A near-infrared brain oxygen detection system and method

Abstract

The present invention discloses a near-infrared brain oxygen detection system and method. The near-infrared brain oxygen detection system of the present invention has multiple detection units, which is conducive to improving the detection resolution. In addition, by staggering the near-infrared light source and the photoelectric sensor, the interference signal received is reduced to reduce the noise of the interference signal, which can effectively improve the accuracy and precision of the brain blood oxygen data, and overcome the technical problem of low data accuracy in the near-infrared spectrum brain oxygen detection system in the prior art. In addition, the near-infrared brain oxygen detection system adopts a producer / consumer mode in the data reading link and the data processing link, which can effectively improve the running efficiency of the program, thereby improving the acquisition speed of brain blood oxygen data and improving the real-time data acquisition.

Description

Technical Field

[0001] The present invention relates to the field of brain information collection, and in particular to a near-infrared brain oxygen detection system and method. Background Art

[0002] In recent years, as a new force in medical imaging technology, near-infrared spectroscopy (NIRS) is gradually being applied to the field of biomedicine and has now become a hot topic of research. The principle of NIRS imaging is the interaction between light and brain tissue. NIRS is based on the absorption spectra of the main chromophores in living tissues, combined with the propagation law of light in tissues, and uses the good penetrating ability of near-infrared light to study the information it carries when it is emitted after a series of absorption and scattering in tissues.

[0003] In addition, near-infrared spectroscopy has been widely used as a brain oxygen monitoring technology. This technology uses the relative transparency of the near-infrared frequency band to biological tissues and obtains changes in the concentrations of oxyhemoglobin and deoxyhemoglobin by detecting the optical properties of tissues. Compared with other technologies for monitoring cortical functional activities such as functional magnetic resonance imaging and electroencephalography, near-infrared spectroscopy technology can simultaneously have higher spatial resolution and temporal resolution. At the same time, near-infrared spectroscopy technology can monitor brain functional activities non-invasively and continuously, with a small device size and low detection cost. However, the known near-infrared spectroscopy brain oxygen detection system has the defect of low data accuracy, and therefore needs to be improved. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, one object of the present invention is to provide a near-infrared brain oxygen detection system for improving the accuracy of brain blood oxygen data.

[0005] To this end, a second object of the present invention is to provide a near-infrared brain oxygen detection method for quickly acquiring brain blood oxygen data.

[0006] The technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a near-infrared brain oxygen detection system, comprising a main control circuit, a light source driving circuit for driving a near-infrared light source, and a plurality of detection units, wherein the detection unit comprises a near-infrared light source and a photoelectric sensor, wherein the near-infrared light source can emit near-infrared light of two different wavelengths, wherein the output end of the photoelectric sensor is connected to the input end of the main control circuit, wherein the output end of the main control circuit is connected to the input end of the light source driving circuit, wherein the output end of the light source driving circuit is connected to the input end of the near-infrared light source, wherein the detection unit is used to emit near-infrared light to brain tissue and receive near-infrared light emitted after being scattered and refracted by the brain tissue, wherein the near-infrared light source and the photoelectric sensor are arranged in an alternating manner.

[0008] Furthermore, the brain tissue includes parietal lobe tissue and / or temporal lobe tissue.

[0009] Furthermore, the horizontal distance between the near-infrared light source and the photoelectric sensor ranges from 1.8 cm to 2.5 cm.

[0010] Furthermore, the horizontal spacing of the photoelectric sensors ranges from 3.6 cm to 4.8 cm.

[0011] Furthermore, the longitudinal spacing of the photoelectric sensors ranges from 2.8 cm to 3.2 cm.

[0012] Furthermore, the wavelength range of the near-infrared light emitted by the near-infrared light source is 760nm to 850nm.

[0013] Furthermore, the main control circuit includes a sub-main control circuit and a computer, the computer is connected to the sub-main control circuit, the output end of the sub-main control circuit is connected to the input end of the light source driving circuit, and the output end of the photoelectric sensor is connected to the input end of the sub-main control circuit.

[0014] Furthermore, the light source driving circuit includes a digital-to-analog conversion circuit and a voltage-to-current conversion circuit, the output end of the main control circuit is connected to the input end of the digital-to-analog conversion circuit, the output end of the digital-to-analog conversion circuit is connected to the input end of the voltage-to-current conversion circuit, and the output end of the voltage-to-current conversion circuit is connected to the input end of the near-infrared light source.

[0015] Furthermore, the light source driving circuit also includes a low-pass filter circuit, the output end of the digital-to-analog conversion circuit is connected to the input end of the low-pass filter circuit, and the output end of the low-pass filter circuit is connected to the input end of the voltage-current conversion circuit.

[0016] In a second aspect, the present invention provides a near-infrared brain oxygen detection method, which is applied to the near-infrared brain oxygen detection system, comprising:

[0017] Placing a detection unit in the brain to emit near-infrared light to the brain tissue, wherein the detection unit receives the near-infrared light emitted after being scattered and refracted by the brain tissue;

[0018] The main control circuit reads and processes the near-infrared light received by the detection unit to obtain cerebral blood oxygen data, wherein the cerebral blood oxygen data includes oxygenated hemoglobin concentration and / or deoxygenated hemoglobin concentration;

[0019] Among them, the software structure of the data reading link and the data processing link adopts the producer / consumer model.

[0020] The beneficial effects of the present invention are:

[0021] The near-infrared brain oxygen detection system of the present invention has multiple detection units, which is conducive to improving the detection resolution; in addition, by staggering the near-infrared light source and the photoelectric sensor, the interference signal received is reduced to reduce the noise of the interference signal, which can effectively improve the accuracy and precision of the brain blood oxygen data, and overcome the technical problem of low data accuracy in the near-infrared spectrum brain oxygen detection system in the prior art. In addition, the near-infrared brain oxygen detection system adopts a producer / consumer model in the data reading link and the data processing link, which can effectively improve the running efficiency of the program, thereby improving the acquisition speed of brain blood oxygen data and improving the real-time data acquisition.

[0022] In addition, the present invention can further improve the accuracy of cerebral blood oxygen data by using parietal lobe tissue and / or temporal lobe tissue as detection sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural block diagram of a specific embodiment of the near-infrared brain oxygen detection system of the present invention;

[0024] Figure 2 It is a schematic diagram of a specific embodiment of a headgear of a near-infrared brain oxygen detection system of the present invention;

[0025] Figure 3 It is a schematic diagram of another specific embodiment of the headgear of the near-infrared brain oxygen detection system of the present invention. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0027] Example 1

[0028] refer to Figure 1 , Figure 1: is a structural block diagram of a specific embodiment of the near-infrared brain oxygen detection system of the present invention; the near-infrared brain oxygen detection system includes a main control circuit, a light source driving circuit for driving a near-infrared light source, and a plurality of detection units. In this embodiment, the detection system has at least twenty detection units, and the detection units include a near-infrared light source and a photoelectric sensor. The near-infrared light source can emit near-infrared light of two different wavelengths, and the range of the two wavelengths is 760nm to 850nm. It is only necessary to ensure that different wavelengths are selected. The emission power ranges of the two wavelengths of light are 10mw-15mw and 10mw-18mw respectively; the plurality of detection units are used to emit near-infrared light to brain tissue and receive the near-infrared light scattered and refracted by the brain tissue. The near-infrared light emitted by the main control circuit is arranged in an interlaced manner with the near-infrared light source and the photoelectric sensor. Specifically, the output end of the main control circuit is connected to the input end of the light source driving circuit, and the output end of the light source driving circuit is connected to the input end of the near-infrared light source so that the near-infrared light source emits near-infrared light to the brain tissue, and the photoelectric sensor is responsible for detecting the near-infrared light signal emitted after scattering and refraction by the brain tissue. The output end of the photoelectric sensor is connected to the input end of the main control circuit to transmit the received near-infrared light signal to the main control circuit, wherein the main control circuit is used to complete data reading and shunting, demodulation and extraction of tissue hemodynamic information carried therein, brain blood oxygen data storage and display and other functions according to the near-infrared light signal received by the photoelectric sensor. In this embodiment, the main control circuit includes a sub-main control circuit and a computer, the sub-main control circuit is connected to the computer to receive the control instruction of the computer, the output end of the sub-main control circuit is connected to the input end of the light source driving circuit, and the output end of the photoelectric sensor is connected to the input end of the sub-main control circuit. Specifically, the sub-main control circuit includes a microcontroller, and the microcontroller adopts a USB microcontroller chip CY7C68013 to realize USB communication between the microcontroller and the computer.

[0029] The near-infrared brain oxygen detection system of the present invention has multiple detection units. The increase in the number of near-infrared light sources and photoelectric sensors is conducive to the overall improvement of the resolution of the detected part; by introducing the frequency division multiplexing technology and modulation and demodulation technology in the communication field, multi-channel synchronous detection is realized; in addition, by staggered arrangement and distribution of the near-infrared light source and the photoelectric sensor, the reception of interference signals is reduced to reduce the noise of the interference signals, which can effectively improve the accuracy and precision of cerebral blood oxygen data, and overcome the technical problem of low data accuracy in the near-infrared spectrum brain oxygen detection system in the prior art. Specifically, the signal of the near-infrared light source of the detection unit is encoded, and one photoelectric sensor receives the signal of one near-infrared light source corresponding to the encoding. The photoelectric sensor can filter out the interference signal according to different encodings to detect the near-infrared light emitted by the corresponding encoded near-infrared light source; coupled with the staggered arrangement and distribution of the near-infrared light source and the photoelectric sensor, the photoelectric sensor can further reduce the number of other encoded near-infrared light signals received by the photoelectric sensor to reduce the noise of the interference signal.

[0030] Furthermore, the near-infrared light source is implemented by a light-emitting diode (LED). Since the LED is a nonlinear device, directly driving the LED light source with a voltage signal will cause the light intensity signal emitted by the light source to be distorted. Therefore, in this embodiment, the light source driving circuit uses a current signal to drive the LED light source. Figure 1 The light source driving circuit includes a digital-to-analog conversion circuit, a low-pass filter circuit, and a voltage-to-current conversion circuit. The output end of the main control circuit is connected to the input end of the digital-to-analog conversion circuit, the output end of the digital-to-analog conversion circuit is connected to the input end of the low-pass filter circuit, the output end of the low-pass filter circuit is connected to the input end of the voltage-to-current conversion circuit, and the output end of the voltage-to-current conversion circuit is connected to the input end of the near-infrared light source. The digital-to-analog conversion circuit receives the control instruction (such as a digital frequency signal) output by the main control circuit to output the sinusoidal carrier signal required by the near-infrared light source, and then the low-pass filter circuit filters out the high-frequency noise generated by the power supply or other interference in the sinusoidal carrier signal. Finally, the voltage-to-current conversion circuit converts the voltage signal into a current signal to drive the near-infrared light source.

[0031] Furthermore, the brain tissue includes parietal lobe tissue and / or temporal lobe tissue. In this embodiment, the detection range of multiple detection units covers the area where the left and right parietal lobe tissues and part of the left and right temporal lobe tissues are located. By using the parietal lobe tissue and the temporal lobe tissue as the detection sites, the accuracy of the cerebral blood oxygen data can be further improved.

[0032] It is worth noting that the depth of brain oxygen detection is mainly determined by two parameters: wavelength and the distance between the light source and the photoelectric sensor. The distance between the light source and the photoelectric sensor determines whether the light can pass through the neural tissue: In general, the farther the distance between the light source and the photoelectric sensor, the deeper the detection. However, if the distance is too far, the light intensity reaching the photoelectric sensor will be too weak. The ideal distance is determined by the capillary depth and demographic parameters of the subject. For Chinese people, black skin and black hair absorb most wavelengths of light, so a shorter distance between the light source and the photoelectric sensor should be selected to increase the detected light intensity. In the standard human brain penetrating skull study, the path of light penetration is six times the distance between the light source and the photoelectric sensor. Therefore, it can be concluded that if the distance between the light source and the photoelectric sensor is too close, the detection depth will be too shallow to reach the cortical tissue. If the distance is too far, the near-infrared light emitted from the tissue will be attenuated too much and cannot be detected or the detected signal will have too much noise. Therefore, each pair of light sources and photoelectric sensors are staggered and the corresponding distance range is set. Specifically, the horizontal distance between the near-infrared light source and the photoelectric sensor ranges from 1.8cm to 2.5cm. The horizontal spacing range of the photoelectric sensors is 3.6cm to 4.8cm, and the vertical spacing range of the photoelectric sensors is 2.8cm to 3.2cm. In actual use, the photoelectric sensors and near-infrared light sources are set on the detection headgear. In order to make the system adapt to more test situations, the detection headgear needs to be easy to wear and minimize the interference to the subjects. At the same time, the detection headgear is also required to shield the ambient light and improve the signal-to-noise ratio of the detection signal. Figure 2 , Figure 2 It is a schematic diagram of a specific embodiment of the headgear of the near-infrared brain oxygen detection system of the present invention; in this embodiment, 20 light source-photoelectric sensor pairs, i.e., 20 detection channels, are arranged on the detection headgear D, and the near-infrared light source A and the photoelectric sensor B are arranged in an alternating manner. The spacing between the near-infrared light source A and the photoelectric sensor B is 2 cm, the horizontal spacing between the photoelectric sensors B is 4.2 cm, and the longitudinal spacing between the photoelectric sensors B is 3 cm. The detection area of ​​the detection headgear D is 15 cm × 8 cm, which can cover the left and right parietal lobes and part of the left and right temporal lobes of an adult's head. In addition, for the convenience of wearing, the detection headgear D is provided with ear hooks F on both sides, as well as a chin hanging ring E for fixing the headgear. The near-infrared light source A is selected to be realized by a two-color wavelength light-emitting diode, and the wavelengths of the light source are selected to be 760 nm and 850 nm, respectively, and the maximum emission powers of the two wavelengths of light are 15 mw and 18 mw, respectively. Finally, the photoelectric sensor is realized by a photodiode.

[0033] When the detection unit and the international electroencephalogram (EEG) positioning system are both present and set on the detection headset, refer to Figure 3 , Figure 3This is another specific embodiment of the headgear of the near-infrared brain oxygen detection system of the present invention. The EEG includes 64 brain electrodes C. In order to avoid cross-detection with the EEG, the near-infrared light source A and the photoelectric sensor B are placed near these brain electrodes to form corresponding channels of different lengths. Among them, the near-infrared light source A and the photoelectric sensor B cannot be set on the same straight line with the brain electrodes C to avoid interference caused by signal coupling.

[0034] Example 2

[0035] refer to Figure 1 and Figure 2 A near-infrared brain oxygen detection method, applied to the near-infrared brain oxygen detection system of Example 1, comprising:

[0036] The detection unit is placed in the left and right parietal lobes and part of the left and right temporal lobes of the brain to emit near-infrared light to the brain tissue, and the detection unit receives the near-infrared light emitted after being scattered and refracted by the brain tissue;

[0037] The main control circuit reads and processes the near-infrared light received by the detection unit to obtain cerebral blood oxygen data, where the cerebral blood oxygen data includes oxygenated hemoglobin concentration and / or deoxygenated hemoglobin concentration; wherein the method for performing data processing to obtain cerebral blood oxygen data adopts an existing data processing method, which will not be described in detail here;

[0038] It is worth noting that the software structure of the data reading and data processing links adopts the producer / consumer model.

[0039] In this embodiment, the data processing in the computer is implemented by LabVIEW software system, and the software structure adopts producer / consumer design mode. The two parallel While loops of the data reading link and the data processing link share the same cache queue. In the While loop of the data reading link, the data in the USB is read and written into the cache queue; in the while loop of the data processing link, the data in the cache queue is read and further processed. The advantage of this parallel multi-loop structure is that the data reading link does not need to wait until the data processing link is completed before the next reading, and the data processing link does not need to wait until the data reading link is completed to continuously process data. The application of this design mode can improve the running efficiency of the program, improve the real-time performance of the program, and then improve the acquisition speed of cerebral blood oxygen data and improve the real-time performance of data acquisition.

[0040] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A near-infrared brain oxygen detection system, characterized in that: It comprises a main control circuit, a light source driving circuit for driving a near-infrared light source, and a plurality of detection units, wherein the detection unit is a near-infrared light source-photoelectric sensor pair, wherein the near-infrared light source can emit near-infrared light of two different wavelengths, wherein the output end of the photoelectric sensor is connected to the input end of the main control circuit, wherein the output end of the main control circuit is connected to the input end of the light source driving circuit, wherein the output end of the light source driving circuit is connected to the input end of the near-infrared light source, wherein the detection unit is used to emit near-infrared light to brain tissue and receive near-infrared light emitted after being scattered and refracted by the brain tissue; wherein the plurality of detection units and the international electroencephalogram positioning system are arranged in a detection headgear for brain oxygen detection, wherein the international electroencephalogram positioning system comprises a plurality of brain electrodes, wherein the near-infrared light source and the photoelectric sensor are arranged near the brain electrodes, wherein the near-infrared light source and the photoelectric sensor are arranged in a staggered manner, wherein the near-infrared light source and the brain electrodes are not on the same straight line, wherein the photoelectric sensor and the brain electrodes are not on the same straight line; The detection area of ​​the detection head cover is 15cm×8cm; The brain tissue includes parietal lobe tissue and / or temporal lobe tissue; The horizontal distance between the near-infrared light source and the photoelectric sensor ranges from 1.8 cm to 2.5 cm; The horizontal spacing range of the photoelectric sensors is 3.6 cm to 4.8 cm; The longitudinal spacing of the photoelectric sensors ranges from 2.8 cm to 3.2 cm.

2. The near-infrared brain oxygen detection system according to claim 1, characterized in that: The light source driving circuit includes a digital-to-analog conversion circuit, a low-pass filtering circuit and a voltage-to-current conversion circuit. The output end of the main control circuit is connected to the input end of the digital-to-analog conversion circuit, the output end of the digital-to-analog conversion circuit is connected to the input end of the low-pass filtering circuit, the output end of the low-pass filtering circuit is connected to the input end of the voltage-to-current conversion circuit, and the output end of the voltage-to-current conversion circuit is connected to the input end of the near-infrared light source.

3. The near-infrared brain oxygen detection system according to claim 1, characterized in that: The wavelength range of the near infrared light emitted by the near infrared light source is 760nm to 850nm.

4. The near-infrared brain oxygen detection system according to claim 1, characterized in that: The main control circuit includes a sub-main control circuit and a computer, the computer is connected to the sub-main control circuit, the output end of the sub-main control circuit is connected to the input end of the light source driving circuit, and the output end of the photoelectric sensor is connected to the input end of the sub-main control circuit.

5. A near-infrared brain oxygen detection method, applied to the near-infrared brain oxygen detection system according to any one of claims 1 to 4, characterized in that: include: Placing a detection unit in the brain to emit near-infrared light to the brain tissue, wherein the detection unit receives the near-infrared light emitted after being scattered and refracted by the brain tissue; The main control circuit reads and processes the near-infrared light received by the detection unit to obtain cerebral blood oxygen data, wherein the cerebral blood oxygen data includes oxygenated hemoglobin concentration and / or deoxygenated hemoglobin concentration; Among them, the software structure of the data reading link and the data processing link adopts the producer / consumer mode. The software structure is a parallel multi-loop structure. The two parallel While loops of the data reading link and the data processing link share the same cache queue. In the While loop of the data reading link, the data in the USB is read and written into the cache queue; in the while loop of the data processing link, the data in the cache queue is read for processing.

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