Method and apparatus for material photoacoustic spectroscopy
By processing photoacoustic signal data using a dual calibration method, the problems of optical variability and laser instability in photoacoustic spectroscopy measurements are solved, achieving consistency between photoacoustic spectra and true optical absorption spectra, and supporting the accurate analysis of molecular components in biological tissues.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNION PHOTOACOUSTIC TECH CO LTD
- Filing Date
- 2025-09-24
- Publication Date
- 2026-07-14
AI Technical Summary
Existing photoacoustic spectroscopy measurement methods suffer from optical variability in biological tissues and instability of laser systems, resulting in inconsistent photoacoustic signal intensities and making it difficult to achieve accurate quantification of molecular components.
A dual calibration method is adopted, which processes photoacoustic signal data through reconstruction algorithm, generates image and obtains photoacoustic signal intensity value, and performs calibration by combining the light absorption coefficients of standard solution and test solution to obtain the relative light absorption coefficient of test solution.
It improves the consistency between photoacoustic spectroscopy and true optical absorption spectrum, simplifies system operation, and enables precise analysis of molecular components in biological tissues.
Smart Images
Figure CN121384822B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optical measurement technology, and specifically to a method and apparatus for measuring photoacoustic spectra of materials. Background Technology
[0002] Photoacoustic imaging is a novel biomedical imaging method that combines optical absorption contrast with ultrasound spatial resolution. Its basic principle is based on the photoacoustic effect: when pulsed laser light irradiates biological tissue, chromophores (such as hemoglobin, melanin, and exogenous probes) absorb light energy and experience a transient temperature rise, triggering thermoelastic expansion and radiating broadband acoustic signals detectable by an ultrasound transducer. Because different tissues or molecules possess unique optical absorption characteristics within specific wavelength ranges, photoacoustic imaging can not only achieve high-resolution visualization of anatomical structures but also acquire functional and molecular information through multi-wavelength excitation, such as blood oxygen saturation, vascular distribution, metabolic state, and the distribution of exogenous drugs or probes. Furthermore, photoacoustic spectroscopy, by acquiring and analyzing photoacoustic signals from the same region at multiple wavelengths, can identify and quantify the concentration of various chromophores in tissues. Therefore, it shows great application potential in early disease diagnosis, drug delivery monitoring, tumor microenvironment assessment, and personalized treatment response tracking. Especially due to its advantages such as being non-invasive, radiation-free, highly sensitive, and capable of penetrating deep tissues, photoacoustic imaging is gradually becoming a key technology in preclinical research and translational medicine.
[0003] However, in practical applications, existing photoacoustic spectroscopy measurement methods still face significant challenges in quantitative accuracy, severely limiting their ability to accurately characterize molecules at the molecular level. Traditional techniques typically employ multi-wavelength pulsed lasers to sequentially irradiate samples and reconstruct the absorption spectrum based on the measured photoacoustic signal intensity. However, this process generally overlooks the impact of two key physical factors on signal consistency: first, the energy stability and spot uniformity of the pulsed laser vary at different wavelengths and irradiation orientations; second, the optical parameters of biological tissues (such as scattering coefficient, refractive index, and anisotropy factor) are wavelength-dependent, leading to uneven distribution of luminous flux (i.e., local photodeposited energy) within the tissue at different wavelengths. These factors directly result in the photoacoustic signal intensity varying due to fluctuations in local luminous flux, even if the same tissue has a definite absorption coefficient at different wavelengths. Especially in structurally complex biological tissues (such as tumor tissue), heterogeneity exacerbates the uncertainty of light transmission, making the measured photoacoustic signal unable to accurately reflect the intrinsic absorption characteristics of the target molecule. Therefore, directly using the original photoacoustic signal as an absorption intensity indicator for spectral reconstruction often introduces significant biases, making it difficult to achieve accurate quantification of chromophores.
[0004] Currently, although existing technologies attempt to correct this by introducing reference samples, calibration curves, or optical models, these methods typically rely on additional equipment, increase operational complexity, or require prior optical parameters, making it difficult to achieve fast, convenient, and universally applicable luminous flux compensation in practical imaging systems. Furthermore, most solutions fail to effectively address the impact of laser spatial illumination inconsistencies on the comparability of multi-wavelength data, resulting in a lack of reliable normalization basis for cross-wavelength signals.
[0005] Therefore, to solve the above problems, this invention proposes a novel photoacoustic spectroscopy measurement method that simplifies system operation and effectively addresses the optical differences in biological tissues and the instability of laser systems, thereby improving the consistency between photoacoustic spectra and true optical absorption spectra to support the accurate analysis of molecular components in biological tissues. Summary of the Invention
[0006] This invention addresses the technical problems existing in the prior art by providing a method and apparatus for measuring photoacoustic spectra of materials.
[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:
[0008] A method for measuring photoacoustic spectroscopy of materials includes the following specific steps:
[0009] S1: Collect photoacoustic signal data of the standard solution and the test solution at different wavelengths respectively;
[0010] S2: The above photoacoustic signal data is processed by the reconstruction algorithm to generate an image, and the photoacoustic signal intensity value I of the standard solution and the test solution in each region and at each scanned wavelength is obtained using the above image;
[0011] S3: Perform dual calibration on the photoacoustic signal intensity values I of the standard solution and the test solution obtained above to obtain the relative light absorption coefficient of the test solution.
[0012] The beneficial effects of this invention are as follows: During the measurement process, firstly, the photoacoustic signal data of the collected standard solution and the test solution at different wavelengths are processed by the reconstruction algorithm to generate images. At the same time, the photoacoustic signal intensity values I of the standard solution and the test solution at each region and each scanned wavelength are obtained based on the generated images. Then, the photoacoustic signal intensity values I of the standard solution and the test solution are double-calibrated to obtain the relative light absorption coefficient of the test solution. The measurement is convenient and significantly improves the consistency between the photoacoustic spectrum and the true optical absorption spectrum.
[0013] This invention provides a rapid, convenient, and accurate photoacoustic spectroscopy measurement method based on a photoacoustic imaging system. This method simplifies system operation and effectively addresses the optical differences in biological tissues and the instability of laser systems, thereby improving the consistency between photoacoustic spectra and true optical absorption spectra to support the accurate analysis of molecular components in biological tissues.
[0014] Based on the above technical solution, the present invention can be further improved as follows.
[0015] Furthermore, step S3 includes the following specific steps:
[0016] S31: Perform a calibration on the photoacoustic signal intensity values I of the standard solution and the test solution obtained above to obtain the photoacoustic signal intensity I' of the standard solution and the test solution;
[0017] S32: Recalibrate the photoacoustic signal intensity I' of the standard solution and the test solution obtained above to obtain the photoacoustic signal intensity I'' of the standard solution and the test solution. The final I'' represents the relative light absorption coefficient of the test solution.
[0018] The advantages of adopting the above-mentioned further scheme are that the method is simple and the design is reasonable. This method can perform dual calibration on the photoacoustic signal intensity value I of the collected standard solution and the test solution to obtain the photoacoustic signal intensity I''. The final I'' represents the relative light absorption coefficient of the test solution. The result can reflect the true optical absorption characteristics of the test solution and has cross-system comparability.
[0019] Further, step S31 includes the following specific steps: dividing the photoacoustic signal intensity at each position of the test solution module by the photoacoustic signal intensity at the same position in the standard solution module to obtain the photoacoustic signal intensity after one calibration, i.e.
[0020] ,
[0021] .
[0022] The advantages of adopting the above-mentioned further scheme are that the method is simple and the design is reasonable. The photoacoustic signal intensity I' of the test solution after one calibration can be obtained through one calibration. The calibration is convenient and efficient. It is conducive to the normalization of laser energy and eliminates the influence of non-uniform laser energy at different orientations.
[0023] Furthermore, step S32 includes the following specific steps: Increasing the photoacoustic signal intensity of the control solution after one calibration. Divide by the known light absorption coefficient of the standard solution To obtain the system calibration coefficient K, i.e.
[0024] ,
[0025] The photoacoustic signal intensity of the test solution after one calibration Divide by the system calibration coefficient K to obtain the photoacoustic signal intensity of the test solution after secondary calibration. ,Right now
[0026] .
[0027] The advantages of adopting the above-mentioned further scheme are that the method is simple and the design is reasonable. The photoacoustic signal intensity I'' of the test solution after secondary calibration can be obtained through secondary calibration. The calibration is convenient and efficient, and the consistency between the photoacoustic spectrum and the real optical absorption spectrum is further improved.
[0028] Furthermore, S2 includes the following specific steps: calculating the difference between the maximum and minimum values of all pixels in each region of the generated image, and recording it as the photoacoustic signal intensity of the solution in the capillary of that region; processing each frame of the image in the same way to obtain the photoacoustic signal intensity values I of the standard solution and the test solution in each region and at each scanned wavelength.
[0029] The advantages of adopting the above-mentioned further scheme are that the method is simple and the design is reasonable. By calculating the difference between the maximum and minimum values of all pixels in each region of the generated image, the photoacoustic signal intensity of the solution in the capillary in that region can be obtained.
[0030] Furthermore, S3 is followed by S4: plotting a photoacoustic spectrum curve with the laser wavelength as the abscissa and the relative light absorption coefficient as the ordinate.
[0031] The advantages of adopting the above-mentioned further scheme are that the method is simple and the design is reasonable. After completing the dual calibration, the photoacoustic spectrum curve is plotted with the laser wavelength as the abscissa and the relative light absorption coefficient as the ordinate. The result can reflect the true optical absorption characteristics of the solution under test and has cross-system comparability.
[0032] Furthermore, before S1, S0 is included: filling a standard solution in the standard channel of the calibration solution module, filling a control solution in one test channel of the test solution module, and filling the remaining test channels of the test solution module with test solutions.
[0033] The advantages of adopting the above-mentioned further scheme are that the method is simple, the design is reasonable, the standard solution module and the solution to be tested are prepared in advance, which facilitates the rapid subsequent measurement and the measurement efficiency is high.
[0034] Furthermore, the standard solution and the control solution in S0 are both CuSO4 solutions with the same concentration, and the concentration of the CuSO4 solution is 0.1 mol / L-0.5 mol / L.
[0035] The advantages of adopting the above-mentioned further scheme are that the method is simple, and it is more reasonable to use 0.1mol / L-0.5mol / L CuSO4 solution as the standard solution and control solution. CuSO4 in this concentration range can provide a stable photoacoustic signal reference and further improve the consistency between the photoacoustic spectrum and the real optical absorption spectrum.
[0036] Furthermore, the standard channel and the multiple channels to be tested in S0 are capillaries.
[0037] The advantage of adopting the above-mentioned further scheme is that the use of capillary tubes for the standard channel and the test channel is more reasonable. It can accommodate both the standard solution and the test solution, and it is also conducive to the measurement of material components with high accuracy.
[0038] The present invention also relates to an apparatus for the photoacoustic spectroscopy measurement method for materials as described above.
[0039] The beneficial effect of adopting the above-mentioned further solutions is that the present invention provides a material photoacoustic spectroscopy measurement device. This device is not only easy to operate, but also can effectively cope with the optical differences of biological tissues and the instability of laser systems, thereby improving the consistency between photoacoustic spectra and true optical absorption spectra, so as to support the accurate analysis of molecular components in biological tissues, and the measurement is fast, convenient and accurate. Attached Figure Description
[0040] Figure 1 This is a flowchart of the measurement method in this invention;
[0041] Figure 2 This is a photoacoustic spectrum curve of the present invention;
[0042] Figure 3 This is a schematic diagram of the photoacoustic image in this invention;
[0043] Figure 4 This is a schematic diagram of the overall structure of the measuring device in the first embodiment of the present invention;
[0044] Figure 5 This is a schematic diagram of the overall structure of the measuring device in the second embodiment of the present invention;
[0045] Figure 6 This is a partial structural schematic diagram of the measuring device in this invention;
[0046] Figure 7 This is a schematic diagram of the mounting plate in this invention;
[0047] Figure 8 This is a schematic diagram of the structure of the magnet block in this invention.
[0048] The attached diagram lists the components represented by each number as follows:
[0049] 1. Mounting plate; 2. Connecting bracket; 3. Circular hole; 4. Capillary tube; 5. Rectangular groove; 6. Through hole; 7. Magnet block; 8. Bolt. Detailed Implementation
[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0051] In the description of this application, 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0052] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this technology based on the specific circumstances.
[0053] In the description of this application, spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., are used herein to describe the relationship between one element or feature shown in the figures and other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "below" or "under" or "below" of other elements or features will be oriented "above" other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein are interpreted accordingly.
[0054] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.
[0055] Example 1
[0056] like Figures 1 to 3 As shown, this embodiment provides a method for measuring the photoacoustic spectrum of materials, including the following specific steps:
[0057] S1: Collect photoacoustic signal data of the standard solution and the test solution at different wavelengths respectively;
[0058] S2: The above photoacoustic signal data is processed by the reconstruction algorithm to generate an image, and the photoacoustic signal intensity value I of the standard solution and the test solution in each region and at each scanned wavelength is obtained using the above image;
[0059] S3: Perform dual calibration on the photoacoustic signal intensity values I of the standard solution and the test solution obtained above to obtain the relative light absorption coefficient of the test solution.
[0060] During the measurement process, firstly, the photoacoustic signal data of the collected standard solution and the test solution at different wavelengths are processed by the reconstruction algorithm to generate images. At the same time, the photoacoustic signal intensity values I of the standard solution and the test solution at each region and each scanned wavelength are obtained based on the generated images. Then, the photoacoustic signal intensity values I of the standard solution and the test solution are double-calibrated to obtain the relative light absorption coefficient of the test solution. The measurement is convenient and significantly improves the consistency between the photoacoustic spectrum and the true optical absorption spectrum.
[0061] Based on the above scheme, the specific steps for acquiring photoacoustic signal data of the standard solution and the test solution at different wavelengths in S1 are as follows:
[0062] The assembled standard solution and the test solution module are placed in the photoacoustic imaging system, and photoacoustic imaging scanning is performed under the condition of filling with water medium.
[0063] During the data acquisition process, the photoacoustic imaging system is first controlled to move the standard solution module into the measurement plane to ensure that the sampling area covers the entire capillary signal, and then multi-wavelength scanning is performed to acquire the photoacoustic signal data of the standard solution.
[0064] After completion, the photoacoustic imaging system is controlled to move the solution module to be tested into the measurement plane and collect multi-wavelength photoacoustic data in the same way; if there are multiple solution modules to be tested, the photoacoustic imaging system is controlled to scan each solution module to be tested individually in the same way and collect raw data of multi-wavelength photoacoustic signals.
[0065] Based on the above scheme, the specific operations of how the standard solution module and the test solution module are sent into or out of the photoacoustic imaging system are existing technologies and will not be described in detail here.
[0066] This embodiment provides a fast, convenient, and accurate photoacoustic spectroscopy measurement method based on a photoacoustic imaging system. This method simplifies system operation and effectively addresses the optical differences in biological tissues and the instability of laser systems, thereby improving the consistency between photoacoustic spectra and true optical absorption spectra to support the accurate analysis of molecular components in biological tissues.
[0067] Example 2
[0068] Based on Example 1, in this example, step S3 includes the following specific steps:
[0069] S31: Perform a calibration on the photoacoustic signal intensity values I of the standard solution and the test solution obtained above to obtain the photoacoustic signal intensity I' of the standard solution and the test solution;
[0070] S32: Recalibrate the photoacoustic signal intensity I' of the standard solution and the test solution obtained above to obtain the photoacoustic signal intensity I'' of the standard solution and the test solution. The final I'' represents the relative light absorption coefficient of the test solution.
[0071] This method is simple and reasonably designed. It can perform dual calibration on the photoacoustic signal intensity value I of the collected standard solution and the test solution to obtain the photoacoustic signal intensity I''. The final I'' represents the relative light absorption coefficient of the test solution. The result can reflect the true optical absorption characteristics of the test solution and has cross-system comparability.
[0072] Example 3
[0073] Based on Example 2, in this example, S31 includes the following specific steps: dividing the photoacoustic signal intensity at each position of the test solution module by the photoacoustic signal intensity at the same position in the standard solution module to obtain the photoacoustic signal intensity after one calibration, i.e.
[0074] ,
[0075] .
[0076] This method is simple and reasonably designed. The photoacoustic signal intensity I' of the test solution after one calibration can be obtained through a single calibration. The calibration is convenient and efficient, which is conducive to the normalization of laser energy and the elimination of the influence of non-uniform laser energy at different orientations.
[0077] Example 4
[0078] Based on any one of Examples 2 to 3, in this example, S32 includes the following specific steps: Increasing the photoacoustic signal intensity of the control solution after one calibration. Divide by the known light absorption coefficient of the standard solution To obtain the system calibration coefficient K, i.e.
[0079] ,
[0080] The photoacoustic signal intensity of the test solution after one calibration Divide by the system calibration coefficient K to obtain the photoacoustic signal intensity of the test solution after secondary calibration. ,Right now
[0081] .
[0082] This method is simple and reasonably designed. The photoacoustic signal intensity I'' of the test solution after secondary calibration can be obtained through secondary calibration. The calibration is convenient and efficient, and further improves the consistency between the photoacoustic spectrum and the true optical absorption spectrum.
[0083] Example 5
[0084] Based on the above embodiments, in this embodiment, S2 includes the following specific steps: calculating the difference between the maximum and minimum values of all pixels in each region of the generated image, and recording it as the photoacoustic signal intensity of the solution in the capillary of that region; processing each frame of the image in the same way to obtain the photoacoustic signal intensity values I of the standard solution and the test solution in each region and at each scanned wavelength.
[0085] This method is simple and well-designed. By calculating the difference between the maximum and minimum values of all pixels in each region of the generated image, the photoacoustic signal intensity of the solution in the capillary in that region can be obtained.
[0086] Based on the above scheme, the collected data is used to generate images through a reconstruction algorithm (such as the UBP algorithm). The reconstructed images can display the signals of the solution in the capillary of each channel in the standard module and the module under test (see the schematic diagram of a single frame image). Figure 3(As shown).
[0087] In addition, the full name of the UBP algorithm mentioned above is Universal Back-Projection.
[0088] Example 6
[0089] Based on the above embodiments, this embodiment further includes S4 after S3: plotting a photoacoustic spectrum curve with the laser wavelength as the abscissa and the relative light absorption coefficient as the ordinate (see Appendix). Figure 2 ).
[0090] This method is simple and well-designed. After completing dual calibration, a photoacoustic spectrum curve is plotted with the laser wavelength as the abscissa and the relative light absorption coefficient as the ordinate. The results can reflect the true optical absorption characteristics of the solution under test and have cross-system comparability.
[0091] Based on the above scheme, Appendix Figure 2 The three curves in the figure represent the results of measurements on three different materials. The horizontal axis represents the laser wavelength (unit: nm), and the vertical axis represents the relative light absorption coefficient.
[0092] Example 7
[0093] Based on the above embodiments, in this embodiment, S0 is included before S1: filling a standard solution in the standard channel of the calibration solution module, filling a control solution in one test channel of the test solution module, and filling the remaining test channels of the test solution module with test solutions.
[0094] This method is simple and well-designed. It requires pre-preparing standard solution modules and test solution modules, which facilitates rapid subsequent measurements and results in high measurement efficiency.
[0095] Based on the above scheme, the standard solution module contains a standard solution of the same concentration. This standard solution is resistant to laser irradiation, does not decompose, does not deteriorate, is not photobleached, and can be reused.
[0096] In addition, the standard solution should be replaced every 3-6 months under normal conditions.
[0097] Example 8
[0098] Based on Example 7, in this example, the standard solution and the control solution in S0 are both CuSO4 solutions with the same concentration, and the concentration of the CuSO4 solution is 0.1mol / L-0.5mol / L.
[0099] This method is simple. It is reasonable to use 0.1mol / L-0.5mol / L CuSO4 solution as the standard and control solutions. CuSO4 in this concentration range can provide a stable photoacoustic signal reference and further improve the consistency between the photoacoustic spectrum and the real optical absorption spectrum.
[0100] Preferably, in this embodiment, the standard solution and the control solution in S0 are both 0.2 mol / L CuSO4 solutions.
[0101] Example 9
[0102] Based on any one of Embodiments 7 to 8, in this embodiment, the standard channel and the multiple channels to be tested in S0 are capillaries.
[0103] The use of capillary tubes in this scheme for both the standard channel and the test channel is reasonable. It can accommodate both the standard solution and the test solution, and it is also conducive to the measurement of material components with high accuracy.
[0104] Example 10
[0105] Based on the above embodiments, such as Figure 4 and Figure 8 As shown, this embodiment also provides an apparatus for the material photoacoustic spectroscopy measurement method described above.
[0106] The material photoacoustic spectroscopy measurement device provided in this embodiment includes a photoacoustic imaging system, a standard solution module, and a test solution module. The specific structures of each part are as follows:
[0107] (1) The photoacoustic imaging system uses existing technology, and its specific structure and principle will not be described in detail here.
[0108] (2) The standard solution module and the test solution module have the same structure. Both include two mounting plates 1, which are arranged opposite to each other and connected at their center by a connecting bracket 2.
[0109] Preferably, in this embodiment, the connecting frame 2 has a rectangular cross-section.
[0110] Alternatively, the aforementioned connecting frame 2 can also be a frame with a circular cross-section.
[0111] Preferably, the two mounting plates 1 are circular plates, each with multiple pairs of through circular holes 3 facing each other, and the multiple circular holes 3 on each circular plate are evenly spaced along the circumference of the plate. Each pair of circular holes 3 is connected by a capillary tube 4.
[0112] Furthermore, the number of circular holes 3 provided on the two mounting plates 1 can be designed according to the actual situation, and is not limited here.
[0113] In addition, rectangular grooves 5 are provided at the center of the two mounting plates 1 on the side that are close to each other, and the two ends of the connecting bracket 2 extend into the two rectangular grooves 5 respectively; moreover, through holes 6 are provided on the side that are far from each other, respectively communicating with the two rectangular grooves 5. During assembly, the bolt 8 passes through the through hole 6 and the rectangular groove 5 and is threaded to one end of the connecting bracket 2, and threaded holes are provided at both ends of the connecting bracket 2.
[0114] During assembly, one standard solution module is used, while one or more test solution modules can be used. When multiple test solution modules are used, they are stacked and distributed with one standard solution module from top to bottom, and the position of the standard solution module is not restricted.
[0115] In addition, the circular holes between adjacent modules correspond one-to-one and are interconnected.
[0116] Preferably, in this embodiment, during assembly, two adjacent modules can be connected by magnets. Specifically, the two mounting plates 1 corresponding to the two modules are attached to each other, and magnet blocks 7 are installed at the two through holes 6 corresponding to the two mounting plates 1 respectively. The two magnet blocks 7 attract each other to connect the two modules.
[0117] In addition, each magnet block 7 has a through hole at its center so that a bolt can pass through.
[0118] This embodiment provides a photoacoustic spectroscopy measurement device for materials. This device is easy to operate and can effectively cope with the optical differences of biological tissues and the instability of laser systems, thereby improving the consistency between photoacoustic spectra and true optical absorption spectra, so as to support the accurate analysis of molecular components in biological tissues. The measurement is fast, convenient and accurate.
[0119] The photoacoustic spectroscopy measurement method for materials provided by this invention includes the following specific steps:
[0120] S0: Fill the standard channel in the calibration solution module with standard solution, fill the control solution in one test channel of the test solution module, and fill the remaining test channels of the test solution module with test solution.
[0121] S1: Collect photoacoustic signal data of the standard solution and the test solution at different wavelengths respectively;
[0122] S2: The above photoacoustic signal data is processed by the reconstruction algorithm to generate an image, and the difference between the maximum and minimum values of all pixels in each region of the generated image is calculated and recorded as the photoacoustic signal intensity of the solution in the capillary in that region; each frame of the image is processed in the same way to obtain the photoacoustic signal intensity values I of the standard solution and the test solution in each region and at each scanned wavelength.
[0123] Dual calibration in S3 includes the following specific steps:
[0124] (1) First calibration (spot uniformity correction): Divide the photoacoustic signal intensity at each position of the test solution module by the photoacoustic signal intensity at the same position in the standard solution module to obtain the photoacoustic signal intensity after the first calibration, i.e.
[0125] ,
[0126] ,
[0127] (2) Secondary calibration (relative quantitative correction): The photoacoustic signal intensity of the control solution after the first calibration is adjusted. Divide by the known light absorption coefficient of the standard solution To obtain the system calibration coefficient K, i.e.
[0128] ,
[0129] The photoacoustic signal intensity of the test solution after one calibration Divide by the system calibration coefficient K to obtain the photoacoustic signal intensity of the test solution after secondary calibration. ,Right now
[0130] ,
[0131] S4: Plot the photoacoustic spectrum curve with the laser wavelength as the abscissa and the relative light absorption coefficient as the ordinate.
[0132] This invention provides a rapid, convenient, and accurate photoacoustic spectral measurement method based on a photoacoustic imaging system, involving the design and implementation of related algorithms, hardware devices, and scanning control software. This method significantly improves the consistency between the photoacoustic spectrum and the true optical absorption spectrum through joint measurement of the standard solution and the test solution, and two-stage calibration.
[0133] Furthermore, the novel photoacoustic spectroscopy measurement method proposed in this invention simplifies system operation and effectively addresses the optical differences in biological tissues and the instability of laser systems, thereby improving the consistency between photoacoustic spectra and true optical absorption spectra to support the accurate analysis of molecular components in biological tissues.
[0134] Compared with the prior art, the present invention has the following advantages:
[0135] 1. This invention provides a convenient photoacoustic spectral measurement method that can be implemented in existing photoacoustic imaging systems without the need for complex additional equipment;
[0136] 2. This invention achieves unified normalization and quantification of cross-wavelength signals through modular design and standard solution comparison;
[0137] 3. This invention improves the consistency between photoacoustic spectrum and true light absorption spectrum, significantly enhancing the reliability of its application in functional imaging, disease diagnosis, and drug monitoring.
[0138] 4. The method provided by this invention has good versatility and scalability, and is suitable for quantitative research on various biological tissues and under different experimental conditions;
[0139] 5. In this invention, the coaxially fixed standard solution module and test solution module facilitate the installation and disassembly of the sample mold. Furthermore, during scanning, only the sample mold needs to be moved up and down to ensure that multi-wavelength photoacoustic signals are acquired from all modules while maintaining a constant light intensity distribution.
[0140] While embodiments or examples of this disclosure have been described with reference to the accompanying drawings, it should be understood that the above embodiments are merely exemplary embodiments or examples, and the scope of the invention is not limited by these embodiments or examples, but only by the granted claims and their equivalents. Various elements in the embodiments or examples may be omitted or replaced by their equivalents. Furthermore, the steps may be performed in a different order than that described in this disclosure. Further, various elements in the embodiments or examples may be combined in various ways. Importantly, as the technology evolves, many elements described herein can be replaced by equivalents that appear after this disclosure.
Claims
1. A method for measuring photoacoustic spectroscopy of materials, characterized in that, The specific steps include the following: S1: Collect photoacoustic signal data of the standard solution and the test solution at different wavelengths respectively; S2: The above photoacoustic signal data is processed by the reconstruction algorithm to generate an image, and the photoacoustic signal intensity value I of the standard solution and the test solution in each region and at each scanned wavelength is obtained using the above image; S3: Perform dual calibration on the photoacoustic signal intensity values I of the standard solution and the test solution obtained above to obtain the relative light absorption coefficient of the test solution; S3 includes the following specific steps: S31: Perform a calibration on the photoacoustic signal intensity values I of the standard solution and the test solution obtained above to obtain the photoacoustic signal intensity I' of the standard solution and the test solution; Specifically, S31 includes the following steps: dividing the photoacoustic signal intensity at each position of the test solution module by the photoacoustic signal intensity at the same position in the standard solution module to obtain the photoacoustic signal intensity after one calibration, i.e. ， ； S32: Recalibrate the photoacoustic signal intensity I' of the standard solution and the test solution obtained above to obtain the photoacoustic signal intensity I'' of the standard solution and the test solution. The final I'' represents the relative light absorption coefficient of the test solution. Specifically, S32 includes the following steps: Increasing the photoacoustic signal intensity of the control solution after one calibration. Divide by the known light absorption coefficient of the standard solution To obtain the system calibration coefficient K, i.e. ， The photoacoustic signal intensity of the test solution after one calibration Divide by the system calibration coefficient K to obtain the photoacoustic signal intensity of the test solution after secondary calibration. ,Right now 。 2. The material photoacoustic spectroscopy measurement method according to claim 1, characterized in that, The S2 includes the following specific steps: calculating the difference between the maximum and minimum values of all pixels in each region of the generated image, and recording it as the photoacoustic signal intensity of the solution in the capillary of that region; processing each frame of the image in the same way to obtain the photoacoustic signal intensity values I of the standard solution and the test solution in each region and at each scanned wavelength.
3. The material photoacoustic spectroscopy measurement method according to claim 1, characterized in that, S3 is followed by S4: plotting a photoacoustic spectrum curve with the laser wavelength as the abscissa and the relative light absorption coefficient as the ordinate.
4. The material photoacoustic spectroscopy measurement method according to claim 1, characterized in that, Before S1, S0 is also included: filling a standard solution in the standard channel of the calibration solution module, filling a control solution in one test channel of the test solution module, and filling the remaining test channels of the test solution module with test solutions.
5. The material photoacoustic spectroscopy measurement method according to claim 4, characterized in that, The standard solution and control solution in S0 are both CuSO4 solutions with the same concentration, which is 0.1 mol / L to 0.5 mol / L.
6. The material photoacoustic spectroscopy measurement method according to claim 4, characterized in that, The standard channel and multiple channels to be tested in S0 are capillaries.