application, and within the spirit and principles of this application, should be included within the scope of protection of this application.

Claims

1. An intelligent safety biopsy needle integrating fiber optic pressure feedback obstacle avoidance function, characterized in that, include The puncture assembly includes an outer puncture tube and a biopsy inner needle slidably sleeved within the outer puncture tube. The sidewall of the biopsy inner needle has a microgroove, and an optical fiber is embedded in the microgroove. The optical fiber is provided with a first grating and a second grating along the axial direction. The first grating is rigidly bonded to the inner wall of the microgroove, and the second grating is sleeved with a microtube to make a part of the optical fiber suspend in a suspended state. A control handle is connected to the tail of the puncture assembly. It contains a miniature light source, a spectral demodulation plate, a microprocessor, and an electromagnetic release mechanism. The miniature light source is connected to the optical fiber. The electromagnetic release mechanism includes a moving iron core and a reset spring. The tail end of the biopsy needle is connected to the moving iron core, and under the drive of the moving iron core, it switches between a first position extending out of the puncture tube and a second position retracting into the inner cavity of the puncture tube; The microprocessor is connected to the spectral demodulation board and the electromagnetic release mechanism respectively, and is configured to calculate the pure strain variable based on the wavelength drift of the first grating and the second grating and convert it into the axial resistance of the biopsy needle; perform time differentiation on the axial resistance to obtain the resistance change rate; when it is determined that the resistance change rate is greater than the trigger threshold and the duration exceeds the set time limit, send a power cut-off signal to the electromagnetic release mechanism; When the electromagnetic release mechanism is de-energized, the compressed reset spring pushes the moving iron core backward, causing the biopsy needle to switch from the first position to the second position.

2. The intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function as described in claim 1, characterized in that, The microprocessor is equipped with a high-frequency sampling module. The microprocessor obtains the data output by the spectral demodulation board through the high-frequency sampling module at a set high-frequency sampling rate, and performs time derivative calculation on the axial resistance to obtain the real-time resistance change rate.

3. The intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function as described in claim 2, characterized in that, The high-frequency sampling rate is configured to be greater than or equal to 2kHz; the discrimination logic in the microprocessor is configured such that the trigger threshold is set to 1.5N / s and the set time limit is set to 3ms; when the microprocessor calculates the time derivative value of the axial resistance in real time and it exceeds the trigger threshold, and the duration of the state exceeding the trigger threshold meets the set time limit condition, the power supply cut-off signal is sent to the electromagnetic release mechanism.

4. The intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function as described in claim 1, characterized in that, The first grating is a strain sensing grating, and the second grating is a temperature compensation reference grating; the fiber core segment containing the first grating is bonded to the inner wall of the microgroove with rigid adhesive; one end of the microtube is closed, and the other end is sealed to the inner wall of the microgroove, so that the second grating is isolated in the cavity.

5. The intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function as described in claim 4, characterized in that, The logic configuration within the microprocessor is as follows: to obtain the first center wavelength drift amount generated by the first grating and the second center wavelength drift amount generated by the second grating; to use the second center wavelength drift amount as an environmental temperature compensation term, to subtract the wavelength change component caused by the environmental temperature change from the first center wavelength drift amount, to calculate the pure strain variable, and to linearly convert the pure strain variable into the axial resistance by combining the elastic modulus and cross-sectional area parameters of the biopsy needle.

6. The intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function as described in claim 1, characterized in that, The electromagnetic release mechanism also includes a stationary iron core and a housing, with the moving iron core slidably passing through the housing coaxially; the reset spring is sleeved on the outside of the moving iron core, with one end abutting against the flange of the moving iron core and the other end abutting against the inner wall of the housing; when the electromagnetic release mechanism is energized, the stationary iron core generates electromagnetic attraction to overcome the elastic force of the reset spring and attract the moving iron core.

7. The intelligent safety biopsy needle with integrated fiber optic pressure feedback obstacle avoidance function as described in claim 6, characterized in that, The reset spring is equipped with a set stiffness coefficient, so that at the instant when the electromagnetic release mechanism disconnects the power supply to make the stationary iron core lose its electromagnetic attraction, the reset spring releases the compression potential energy and forcibly pushes the biopsy needle backward and back to the second position of the inner cavity of the puncture tube within a physical rebound time of less than or equal to 10ms, and the retraction endpoint is in a hidden state without sharp obtuse angles.

8. A control method for an intelligent safety biopsy needle that implements the integrated fiber optic pressure feedback obstacle avoidance function as described in any one of claims 1 to 7, characterized in that, include The wavelength shift of the first grating and the second grating on the optical fiber within the microgroove on the sidewall of the biopsy needle is obtained; The pure strain variable is calculated based on the wavelength shift of the first grating and the second grating, and then converted into the axial resistance of the biopsy needle. The rate of change of resistance is obtained by differentiating the axial resistance over time. When it is determined that the resistance change rate is greater than the trigger threshold and the duration exceeds the set time limit, a power cut-off signal is sent to the electromagnetic release mechanism to de-energize the electromagnetic release mechanism and drive the biopsy inner needle to retract into the inner lumen of the puncture outer tube through the reset spring.

9. The control method as described in claim 8, characterized in that, The step of calculating the pure strain variable based on the wavelength shift of the first and second gratings and converting it into the axial resistance of the biopsy needle includes: The wavelength drift of the second grating in a suspended state is determined as the temperature compensation reference value; Subtract the temperature compensation reference value from the wavelength drift of the rigidly bonded first grating to extract the pure strain variable after the temperature interference is removed. The axial resistance is calculated by multiplying the pure strain variable with the material elastic modulus and cross-sectional area of ​​the biopsy needle.

10. The control method as described in claim 8, characterized in that, The process of differentiating the axial resistance over time to obtain the rate of change of resistance, and subsequent judgment steps, include... The derivative of the axial resistance as a function of time is calculated in real time at a frequency set to 2kHz to generate the real-time rate of change of the resistance. The rate of change of resistance is compared numerically with the trigger threshold set to 1.5 N / s; When the continuous comparison results show that the resistance change rate is greater than 1.5 N / s for a period of time exceeding the set time limit of 3 ms, a high-level touch recognition signal is generated, and the operation of sending the power cut-off signal to the electromagnetic release mechanism is performed according to the touch recognition signal.

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