A tissue blood oxygen micro-tomography device

Abstract

The present invention discloses a tissue blood oxygen micro-tomography device. It includes: a dual-wavelength laser output module for outputting a dual-wavelength laser beam; a polarization splitter module for polarizing the dual-wavelength laser beam to form a first polarized laser beam and transmitting the first polarized laser beam; a scanning detection module for reflecting the first polarized laser beam to each position to be detected of the sample to be tested, and the scanning detection module is also used to reflect the second polarized laser beam to the polarization splitter module; an imaging module, the imaging module includes: a wavelength splitter device, a slit plate, and an array photodetector arranged in sequence along the transmission path of the second polarized laser beam; and also includes a displacement control module for moving the slit plate. The present invention designs a movable slit device on the detection array, realizes dual-wavelength information detection and blood oxygen tomography, avoids the loss of the optical shutter caused by the switching of the incident light, and realizes tissue blood oxygen micro-tomography at a lower cost.

Description

Technical Field

[0001] The present invention relates to the technical field of optical imaging, and in particular to a tissue blood oxygen micro-tomography imaging device. Background Art

[0002] Optical imaging technology uses light to image tissues. Different components in tissues have different light absorption, scattering or fluorescence characteristics, which form contrast in the optical image and show the structural and functional changes in the tissue. Optical blood oxygen imaging mainly uses the absorption characteristics of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb) in the blood for imaging. The characteristic absorption spectra of HbO2 and Hb are different. By irradiating biological tissues with light of the peak wavelengths of the characteristic absorption spectra of HbO2 and Hb, the concentration changes of HbO2 and Hb can be analyzed, forming a distribution map of blood oxygen concentration in two-dimensional space.

[0003] Optical blood oxygen imaging mostly uses dual-wavelength alternating irradiation to obtain blood oxygen images. The detector obtains the output light signal of a single wavelength in time, and analyzes the blood oxygen image through the dual-wavelength signals detected successively. Dual-wavelength alternating irradiation requires wavelength switching, and a shutter is often used to control the opening and closing of the two lasers. The light power at the laser emission position is relatively large. After long-term use, the optical shutter is severely damaged, which increases the cost of equipment maintenance. When dual wavelengths are used to simultaneously irradiate biological tissues, a two-dimensional photomultiplier tube (PMT) array is used to detect the output signal. Each column of array elements on the PMT corresponds to an output signal of one wavelength, and the output light of the two wavelengths is respectively matched to two photodetectors through a spectroscopic device. However, the cost of the two-dimensional PMT is high, and the more array elements there are, the lower the sensitivity and other performance of a single array element. The simultaneous acquisition of more channels also puts higher requirements on the data acquisition and processing system. Summary of the invention

[0004] The present invention provides a tissue blood oxygen micro-tomography device to solve the problems of high cost and low sensitivity of tissue blood oxygen imaging systems in the prior art.

[0005] An embodiment of the present invention provides a tissue blood oxygen micro-tomography device, which includes:

[0006] A dual-wavelength laser output module, used for outputting a dual-wavelength laser beam;

[0007] a polarization splitting module, located on the transmission path of the dual-wavelength laser beam, for polarizing the dual-wavelength laser beam to form a first polarized laser beam, and transmitting the first polarized laser beam;

[0008] A scanning detection module, located on the transmission path of the first polarized laser beam, is used to reflect the first polarized laser beam to each to-be-detected position of the sample to be detected, the first polarized laser beam forms a second polarized laser beam after being acted upon by the to-be-detected position, the scanning detection module is also used to reflect the second polarized laser beam to the polarization splitting module, and the polarization splitting module is also used to reflect the second polarized laser beam to the imaging module; the polarization direction of the first polarized laser beam is perpendicular to the polarization direction of the second polarized laser beam;

[0009] An imaging module is located on the transmission path of the second polarized laser beam, and the imaging module includes: a wavelength splitter, a slit plate, and an array photodetector sequentially arranged along the transmission path of the second polarized laser beam; and also includes a displacement control module for moving the slit plate;

[0010] Among them, the wavelength splitter is used to separate the second polarized laser beam into a first wavelength polarized beam and a second wavelength polarized beam; the displacement control module is used to periodically control the slit in the slit plate to be located on the transmission path of the first wavelength polarized beam, or, to be located on the transmission path of the second wavelength polarized beam, so that the array photodetector successively images the first wavelength polarized beam and the second wavelength polarized beam.

[0011] Optionally, the polarization beam splitting module comprises: a polarizer and a polarization beam splitter sequentially arranged along the transmission path of the dual-wavelength laser beam;

[0012] The polarizer is used for polarizing the dual-wavelength laser beam to form a first polarized laser beam, and the polarization beam splitter is used for transmitting the first polarized laser beam.

[0013] Optionally, the scanning detection module includes: an xy scanning galvanometer, a scanning lens and an objective lens arranged along the transmission path of the first polarized laser beam;

[0014] The xy scanning galvanometer is used to receive the first polarized laser beam, and reflect the first polarized laser beam through the scanning lens and the objective lens in sequence to reach the sample to be tested; wherein the xy scanning galvanometer is used to change the reflection direction of the first polarized laser beam to change the first polarized laser beam to different positions to be tested of the sample to be tested.

[0015] Optionally, the imaging module also includes: an analyzer and an imaging lens located between the wavelength spectrometer and the polarization spectrometer module, the analyzer being used to pass the second polarized laser beam reflected by the polarization spectrometer module to the imaging lens, and the second polarized laser beam enters the wavelength spectrometer after passing through the imaging lens.

[0016] Optionally, the wavelength splitter device is a diffraction grating or a beam splitter prism.

[0017] Optionally, the array photodetector is a plurality of long strip photodetectors arranged along a first direction; the length direction of the slit of the slit plate extends along the first direction; the displacement control module controls the slit plate to move periodically along a second direction, and the first direction is perpendicular to the second direction.

[0018] Optionally, the number of the array photodetectors is at least 5.

[0019] Optionally, the array photodetector is an image sensor composed of a linear array photomultiplier tube, an avalanche photodiode, a silicon photodiode, a CCD or a CMOS.

[0020] Optionally, the slit width in the slit plate is greater than the maximum wavelength of the dual-wavelength laser beam and less than the deviation distance between the first wavelength polarized beam and the second wavelength polarized beam.

[0021] Optionally, the dual wavelengths in the dual-wavelength laser beam are 532 nm and 638 nm respectively.

[0022] The technical solution of the embodiment of the present invention uses a wavelength spectrometer, a slit plate and a displacement control module for controlling the movement of the slit plate, so that the slit of the slit plate moves, and light of different wavelengths is successively transmitted to hit the array photodetector, thereby avoiding the use of a shutter. In addition, since the light intensity at the detection position is attenuated by the system and the incident tissue, the intensity is greatly reduced, thereby avoiding optical loss of the shading device. At the same time, the use of a single-row PMT reduces the cost of the detection module and the requirements for data acquisition and processing speed.

[0023] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 2 is a schematic structural diagram of a tissue blood oxygen micro-tomography device provided in an embodiment of the present invention;

[0026] Figure 2is a schematic structural diagram of another tissue blood oxygen micro-tomography device provided according to an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of slit displacement in an imaging system is provided according to an embodiment of the present invention;

[0028] Figure 4 It is a schematic diagram of obtaining different depth information of a sample to be tested by a multi-distance array photoelectric detector provided by an embodiment of the present invention;

[0029] Figure 5 It is a schematic diagram of scanning a target sample by an xy scanning galvanometer according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0032] Figure 1 FIG. 1 is a schematic diagram of the structure of a tissue blood oxygen micro-tomography imaging device provided by an embodiment of the present invention. This embodiment can be applied to a tissue blood oxygen display imaging system, such as Figure 1 As shown, the device comprises:

[0033] The dual-wavelength laser output module 100 is used to output a dual-wavelength laser beam 500 .

[0034] The polarization splitting module 200 is located on the transmission path of the dual-wavelength laser beam 500 , and is used to polarize the dual-wavelength laser beam 500 to form a first polarized laser beam 510 , and transmit the first polarized laser beam 510 .

[0035] The scanning detection module 300 is located on the transmission path of the first polarized laser beam 510, and is used to reflect the first polarized laser beam 510 to each detection position of the sample 600 to be tested. The first polarized laser beam 510 forms a second polarized laser beam 520 after passing through the detection position. The scanning detection module is also used to reflect the second polarized laser beam 520 to the polarization splitting module 200, and the polarization splitting module 200 is also used to reflect the second polarized laser beam 520 to the imaging module; the polarization direction of the first polarized laser beam 510 is perpendicular to the polarization direction of the second polarized laser beam 520.

[0036] The imaging module 400 is located on the transmission path of the second polarized laser beam 520. The imaging module 400 includes: a wavelength spectrometer 410, a slit plate 420, and an array photodetector 430 arranged in sequence along the transmission path of the second polarized laser beam 520; and also includes a displacement control module 440 for moving the slit plate.

[0037] Among them, the wavelength splitter 410 is used to separate the second polarized laser beam 520 into a first wavelength polarized beam 521 and a second wavelength polarized beam 522; the displacement control module 440 is used to periodically control the slit in the slit plate 420 to be located on the transmission path of the first wavelength polarized beam 521, or, to be located on the transmission path of the second wavelength polarized beam 522, so that the array photodetector 430 successively images the first wavelength polarized beam 521 and the second wavelength polarized beam 522.

[0038] Among them, the dual-wavelength laser output module 100 can be two independent single-wavelength continuous light lasers. The wavelength splitter 410 can be a device that emits light beams of different wavelengths in different directions through the splitter to achieve the purpose of splitting. The displacement control module 440 is used to move the slit plate to respectively transmit light of different wavelengths to the imaging system, thereby achieving the purpose of imaging. The array photodetector 430 is used to convert the collected light signal into an electrical signal and output calculation imaging. The polarization splitter module 200 can be used to separate the dual-wavelength laser beam 500 in the form of linearly polarized light to form a first polarized laser beam 510. The displacement control module 440 can be a stepping motor.

[0039] Specifically, the dual-wavelength laser output utilizes the different light absorption, scattering or fluorescence characteristics of different components in the tissue in the field of optical imaging technology to form a contrast in the image, thereby showing the changes in the structure and function of the tissue. The dual-wavelength laser output can detect the changes in the structure and function between two components with different absorption characteristics in the tissue. Among them, the dual-wavelength laser output module 100 also includes a collimator 210, which is used to collimate the laser output by the laser to the polarization splitter module 200.

[0040] For example, in an optical blood oxygen imaging system, since the characteristic absorption spectra of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb) in the blood are different, by incident light with the peak wavelengths of the characteristic absorption spectra of HbO2 and Hb respectively on biological tissues, the concentration changes of HbO2 and Hb can be analyzed, thereby forming a distribution map of blood oxygen concentration in two-dimensional space.

[0041] It can be understood that the dual-wavelength laser output module 100 outputs a dual-wavelength laser beam 500 corresponding to the peak wavelengths of the characteristic absorption spectra of HbO2 and Hb, and the dual-wavelength laser beam 500 enters the polarization splitting module 200, and the polarization splitting module 200 polarizes the dual-wavelength laser beam 500 into P polarized light, and uses the P polarized light of the dual-wavelength laser beam 500 as the first polarized laser beam 510, and the first polarized laser beam 510 passes through the polarization splitting module 200. Polarization splitting of the dual-wavelength laser beam 500 can improve the beam quality, improve the coherence and energy of light, and thus make the imaging effect more stable in the optical blood oxygen composition imaging system, and ensure the accuracy of the results.

[0042] Furthermore, the first polarized laser beam 510 enters the scanning detection module 300, and the scanning detection module 300 adjusts and reflects the first polarized laser beam 510 to each detection position of the sample to be detected 600. The first polarized laser beam 510 forms S polarized light perpendicular to the direction of the P polarized light according to the position to be detected, and the S polarized light is used as the second polarized laser beam 520. The reflected second polarized laser beam 520 passes through the scanning detection module 300 again, and the scanning detection module 300 adjusts and reflects the second polarized laser beam 520 to the polarization splitting module 200, and then reflects the second polarized laser beam 520 to the imaging module 400 through the polarization splitting module 200.

[0043] That is, the second polarized laser beam 520 is reflected to the wavelength splitter 410 by the polarization splitting module 200, and the wavelength splitter 410 splits the second polarized laser beam 520 into a first wavelength polarized beam 521 and a second wavelength polarized beam 522 with different emission angles according to different wavelengths. The displacement control module 440 moves the slit plate 420 so that the first wavelength polarized beam 521 acts on the array photodetector 430, and then the array photodetector 430 transmits a signal to form an image of the first wavelength polarized beam 521; the displacement control module 440 moves the slit plate 420 so that the second wavelength polarized beam 522 acts on the array photodetector 430, and then the array photodetector 430 transmits a signal to form an image of the second wavelength polarized beam 522.

[0044] The embodiment of the present invention provides a tissue blood oxygen micro-tomography imaging device, including a dual-wavelength laser output module, a polarization splitter module, a scanning detection module, and an imaging module. The dual-wavelength laser output module outputs light incident on the sample to be tested through the same optical path, and the imaging module separates the dual-wavelength laser beams of the output signal, and through a movable optical slit device, the separated laser beams are respectively irradiated on different positions of the array photodetector, so that the array photodetector collects and detects the dual-wavelength output light signal respectively, and optically analyzes the dual-wavelength output light signal to achieve tissue imaging. This reduces the cost of the detection module and the requirements for data acquisition and processing speed, and ensures imaging efficiency.

[0045] Figure 2 Schematic diagram of another tissue blood oxygen micro-tomography device provided according to an embodiment of the present invention.

[0046] Optionally, the polarization splitting module 200 includes: a polarizer 220 and a polarization beam splitter 230 which are sequentially arranged along the transmission path of the dual-wavelength laser beam 500 .

[0047] The polarizer 220 is used to polarize the dual-wavelength laser beam 500 to form a first polarized laser beam 510 , and the polarization beam splitter 230 is used to transmit the first polarized laser beam 510 .

[0048] Exemplarily, the polarizer 220 may be a linear polarizer, and the polarization beam splitter 220 may have a light splitting surface coated with a film layer that transmits P-polarized light and reflects S-polarized light.

[0049] Thus, the dual-wavelength laser output module 100 outputs a dual-wavelength laser beam 500 corresponding to the peak wavelengths of the characteristic absorption spectra of HbO2 and Hb, and the dual-wavelength laser beam 500 enters the polarization splitting module 200. The polarizer 220 in the polarization splitting module 200 polarizes the dual-wavelength laser beam 500 into P polarized light, and the P polarized light of the dual-wavelength laser beam 500 is used as the first polarized laser beam 510. At the same time, the first polarized laser beam 510 passes through the polarization beam splitter 230 through the film layer that transmits P polarized light and reflects S polarized light, and the first polarized laser beam 510 enters the scanning detection module 300. Polarization splitting of the dual-wavelength laser beam and detecting the polarized split beam in the sample to be tested can improve the beam quality, improve the coherence and energy of light, and thus make the imaging effect more stable in the optical blood oxygen composition imaging system, and ensure the accuracy of the results.

[0050] Optional, such as Figure 2 As shown, the scanning detection module 300 includes: an xy scanning galvanometer 310 , a scanning lens 320 and an objective lens 330 arranged along the transmission path of the first polarized laser beam 510 .

[0051] The xy scanning galvanometer 310 is used to receive the first polarized laser beam 510, and reflect the first polarized laser beam 510 to pass through the scanning lens 320 and the objective lens 330 in sequence to reach the sample to be tested 600; wherein, the xy scanning galvanometer 310 is used to change the reflection direction of the first polarized laser beam 510 to change the first polarized laser beam 510 to different positions to be tested of the sample to be tested 600.

[0052] The scanning lens 320 and the objective lens 330 can be used to focus the first polarized laser beam 510 onto the imaging focal plane of the sample. The objective lens 330 also determines the magnification of the imaging system.

[0053] Exemplarily, the wavelength laser output module 100 outputs a dual-wavelength laser beam 500 corresponding to the peak wavelengths of the characteristic absorption spectra of HbO2 and Hb, and the dual-wavelength laser beam 500 enters the polarization splitting module 200. The polarizer 220 in the polarization splitting module 200 polarizes the dual-wavelength laser beam 500 into P polarized light, and the P polarized light of the dual-wavelength laser beam 500 is used as the first polarized laser beam 510. At the same time, the first polarized laser beam 510 transmits the polarization beam splitter 230, and the first polarized laser beam 510 enters the xy scanning galvanometer 310 in the scanning detection module 300, and is focused on the imaging focal plane of the sample to be tested through the scanning lens 320 and the objective lens 330. The reflection direction of the first polarized laser beam 510 is changed by adjusting the angle of the xy scanning galvanometer 310, and the beam is focused on different points to be tested of the sample to be tested 600 through the scanning lens 320 and the objective lens 330.

[0054] The first polarized laser beam passes through the xy scanning galvanometer, scanning lens and objective lens, so that the light is focused onto the imaging focal plane of the sample to be tested, which facilitates the control and adjustment of the magnification of the imaging system and ensures the accuracy of imaging.

[0055] Optional, such as Figure 2 As shown, the imaging module 400 also includes: an analyzer 450 and an imaging lens 460 located between the wavelength spectrometer 410 and the polarization spectrometer module 200. The analyzer 450 is used to pass the second polarized laser beam 520 reflected by the polarization spectrometer module 200 to the imaging lens 460. The second polarized laser beam 520 enters the wavelength spectrometer 410 after passing through the imaging lens 460.

[0056] The imaging lens 460 and the objective lens 330 jointly determine the magnification of the imaging system.

[0057] Exemplarily, the wavelength laser output module 100 outputs a dual-wavelength laser beam 500 corresponding to the peak wavelengths of the characteristic absorption spectra of HbO2 and Hb, and the dual-wavelength laser beam 500 enters the polarization splitting module 200. The polarizer 220 in the polarization splitting module 200 polarizes the dual-wavelength laser beam 500 into P-polarized light, and uses the P-polarized light of the dual-wavelength laser beam 500 as the first polarized laser beam 510. At the same time, the first polarized laser beam 510 transmits the polarization beam splitter 230, and the first polarized laser beam 510 enters the xy scanning galvanometer 310 in the scanning detection module 300, and passes through the scanning lens 320 and the objective lens 330, and is focused on the imaging focal plane of the sample to be tested 600. The reflection direction of the first polarized laser beam 510 is changed by adjusting the angle of the xy scanning galvanometer 310, and the beam is focused on different points to be tested of the sample to be tested 600 through the scanning lens 320 and the objective lens 330. The first polarized laser beam 510 forms S polarized light perpendicular to the direction of the P polarized light according to the position to be detected, and the S polarized light is used as the second polarized laser beam 520. The reflected second polarized laser beam 520 then passes through the analyzer 450 in the imaging module 400. The analyzer 450 filters the incident P polarized light and only detects the S polarized light reflected and / or transmitted by the sample to be tested 600. The second polarized laser beam 520 is filtered by the analyzer 450, amplified by the imaging lens 460 and passes through the wavelength spectrometer 410. The wavelength spectrometer 410 splits the second polarized laser beam 520 into a first wavelength polarized beam 521 and a second wavelength polarized beam 522 with different exit angles according to different wavelengths. Among them, the analyzer 450 can be a linear polarizer, which is only used to transmit the second polarized laser beam 520 and shield other stray light, which is beneficial to improve the imaging quality.

[0058] Optionally, the wavelength splitter device 410 is a diffraction grating or a beam splitter prism.

[0059] Specifically, a diffraction grating or a beam splitter prism is used as the wavelength splitter device 410 to separate the emission directions of lights of different wavelengths, so as to transmit the corresponding wavelength emission lights to the imaging system.

[0060] Optional, such as Figure 3 As shown, the array photodetector 430 is a plurality of long strip photodetectors arranged along a first direction Y; the length direction of the slit 421 of the slit plate 420 extends along the first direction Y; the displacement control module 440 controls the slit plate 420 to move periodically along a second direction X, and the first direction Y is perpendicular to the second direction X.

[0061] Exemplarily, the first direction and the second direction are the Y direction and the X direction perpendicular to each other, respectively, and the wavelength splitter 410 splits the second polarized laser beam 520 into a first wavelength polarized beam 521 and a second wavelength polarized beam 522 with different emission angles according to different wavelengths. The displacement control module 440 controls the slit plate 420 to move periodically along the X direction, and the displacement control module 440 controls the slit plate 420 to respectively overlap the first wavelength polarized beam 521 with the slit 421; or, controls the second wavelength polarized beam 522 to overlap with the slit 421. Time-sharing detection of the first wavelength polarized beam 521 and the second wavelength polarized beam 522 is achieved by rapidly moving the slit plate in the X direction.

[0062] A movable slit device is set in the imaging module, and a spectroscopic device is used to project the emitted light of different wavelengths to different slit positions, and the slit is moved to achieve time-sharing detection of different wavelengths. The switching of light of different wavelengths is moved from the laser emission position to the detector position, avoiding optical loss of the shading device.

[0063] Optional, continue to refer to Figure 3 The width of the slit 421 in the slit plate 420 is greater than the maximum wavelength of the dual-wavelength laser beam 500 and smaller than the deviation interval between the first wavelength polarized beam 521 and the second wavelength polarized beam 522 .

[0064] Exemplarily, the first direction and the second direction are the Y direction and the X direction perpendicular to each other, respectively, and the wavelength splitter 410 splits the second polarized laser beam 520 into a first wavelength polarized beam 521 and a second wavelength polarized beam 522 with different emission angles according to different wavelengths. The distance between the wavelength splitter 410 and the array photodetector 430 along the Y direction is adjusted so that the first wavelength polarized beam 521 and the second wavelength polarized beam 522 are irradiated on the array photodetector 430. The displacement control module 440 controls the slit plate 420 to move periodically along the X direction. The displacement control module 440 controls the slit plate 420 so that the first wavelength polarized light beam 521 coincides with the slit 421. At this time, only the first wavelength polarized light beam 521 passes through the slit 421 to irradiate the array photodetector 430, and the second wavelength polarized light beam 522 is blocked. Further, the displacement control module 440 controls the slit plate 420 so that the second wavelength polarized light beam 522 coincides with the slit 421. At this time, only the second wavelength polarized light beam 522 passes through the slit 421 to irradiate the array photodetector 430, and the first wavelength polarized light beam 521 is blocked.

[0065] The slit width is larger than the maximum wavelength of the dual-wavelength laser beam to ensure that light of different wavelengths can be incident for imaging and avoid diffraction. The slit width is smaller than the deviation distance between the first wavelength polarized beam and the second wavelength polarized beam to ensure that the two different wavelengths of light are imaged separately, so that the dual-wavelength imaging speed is the same as the single-wavelength imaging speed, ensuring imaging efficiency.

[0066] Optionally, the number of the array photodetectors 430 is at least 5. Specifically, at least tissue information at 5 different depths is collected.

[0067] Specifically, Figure 4 As shown, since the first polarized laser beam 510 diffuses and propagates along an arc path in the tissue, the farther the distance d between the array photodetector 430 and the first polarized laser beam 510 is, the deeper the depth h of the tissue information contained in the beam signal collected by the imaging system is. By placing multiple array photodetectors 430 in parallel at the same time, tissue information at multiple depths can be acquired simultaneously. In the embodiment of the present invention, different detection array elements of the array photodetector are arranged in parallel along the Y direction, and one of the array elements is placed at the center of the optical path at different distances from the center array element, so that tissue information at different depths can be acquired. In the embodiment of the present invention, the number of array photodetectors can be set to at least 5, such as Figure 4 As shown, the photodetector positions can be set to 431, 432, 433, 434, and 435, and five photodetectors at different distances from the first polarized laser beam 510 form an array photodetector 430 to detect tissue information at five different depths.

[0068] In the embodiment of the present invention, an array photodetector is used to detect and image dual wavelengths in the same array photodetector, thereby reducing the cost of the detection module and the requirements for data acquisition and processing speed.

[0069] Optionally, the array photodetector 430 is an image sensor composed of a linear array photomultiplier tube, an avalanche photodiode, a silicon photodiode, a CCD or a CMOS.

[0070] Among them, the photoelectric detector can be used to convert the optical signal into an electrical signal. The detection signal at different depths of the sample to be tested is different, and the absorption characteristics of different wavelengths at different depths in the sample to be tested are calculated.

[0071] Optionally, the dual wavelengths in the dual-wavelength laser beam 500 are 532 nm and 638 nm respectively.

[0072] Specifically, in the optical blood oxygen imaging system, the absorption characteristics of oxygenated hemoglobin (HbO2) and deoxygenated hemoglobin (Hb) in the blood can be used for imaging. Light with the peak wavelength of the characteristic absorption spectrum of HbO2 and Hb is incident on the sample to be tested 600, and the concentration changes of HbO2 and Hb can be analyzed to form a distribution diagram of blood oxygen concentration. The peak wavelength of the characteristic absorption spectrum of HbO2 is 532nm; the peak wavelength of the characteristic absorption spectrum of Hb is 638nm.

[0073] Exemplarily, in the optical blood oxygen imaging system, the wavelength laser output module 100 outputs a dual-wavelength laser beam 500 corresponding to the peak wavelengths of the characteristic absorption spectra of HbO2 and Hb, and the dual-wavelength laser beam includes two wavelengths of 532nm and 638nm. The dual-wavelength laser beam 500 enters the polarization beam splitting module 200, and the polarizer 220 in the polarization beam splitting module 200 polarizes the dual-wavelength laser beam 500 into P polarized light, and uses the P polarized light of the dual-wavelength laser beam 500 as the first polarized laser beam 510. At the same time, the first polarized laser beam 510 transmits the polarization beam splitter 230, and the first polarized laser beam 510 enters the xy scanning galvanometer 310 in the scanning detection module 300, and passes through the scanning lens 320 and the objective lens 330, and is focused on the imaging focal plane of the sample to be tested 600. The reflection direction of the first polarized laser beam 510 is changed by adjusting the angle of the xy scanning galvanometer 310, and the beam is focused on different points to be tested on the sample to be tested through the scanning lens 320 and the objective lens 330. The first polarized laser beam 510 forms an S polarized light perpendicular to the direction of the P polarized light according to the position to be detected, and the S polarized light is used as the second polarized laser beam 520. The reflected second polarized laser beam 520 passes through the analyzer 450 in the imaging module 400, and the analyzer 450 filters the incident P polarized light and only detects the S polarized light reflected and / or transmitted by the sample to be tested. The second polarized laser beam 520 is filtered by the analyzer 450, amplified by the imaging lens 460, and passes through the wavelength spectrometer 410. The wavelength spectrometer 410 splits the second polarized laser beam 520 into a first wavelength polarized beam 521 and a second wavelength polarized beam 522 with different exit angles according to different wavelengths. The wavelength of the first wavelength polarized beam 521 is 532 mm; the wavelength of the second wavelength polarized beam 522 is 638 mm. The distance between the wavelength spectrometer 410 and the array photodetector 430 along the Y direction is adjusted so that the first wavelength polarized beam 521 and the second wavelength polarized beam 522 are irradiated on the array photodetector 430. The displacement control module 440 controls the slit plate 420 to periodically move along the X direction. The displacement control module 440 controls the slit plate 420 so that the first wavelength polarized light beam 521 coincides with the slit 421. At this time, only the first wavelength polarized light beam 521 passes through the slit 421 to irradiate the array photodetector 430, and the second wavelength polarized light beam 522 is blocked. Further, the displacement control module 440 controls the slit plate 420 so that the second wavelength polarized light beam 522 coincides with the slit 421. At this time, only the second wavelength polarized light beam 522 passes through the slit 421 to irradiate the array photodetector 430, and the first wavelength polarized light beam 521 is blocked. The system outputs instructions through the control unit to make the displacement control module 440 reciprocate at high speed at the slit through which the first wavelength polarized light beam 521 passes and the slit through which the second wavelength polarized light beam 522 passes, and collects light intensity signals to transmit to the computer.The light signals collected at the two positions are stored in two wavelength signal storage units. A distribution map of blood oxygen concentration is formed in two-dimensional space. The computer realizes three-dimensional tomography of tissues based on the principle of diffuse light tomography, and realizes three-dimensional tomography of blood oxygen information through two wavelength signals, and analyzes the concentration changes of HbO2 and Hb.

[0074] Among them, the three-dimensional tomography of blood oxygen information calculation first needs to solve the absorption coefficient of the optical path at different depths of the sample tissue to be tested, and obtain the tomographic reconstruction map of the absorption coefficient of the sample tissue to be tested. The calculation formula is as follows:

[0075] ΔM n,m =J n,m (r)Δμ a (r)

[0076] Among them, ΔM n,m represents the slight change in the light intensity signal of the first wavelength polarized light beam 521 or the second wavelength polarized light beam 522 detected by the array photodetector 430; n and m are the number of light beams and photodetectors, respectively, r represents the position coordinate on the optical path, and J is the spatial sensitivity matrix, which represents the weight of the spatial position affecting the measurement result. Δμ a represents a small change in the absorption coefficient and is the parameter to be solved.

[0077] By iterative calculation, solve Δμ a The spatial distribution of is as follows:

[0078] Δμ a =J T (JJ T +αI) -1 ΔM

[0079] α is the regularization coefficient; I is the unit diagonal matrix, which is used to reduce the influence of noise on the reconstruction results during the solution of the inverse problem.

[0080] For dual wavelength incidence, the Δμ of the two wavelengths can be obtained a The concentration changes of HbO2 and Hb are analyzed from this, and the formula is as follows:

[0081]

[0082] Wherein, subscripts 1 and 2 represent two wavelengths, ε is the molar extinction coefficient, and ΔC is the change in hemoglobin concentration.

[0083] Therefore, based on the reconstruction of the absorption coefficient spatial image, the dual-wavelength incident light can further solve the tomographic distribution map of the changes in HbO2 and Hb concentrations.

[0084] The system scans the target sample 600 in two-dimensional space through the xy scanning galvanometer 310. Figure 5 As shown, 10 positions are scanned in each line in the X' direction and the Y' direction, and 10 lines are scanned. Each scanning position contains 5 detection depth information. Image reconstruction is performed in the depth direction. Combined with the two-dimensional scanning data, a three-dimensional tomographic distribution map of blood oxygen information can be obtained.

[0085] A tissue oxygen micro-tomography device provided in an embodiment of the present invention uses dual-wavelength lasers to simultaneously irradiate a sample to be tested, and controls the movement of a slit structure so that only one wavelength of light is irradiated onto the detector at the same time. The use of a single-row, multi-distance photoelectric detector is achieved to achieve the purpose of collecting tissue information at different depths by emitting light of different wavelengths in a time-sharing manner, and three-dimensional tomography of the tissue is achieved by analyzing the dual-wavelength signal. As a result, the cost of the detector in the tissue oxygen imaging system is reduced, and the requirements for high-speed data acquisition, transmission, and storage are also reduced. At the same time, the slit in the embodiment of the present invention is located at the front end of the array photodetector, and the outgoing light signal is attenuated by the system and tissue, and the signal intensity is greatly reduced, which will not cause damage to the device. In addition, the control of a single slit is simpler than that of a shutter, and it only needs to be reciprocated, which simplifies the tissue oxygen micro-tomography device while improving the imaging efficiency.

[0086] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0087] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A tissue oxygen micro-tomography device, characterized in that: include: A dual-wavelength laser output module, used for outputting a dual-wavelength laser beam; a polarization splitting module, located on the transmission path of the dual-wavelength laser beam, for polarizing the dual-wavelength laser beam to form a first polarized laser beam, and transmitting the first polarized laser beam; A scanning detection module, located on the transmission path of the first polarized laser beam, is used to reflect the first polarized laser beam to each to-be-detected position of the sample to be detected, the first polarized laser beam forms a second polarized laser beam after being acted upon by the to-be-detected position, the scanning detection module is also used to reflect the second polarized laser beam to the polarization splitting module, and the polarization splitting module is also used to reflect the second polarized laser beam to the imaging module; the polarization direction of the first polarized laser beam is perpendicular to the polarization direction of the second polarized laser beam; An imaging module is located on the transmission path of the second polarized laser beam, and the imaging module includes: a wavelength splitter, a slit plate, and an array photodetector sequentially arranged along the transmission path of the second polarized laser beam; and also includes a displacement control module for moving the slit plate; The wavelength splitter is used to separate the second polarized laser beam into a first wavelength polarized beam and a second wavelength polarized beam; the displacement control module is used to periodically control the slit in the slit plate to be located on the transmission path of the first wavelength polarized beam, or, located on the transmission path of the second wavelength polarized beam, so that the array photodetector successively images the first wavelength polarized beam and the second wavelength polarized beam; The scanning detection module comprises: an xy scanning galvanometer, a scanning lens and an objective lens arranged along the transmission path of the first polarized laser beam; The xy scanning galvanometer is used to receive the first polarized laser beam, and reflect the first polarized laser beam through the scanning lens and the objective lens in sequence to reach the sample to be tested; wherein the xy scanning galvanometer is used to change the reflection direction of the first polarized laser beam to change the first polarized laser beam to different positions to be tested of the sample to be tested.

2. The tissue oxygen micro-tomography device according to claim 1, characterized in that: The polarization beam splitting module comprises: a polarizer and a polarization beam splitter arranged in sequence along the transmission path of the dual-wavelength laser beam; The polarizer is used for polarizing the dual-wavelength laser beam to form a first polarized laser beam, and the polarization beam splitter is used for transmitting the first polarized laser beam.

3. The tissue blood oxygen micro-tomography imaging device according to claim 1, characterized in that: The imaging module also includes: an analyzer and an imaging lens located between the wavelength spectrometer and the polarization spectrometer module, the analyzer is used to pass the second polarized laser beam reflected by the polarization spectrometer module to the imaging lens, and the second polarized laser beam enters the wavelength spectrometer after passing through the imaging lens.

4. The tissue blood oxygen micro-tomography device according to claim 1 or 3, characterized in that: The wavelength splitter is a diffraction grating or a beam splitter prism.

5. The tissue blood oxygen micro-tomography imaging device according to claim 1, characterized in that: The array photodetector is a plurality of long strip photodetectors arranged along a first direction; the length direction of the slit of the slit plate extends along the first direction; the displacement control module controls the slit plate to move periodically along a second direction, and the first direction is perpendicular to the second direction.

6. The tissue blood oxygen micro-tomography imaging device according to claim 5, characterized in that: The number of the array photodetectors is at least 5.

7. The tissue blood oxygen micro-tomography device according to any one of claims 1, 5 or 6, characterized in that: The array photodetector is one of image sensors composed of linear array photomultiplier tubes, avalanche photodiodes, silicon photodiodes, CCDs or CMOS.

8. The tissue blood oxygen micro-tomography imaging device according to claim 1, characterized in that: The slit width in the slit plate is larger than the maximum wavelength of the dual-wavelength laser beam and smaller than the deviation interval between the first wavelength polarized beam and the second wavelength polarized beam.

9. The tissue blood oxygen micro-tomography imaging device according to claim 1, characterized in that: The dual wavelengths in the dual wavelength laser beam are 532 nm and 638 nm respectively.

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