Non-contact optical coherence elastography endoscope device

Abstract

The utility model discloses a kind of non-contact optical coherence elastic imaging endoscope devices, comprising: non-contact ultrasonic excitation and optical detection integrated probe and high-speed sweep frequency laser, the integrated probe includes air-coupled ultrasonic transducer, collimating optical fiber, off-axis parabolic mirror and polymer resin packaging shell, air-coupled ultrasonic transducer diameter is not greater than 2.5 mm, center frequency is not less than 250 kHz, collimating optical fiber is single-mode fiber and emission end integrated collimator is used to produce collimating beam, off-axis parabolic mirror focal length is greater than 7 mm, the polymer resin packaging shell is used to integrally package integrated probe, the polymer resin packaging shell is designed using 3D printing, and it is windowed at the exit end of the off-axis parabolic mirror;The scanning speed of this high-speed sweep frequency laser is 100 kHz, center wavelength 1310 nm, bandwidth 100 nm, synchronous output trigger clock and sampling clock.

Description

Technical Field

[0001] This invention belongs to the field of biophotonics elastography technology, specifically a non-contact optical coherence elastography endoscope device and its usage method. Background Technology

[0002] Many clinical diseases involve changes in the biomechanical properties of biological tissues, such as shear modulus and Young's modulus, during their occurrence, development, and treatment. For example, atherosclerosis, esophageal cancer, and respiratory syndromes can all lead to hardening or softening of corresponding blood vessels, esophagus, and respiratory tract tissues. Clinical studies have found that changes in the biomechanical properties of human tissues often occur in the early stages of disease development, before structural alterations occur. Therefore, changes in the biomechanical properties of human tissues can serve as biomarkers for many clinical diseases, and their quantification can provide scientific evidence and technical support for the diagnosis, treatment, and prevention of numerous clinical diseases.

[0003] Currently, clinical imaging methods for in vivo elastography include MRI and ultrasound elastography. However, due to technical limitations at the millimeter or sub-millimeter resolution level, they cannot achieve micrometer-level high-resolution quantitative detection of elastic parameters in tissues such as cardiovascular tissue, esophageal tissue, and respiratory tract. There are also some ex vivo testing methods, primarily uniaxial tensile testing, which calculates Young's modulus by recording the stress-strain relationship of the tissue. This method can only be used for ex vivo samples or sections and cannot meet the requirements for clinical in vivo testing.

[0004] Photoelastic imaging (OIE) is an optical-based method for detecting elasticity, including Brillouin scattering elastography, laser speckle elastography, and optical coherence elastography (OCE). Among these, mechanical wave-based OCE, with its advantages of being non-destructive, non-contact, high-resolution, high signal-to-noise ratio, and enabling rapid 3D imaging, has become the most promising OCE technique for multidisciplinary clinical applications and has already undergone initial clinical translation. However, current OCE techniques primarily target exposed tissues such as the eye, skin, and oral cavity. Furthermore, existing OCE techniques often employ large-size hydrocoupled ultrasonic transducers or contact probes to mechanically excite the sample tissue. This is problematic not only because the use of coupling agents can cause physiological rejection but also because the system design is inconvenient for clinical examination and experimental operation. Moreover, it cannot be applied to tissues such as arteries, the esophagus, and the respiratory tract. Utility Model Content

[0005] The purpose of this invention is to provide a non-contact optical coherence elastography endoscope device and its usage method, which solves the technical problems of traditional optical coherence elastography technology, such as the need for coupling agent excitation and the inability to apply it to endoscopic elastography of arteries, esophagus, respiratory tract and other tissues due to size limitations.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a non-contact optical coherence elastography endoscope device, comprising:

[0007] A non-contact ultrasonic excitation and optical detection integrated probe, comprising an air-coupled ultrasonic transducer, a collimating fiber, an off-axis parabolic mirror, and a polymer resin encapsulation shell, is used for non-destructive excitation and optical detection of samples. The air-coupled ultrasonic transducer has a diameter of no more than 2.5 mm and a center frequency of no less than 250 kHz. The collimating fiber is a single-mode fiber with an integrated collimator at the transmitting end to generate a collimated beam. The off-axis parabolic mirror has a focal length greater than 7 mm and is used to focus the ultrasonic pulse and the detection beam. The polymer resin encapsulation shell is used to encapsulate the air-coupled ultrasonic transducer, the collimating fiber, and the off-axis parabolic mirror. The polymer resin encapsulation shell is 3D printed and has a window at the exit end of the off-axis parabolic mirror. The overall outer diameter of the polymer resin encapsulation shell does not exceed 4 mm.

[0008] A high-speed sweeping laser, wherein the scanning speed of the high-speed sweeping laser is 100 kHz, the center wavelength is 1310 nm, the bandwidth is 100 nm, and the synchronous output trigger clock and sampling clock are provided.

[0009] Preferably, the device also includes: an endoscope probe connector, an endoscope probe micro-rotary motor, a programmable electric displacement stage, and a flexible steel fiber endoscope connecting cable, for realizing the rotational scanning of the probe and the radial scanning of the sample to be tested.

[0010] Preferably, the system also includes: an optical isolator and a 2×2 99:1 fiber coupler, which split the incident light from the high-speed swept laser into two beams that enter the sample optical path and the reference optical path respectively, wherein the sample optical path has 99% and the reference optical path has 1%.

[0011] Preferably, the device further includes: an electrically driven fiber optic delay line and a photoelectric balance detector. The electrically driven fiber optic delay line electrically adjusts the optical path of the reference arm according to the different samples to be tested to meet the interference matching conditions between the sample light and the reference light. The photoelectric balance detector can detect and receive the interference of the sample light and the reference light, with a bandwidth of 2.0 GHz.

[0012] Preferably, the system further includes: a timing control unit, an endoscope probe and air-coupled ultrasonic transducer drive module, and a computer. The timing control unit records the trigger clock and sampling clock of the high-speed swept-frequency laser, and outputs a clock for sampling by the photoelectric balance detector and a trigger clock for driving the air-coupled ultrasonic transducer. The endoscope probe and air-coupled ultrasonic transducer drive module has a four-channel signal output function, wherein the first channel is used to output the drive signal of the micro-rotary motor of the endoscope probe, the second channel is used to output the drive signal of the programmable electric displacement stage, the third channel is used to output the drive signal of the air-coupled ultrasonic transducer, and the fourth channel is used to output the sampling monitoring signal. The computer is used for system signal processing and image reconstruction.

[0013] Preferably, the air-coupled ultrasonic transducer uses a planar emission type composite material chip, and the matching layer material of the transmitting end face is designed with multi-layer dielectric material to match the acoustic impedance difference between the chip material and the air medium. The output ultrasonic pulse is reflected by the off-axis parabolic reflector to form a focal spot with a focal spot diameter of 1 mm.

[0014] Preferably, the output end of the collimating fiber integrates a collimating device to ensure that the output light is collimated and output to the off-axis parabolic reflector, where it is reflected to form a focal point.

[0015] Preferably, the off-axis parabolic reflector simultaneously reflects and focuses the ultrasonic pulse and the incident beam, forming a confocal effect of optical and acoustic focal points, so as to achieve synchronous ultrasonic excitation and optical detection.

[0016] The present invention has the following advantages over the prior art:

[0017] This invention proposes a non-contact optical coherence elastography endoscope system, method, and apparatus. The endoscope employs a non-contact ultrasonic excitation and optical detection integrated probe, including an air-coupled ultrasonic transducer with a diameter of less than 2.5 mm and a center frequency of more than 250 kHz to generate non-focused ultrasonic pulses, achieving non-destructive and non-contact excitation of sample tissues. It does not require any coupling agent and can work solely through the air medium, making it perfectly applicable to non-contact excitation for various clinical diseases. In particular, it has the beneficial effect of being suitable for elastography detection of tissues such as arteries, esophagus, and respiratory tract.

[0018] The sample light is collimated by using collimating fiber. A collimating device with a center wavelength of 1310 nm is designed and integrated with a single-mode fiber and placed inside the probe. This has the advantages of easy integration and simple structure.

[0019] An off-axis parabolic reflector is used to achieve synchronous focusing of the ultrasonic pulse and the collimated probe beam, naturally forming a focal point outside the probe with a focal length of 7 mm. The off-axis parabolic reflector can be designed with corresponding optical parameters according to the actual sample characteristics, which has the beneficial effect of being able to adapt to different ultrasonic pulses and probe beams.

[0020] Using 3D printing technology and polymer resin material to encapsulate the shell, windows are set at the emission ends of ultrasonic pulses and probe beams. The overall outer diameter does not exceed 4 mm, which has the advantages of easy overall fixation and packaging, and is simple and convenient.

[0021] Employing a near-infrared sweep laser with a sweep rate of 100 kHz and a center wavelength of 1310 nm, a single A-line scan takes only 10 μs. Combined with an air-coupled ultrasonic transducer, it achieves the beneficial effect of enabling fully non-contact ultrasonic excitation and optical detection. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the non-contact optical coherence elastoscope device of this utility model.

[0023] Figure 2 This is a schematic diagram of the probe of the non-contact optical coherence elastoscope device of this utility model.

[0024] Figure reference numerals: 01-High-speed sweeping laser, 02-Optical isolator, 03-2×2 99:1 fiber optic coupler, 04-Endoscope probe connector, 05-Endoscope probe miniature rotary motor, 06-Programmable electric displacement stage, 07-Flexible steel fiber endoscope connecting cable, 08-Non-contact ultrasonic excitation and optical detection integrated probe, 09-Sample to be tested, 10-Electrically powered fiber optic delay line, 11-Photoelectric balance detector, 12-Timing control unit, 13-Endoscope probe and air-coupled ultrasonic transducer drive module, 14-Computer, 15-Collimating fiber, 16-Air-coupled ultrasonic transducer, 17-Off-axis parabolic reflector, 18-Polymer resin encapsulation shell, 19-Focus point. Detailed Implementation

[0025] To enable those skilled in the art to better understand the solution method of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. However, it is not limited to a specific instance, and this method can be applied to similar situations. Example 1

[0026] Please see Figure 1 and Figure 2A non-contact optical coherence elastography endoscope device includes: a non-contact ultrasonic excitation and optical detection integrated probe 08 and a high-speed frequency-sweeping laser 01. The high-speed frequency-sweeping laser 01 has a scanning speed of 100 kHz, a center wavelength of 1310 nm, a bandwidth of 100 nm, and synchronously outputs a trigger clock and a sampling clock. The non-contact ultrasonic excitation and optical detection integrated probe 08 includes an air-coupled ultrasonic transducer 16, a collimating fiber 15, an off-axis parabolic mirror 17, and a polymer resin encapsulation shell 18, used for non-destructive excitation and optical detection of samples. The air-coupled ultrasonic transducer 16 has a diameter of no more than 2.5 mm and a center frequency of no less than 250 kHz. The collimating fiber 15 is a single-mode fiber with a collimator integrated at the transmitting end to generate a collimated beam. The off-axis parabolic mirror 17 has a focal length greater than 7... The polymer resin encapsulation shell 18 is used to focus the ultrasonic pulse and probe beam. It is used to encapsulate the air-coupled ultrasonic transducer 16, the collimating fiber 15, and the off-axis parabolic mirror 17. The polymer resin encapsulation shell 18 is 3D printed and has a window at the exit end of the off-axis parabolic mirror 17. The overall outer diameter of the polymer resin encapsulation shell 18 does not exceed 4 mm. The exit end of the collimating fiber 15 integrates a collimating device to ensure that the emitted light is collimated and output to the off-axis parabolic mirror 17, forming a focal point 19 after reflection. The air-coupled ultrasonic transducer 16 uses a planar emission type composite material chip. The matching layer material at the emission end face is designed with multi-layer dielectric material to match the acoustic impedance difference between the chip material and the air medium. The output ultrasonic pulse is reflected by the off-axis parabolic mirror 17 to form the focal point 19, and the focal spot diameter of the focal point 19 is 1 mm. mm, the off-axis parabolic reflector 17 reflects and focuses the ultrasonic pulse and the incident beam simultaneously, forming a confocal effect of optical focus and acoustic focus, so as to realize the synchronous operation of ultrasonic excitation and optical detection.

[0027] Furthermore, it also includes an optical isolator 02, a 2×2 99:1 fiber optic coupler 03, an endoscope probe connector 04, an endoscope probe miniature rotary motor 05, a programmable electric displacement stage 06, and a flexible steel fiber endoscope connecting cable 07, used to realize the rotational scanning of the probe and the radial scanning of the sample 09 to be tested. The 2×2 99:1 fiber optic coupler 03 splits the incident light of the high-speed sweep laser 01 into two beams, which enter the sample optical path and the reference optical path respectively, with the sample optical path accounting for 99% and the reference optical path accounting for 1%.

[0028] Furthermore, the system also includes an electrically driven fiber optic delay line 10, a photoelectric balance detector 11, a timing control unit 12, an endoscope probe and air-coupled ultrasonic transducer drive module 13, and a computer 14. The electrically driven fiber optic delay line 10 electrically adjusts the optical path of the reference arm according to the different samples to be tested to meet the interference matching conditions between the sample light and the reference light. The photoelectric balance detector 11 can detect and receive the interference return light of the sample light and the reference light, with a bandwidth of 2.0 GHz. The timing control unit 12 records the trigger clock and sampling clock of the high-speed swept laser 01, and outputs the clock for sampling by the photoelectric balance detector 11 and the trigger clock for driving the air-coupled ultrasonic transducer 16. The endoscope probe and air-coupled ultrasonic transducer drive module 13 has a four-channel signal output function, wherein the first channel is used to output the drive signal of the endoscope probe micro-rotary motor 05, the second channel is used to output the drive signal of the programmable electric displacement stage 06, the third channel is used to output the drive signal of the air-coupled ultrasonic transducer 16, and the fourth channel is used to output the sampling monitoring signal. The computer 14 is used for system signal processing and image reconstruction.

[0029] The working process is as follows: The high-speed sweep laser 01 emits a near-infrared laser with a center wavelength of 1310 nm and a bandwidth of 100 nm. After passing through the optical isolator 02, it is split into two beams by the 2×2 99:1 fiber coupler 03. 99% of the light is incident on the sample optical path, and 1% is incident on the reference optical path. The light entering the sample optical path reaches the non-contact ultrasonic excitation and optical detection integrated probe 08. After being expanded by the collimating fiber 15, it is incident on the off-axis parabolic mirror 17 for reflection and focusing onto the sample test area. Its back-emitted and scattered light returns to the 2×2 99:1 fiber coupler 03 along the original optical path. The light entering the reference optical path is incident on the motorized fiber delay line 10 to achieve optical path scanning of the reference optical path. Its back-reflected light returns to the 2×2 99:1 fiber coupler 03 along the original optical path. The sample light and reference light interfere with each other at the 2×299:1 fiber coupler 03. The interference signal is converted into a digital signal by the photoelectric balance detector 11 and then acquired by the data acquisition card built into the computer 14, converting it into a computer-readable digital signal. The sampling clock is generated by the timing control unit 12, including a wavelength trigger clock and a wavenumber sampling clock. Example 2

[0030] Please see Figure 1 and Figure 2 The specific steps for using the non-contact optical coherence elastography endoscope device provided by this utility model are as follows:

[0031] S1. The non-contact ultrasonic excitation and optical detection integrated probe 08 adopts the MB four-dimensional scanning algorithm. It performs 200 A-line scans at each sampling point to complete one M-scan. Each sampling point completes 1024 samplings in the depth direction. That is, at each imaging section, the endoscope probe micro-rotation motor 05 completes 200 optical scans at each sampling point, for a total of 2 ms of M-scan. After the M-scan is completed at the sampling point, the endoscope probe micro-rotation motor 05 controls the probe to rotate to the next sampling point and repeats the new M-scan. Thus, a total of 1000 sampling points are sampled within a 360° range for one complete MB scan. During the 51st to 70th optical scans, the timing control unit 12 and the endoscope probe and air-coupled ultrasonic transducer drive module 13 output signals to drive the air-coupled ultrasonic transducer 16 to generate ultrasonic pulses, which excite the sample to produce mechanical vibration. The total excitation time is 200 μs.

[0032] S2. The programmable electric displacement stage 06 moves the non-contact ultrasonic excitation and optical detection integrated probe 08 to the next cross-sectional position, repeating the new MB scan to achieve four-dimensional scanning. Data is collected from 100 sampling sections in the radial direction to complete the four-dimensional spatiotemporal scan. The data matrix is ​​(1000, 100, 1024, 200).

[0033] S3. The calculation of the elastic parameters of the sample to be tested adopts a combination of multiple mechanical wave models. First, according to different sample structural characteristics, different mechanical wave models are selected and constructed. The depth resolution algorithm is used to calculate the mechanical wave velocity at each position in the depth direction pixel by pixel. Thus, the tomographic calculation results of the mechanical wave propagation velocity at different depths are obtained. Then, the shear modulus, Young's modulus and other elastic parameters of the sample at different depths are calculated from the mechanical wave velocity, and the three-dimensional mapping of the sample's elastic modulus is realized.

[0034] Of course, the above description is not intended to limit the present invention, nor is the present invention limited to the examples given above. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention. The parts of the present invention not described in detail are common knowledge to those skilled in the art.

Claims

1. A non-contact optical coherence elastography endoscope device, characterized in that, include: A non-contact ultrasonic excitation and optical detection integrated probe (08) includes an air-coupled ultrasonic transducer (16), a collimating fiber (15), an off-axis parabolic mirror (17), and a polymer resin encapsulation shell (18), used for non-destructive excitation and optical detection of samples; the air-coupled ultrasonic transducer (16) has a diameter of no more than 2.5 mm and a center frequency of no less than 250 kHz; the collimating fiber (15) is a single-mode fiber and the transmitting end integrates a collimator to generate a collimated beam; the off-axis parabolic mirror (17) has a focal length greater than 7 kHz. mm, used for focusing ultrasonic pulses and probe beams; the polymer resin encapsulation shell (18) is used to encapsulate the air-coupled ultrasonic transducer (16), the collimating fiber (15) and the off-axis parabolic reflector (17) as a whole. The polymer resin encapsulation shell (18) is designed by 3D printing and has a window at the exit end of the off-axis parabolic reflector (17). The overall outer diameter of the polymer resin encapsulation shell (18) does not exceed 4 mm. A high-speed sweep laser (01) has a scanning speed of 100 kHz, a center wavelength of 1310 nm, a bandwidth of 100 nm, and synchronous outputs a trigger clock and a sampling clock.

2. The non-contact optical coherence elastoscope device according to claim 1, characterized in that, Also includes: Endoscope probe connector (04), endoscope probe micro-rotary motor (05), programmable electric displacement stage (06), flexible steel fiber endoscope connecting cable (07) are used to realize the rotational scanning of the probe and the radial scanning of the sample to be tested (09).

3. The non-contact optical coherence elastoscope device according to claim 1, characterized in that, Also includes: Optical isolator (02) and 2×2 99:1 fiber coupler (03) split the incident light of the high-speed sweep laser (01) into two beams that enter the sample optical path and the reference optical path respectively, wherein the sample optical path is 99% and the reference optical path is 1%.

4. The non-contact optical coherence elastoscope device according to claim 2, characterized in that, Also includes: The electric fiber delay line (10) and the photoelectric balance detector (11) are used. The electric fiber delay line (10) adjusts the optical path of the reference arm according to the different samples (09) to meet the interference matching conditions of the sample light and the reference light. The photoelectric balance detector (11) can return the interference of the sample light and the reference light to the light detector and receive it with a bandwidth of 2.0 GHz.

5. A non-contact optical coherence elastoscope device according to claim 4, characterized in that, Also includes: The system comprises a timing control unit (12), an endoscope probe and air-coupled ultrasonic transducer drive module (13), and a computer (14). The timing control unit (12) records the trigger clock and sampling clock of the high-speed sweep laser (01), and outputs a clock for sampling by the photoelectric balance detector (11) and a trigger clock for driving the air-coupled ultrasonic transducer (16). The endoscope probe and air-coupled ultrasonic transducer drive module (13) has a four-channel signal output function. The first channel is used to output the drive signal of the endoscope probe micro-rotary motor (05), the second channel is used to output the drive signal of the programmable electric displacement stage (06), the third channel is used to output the drive signal of the air-coupled ultrasonic transducer (16), and the fourth channel is used to output the sampling monitoring signal. The computer (14) is used for system signal processing and image reconstruction.

6. The non-contact optical coherence elastoscope device according to claim 1, characterized in that, The air-coupled ultrasonic transducer (16) uses a planar emission type composite material chip. The matching layer material of the transmitting end face is designed with multi-layer dielectric material to match the acoustic impedance difference between the chip material and the air medium. The output ultrasonic pulse is reflected by the off-axis parabolic reflector (17) to form a focal spot (19). The focal spot diameter of the focal spot (19) is 1 mm.

7. The non-contact optical coherence elastoscope device according to claim 1, characterized in that, The collimating fiber (15) has a collimating device integrated at its output end, which ensures that the output light is collimated and output to the off-axis parabolic mirror (17), and forms a focal point (19) after reflection.

8. The non-contact optical coherence elastoscope device according to claim 1, characterized in that, The off-axis parabolic reflector (17) reflects and focuses the ultrasonic pulse and the incident beam simultaneously, forming a confocal effect of optical focus and acoustic focus, so as to realize the synchronous operation of ultrasonic excitation and optical detection.

Images