Flexible OCT probe, design method thereof and OCT imaging method

Abstract

The invention relates to a flexible OCT probe, a design method thereof and an OCT imaging method. The probe comprises a flexible probe body; the integrated light beam scanning device is packaged at the far end of the flexible probe body and is used for performing deflection scanning based on the laser beams to obtain original scanning data; the optical conduction assembly is used for transmitting the laser beams to the integrated light beam scanning device, receiving reflection signals transmitted back by the integrated light beam scanning device and transmitting the reflection signals to the detection system; and the measurement and control circuit is electrically connected with the integrated light beam scanning device and is used for driving the integrated light beam scanning device to deflect and monitoring a deflection angle based on a feedback signal generated by the integrated light beam scanning device. Therefore, by integrating the MEMS scanning mirror into the OCT probe, the problems of limited space and insufficient visual field in in-vivo diagnosis and treatment are solved, and the imaging quality of the OCT probe is improved while the size of the OCT probe is reduced.

Description

Technical Field

[0001] This application relates to the field of microelectromechanical system (MEMS) device application technology, and in particular to a flexible OCT (Optical Coherence Tomography) probe and its design method, as well as an OCT imaging method. Background Technology

[0002] Optical coherence tomography (OCT) is a non-invasive, high-resolution biomedical imaging technique. With the continuous development of minimally invasive surgical techniques, the need for real-time, high-precision three-dimensional imaging within the narrow and tortuous cavities of the human body (such as sinuses, bronchi, and bile ducts) is becoming increasingly urgent. However, traditional OCT systems are bulky, and their probe size and rigid structure severely limit their application in minimally invasive surgical scenarios. Developing an OCT probe that combines miniaturization, high flexibility, and high imaging quality has become a key challenge in promoting the development of precision minimally invasive surgery.

[0003] In related technologies, a typical structure for achieving intracavitary imaging in OCT involves integrating a set of microlenses at the probe tip and using mechanical rotation or translation of the optical fiber to achieve scanning. Another approach involves using a large-sized galvanometer or rotating mirror for scanning externally, and then coupling the beam into a flexible catheter through a complex optical path. However, both methods are limited by traditional lens optical design, resulting in space constraints and insufficient field of view during in vivo diagnosis and treatment, which urgently need to be addressed. Summary of the Invention

[0004] This application provides a flexible OCT probe and its design method, as well as an OCT imaging method, to solve the problems of limited space and insufficient field of view in in vivo diagnosis and treatment of related OCT probes, thereby reducing the size of the OCT probe while improving the imaging quality of the OCT probe.

[0005] To achieve the above objectives, a first aspect of this application provides a flexible OCT probe, comprising: Flexible probe body; An integrated beam scanning device is encapsulated at the distal end of the flexible probe body. The integrated beam scanning device is used to perform deflection scanning based on a laser beam to obtain raw scanning data. An optical transmission component is provided, which transmits a laser beam to the integrated beam scanning device, receives a reflected signal from the integrated beam scanning device, and transmits the reflected signal to the detection system. A measurement and control circuit is electrically connected to the integrated beam scanning device, used to drive the integrated beam scanning device to deflect, and to monitor the deflection angle based on the feedback signal generated by the integrated beam scanning device.

[0006] According to one embodiment of this application, the integrated beam scanning device includes: a scanning lens, a piezoelectric actuator assembly, and a built-in angle sensor, wherein... The piezoelectric actuator group is used to drive the scanning lens to deflect; The built-in angle sensor is used to monitor the deflection angle of the scanning lens and generate the feedback signal based on the deflection angle.

[0007] According to one embodiment of this application, the built-in angle sensor is at least one of a piezoresistive angle sensor, a capacitive angle sensor, and a photoelectric angle sensor.

[0008] According to one embodiment of this application, the measurement and control circuit includes: A voltage output module, wherein the voltage output module is used to apply a driving voltage to the piezoelectric actuator assembly; A voltage acquisition module, which is used to acquire the feedback signal of the built-in angle sensor; The main control module is used to calculate the actual deflection angle of the scanning lens based on the feedback signal, compare the actual deflection angle with the target deflection angle, and adjust the driving voltage based on the comparison result until the actual deflection angle is the same as the target deflection angle.

[0009] According to one embodiment of this application, the optical transmission component includes: an optical fiber and a collimating lens, wherein, The collimating lens is disposed between the optical output path of the optical fiber and the integrated beam scanning device, and the collimating lens is used to collimate or focus the laser beam.

[0010] According to one embodiment of this application, the flexible probe body is a multi-degree-of-freedom probe actuator, comprising: A shape sensing module is used to sense the bending shape of the flexible probe body; A contact force sensing module is used to calculate the contact force at the end of the flexible probe body based on the bending shape and the driving force of the flexible probe body.

[0011] According to one embodiment of this application, the aforementioned flexible OCT probe further includes: An image processing device is used to receive the original scan data and perform stitching and three-dimensional reconstruction processing on the original scan data to generate a three-dimensional OCT image.

[0012] According to one embodiment of this application, the original scan data is a depth-resolved reflectance distribution signal of multiple target location points.

[0013] According to the flexible OCT probe proposed in this application, an integrated beam scanning device encapsulated at the distal end of the flexible probe body performs deflection scanning based on a laser beam to obtain raw scanning data. The laser beam is transmitted to the integrated beam scanning device via an optical transmission component, and the reflected signal returned by the integrated beam scanning device is received and transmitted to the detection system. The integrated beam scanning device is driven to deflect via a measurement and control circuit, and the deflection angle is monitored based on the feedback signal generated by the integrated beam scanning device. Thus, by integrating a MEMS (Micro-Electro-Mechanical Systems) scanning mirror into the OCT probe, the problems of limited space and insufficient field of view in in vivo diagnosis and treatment are solved, reducing the size of the OCT probe while improving the imaging quality.

[0014] To achieve the above objectives, a second aspect of this application provides an OCT imaging method, which employs the flexible OCT probe described in the first aspect embodiment, wherein the OCT imaging method includes the following steps: The integrated beam scanning device is driven by the measurement and control circuit to perform laser scanning, so that the laser beam scans the target biological tissue in the target human cavity along a preset path. The optical transmission component receives the reflected signal returned from the target biological tissue and transmits the reflected signal to the detection system to obtain the raw scan data; The original scan data is stitched together and reconstructed in three dimensions to produce a three-dimensional OCT image.

[0015] The OCT imaging method proposed in the embodiments of this application solves the problems of limited space and insufficient field of view in in vivo diagnosis and treatment by using a flexible OCT probe, thereby reducing the size of the OCT probe while improving the imaging quality of the OCT probe.

[0016] To achieve the above objectives, a third aspect of this application proposes a design method for a flexible OCT probe, which is applied to the flexible OCT probe described in the first aspect embodiment. The design method for the flexible probe body includes the following steps: Medical imaging data of the target human body cavity is acquired, and the three-dimensional structure of the target human body cavity is reconstructed based on a preset statistical shape model and the medical imaging data to obtain a three-dimensional anatomical model of the target human body cavity. The working space of the flexible probe body within the target human cavity is determined based on the three-dimensional anatomical model, and the initial structural parameters of the flexible probe body are determined based on the working space, wherein the initial structural parameters include at least one of outer diameter, length and limit bending angle. A mechanical mapping relationship between the driving force and bending angle of the flexible probe body is established. Based on the mechanical mapping relationship, and with the limit bending angle and limit load as constraints, a size parameter optimization model of the flexible probe body is constructed. The target structural parameters of the flexible probe body are obtained by using a preset heuristic algorithm and the size parameter optimization model.

[0017] According to the design method of the flexible OCT probe proposed in the embodiments of this application, the working space and initial structural parameters of the probe are determined by reconstructing a three-dimensional model of the cavity through individual medical images; then, a mechanical mapping relationship between driving force and bending angle is established, and an optimization model is constructed with this relationship, the limit bending angle, and the limit load as constraints. The optimal structural parameters are obtained by solving the algorithm, so as to realize the collaborative automated design of the probe from anatomical adaptation to mechanical performance.

[0018] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0019] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a block diagram of a flexible OCT probe according to an embodiment of this application; Figure 2 This is a schematic diagram of a piezoelectric driver array structure for a MEMS scanning mirror according to an embodiment of this application; Figure 3 This is a schematic diagram of a spiral distributed FBG (Fiber Bragg Grating) sensor according to an embodiment of this application; Figure 4 A flowchart of the OCT imaging method provided according to an embodiment of this application. Figure 5 This is a flowchart of a design method for a flexible OCT probe according to an embodiment of this application. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0021] The following describes, with reference to the accompanying drawings, a flexible OCT probe and its design method, and an OCT imaging method proposed according to embodiments of this application. First, the flexible OCT probe proposed according to embodiments of this application will be described with reference to the accompanying drawings.

[0022] Figure 1 This is a block diagram of a flexible OCT probe according to an embodiment of this application.

[0023] like Figure 1 As shown, the flexible OCT probe 10 includes the following steps: a flexible probe body 100, an integrated beam scanning device 200, an optical transmission component 300, and a measurement and control circuit 400. The integrated beam scanning device 200 is encapsulated at the distal end of the flexible probe body 100 and is used for deflection scanning based on a laser beam to obtain raw scanning data. The optical transmission component 300 is used to transmit the laser beam to the integrated beam scanning device 200, receive the reflected signal returned by the integrated beam scanning device 200, and transmit the reflected signal to the detection system. The measurement and control circuit 400 is electrically connected to the integrated beam scanning device 200, and is used to drive the integrated beam scanning device 200 to deflect, and monitor the deflection angle based on the feedback signal generated by the integrated beam scanning device 200.

[0024] Specifically, the flexible OCT probe 10 proposed in this application mainly consists of a flexible probe body 100, an integrated beam scanning device 200, an optical transmission component 300, and a measurement and control circuit 400. The flexible probe body 100 refers to the mechanical support and motion carrier of the entire flexible OCT probe 10, typically made of a biocompatible, flexible, and highly elastic material (such as nickel-titanium alloy), and structurally designed as a multi-degree-of-freedom continuum or a serpentine actuator. The integrated beam scanning device 200 is a miniature scanner encapsulated at the distal end of the flexible probe body 100 (i.e., the end inserted into the patient's body and close to the target tissue). It can replace the lens group and CCD (Charge Coupled Device) / CMOS (Complementary Metal-Oxide-Semiconductor) imaging system in traditional OCT probes. Through controlled deflection, the laser beam is guided to scan the tissue surface point by point, thereby acquiring the raw optical signals (i.e., raw scan data) used to construct the image. The optical transmission component 300 is the "optical conduit" responsible for the input and return of optical signals (i.e., laser beams). It can efficiently transmit the probe light from an external laser source to the integrated beam scanning device 200. Simultaneously, it collects the optical signals reflected back from the tissue and then reflected by the integrated beam scanning device 200, couples them back to the optical fiber, and transmits them back to the external interferometer and detector system (i.e., the OCT system host outside the probe). The measurement and control circuit 400 is the "brain" that realizes the precise motion control of the integrated beam scanning device 200. It can command the movement of the integrated beam scanning device 200 through wires, generate corresponding electrical signals, and further convert them into digital signals as feedback signals to be transmitted back to the measurement and control circuit 400. The measurement and control circuit 400 can analyze this feedback signal to accurately monitor the deflection angle of the lens in the integrated beam scanning device 200, and dynamically adjust the integrated beam scanning device 200 based on this, forming a closed-loop control system of "command-sensing-calibration", thereby ensuring the accuracy and stability of beam scanning.

[0025] In some embodiments, the original scan data is a depth-resolved reflectance distribution signal of multiple target location points.

[0026] Understandably, the target location points are a series of specific locations on the surface of biological tissue that are sequentially irradiated by the laser beam through precise deflection by the integrated beam scanning device.

[0027] In other words, the raw data obtained by the flexible OCT probe 10 through scanning is essentially a series of signals recording the three-dimensional optical properties of the tissue. Specifically, the laser beam sequentially irradiates multiple specific locations (i.e., target locations) on the tissue surface. For each irradiated point, the system can not only record surface information but also measure the backscattered light intensity (reflectivity) of the tissue at different depths along the beam direction (depth), forming an intensity distribution curve that varies with depth (i.e., depth-resolved reflectivity distribution signal, i.e., sequential A-Scan (Amplitude Scan) signal). Arranging these depth distribution signals corresponding to all irradiated points according to their spatial positions constitutes the raw data basis for subsequent reconstruction of two-dimensional or three-dimensional OCT images, which directly reflects the spatial and optical properties of the microstructure inside biological tissues.

[0028] Optionally, in some embodiments, the integrated beam scanning device 200 includes: a scanning lens, a piezoelectric actuator assembly, and a built-in angle sensor, wherein the piezoelectric actuator assembly is used to drive the scanning lens to deflect; and the built-in angle sensor is used to monitor the deflection angle of the scanning lens and generate a feedback signal based on the deflection angle.

[0029] Specifically, the integrated beam scanning device 200 is a MEMS scanning mirror, a miniature scanner manufactured using MEMS technology that integrates a movable lens (i.e., a scanning lens), an actuator (such as a piezoelectric actuator), and an angle sensor. As an optical execution terminal, the MEMS scanning mirror directly changes the emission direction of the laser beam through physical deflection, thereby achieving point-to-point scanning of the target tissue surface. The surface of the scanning lens is typically coated with a high-reflectivity metal (such as a mirror) to ensure light efficiency. The MEMS scanning mirror offers advantages such as miniaturization, high scanning frequency, and low cost. Combined with sensing algorithms, it can achieve 3D representation of the physical information of biological tissues, aiding in pathological diagnosis. The MEMS scanning mirror is fabricated using MEMS technology, requiring multiple photolithography and etching processes. The packaging here includes the packaging of the MEMS scanning mirror and the overall packaging of the flexible OCT probe 10.

[0030] The MEMS scanning mirror is packaged as follows: it is attached to a PCB (Printed Circuit Board), and the electrodes on the MEMS scanning mirror are electrically interconnected with the electrodes on the PCB through wire bonding. By applying voltage to the electrodes on the PCB, the MEMS scanning mirror deflects, achieving the beam scanning function. The MEMS scanning mirror is vacuum-sealed using a tubular package, with pins reserved at the package for connection to the measurement and control circuit. The overall packaging of the flexible OCT probe 10 consists of the following components: the MEMS scanning mirror packaging structure, the laser (located at the proximal end of the flexible OCT probe (within the external system host)), the detector (mainly located within the system host), the optical fiber (running through the entire flexible probe body 100, serving as the only channel connecting the remote integrated beam scanning device 200 and the proximal light source / detector), and the lens (a miniaturized optical lens, such as a self-focusing lens or a spherical lens, packaged at the distal end of the flexible probe body 100, immediately before the MEMS scanning mirror). The exterior can be filled with other materials to prevent the ingress of solutions, gases, or other substances. The overall size of the MEMS scanning mirror is in the hundreds of micrometers. It adopts micro-nano packaging technology to achieve conduction with the measurement and control circuit 400. Vacuum packaging is used to ensure the stability and lifespan of the flexible OCT probe 10.

[0031] like Figure 2 As shown, piezoelectric actuators, serving as both a power source and transmission mechanism, can utilize the inverse piezoelectric effect of piezoelectric materials (such as lead zirconate titanate), meaning that when a voltage is applied, the material undergoes precise deformation at the micrometer or even nanometer scale. This is achieved through specific mechanical structures (such as...) Figure 2 The sinusoidal folding beam shown amplifies and transmits this micro-deformation, converting it into a mechanical force that drives the scanning lens to deflect. The actuators are arranged in pairs or groups to achieve the deflection of the scanning lens in two orthogonal directions, thereby completing the two-dimensional scan.

[0032] The built-in angle sensor can convert the mechanical deflection angle of the scanning lens into a measurable electrical signal change (such as a change in resistance, capacitance or photocurrent) in real time and directly, and then convert the electrical signal into a digital signal and output it to the measurement and control circuit 400.

[0033] Therefore, the integrated design of the actuator and sensor enables direct, in-situ, real-time measurement and control of the scanning lens angle, eliminating transmission errors and external interference, and ensuring the accuracy and stability of the scanning trajectory, which is the foundation for obtaining high-quality OCT images. Furthermore, integrating the driving and sensing functions onto a MEMS chip at the hundred-micron scale is the core of achieving the sub-millimeter size of the probe. This integrated design reduces external connections and assembly steps, improving the long-term reliability of the entire flexible OCT probe under complex in vivo environments (such as temperature and humidity variations).

[0034] Optionally, in some embodiments, the built-in angle sensor is at least one of a piezoresistive angle sensor, a capacitive angle sensor, and a photoelectric angle sensor.

[0035] Understandably, there are various types of built-in angle sensors available, such as piezoresistive, capacitive, and photoelectric angle sensors. The principle of a piezoresistive angle sensor is that when the scanning lens deflects, causing strain in its supporting beam (such as a spring beam), the resistance of the piezoresistive material fabricated on the beam changes linearly. By measuring this change in resistance, the strain of the beam can be deduced, and thus the deflection angle of the scanning lens can be calculated. A capacitive angle sensor utilizes the principle of a parallel-plate capacitor, using the scanning lens or its connecting structure as a movable electrode, with a fixed electrode placed below or to the side, forming a miniature capacitor. When the scanning lens deflects, the overlap area or spacing between the two plates changes, resulting in a change in capacitance. By precisely measuring the change in capacitance, minute angular displacements can be accurately calculated. Photoelectric angle sensors typically involve a light source (such as a miniature LED (Light-Emitting Diode)) and a photodetector. The deflection of the scanning lens can block or change the light path reflected onto the detector, thereby causing a change in the intensity of the light received by the detector or the position of the light spot. This change can be converted into a current or voltage signal.

[0036] Regardless of the type of sensor chosen, it can convert the non-electrical quantity of the mechanical deflection angle of the scanning lens into an electrical signal (i.e., a feedback signal) that can be accurately read and processed by subsequent circuits in real time and in situ. Depending on the specific design requirements for sensitivity, size, power consumption, and interference immunity, one or a combination of these sensors can be selected.

[0037] Optionally, in some embodiments, the measurement and control circuit 400 includes: a voltage output module, a voltage acquisition module, and a main control module, wherein the voltage output module is used to apply a driving voltage to the piezoelectric actuator group; the voltage acquisition module is used to acquire the feedback signal of the built-in angle sensor; the main control module is used to calculate the actual deflection angle of the scanning lens according to the feedback signal, compare the actual deflection angle with the target deflection angle, and adjust the driving voltage based on the comparison result until the actual deflection angle is the same as the target deflection angle.

[0038] Specifically, the measurement and control circuit 400 is connected to the positive and negative terminals of the MEMS scanning mirror (i.e., the integrated beam scanning device 200) and the positive and negative terminals of the built-in angle sensor. It monitors and controls the deflection angle of the scanning mirror in real time, enabling integrated driving, detection, and control of the MEMS scanning mirror, thus achieving stable scanning. The measurement and control circuit mainly includes a voltage output module, a voltage acquisition module, and a main control module. These three modules work together to form a complete "command-sensing-calibration" closed-loop control system. The voltage output module can generate and output a high-voltage drive signal (voltage) with specific waveform, amplitude, and frequency according to the control command, which is directly applied to the piezoelectric actuator group within the integrated beam scanning device 200. Since the piezoelectric material deforms under a high-voltage electric field, the voltage output by this voltage output module can directly determine the deformation of the actuator, thereby controlling the target deflection angle of the scanning mirror. The voltage acquisition module may include signal conditioning circuitry (such as amplification, filtering, and analog-to-digital converters) to acquire, in real-time and with high precision, weak analog electrical signals (such as resistive voltage dividers, charge, or photocurrent signals) output by the built-in angle sensor, reflecting the actual deflection state of the scanning lens. This signal is then purified, amplified, and converted into a digital signal (i.e., a feedback signal). Upon receiving the digital feedback signal from the voltage acquisition module, the main control module calculates the actual deflection angle of the scanning lens in real-time based on a preset sensor calibration curve (i.e., a model showing the correspondence between the feedback signal and the angle). The calculated actual deflection angle is then compared in real-time with the target deflection angle required by the imaging system (determined by the scanning pattern) to calculate the angle error. Based on this angle error, a specific control algorithm (such as PID (Proportion Integration Differentiation) control) is used to calculate the required adjustment of the drive voltage value, and a new command is sent to the voltage output module.

[0039] Thus, through a continuous cycle of "acquisition-calculation-comparison-adjustment", the driving voltage is dynamically corrected, ultimately making the actual deflection angle infinitely close to and stable at the target deflection angle, thereby achieving precise control of the scanning lens angle.

[0040] Optionally, in some embodiments, the optical transmission component 300 includes an optical fiber and a collimating lens, wherein the collimating lens is disposed between the optical fiber's output optical path and the integrated beam scanning device 200, and the collimating lens is used to collimate or focus the laser beam.

[0041] Specifically, to transform the raw laser beam into a usable scanning beam, the optical transmission component 300 consists of two main parts: an optical fiber (or fiber bundle) and a collimating lens at the end of the fiber for beam collimation or focusing. The optical fiber is responsible for transmitting the laser beam from an external laser source with low loss and flexibility from the proximal end (external) of the flexible OCT probe 10 to the distal end (in-body working site) of the flexible OCT probe 10. Simultaneously, it also transmits scattered light carrying information reflected from the tissue back to the detector. The collimating lens is positioned between the optical fiber's output path and the integrated beam scanning device 200, and can perform beam shaping, i.e., collimation and focusing, on the laser beam emitted from the fiber end face. Since the light emitted from the fiber is divergent, the collimating lens converts it into a parallel beam. The advantage of this is that when the parallel beam is reflected by the scanning lens, the spot size and energy density remain relatively stable within a certain scanning angle and distance, which is crucial for obtaining uniform imaging resolution and signal strength. In some designs that require higher lateral resolution, collimating lenses can focus a beam of light onto a very small point on the scanning lens or tissue surface, thereby improving the spatial resolution of the image.

[0042] The collaborative workflow of the optical transmission component 300 and the integrated beam scanning device 200 is as follows: The laser beam is transmitted to the far end of the flexible OCT probe 10 through the optical fiber of the optical transmission component 300; the laser beam is emitted from the end face of the optical fiber at a divergence angle and is immediately received and shaped (becomes parallel or converged light) by the collimating lens of the optical transmission component 300; the shaped beam illuminates the scanning lens of the integrated beam scanning device 200; the scanning lens deflects, projecting the shaped beam onto different points on the tissue surface for scanning; the scattered light reflected back from the tissue travels in reverse along the same path: first reflected by the scanning lens, then collected by the collimating lens and efficiently coupled back to the optical fiber, and finally transmitted back to the detector.

[0043] Optionally, in some embodiments, the flexible probe body 100 is a multi-degree-of-freedom probe actuator, including: a shape sensing module and a contact force sensing module, wherein the shape sensing module is used to sense the bending shape of the flexible probe body 100; and the contact force sensing module is used to calculate the contact force at the end of the flexible probe body 100 based on the bending shape and the driving force of the flexible probe body 100.

[0044] Understandably, the flexible probe body 100 is not only a bendable mechanical structure, but also an intelligent actuator with proprioceptive capabilities. The flexible probe body 100 can be a multi-degree-of-freedom continuum or a serpentine actuator made of a hyperelastic material (such as nickel-titanium alloy). Through the pulling of the internal drive wire, it can actively bend in multiple directions, thereby achieving flexible obstacle avoidance and precise positioning in complex human body cavities.

[0045] Specifically, the flexible probe body 100 mainly includes a shape sensing module and a contact force sensing module. The shape sensing module can be an FBG sensor spirally distributed on the surface of the endoscope actuator, such as... Figure 3 As shown, an FBG sensor is a miniature sensor etched on an optical fiber. When the optical fiber is subjected to bending strain, the wavelength of the reflected light will shift. By calculating the wavelength shift data of multiple FBG sensors, the real-time bending shape of the entire flexible probe body 100 in three-dimensional space (i.e., the curvature and direction of each segment) can be reconstructed.

[0046] The contact force sensing module can indirectly and non-invasively calculate the magnitude of the contact force between the end of the flexible probe body 100 (the part that first touches the object) and the biological tissue. This process is a model-based static mechanical solution process that relies on two core inputs: the bending shape of the flexible probe body 100 and the driving force of the flexible probe body 100. When the end of the flexible probe body 100 is freely suspended, its shape is uniquely determined by the internal driving force. When the end contacts the tissue, the contact force causes a measurable distortion in its shape. The driving force of the flexible probe body 100 originates from the force pulling the driving wire that runs through the flexible probe body 100. This parameter can be measured by a driving force sensor (such as a miniature tension sensor) installed near the proximal end of the driving wire (i.e., the end that remains outside the body).

[0047] Furthermore, to understand the mathematical relationship between the readings (strain) of the internal FBG sensors and the external spatial morphology (curvature, torsion) of the flexible probe body 100 when it bends, a mathematical model (i.e., the curvature-strain model for each FBG sensor) can be established through mechanical analysis. This model describes the tensile and shear strains generated by the optical fibers laid along the spiral path inside the flexible probe body 100 when it bends (generates curvature) and torsions. Based on this model, the one-to-one correspondence between the strain value measured by each FBG sensor and the local curvature of the flexible probe body 100 can be clearly defined. Secondly, the system can read the strain measurements of multiple FBG sensors wound spirally on the flexible probe body 100 in real time. Using the curvature-strain model established in the previous step, the strain measurement value of each FBG sensor can be expressed as a function of the curvature and torsion of the flexible probe body 100, and these values ​​can be combined into a system of equations. By solving the system of equations, the actual curvature and torsion angle of each segment of the flexible probe body 100 (corresponding to the FBG sensor position) can be obtained. By integrating these local curvature and torsion angle information, the continuous bending shape of the entire flexible probe body 100 in three-dimensional space can be reconstructed. Finally, based on the reconstructed complete spatial curve, the spatial coordinates of the end of the flexible probe body 100 can be accurately calculated.

[0048] The working principle of the contact force sensing module is based on the core ideas of shape comparison and static inversion. First, before leaving the factory, calibration establishes a one-to-one correspondence between the driving force of the flexible probe body 100 in a non-contact state and its bending shape, forming a benchmark database. In actual operation, the contact force sensing module can receive the actual bending shape from the shape sensing module in real time and compare it with the expected non-contact shape retrieved from the benchmark data based on the current measured driving force. When the end of the flexible probe body 100 contacts the tissue, the contact force causes a measurable deviation in the actual shape; through the preset probe deformation-mechanical mapping relationship, the equivalent resultant force acting on the end can be calculated from this shape deviation. Finally, combining the known driving force and the calculated equivalent resultant force, the static equilibrium equation can be used for inversion calculation, which can indirectly and accurately solve for the actual contact force between the probe end and the biological tissue, thereby achieving real-time, non-invasive force feedback without the need for an end force sensor.

[0049] Optionally, in some embodiments, the flexible OCT probe 10 further includes an image processing device, which receives raw scan data and performs stitching and three-dimensional reconstruction processing on the raw scan data to generate a three-dimensional OCT image.

[0050] Specifically, the flexible OCT probe 10 can also be equipped with an image processing device. This device can be a dedicated processor (such as a GPU) integrated into the probe system host, or a computer running specific software. Its core function is to receive the raw, sequential depth scan data (i.e., A-Scan signals from multiple spatial points) acquired by the integrated beam scanning device 200 and execute real-time image stitching and 3D reconstruction algorithms. The image processing device first uses image correlation-based registration and fusion technology to stitch continuously acquired two-dimensional cross-sectional images into a coherent whole, eliminating misalignment caused by probe movement. Then, it uses advanced algorithms such as deep learning to reconstruct and render the stitched two-dimensional sequence into 3D volumetric data, ultimately generating a high-resolution 3D OCT image or holographic projection that can be observed, sectioned, and quantitatively analyzed from multiple angles. This transforms the raw optical signals acquired by the probe into intuitive stereoscopic images that can be directly used for clinical diagnosis and surgical navigation, completing a closed-loop process from data acquisition to visual diagnosis.

[0051] In summary, the flexible OCT probe proposed in this application has at least the following beneficial effects: (1) This application provides a sub-millimeter flexible OCT probe with integrated MEMS scanning mirror. By using MEMS scanning mirror to achieve miniaturized packaging of the optical scanning system, the overall size of the probe is reduced to the sub-millimeter level, which significantly improves its passability and applicability in narrow cavities.

[0052] (2) The flexible OCT probe in this application embodiment can be customized according to the anatomical characteristics of different human body parts, and the structural parameters of its multi-degree-of-freedom actuator can be customized. Through the optimized design based on the working space of the target human body cavity, the outer diameter, length, maximum bending angle and other functional parameters of the probe can be flexibly adjusted to achieve dynamic adaptation to complex physiological structures.

[0053] (3) The embodiments of this application utilize MEMS scanning mirrors to achieve rapid and precise two-dimensional and three-dimensional scanning of light beams, replacing traditional lens groups and image sensors. This not only simplifies the optical path structure but also effectively improves imaging resolution and signal-to-noise ratio, enabling the easy acquisition of high-quality tissue tomographic images.

[0054] (4) The flexible OCT probe of this application embodiment can achieve high-resolution three-dimensional imaging while integrating multi-degree-of-freedom active motion control and real-time end contact force sensing function. It can provide mechanical property information of biological tissues and assist in judging the nature of lesions. It has important theoretical value and clinical application prospects in minimally invasive diagnosis and surgical navigation.

[0055] (5) The flexible OCT probe in this application focuses on key technologies such as minimally invasive intervention, accurate diagnosis, high-quality imaging and operational safety, and is expected to improve the accuracy and safety of related treatments.

[0056] According to the flexible OCT probe proposed in this application, an integrated beam scanning device encapsulated at the distal end of the flexible probe body performs deflection scanning based on a laser beam to obtain raw scanning data. The laser beam is transmitted to the integrated beam scanning device via an optical transmission component, and the reflected signal returned by the integrated beam scanning device is received and transmitted to the detection system. The integrated beam scanning device is driven to deflect via a measurement and control circuit, and the deflection angle is monitored based on the feedback signal generated by the integrated beam scanning device. Thus, by integrating a MEMS (Micro-Electro-Mechanical Systems) scanning mirror into the OCT probe, the problems of limited space and insufficient field of view in in vivo diagnosis and treatment are solved, reducing the size of the OCT probe while improving the imaging quality.

[0057] The following describes an OCT imaging method according to an embodiment of this application with reference to the accompanying drawings. This method employs… Figure 1 The flexible OCT probe of the embodiment.

[0058] Figure 4 This is a flowchart of an OCT imaging method according to an embodiment of this application.

[0059] like Figure 4 As shown, this OCT imaging method includes the following steps: In step S401, the integrated beam scanning device is driven by the measurement and control circuit to perform laser scanning, so that the laser beam scans the target biological tissue in the target human cavity according to the preset path.

[0060] Specifically, leveraging the flexibility and maneuverability of the flexible probe body (i.e., a multi-degree-of-freedom actuator), it is gradually delivered to the vicinity of the target area requiring imaging through natural orifices of the human body (i.e., target cavities such as the nasal cavity, oral cavity, and ear canal) or minimally invasive incisions. During the insertion of the flexible probe body into the target cavities, a shape sensing module can display its three-dimensional trajectory within the cavity in real time, enabling visual navigation. Simultaneously, a contact force sensing module can monitor the contact force between the tip of the flexible probe body and biological tissue, preventing scratches or perforations and ensuring a safe insertion process.

[0061] Furthermore, the system can generate scanning path instructions (i.e., target deflection angle sequence) according to the imaging mode (such as two-dimensional B-scan or three-dimensional volume scanning). The voltage output module of the measurement and control circuit applies a precise driving voltage to the piezoelectric driver group in the integrated beam scanning device according to the scanning path instructions. The driver drives the scanning lens to produce micron-level precision deflection. At the same time, the built-in angle sensor can monitor the actual deflection angle in real time and generate a feedback signal. The main control module of the measurement and control circuit performs real-time comparison and adjustment based on this to ensure that the beam deflection is highly consistent with the preset path.

[0062] In step S402, the reflected signal returned from the target biological tissue is received through the optical transmission component, and the reflected signal is transmitted to the detection system to obtain the raw scan data.

[0063] Specifically, when a laser beam illuminates a point in the target biological tissue, some of the light is backscattered by the microstructures at different depths within the tissue. This weak scattered light returns along its original path, is first reflected by the scanning lens, and then efficiently collected by the collimating lens in the optical transmission component and coupled into the optical fiber. The optical fiber acts as a channel, transmitting the reflected light signal carrying depth information to an external detection system. In the detection system, the reflected light interferes with the reference light, is converted into an electrical signal by the detector, and after processing, the raw scan data for that scanning point is obtained.

[0064] In step S403, the original scan data is stitched together and three-dimensional reconstruction is performed to produce a three-dimensional OCT image.

[0065] Specifically, the raw scan data acquired in sequence is first stitched together in real time. Techniques such as two-frame registration and template matching are used to eliminate image misalignment and artifacts caused by probe movement or jitter, forming a spatially accurate and coherent two-dimensional image sequence (B-Scan). Subsequently, a deep learning-based three-dimensional reconstruction algorithm processes this sequence: it learns the light field depth information through a convolutional neural network and optimizes it by introducing a Fresnel diffraction physical model, directly reconstructing high-quality three-dimensional volume data. This generates high-resolution three-dimensional OCT images or holographic projections that can be observed, sectioned, and quantitatively analyzed from multiple angles, ultimately completing the intelligent conversion from raw optical signals to stereoscopic diagnostic images.

[0066] The OCT imaging method proposed in the embodiments of this application solves the problems of limited space and insufficient field of view in in vivo diagnosis and treatment by using a flexible OCT probe, thereby reducing the size of the OCT probe while improving the imaging quality of the OCT probe.

[0067] Next, referring to the accompanying drawings, a design method for a flexible OCT probe according to an embodiment of this application will be described, which is applied to... Figure 1 The flexible OCT probe of the embodiment.

[0068] Figure 5 This is a flowchart of a design method for a flexible OCT probe according to an embodiment of this application.

[0069] In step S501, medical imaging data of the target human body cavity is acquired, and the three-dimensional structure of the target human body cavity is reconstructed based on a preset statistical shape model and medical imaging data to obtain a three-dimensional anatomical model of the target human body cavity.

[0070] Understandably, medical imaging data for target human cavities refers to CT (Computed Tomography) or MRI (Magnetic Resonance Imaging) scans of the target patient, providing tomographic image information of the target cavity (such as the sinuses or bronchi of a specific patient). Predefined Statistical Shape Models (SSMs) are mathematical models built by analyzing a large amount of imaging data from similar organs; they describe the main patterns of change in the organ's shape.

[0071] Specifically, in order to make the structural parameters of the multi-degree-of-freedom actuator of the flexible OCT probe more in line with the physiological characteristics of the human body, the personalized three-dimensional anatomical structure (i.e., three-dimensional anatomical model) of the target human body cavity can be reconstructed by acquiring medical imaging data of the target patient's target human body cavity and combining it with a preset statistical shape model, so as to provide accurate geometric basis for subsequent customized design.

[0072] In step S502, the working space of the flexible probe body within the target human cavity is determined based on the three-dimensional anatomical model, and the initial structural parameters of the flexible probe body are determined based on the working space. The initial structural parameters include at least one of outer diameter, length, and limit bending angle.

[0073] Understandably, the workspace refers to the collection of all positions that the end of the flexible probe body can and needs to reach within the target human body cavity, while avoiding unexpected collisions with the walls of the target human body cavity.

[0074] Specifically, based on the reconstructed three-dimensional anatomical model, the spatial range (workspace) required for the flexible probe body to move safely and effectively within the target human cavity is analyzed and determined. Based on this, the initial dimensions necessary for the flexible probe body to achieve this movement are derived, such as the outer diameter (which must be smaller than the inner diameter at the narrowest point of the cavity to ensure passage), the length (which must be sufficient to reach the farthest target point within the workspace from the entrance), and the maximum bending capacity (i.e., the limit bending angle, which refers to the maximum angle value that the end of the flexible probe body can reach without plastic deformation or damage). This enables customized design based on the physiological structure of different parts of the human body (such as sinuses and ear canals).

[0075] In step S503, a mechanical mapping relationship between the driving force and bending angle of the flexible probe body is established. Based on the mechanical mapping relationship, with the limit bending angle and limit load as constraints, a size parameter optimization model of the flexible probe body is constructed. The target structural parameters of the flexible probe body are obtained by using a preset heuristic algorithm and size parameter optimization model.

[0076] Specifically, considering the hyperelastic properties of nickel-titanium alloy tubes, a mechanical mapping relationship (mathematical model) between the driving force and bending angle of the flexible probe body based on a second-order Euler Bernoulli beam can be established. This model considers factors such as the hyperelasticity of the material and the geometric nonlinearity of the structure. This mechanical mapping relationship is then used as the core physical basis, together with the limit bending angle in step S502 and the limit load (the maximum force that the material or structure can withstand) to ensure structural safety, to form a set of stringent multiphysics constraints. The detailed dimensional parameters of the flexible probe body (such as the geometric dimensions of each segment and the layout of the driving wire) are set as optimization variables, and a complex nonlinear constraint optimization model (i.e., the dimensional parameter optimization model) is constructed. Finally, a preset heuristic intelligent algorithm (such as a genetic algorithm) is used to automatically and efficiently search in this high-dimensional parameter space to solve for the optimal combination of target structural parameters that can simultaneously meet all motion performance, mechanical strength, and safety boundary requirements, thereby realizing the automation, optimization, and high performance of the flexible probe body design.

[0077] According to the design method of the flexible OCT probe proposed in the embodiments of this application, the working space and initial structural parameters of the probe are determined by reconstructing a three-dimensional model of the cavity through individual medical images; then, a mechanical mapping relationship between driving force and bending angle is established, and an optimization model is constructed with this relationship, the limit bending angle, and the limit load as constraints. The optimal structural parameters are obtained by solving the algorithm, so as to realize the collaborative automated design of the probe from anatomical adaptation to mechanical performance.

[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0079] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0080] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A flexible OCT probe, characterized in that, include: Flexible probe body; An integrated beam scanning device is encapsulated at the distal end of the flexible probe body. The integrated beam scanning device is used to perform deflection scanning based on a laser beam to obtain raw scanning data. An optical transmission component is provided, which transmits a laser beam to the integrated beam scanning device, receives a reflected signal from the integrated beam scanning device, and transmits the reflected signal to the detection system. A measurement and control circuit is electrically connected to the integrated beam scanning device, used to drive the integrated beam scanning device to deflect, and to monitor the deflection angle based on the feedback signal generated by the integrated beam scanning device.

2. The flexible OCT probe according to claim 1, characterized in that, The integrated beam scanning device includes: scanning lenses, a piezoelectric actuator assembly, and a built-in angle sensor, wherein, The piezoelectric actuator group is used to drive the scanning lens to deflect; The built-in angle sensor is used to monitor the deflection angle of the scanning lens and generate the feedback signal based on the deflection angle.

3. The flexible OCT probe according to claim 2, characterized in that, The built-in angle sensor is at least one of a piezoresistive angle sensor, a capacitive angle sensor, and a photoelectric angle sensor.

4. The flexible OCT probe according to claim 2, characterized in that, The measurement and control circuit includes: A voltage output module, wherein the voltage output module is used to apply a driving voltage to the piezoelectric actuator assembly; A voltage acquisition module, which is used to acquire the feedback signal of the built-in angle sensor; The main control module is used to calculate the actual deflection angle of the scanning lens based on the feedback signal, compare the actual deflection angle with the target deflection angle, and adjust the driving voltage based on the comparison result until the actual deflection angle is the same as the target deflection angle.

5. The flexible OCT probe according to claim 1, characterized in that, The optical transmission component includes: an optical fiber and a collimating lens, wherein, The collimating lens is disposed between the optical output path of the optical fiber and the integrated beam scanning device, and the collimating lens is used to collimate or focus the laser beam.

6. The flexible OCT probe according to claim 1, characterized in that, The flexible probe body is a multi-degree-of-freedom probe actuator, including: A shape sensing module is used to sense the bending shape of the flexible probe body; A contact force sensing module is used to calculate the contact force at the end of the flexible probe body based on the bending shape and the driving force of the flexible probe body.

7. The flexible OCT probe according to claim 1, characterized in that, Also includes: An image processing device is used to receive the original scan data and perform stitching and three-dimensional reconstruction processing on the original scan data to generate a three-dimensional OCT image.

8. The flexible OCT probe according to claim 1, characterized in that, The original scan data consists of depth-resolved reflectance distribution signals at multiple target locations.

9. An OCT imaging method, characterized in that, The method employs the flexible OCT probe as described in any one of claims 1-8, wherein the method includes the following steps: The integrated beam scanning device is driven by the measurement and control circuit to perform laser scanning, so that the laser beam scans the target biological tissue in the target human cavity along a preset path. The optical transmission component receives the reflected signal returned from the target biological tissue and transmits the reflected signal to the detection system to obtain the raw scan data; The original scan data is stitched together and reconstructed in three dimensions to produce a three-dimensional OCT image.

10. A design method for a flexible OCT probe, characterized in that, The method is applied to the flexible OCT probe as described in any one of claims 1-8, wherein the method includes the following steps: Medical imaging data of the target human body cavity is acquired, and the three-dimensional structure of the target human body cavity is reconstructed based on a preset statistical shape model and the medical imaging data to obtain a three-dimensional anatomical model of the target human body cavity. The working space of the flexible probe body within the target human cavity is determined based on the three-dimensional anatomical model, and the initial structural parameters of the flexible probe body are determined based on the working space, wherein the initial structural parameters include at least one of outer diameter, length and limit bending angle. A mechanical mapping relationship between the driving force and bending angle of the flexible probe body is established. Based on the mechanical mapping relationship, and with the limit bending angle and limit load as constraints, a size parameter optimization model of the flexible probe body is constructed. The target structural parameters of the flexible probe body are obtained by using a preset heuristic algorithm and the size parameter optimization model.

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