A photoacoustic imaging apparatus and method

Abstract

The application discloses a photoacoustic imaging device and method, and belongs to the technical field of photoacoustic imaging.The device comprises a laser emission module, a light splitting module, a photoacoustic imaging module, a spectrum analysis module, a motion module and a data analysis module, the laser emission module emits pulsed laser, the pulsed laser is split into first parallel light and second parallel light through the light splitting module, the ultrasonic transducer in the photoacoustic imaging module collects the ultrasonic signal generated by the first parallel light focused on the sample tissue surface, the spectrometer in the spectrum analysis module collects the plasma generated by the second parallel light focused on the sample surface, the data analysis module receives the data collected by the photoacoustic imaging module and the spectrum analysis module, analyzes the sample tissue morphology and element content, detects whether the tissue is abnormal through the photoacoustic imaging method, then analyzes the main element content change of the tissue through the laser-induced breakdown method, analyzes the degree of tissue lesion, and provides effective information for disease diagnosis and research.

Description

Technical Field

[0001] This invention belongs to the field of photoacoustic imaging technology, and particularly relates to a photoacoustic imaging device and method. Background Technology

[0002] Photoacoustic imaging is a non-invasive imaging technique that combines the high contrast of optical imaging with the high penetration of ultrasound imaging. It works by irradiating tissue with a pulsed laser, causing the tissue to absorb energy and expand thermally, generating sound waves. These sound waves are received by an external ultrasound transducer and converted into electrical signals, ultimately reconstructing an image of the tissue. Photoacoustic imaging technology combines the advantages of high contrast in optical imaging and high imaging depth in ultrasound imaging, offering features such as non-invasiveness, high resolution and contrast, deeper imaging capabilities, and no need for external labeling. It has wide applications and potential in medical imaging fields such as cardiovascular disease diagnosis, neurological diseases, tumor detection and diagnosis, and real-time imaging.

[0003] However, existing photoacoustic imaging technology in the field of biological tissue detection can only obtain sample images through imaging and determine tissue health or disease through image methods, but cannot provide more accurate judgments and more effective information through quantitative analysis.

[0004] Laser-induced breakdown spectroscopy can rapidly analyze elemental information and is widely used in various fields. As a simple, fast, and direct elemental detection technology, it has great potential in the field of animal tissue and organ testing. It can provide effective information for medical diagnosis and disease prevention by analyzing changes in the content of major elements in tissues.

[0005] Therefore, there is an urgent need for a solution that combines photoacoustic imaging technology and laser-induced breakdown spectroscopy to achieve rapid detection of tissue morphology and analysis of tissue health. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a photoacoustic imaging device and method that simultaneously performs photoacoustic imaging detection and laser-induced breakdown spectroscopy analysis on sample tissues.

[0007] The objective of this invention is achieved through the following technical solution: a photoacoustic imaging device, comprising:

[0008] Laser emitting module, used to emit pulsed laser;

[0009] The beam splitting module is used to receive the pulsed laser emitted by the laser emitting module and split the beam into a first parallel beam and a second parallel beam.

[0010] The photoacoustic imaging module includes a first channel lens and an ultrasonic transducer. The first parallel light passes through the first channel lens and the light spot is directly focused onto the surface of the sample tissue, exciting and generating an ultrasonic signal, which is then acquired by the ultrasonic transducer.

[0011] The spectral analysis module includes a second channel lens, a dichroic mirror, a third channel lens, and a spectrometer. The second parallel light passes through the dichroic mirror and the second channel lens in sequence and is focused onto the sample surface, exciting the sample surface to generate plasma. The plasma passes through the second channel lens and is reflected by the dichroic mirror, and then enters the spectrometer through the third channel lens.

[0012] The motion module is used to carry and adjust the position of the sample;

[0013] The data analysis module is used to receive data collected by the photoacoustic imaging module and the spectral analysis module, and to perform joint analysis on the sample tissue morphology and sample tissue element content.

[0014] Furthermore, the laser emitting module includes a laser and a beam expander.

[0015] Furthermore, the laser is a pulsed laser.

[0016] Furthermore, the beam splitting module is a lateral displacement beam splitting prism, which can adjust the energy distribution of the first parallel light and the second parallel light, and dynamically adjust the energy distribution ratio according to different detection objects.

[0017] Furthermore, the energy distribution ratio of the first parallel light and the second parallel light is 1:1;

[0018] Furthermore, the motion module includes a water tank, the ultrasonic transducer is laterally arranged in the water tank, the sample is placed in or under the water tank, and the water tank and the sample are isolated by a membrane.

[0019] Furthermore, the motion module includes an X-axis displacement stage, a Y-axis displacement stage, and a Z-axis displacement stage.

[0020] Furthermore, the data analysis module includes a data acquisition card and a controller.

[0021] Furthermore, the joint analysis specifically involves: obtaining structural information of the sample tissue through photoacoustic imaging images acquired by the photoacoustic imaging module, thereby enabling the determination of the sample's morphological information; and comparing the elemental content of the sample tissue obtained through laser-induced spectral analysis by the spectral analysis module with the elemental content of healthy tissue, thereby enabling the determination of the degree of lesion in the sample.

[0022] The present invention also provides a photoacoustic imaging method, comprising the following steps:

[0023] The sample position is adjusted and fixed using the motion module;

[0024] Pulsed laser light is emitted via a laser emission module;

[0025] The beam splitting module receives the pulsed laser emitted by the laser emitting module and splits it into a first parallel beam and a second parallel beam.

[0026] After passing through the first channel lens, the first parallel light spot is directly focused onto the surface of the sample tissue, exciting and generating an ultrasonic signal which is then collected by an ultrasonic transducer.

[0027] The second parallel light passes through a dichroic mirror and a second channel lens in sequence and is focused onto the sample surface, exciting the sample surface to generate plasma. The plasma passes through the second channel lens and is reflected by the dichroic mirror, and then enters the spectrometer through the third channel lens.

[0028] By adjusting the horizontal position of the sample using a motion module, large-area mosaic imaging of the sample tissue can be achieved.

[0029] The data analysis module receives data collected by the photoacoustic imaging module and the spectral analysis module, and performs joint analysis on the morphology and elemental content of the sample tissue to obtain the lesion results of the sample tissue.

[0030] The beneficial effects of this invention are:

[0031] 1. This invention can simultaneously perform photoacoustic imaging and laser-induced breakdown spectroscopy analysis on sample tissues. It can obtain tissue structure information through photoacoustic imaging, quickly locate abnormal areas, and provide guidance for subsequent laser-induced breakdown spectroscopy analysis.

[0032] 2. The laser-induced breakdown spectroscopy analysis technology in this invention can obtain the content of some elements in the tissue and perform quantitative analysis by combining the differences in the content of the same elements in healthy or conventional tissues, thereby providing more accurate quantitative information to guide disease diagnosis.

[0033] 3. The photoacoustic imaging method and apparatus provided in this invention generate photoacoustic signals during laser-induced breakdown spectral analysis, which can be collected using a photoacoustic detector for laser energy detection and calibration. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1This is a schematic diagram of the photoacoustic imaging device in this invention;

[0036] Figure 2 This is a schematic diagram of the photoacoustic signal acquisition principle in this invention;

[0037] Figure 3 This is a schematic diagram of the principle of laser-induced breakdown spectral elemental analysis in this invention;

[0038] Figure 4 This is a flowchart of the biological tissue detection process in this invention;

[0039] Figure labels: 1-Laser, 2-Beam expander, 3-Side displacement beam splitter, 4-First channel lens, 5-Ultrasonic transducer, 6-Sample, 7-Water tank, 8-Z-axis displacement stage, 9-Y-axis displacement stage, 10-X-axis displacement stage, 11-Dichroic mirror, 12-Second channel lens, 13-Third channel lens, 14-Spectrometer, 15-Data acquisition card and controller. Detailed Implementation

[0040] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0041] It should be understood that although the terms first, second, third, etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first information may also be referred to as second information without departing from the scope of this invention, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0042] The present invention will now be described in detail with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0043] like Figure 1 As shown, an embodiment of the present invention provides a photoacoustic imaging device, comprising:

[0044] Laser emitting module, used to emit pulsed laser.

[0045] The laser emitting module includes a laser 1 and a beam expander 2, which expands the pulsed laser emitted by the laser 1 into a parallel beam with a diameter of D through the beam expander 2.

[0046] The beam splitting module is used to receive the pulsed laser emitted by the laser emitting module and split it into a first parallel beam and a second parallel beam. The first parallel beam and the second parallel beam are still parallel to each other in the same direction and form a 90° angle with respect to the incident light.

[0047] The beam splitting module is a lateral displacement beam splitter 3, which can adjust the energy distribution of the first parallel light and the second parallel light, and the distance between the first parallel light and the second parallel light depends on the size of the lateral displacement beam splitter 3.

[0048] The photoacoustic imaging module includes a first channel lens 4 and an ultrasonic transducer 5. The first parallel light beam, after passing through the first channel lens 4, is directly focused onto the surface of the sample 6 tissue, generating an ultrasonic signal. This signal is acquired by the ultrasonic transducer 5 and converted into an electrical signal, stored in the data acquisition card of the data analysis module. This module can be used for photoacoustic imaging of the sample 6 tissue. Because the sample is focused using an optical focusing method, its optical resolution is higher than its acoustic resolution, thus enabling the reconstruction of a high-resolution photoacoustic imaging image. Figure 2 As shown, when the pulsed light spot generated by the laser is focused on the sample surface tissue, the sample tissue will generate an ultrasonic signal. At this time, the ultrasonic transducer can collect the ultrasonic signal. The tissue image of the sample can be reconstructed mainly by using the amplitude value and time difference of the signal, combined with the propagation speed of the ultrasound.

[0049] The spectral analysis module includes a dichroic mirror 11, a second-channel lens 12, a third-channel lens 13, and a spectrometer 14. The second parallel light passes sequentially through the dichroic mirror 11 and the second-channel lens 12 before being focused onto the surface of sample 6, exciting plasma to be generated on the surface of sample 6. The plasma passes through the second-channel lens 12 and is reflected by the dichroic mirror 11, then enters the spectrometer 14 through the third-channel lens 13. The spectrometer 14 acquires elemental content curves of sample 6 at different wavelengths. Analysis yields content curves of specific elements in the sample at different wavelengths, such as... Figure 3 As shown, the horizontal axis represents wavelength, and the vertical axis represents the content of elements at a specific wavelength. Different tissues have different elemental characteristics and generally have peak values ​​at a specific wavelength. By analyzing the peak values, tissues can be quantitatively analyzed and evaluated.

[0050] When the device performs spectral analysis, since the laser is focused on the surface of sample 6, the ultrasonic transducer 5 in the photoacoustic imaging module can still receive the photoacoustic signal. The stronger the laser energy, the stronger the photoacoustic signal intensity received by the ultrasonic transducer 5, and there is a corresponding relationship between the intensity of the received photoacoustic signal and the laser energy during spectral analysis.

[0051] Therefore, during spectral analysis, the laser energy can also be monitored by detecting the change in photoacoustic signal intensity through the ultrasonic transducer 5 in the photoacoustic imaging module.

[0052] Preferably, the correspondence between photoacoustic signal intensity and laser energy can be obtained by pre-measuring or simulating in the same tissue, specifically presenting a linear relationship or a low-order relationship. In this way, the corresponding relationship curve can be established through only one experiment. During the spectral analysis process, the actual laser energy in the spectral analysis module can be known by viewing the photoacoustic signal intensity received in the photoacoustic imaging module. As a reference and guide, the laser energy intensity adjustment can be calibrated in real time during spectral analysis.

[0053] The motion module is used to support and adjust the position of sample 6. By moving the X and Y displacement stages in the motion module, photoacoustic imaging signals of the sample tissue at different positions can be acquired. By moving the Z displacement stage in the motion module, photoacoustic signals of the sample tissue at different depth positions can be acquired. Finally, a three-dimensional photoacoustic imaging image of the sample tissue can be reconstructed.

[0054] The data analysis module, including a data acquisition card and a controller 15, is used to receive data acquired by the photoacoustic imaging module and the spectral analysis module, and to perform joint analysis on the tissue morphology and elemental content of sample 6.

[0055] Specifically, the joint analysis involves: obtaining structural information of the sample tissue through photoacoustic imaging images acquired by the photoacoustic imaging module, thereby enabling the determination of the sample's morphological information; and comparing the elemental content of the sample tissue obtained through laser-induced spectral analysis by the spectral analysis module with the elemental content of healthy tissue, thereby enabling the determination of the degree of lesion in the sample and providing guidance for disease diagnosis.

[0056] Preferably, the laser 1 is a 532nm nanosecond pulsed laser.

[0057] Preferably, the motion module includes a water tank 7, the ultrasonic transducer 5 is laterally arranged in the water tank 7, and the sample 6 is placed in or below the water tank 7. The water tank 7 and the sample 6 are isolated by a thin film. The water in the water tank 7 efficiently transmits the weak ultrasonic signal generated by the sample 6 to the ultrasonic transducer 5, avoiding the rapid attenuation of ultrasonic waves in the air.

[0058] Preferably, the motion module includes an X-axis displacement stage 10, a Y-axis displacement stage 9, and a Z-axis displacement stage 8; wherein, the Z-axis displacement stage 8 enables the laser dot array to focus on the sample 6, so that the optical focus is exactly irradiated on the surface of the sample 6 and three-dimensional imaging is performed; the X-axis displacement stage 10 and the Y-axis displacement stage 9 enable large-area scanning of the surface of the sample 6, thereby achieving large-area stitched imaging of the tissue of the sample 6.

[0059] The present invention also provides a photoacoustic imaging method, comprising the following steps:

[0060] The sample position is adjusted and fixed by the motion module.

[0061] Pulsed laser light is emitted through a laser emission module.

[0062] The beam splitter receives the pulsed laser emitted by the laser emission module and splits it into a first parallel beam and a second parallel beam.

[0063] The first parallel light beam is directly focused onto the surface of the sample tissue after passing through the first channel lens, which excites and generates an ultrasonic signal, which is then collected by an ultrasonic transducer.

[0064] The second parallel light passes through a dichroic mirror and a second channel lens in sequence and is focused onto the sample surface, exciting the sample surface to generate plasma. The plasma passes through the second channel lens and is reflected by the dichroic mirror, and then enters the spectrometer through the third channel lens.

[0065] By adjusting the horizontal position of the sample using a motion module, large-area mosaic imaging of the sample tissue can be achieved.

[0066] The data analysis module receives data collected by the photoacoustic imaging module and the spectral analysis module, and performs joint analysis on the morphology and elemental content of the sample tissue to obtain the lesion results of the sample tissue.

[0067] With the device and method of this invention, when performing health checks on biological tissue samples, photoacoustic imaging can be used to image and detect the tissue. The reconstructed photoacoustic image provides structural information about the tissue, allowing for an intuitive assessment of its morphology. For example, imaging can reveal vascular distribution or tumor structures. However, photoacoustic imaging alone cannot provide a quantitative analysis of the degree of tissue lesions. Therefore, combining laser-induced spectroscopy further yields the elemental content of the tissue at specific wavelengths. By comparing this content with that of healthy tissue, the degree of tissue lesions can be quantitatively determined, providing guidance and suggestions for disease treatment and prevention. The implementation process is as follows: Figure 4 As shown.

[0068] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only.

[0069] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A photoacoustic imaging device, characterized in that, include: Laser emitting module, used to emit pulsed laser; The beam splitting module is used to receive the pulsed laser emitted by the laser emitting module and split the beam into a first parallel beam and a second parallel beam. The photoacoustic imaging module includes a first channel lens and an ultrasonic transducer. The first parallel light passes through the first channel lens and the light spot is directly focused onto the surface of the sample tissue, exciting and generating an ultrasonic signal, which is then acquired by the ultrasonic transducer. The spectral analysis module includes a second channel lens, a dichroic mirror, a third channel lens, and a spectrometer. The second parallel light passes through the dichroic mirror and the second channel lens in sequence and is focused onto the sample surface, exciting the sample surface to generate plasma. The plasma passes through the second channel lens and is reflected by the dichroic mirror, and then enters the spectrometer through the third channel lens. The motion module is used to carry and adjust the position of the sample; The data analysis module is used to receive data collected by the photoacoustic imaging module and the spectral analysis module, and to perform joint analysis on the sample tissue morphology and sample tissue element content.

2. The apparatus according to claim 1, characterized in that, The laser emitting module includes a laser and a beam expander.

3. The apparatus according to claim 2, characterized in that, The laser is a pulsed laser.

4. The apparatus according to claim 1, characterized in that, The beam splitting module is a lateral displacement beam splitting prism, which can adjust the energy distribution of the first parallel light and the second parallel light, and dynamically adjust the energy distribution ratio according to different detection objects.

5. The apparatus according to claim 4, characterized in that, The energy distribution ratio of the first parallel light and the second parallel light is 1:

1.

6. The apparatus according to claim 1, characterized in that, The motion module includes a water tank, the ultrasonic transducer is laterally arranged in the water tank, the sample is placed in or under the water tank, and the water tank and the sample are isolated by a membrane.

7. The apparatus according to claim 1, characterized in that, The motion module includes an X-axis displacement stage, a Y-axis displacement stage, and a Z-axis displacement stage.

8. The apparatus according to claim 1, characterized in that, The data analysis module includes a data acquisition card and a controller.

9. The apparatus according to claim 1, characterized in that, The joint analysis specifically involves: obtaining structural information of the sample tissue through photoacoustic imaging images acquired by the photoacoustic imaging module, thereby enabling the determination of the sample's morphological information; and comparing the elemental content of the sample tissue obtained through laser-induced spectral analysis by the spectral analysis module with the elemental content of healthy tissue, thereby enabling the determination of the degree of lesion in the sample.

10. A photoacoustic imaging method based on the apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: The sample position is adjusted and fixed using the motion module; Pulsed laser light is emitted via a laser emission module; The beam splitting module receives the pulsed laser emitted by the laser emitting module and splits it into a first parallel beam and a second parallel beam. After passing through the first channel lens, the first parallel light spot is directly focused onto the surface of the sample tissue, exciting and generating an ultrasonic signal which is then collected by an ultrasonic transducer. The second parallel light passes through a dichroic mirror and a second channel lens in sequence and is focused onto the sample surface, exciting the sample surface to generate plasma. The plasma passes through the second channel lens and is reflected by the dichroic mirror, and then enters the spectrometer through the third channel lens. By adjusting the horizontal position of the sample using a motion module, large-area mosaic imaging of the sample tissue can be achieved. The data analysis module receives data collected by the photoacoustic imaging module and the spectral analysis module, and performs joint analysis on the morphology and elemental content of the sample tissue to obtain the lesion results of the sample tissue.

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