Measuring device, measuring method, and program

Abstract

To provide a measurement device, a measurement method and a program that can measure an oxygen saturation degree based on a near infrared spectroscopy and a blood flow rate based on a diffusion correlation spectroscopy.SOLUTION: A measurement device comprises: a light transmission probe, in which first light generated by a first light source and second light generated by a second light source are switched to be input, and that irradiates a living body with the first light and the second light; a first light reception probe that is installed being apart from the light transmission probe, receives first reception first light from the living body for the first light with which the living body is irradiated, and receives first reception second light from the living body for the second light with which the living body is irradiated; a second light reception probe that is installed being apart from the light transmission probe and the first light reception probe, receives second reception first light from the living body for the first light with which the living body is irradiated, and receives second reception second light from the living body for the second light with which the living body is irradiated; and a second detection unit that detects a light amount on the basis of each of the first reception first light, the first reception second light, the second reception first light and the first reception second light.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a measuring device, a measuring method, and a program. [Background technology]

[0002] Near-infrared spectroscopy (NIRS) and diffusion correlation spectroscopy (DCS) are known as non-invasive optical measurement techniques for living organisms. Near-infrared spectroscopy is used to measure oxygen saturation by utilizing the fact that the degree to which near-infrared light is absorbed changes depending on the oxygenation state of hemoglobin. Diffusion correlation spectroscopy is used to measure blood flow velocity by utilizing the diffusion phenomenon of near-infrared light associated with the movement of red blood cells.

[0003] By simultaneously measuring oxygen saturation using near-infrared spectroscopy and blood flow using diffusion correlation spectroscopy, and combining the information, the oxygen metabolic rate in local tissues can be determined. A technique is known that can accurately measure the degree of light absorption in deep tissues of the human body, fruits, etc., by correcting for the influence of superficial tissues (see, for example, Patent Document 1). In this technique, the optical measuring device has a probe equipped with one light-emitting diode and two photodiodes. Of the light from the light-emitting diode, the light that has passed through the superficial and deep layers of the tissue is received by one photodiode, and the light that has passed through the superficial and deep layers of the tissue, but with a different passage distance through the deep layer than the light detected by the other photodiode, is received by the other photodiode. The control unit calculates the propagation constant in the medium through which the light propagates based on the light intensity of the light received by each photodiode. A calculation formula corresponding to the fat thickness of the input tissue is selected, and the light absorption coefficient of the muscle tissue is determined by the calculation formula based on the fat thickness and spatial slope. Based on the determined light absorption coefficient, the hemoglobin concentration and oxygen saturation are determined. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 5062698 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, conventional techniques for measuring deep tissue blood flow, oxygen saturation, and oxygen metabolic rate require separate measurement devices for near-infrared spectroscopy and diffusion correlation spectroscopy, resulting in large and expensive equipment that is unsuitable for dynamic measurements taken during exercise. The present invention has been made to solve the aforementioned problems and aims to provide a measuring device, a measuring method, and a program that can measure oxygen saturation measured by near-infrared spectroscopy and blood flow rate measured by diffusion correlation spectroscopy. [Means for solving the problem]

[0006] One embodiment of the present invention includes a first light source that generates first light having a first wavelength, a second light source that generates second light having a second wavelength different from the first wavelength, a light transmitting probe that switches between inputting the first light generated by the first light source 101 and the second light generated by the second light source 102 and irradiates a living organism with the first light and the second light, a first light receiving probe that is installed at a distance from the light transmitting probe and receives first received light, which is light from the living organism when the first light is irradiated onto the living organism, and receives first received light, which is light from the living organism when the second light is irradiated onto the living organism, and the light transmitting probe and the The measuring device comprises: a second light-receiving probe installed at a distance from the first light-receiving probe, which receives a second light-receiving first ray, which is light from the living body when the first light is irradiated onto the living body, and a second light-receiving second ray, which is light from the living body when the second light is irradiated onto the living body; a first detection unit which detects the first light-receiving first ray quantity based on the first light-receiving first ray received by the first light-receiving probe and detects the first light-receiving second ray quantity based on the first light-receiving second ray; and a second detection unit which detects the second light-receiving first ray quantity based on the second light-receiving first ray received by the second light-receiving probe and detects the second light-receiving second ray quantity based on the first light-receiving second ray. One embodiment of the present invention further comprises a deriving unit that derives oxygen saturation and blood flow velocity based on the first received first light quantity and the first received second light quantity detected by the first detection unit and the second received first light quantity and the second received second light quantity detected by the second detection unit, and derives tissue oxygen metabolic rate based on the derived oxygen saturation and blood flow velocity. In one embodiment of the present invention, the measuring device described above, the derivation unit derives a first received first light autocorrelation function and a second received first light autocorrelation function from the time changes of the first received first light quantity and the second received first light quantity, respectively, and derives a first received first light blood flow velocity and a second received first light blood flow velocity based on the derived first received first light autocorrelation function and the second received first light autocorrelation function, respectively, and derives a first received second light autocorrelation function and a second received second light autocorrelation function from the time changes of the first received second light quantity and the second received second light quantity, respectively, and derives a first received second light blood flow velocity and a second received second light blood flow velocity based on the derived first received second light autocorrelation function and the second received second light autocorrelation function, respectively. In one embodiment of the present invention, the measuring device described above, the derivation unit derives the first received first photoblood flow velocity and the second received first photoblood flow velocity using the first wavelength in the diffusion correlation equation, and derives the first received second photoblood flow velocity and the second received second photoblood flow velocity using the second wavelength. In one embodiment of the present invention, the measuring device described above derives the relative absorption coefficients at the first and second wavelengths based on the first received light quantity, the second received light quantity, the first received light quantity, and the second received light quantity, and derives the oxygen saturation based on the derived relative absorption coefficients. In one embodiment of the present invention, the measuring device described above derives the oxygen saturation based on the distance between the light transmitting probe and the first light receiving probe and the distance between the light transmitting probe and the second light receiving probe. In one embodiment of the present invention, the measuring device described above has a derivation unit that derives tissue oxygen saturation based on the oxygen saturation and derives tissue oxygen metabolic rate based on the blood flow velocity and the tissue oxygen saturation. One embodiment of the present invention further comprises a signal detection unit that detects a signal generated when the living body undergoes muscle contraction or muscle relaxation, wherein the first detection unit detects the first received light quantity and the first received light quantity based on the signal detected by the signal detection unit, and the second detection unit detects the second received light quantity and the second received light quantity based on the signal detected by the signal detection unit. One embodiment of the present invention further comprises a control unit that switches between inputting the first light generated by the first light source 101 and the second light generated by the second light source 102 to the light transmitting probe.

[0007] One embodiment of the present invention includes a first light source that generates first light having a first wavelength, a second light source that generates second light having a second wavelength different from the first wavelength, a light transmitting probe that switches between inputting the first light generated by the first light source 101 and the second light generated by the second light source 102 and irradiates the living body with the first light and the second light, a first light receiving probe that is installed at a distance from the light transmitting probe and receives first light receiving first light, which is light from the living body when the living body is irradiated with the first light, and receives first light receiving second light, which is light from the living body when the living body is irradiated with the second light, and irradiates the living body with the second light A measurement method performed by a measuring device comprising: a second light-receiving probe that receives a second light, which is light from the living organism, when the first light-receiving probe receives a first light, and a first detection unit that detects a first light quantity based on the first light received by the first light-receiving probe and detects a second light quantity based on the first light, and a second detection unit that detects a second light quantity based on the second light received by the second light-receiving probe and detects a second light quantity based on the first light, wherein the measurement method derives oxygen saturation and blood flow velocity based on the first light quantity and the first light quantity detected by the first detection unit and the second light quantity detected by the second detection unit, and derives tissue oxygen metabolic rate based on the derived oxygen saturation and blood flow velocity.

[0008] One embodiment of the present invention includes a first light source that generates first light having a first wavelength, a second light source that generates second light having a second wavelength different from the first wavelength, a light transmitting probe that switches between inputting the first light generated by the first light source 101 and the second light generated by the second light source 102 and irradiates the living body with the first light and the second light, a first light receiving probe that is installed at a distance from the light transmitting probe and receives first received light, which is light from the living body when the first light is irradiated onto the living body, and receives first received light, which is light from the living body when the second light is irradiated onto the living body, and a second light receiving probe that is installed at a distance from the light transmitting probe and the first light receiving probe and receives second received light, which is light from the living body when the first light is irradiated onto the living body, and irradiates the living body with the second light The computer of the measuring device comprises a second light-receiving probe that receives a second light, which is light from the living body when it is shone upon it; a first detection unit that detects the amount of first light received based on the first light received by the first light-receiving probe and detects the amount of second light received based on the second light received; and a second detection unit that detects the amount of first light received based on the second light received by the second light-receiving probe and detects the amount of second light received based on the second light received. The computer of the measuring device is programmed to derive oxygen saturation and blood flow velocity based on the first light amount and the first light amount detected by the first detection unit and the second light amount detected by the second detection unit, and to derive tissue oxygen metabolic rate based on the derived oxygen saturation and blood flow velocity. [Effects of the Invention]

[0009] According to embodiments of the present invention, a measuring device, a measuring method, and a program can be provided that can measure oxygen saturation measured by near-infrared spectroscopy and blood flow rate measured by diffusion correlation spectroscopy. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of a measuring device 100 according to an embodiment. [Figure 2] This figure shows an example of the operation of the measuring device 100 according to this embodiment. [Figure 3] This is a flowchart showing an example of the operation of the measurement apparatus 100 according to the present embodiment. [Figure 4] This is a diagram showing an example of a measurement apparatus 100a according to a modification of the embodiment. [Figure 5A] This is a diagram for explaining an example of the operation of the measurement apparatus 100a according to the modification of the embodiment. [Figure 5B] This is a diagram for explaining an example of the operation of the measurement apparatus 100a according to the modification of the embodiment. [Figure 6] This is a diagram for explaining spatially resolved spectroscopy. [Figure 7] This is a diagram showing an example of the relationship between wavelength and absorption coefficient. [Figure 8] This is a flowchart showing an example of the operation of the measurement apparatus 100a according to the modification of the embodiment. [Figure 9] This is a diagram showing an example of analysis timings of the measurement apparatus 100a according to the modification of the embodiment. [Figure 10] This is a diagram for explaining muscle contraction and relaxation. [Figure 11] This is a diagram showing an example of analysis timings of the measurement apparatus 100a according to the modification of the embodiment. [Figure 12] This is a diagram showing an example of a comparison of measurement results of the measurement apparatus 100a according to the modification of the embodiment. [Figure 13A] This is a diagram showing an example of measurement results of the measurement apparatus 100a according to the modification of the embodiment. [Figure 13B] This is a diagram showing an example of measurement results of the measurement apparatus 100a according to the modification of the embodiment. [Figure 13C] This is a diagram showing an example of measurement results of the measurement apparatus 100a according to the modification of the embodiment. [Figure 13D] This is a diagram showing an example of measurement results of the measurement apparatus 100a according to the modification of the embodiment. [Figure 14] This is a diagram showing an example of measurement results of the measurement apparatus 100a according to the modification of the embodiment. [Mode for Carrying Out the Invention]

[0011] Next, a measuring device, measuring method, and program according to an embodiment of the present invention will be described with reference to the drawings. The embodiments described below are merely examples, and the embodiments to which the present invention is applied are not limited to the embodiments described below. In all the figures used to illustrate the embodiments, components with the same function are given the same reference numerals, and repeated explanations are omitted. Furthermore, in this application, "based on XX" means "based on at least XX," and includes cases where it is based on another element in addition to XX. Also, "based on XX" is not limited to cases where XX is used directly, but also includes cases where it is based on something that has been calculated or processed from XX. "XX" is any element (for example, any information).

[0012] (Embodiment) (Measuring device) Hereinafter, a measuring device according to an embodiment of the present invention will be described with reference to the drawings. Figure 1 shows an example of a measuring device 100 according to an embodiment. The measuring device 100 includes a first light source 101, a second light source 102, a light transmitting probe 103, a first light receiving probe 104, a second light receiving probe 105, a first detection unit 106, a second detection unit 107, a control unit 108, and a probe holder PH. In the example shown in Figure 1, the light transmitting probe 103, the first light receiving probe 104, and the second light receiving probe 105 are attached to a biological surface (body surface) such as the forearm FA. The following description will continue with the case where the forearm FA is used as an example of a body surface. The light transmitting probe 103, the first light receiving probe 104, and the second light receiving probe 105 are fixed to the forearm FA by the probe holder PH.

[0013] The first light source 101 generates first light. An example of the first light source 101 is a near-infrared laser. A near-infrared laser generates electromagnetic waves (coherent light) in the region of wavelength 800 to 2500 nm and wavenumber 12500 to 4000 cm⁻¹. In this embodiment, the first light source 101 generates electromagnetic waves with a first wavelength λ1. The first wavelength λ1 is from 775 nm to 795 nm. The second light source 102 generates second light. An example of the second light source 102 is a near-infrared laser. In this embodiment, the second light source 102 generates electromagnetic waves with a second wavelength λ2. The second wavelength λ2 is between 820 nm and 840 nm. The control unit 108 switches the first light source 101 and the second light source 102 such that when the first light source 101 is on, the second light source 102 is turned off, and when the second light source 102 is on, the first light source 101 is turned off.

[0014] The light-transmitting probe 103 is connected to the first light source 101 and the second light source 102. The light-transmitting probe 103 receives the first light generated by the first light source 101 and the second light generated by the second light source 102, switching between them, and irradiates (inputs) the forearm FA with the first and second light. The first light-receiving probe 104 receives first light (hereinafter referred to as "first received light") which is input to the forearm FA from the light-transmitting probe 103 and is affected by at least one of absorption and diffusion by red blood cells. The first light-receiving probe 104 receives second light (hereinafter referred to as "first received light") which is input to the forearm FA from the light-transmitting probe 103 and is affected by at least one of absorption and diffusion by red blood cells. The first light-receiving probe 104 is attached to the forearm FA at a distance from the light-transmitting probe 103. For example, the first light-receiving probe 104 is attached to the forearm FA at a distance of 2 cm to 4 cm from the light-transmitting probe 103.

[0015] The second light-receiving probe 105 receives the first light (hereinafter referred to as "second received first light") which is input to the forearm FA from the light-transmitting probe 103 and is affected by at least one of absorption and diffusion by red blood cells. The second light-receiving probe 105 receives the second light ("second received second light") which is input to the forearm FA from the light-transmitting probe 103 and is affected by at least one of absorption and diffusion by red blood cells. The second light-receiving probe 105 is installed spaced apart from the light-transmitting probe 103 and the first light-receiving probe 104. For example, the first light-receiving probe 104 is attached to the forearm FA about 1 to 2 cm away from the light-transmitting probe 103 and about 1 to 2 cm away from the first light-receiving probe 104. In the example shown in Figure 1, the positions of the light-transmitting probe 103, the first light-receiving probe 104 and the second light-receiving probe 105 on the forearm FA are aligned in a straight line.

[0016] The first detection unit 106 is configured, for example, by a photon counter and is connected to the first light receiving probe 104. The first detection unit 106 detects the amount of light (hereinafter referred to as "first light amount") based on the first received light (first light amount) received by the first light receiving probe 104, and detects the amount of light (hereinafter referred to as "first light amount") based on the first received light (second light amount). The second detection unit 107 is configured, for example, by a photon counter and is connected to the second light receiving probe 105. The second detection unit 107 detects the amount of light (hereinafter referred to as "second light receiving first light amount") based on the second light received first light received by the second light receiving probe 105, and detects the amount of light (hereinafter referred to as "second light receiving second light amount") based on the second light received second light.

[0017] Figure 2 shows an example of the operation of the measuring device 100 according to this embodiment. Figure 2 shows an example of switching on and off the first light generated by the first light source 101 and the second light generated by the second light source 102, which are input to the light transmitting probe 103. The first light source 101 and the second light source 102 are switched on and off in a short time. When the first light source 101 is on, the second light source 102 is turned off, and when the second light source 102 is on, the first light source 101 is turned off. For example, the first light source 101 is turned on for 495 ms and then turned off. 5 ms after the first light source 101 is turned off, the second light source is turned on for 495 ms and then turned off. The process continues similarly thereafter. The following description will focus on a case where the irradiation time is 495 ms and the rest time is 5 ms. However, this is merely one example of this embodiment, and the respective time intervals for irradiation and rest can be changed as appropriate.

[0018] The light-transmitting probe 103 irradiates (inputs) the forearm FA with either the first light generated by the first light source 101 or the second light generated by the second light source 102. The position on the forearm FA irradiated by the first or second light is the same. The first light transmitted from the light-transmitting probe 103 to the forearm FA propagates through the epidermis and dermis ED, reaching the subcutaneous tissue ST and muscle MU. The first light that reaches the subcutaneous tissue ST is affected by at least one of absorption and diffusion by the red blood cells RBCs contained in the subcutaneous tissue ST. The first light that reaches the muscle MU is affected by at least one of absorption and diffusion by the red blood cells RBCs contained in the muscle MU. In Figure 2, the path of the first light diffused by the red blood cells RBCs is shown by the direction of the arrows. In Figure 2, the thinning of the line indicates that the first light is absorbed each time it hits a red blood cell RBC.

[0019] In the example shown in Figure 2, the first light-receiving probe 104 receives first light that includes at least one of the following: first light that is affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in subcutaneous tissue (ST), and first light that is affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in muscle (MU). The second light-receiving probe 105 receives second light-receiving first light which includes at least one of the first light that is affected by absorption and diffusion by red blood cells (RBCs) contained in subcutaneous tissue (ST) and the first light that is affected by absorption and diffusion by red blood cells (RBCs) contained in muscle (MU). The second light transmitted from the light-transmitting probe 103 to the forearm FA propagates through the epidermis and dermis ED, reaching the subcutaneous tissue ST and muscle MU. The second light that reaches the subcutaneous tissue ST is affected by at least one of absorption and diffusion by the red blood cells RBCs contained in the subcutaneous tissue ST. The second light that reaches the muscle MU is affected by at least one of absorption and diffusion by the red blood cells RBCs contained in the muscle MU. In Figure 2, the path of the second light diffused by the red blood cells RBCs is shown by the direction of the arrows. In Figure 2, the thinning of the line indicates that the second light is absorbed each time it hits a red blood cell RBC.

[0020] In the example shown in Figure 2, the first light-receiving probe 104 receives first-receiving second light which includes at least one of the second light that has been affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in the subcutaneous tissue (ST), and second light that has been affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in the muscle (MU). The second light-receiving probe 105 receives a second light that includes at least one of the following: a second light affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in the subcutaneous tissue (ST), and a second light affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in the muscle (MU).

[0021] (Operation of the measuring device) Figure 3 shows an example of the operation of the measuring device 100 according to this embodiment. (Step S1-1) The first light source 101 generates first light under the control of the control unit 108. (Step S2-1) The first light generated by the first light source 101 is input to the light transmitting probe 103. (Step S3-1) The light-transmitting probe 103 transmits the first light input from the first light source 101 to the forearm FA. (Step S4-1) The second light-receiving probe 105 receives second light-receiving first light which includes at least one of the first light that is affected by absorption and diffusion by red blood cells (RBCs) contained in subcutaneous tissue (ST) and the first light that is affected by absorption and diffusion by red blood cells (RBCs) contained in muscle (MU).

[0022] (Step S5-1) The second received first light, received by the second light receiving probe 105, is input to the second detection unit 107. (Step S6-1) The second detection unit 107 detects the second received first light quantity based on the second received first light input from the second light receiving probe 105. (Step S7-1) The first light-receiving probe 104 receives first light that includes at least one of the following: first light that has been affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in subcutaneous tissue (ST), and first light that has been affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in muscle (MU). (Step S8-1) The first light received by the first light receiving probe 104 is input to the first detection unit 106. (Step S9-1) The first detection unit 106 detects the first amount of first received light based on the first received light input from the first light receiving probe 104.

[0023] (Step S10-1) The second light source 102 generates second light under the control of the control unit 108. (Step S11-1) The second light generated by the second light source 102 is input to the light transmitting probe 103. (Step S12-1) The light-transmitting probe 103 transmits the second light input from the second light source 102 to the forearm FA. (Step S13-1) The second light-receiving probe 105 receives second light that includes at least one of the following: second light that is affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in subcutaneous tissue (ST), and second light that is affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in muscle (MU).

[0024] (Step S14-1) The second light received by the second light receiving probe 105 is input to the second detection unit 107. (Step S15-1) The second detection unit 107 detects the second amount of second received light based on the second received light input from the second light receiving probe 105. (Step S16-1) The first light-receiving probe 104 receives first-receiving second light which includes at least one of the second light that has been affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in the subcutaneous tissue (ST), and second light that has been affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in the muscle (MU). (Step S17-1) The first received second light, received by the first light receiving probe 104, is input to the first detection unit 106. (Step S18-1) The first detection unit 106 detects the amount of the first received second light based on the first received second light input from the first light receiving probe 104. The process then returns to step S1-1 and is repeated.

[0025] In the embodiments described above, an example was described in which the first and second lights are input to the forearm FA, but the invention is not limited to this example. For example, the first and second lights may be input to any muscle tissue of a living body, such as the thigh. In the embodiments described above, an example was described in which the measuring device 100 comprises a first light-receiving probe 104 and a second light-receiving probe 105. However, the invention is not limited to this example. For example, the measuring device 100 may be equipped with three or more light-receiving probes. According to the measuring device 100 of this embodiment, the first light generated by the first light source 101 and the second light generated by the second light source 102 are switched and input (irradiated) to the light transmitting probe 103, and the light transmitting probe 103 inputs either the first light or the second light to the same location (range) in the muscle tissue. The first light-receiving probe 104 can receive first light-receiving light that includes at least one of the first light that is affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in subcutaneous tissue (ST), and first light that is affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in muscle (MU). The first light-receiving probe 104 can receive first-receiving second light which includes at least one of the second light that has been affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in subcutaneous tissue (ST), and the second light that has been affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in muscle (MU). The first detection unit 106 can detect the first amount of first received light based on the first received light received by the first light receiving probe 104, and can detect the first amount of second received light based on the first received second light.

[0026] The second light-receiving probe 105 can receive a second light-receiving first light which includes at least one of the first light that is affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in the subcutaneous tissue (ST), and the first light that is affected by at least one of absorption and diffusion by red blood cells (RBCs) contained in the muscle (MU). The second light-receiving probe 105 can receive a second light-receiving light that includes at least one of the second light affected by absorption and diffusion by red blood cells (RBCs) contained in the subcutaneous tissue (ST), and the second light affected by absorption and diffusion by red blood cells (RBCs) contained in the muscle (MU). The second detection unit 107 can detect the second received first light quantity based on the second received first light received by the second light receiving probe 105, and can detect the first received second light quantity based on the second received second light.

[0027] By configuring the system in this way, the light-transmitting probe 103 for inputting the first light from the first light source 101 and the second light from the second light source 102 into the muscle tissue can be shared. This allows for miniaturization and cost reduction compared to the case where separate light-transmitting probes are provided for inputting the first light from the first light source 101 and the second light from the second light source 102 into the muscle tissue. Furthermore, the first and second lights can be input to the same area of ​​the subject's muscle tissue. Therefore, the first and second light levels can be detected when the first and second lights are input to the same area of ​​the subject's muscle tissue.

[0028] (Modified version of the embodiment) Figure 4 shows an example of a measuring device according to a modified embodiment. The measuring device 100a according to the modified embodiment is equipped with a function to derive blood flow velocity, oxygen saturation, and tissue oxygen metabolic rate from the measuring device 100. The measuring device 100a comprises a first light source 101, a second light source 102, a light transmitting probe 103, a first light receiving probe 104, a second light receiving probe 105, a first detection unit 106, a second detection unit 107, a control unit 108, a probe holder PH, and an information processing device 110. The information processing device 110 derives blood flow velocity, relative concentration and oxygen saturation, and tissue oxygen metabolic rate.

[0029] The information processing device 110 is implemented by a device such as a personal computer, server, smartphone, tablet computer, or industrial computer. The information processing device 110 comprises a data acquisition unit 112, an output unit 114, an output unit 116, a signal detection unit 117, and a storage unit 118. The data acquisition unit 112 collects data. For example, the data acquisition unit 112 collects information indicating the first received light intensity and information indicating the first received light intensity detected by the first detection unit 106, and information indicating the second received light intensity and information indicating the second received light intensity detected by the second detection unit 107. As another example, the data acquisition unit 112 may have an operating unit such as a keyboard and a mouse. In this case, the data acquisition unit 112 inputs information corresponding to the operations performed by the user on the operating unit. As yet another example, the data acquisition unit 112 may input information from an external device. This external device may be, for example, a portable storage medium. In this case, the data acquisition unit 112 receives information indicating the first received first light quantity and information indicating the first received second light quantity, and information indicating the second received first light quantity and information indicating the second received second light quantity.

[0030] The derivation unit 114 acquires information indicating the first received light intensity and information indicating the second received light intensity from the data acquisition unit 112. The derivation unit 114 derives the blood flow velocity based on the acquired information indicating the first received light intensity and information indicating the second received light intensity. For example, the output unit 114 derives blood flow velocity by diffusion correlation spectroscopy. Diffusion correlation spectroscopy is a method for measuring tissue peripheral blood flow dynamics using the scattering of near-infrared light. In other words, diffusion correlation spectroscopy derives blood flow velocity by utilizing the diffusion phenomenon of near-infrared light associated with the movement of red blood cells. Diffusion correlation spectroscopy has several advantages, including the ability to adjust the measurement depth from the skin to deep tissue by changing the distance between probes, non-invasiveness, ease of measurement, minimal restrictions on body movement, high temporal resolution, and the ability to measure peripheral blood flow in any tissue. For example, the derivation unit 114 derives an autocorrelation function (hereinafter referred to as the "first received first light autocorrelation function") from the time change of the first received first light quantity. Based on the derived first received first light autocorrelation function, the derivation unit 114 derives the blood flow velocity (hereinafter referred to as the "first received first light blood flow velocity"). The derivation unit 114 derives an autocorrelation function (hereinafter referred to as the "second-received first light autocorrelation function") from the time change of the second-received first light intensity. Based on the derived second-received first light autocorrelation function, the derivation unit 114 derives the blood flow velocity (hereinafter referred to as the "second-received first light blood flow velocity").

[0031] Furthermore, the derivation unit 114 acquires information indicating the first received second light intensity and information indicating the second received second light intensity from the data acquisition unit 112. The derivation unit 114 derives the blood flow velocity based on the acquired information indicating the first received second light intensity and information indicating the second received second light intensity. For example, the derivation unit 114 derives the blood flow velocity by diffusion correlation spectroscopy. For example, the derivation unit 114 derives an autocorrelation function (hereinafter referred to as the "first-received-second-light autocorrelation function") from the time change of the first-received-second-light amount. Based on the derived first-received-second-light autocorrelation function, the derivation unit 114 derives the blood flow velocity (hereinafter referred to as the "second-received-second-light blood flow velocity"). The derivation unit 114 derives an autocorrelation function (hereinafter referred to as the "second light-receiving second light autocorrelation function") from the time change of the second light-receiving second light quantity. Based on the derived second light-receiving second light autocorrelation function, the derivation unit 114 derives the blood flow velocity (hereinafter referred to as the "second light-receiving second light blood flow velocity"). Specifically, the derivation unit 114 derives the light intensity I(t) from information indicating the amount of light (information indicating the first light intensity of the first reception, information indicating the first light intensity of the second reception, information indicating the second light intensity of the first reception, and information indicating the second light intensity of the second reception). The derivation unit 114 then obtains the autocorrelation function g2(τ) from the derived light intensity I(t) and derives the blood flow velocity from the slope of the obtained autocorrelation function g2(τ).

[0032] Furthermore, the derivation unit 114 derives the light intensity I(t) from the time change of the first received light quantity, and derives an autocorrelation function (hereinafter referred to as the "first received light first autocorrelation function") from the derived light intensity I(t). Based on the derived first received light first autocorrelation function, the derivation unit 114 derives the blood flow velocity (hereinafter referred to as the "first received light first blood flow velocity"). The derivation unit 114 derives the light intensity I(t) from the time change of the second received first light quantity, and derives the autocorrelation function (hereinafter referred to as the "second received first light autocorrelation function") from the derived light intensity I(t). Based on the derived second received first light autocorrelation function, the derivation unit 114 derives the blood flow velocity (hereinafter referred to as the "second received first light blood flow velocity").

[0033] The derivation unit 114 derives the light intensity I(t) from the time change of the first received second light quantity, and derives an autocorrelation function (hereinafter referred to as the "first received second light autocorrelation function") from the derived light intensity I(t). Based on the derived first received second light autocorrelation function, the derivation unit 114 derives the blood flow velocity (hereinafter referred to as the "first received second light blood flow velocity"). The derivation unit 114 derives the light intensity I(t) from the time change of the second received light quantity, and derives the autocorrelation function (hereinafter referred to as the "second received light second autocorrelation function") from the derived light intensity I(t). Based on the derived second received light second autocorrelation function, the derivation unit 114 derives the blood flow velocity (hereinafter referred to as the "second received light second blood flow velocity").

[0034] Figures 5A and 5B illustrate an example of the operation of a measuring device according to a modified embodiment. Here, as an example, we will explain what happens after the light intensity I(t) is derived from information indicating the amount of light. When the flow velocity is zero, the number of photons does not change, and therefore the light intensity I(t) also does not change. For this reason, the autocorrelation function g2(τ) remains constant at a high value. Figure 5A shows the case where the flow velocity is slow. In this case, the change in the number of photons is small, so the change in light intensity I(t) is also small. Therefore, the slope of the autocorrelation function g2(τ) becomes smoother, and the blood flow velocity slows down. Figure 5B shows the case where the flow velocity is high. In this case, the change in the number of photons is large, so the change in light intensity I(t) is also large. Therefore, the slope of the autocorrelation function g2(τ) becomes steeper, and the blood flow velocity increases.

[0035] Furthermore, if we denote the autocorrelation function derived by the derivation unit 114 as G2(τ), then the autocorrelation function G2(τ) can be expressed as shown in equation (1).

number

number

number

[0036] k included in equation (3) D It can be expressed as shown in equation (4).

number

[0037] When the derivation unit 114 obtains information indicating the first received light intensity and information indicating the second received light intensity from the data acquisition unit 112, it inputs the wavelength λ1 of the first light into equation (4) and calculates αD B By deriving the following, the first photon-receiving first photoblood flow velocity and the second photon-receiving first photoblood flow velocity are derived, respectively. When the derivation unit 114 obtains information indicating the first received second light quantity and information indicating the second received second light quantity from the data acquisition unit 112, it inputs the wavelength λ2 of the second light into equation (4) and calculates αD B By deriving the following, the first-receiving second-photon blood flow velocity and the second-receiving second-photon blood flow velocity are derived, respectively.

[0038] Furthermore, the output unit 114 measures tissue oxygen dynamics (hemoglobin concentration) by near-infrared spectroscopy. Near-infrared spectroscopy is a method of measuring tissue oxygen dynamics using near-infrared absorption. In the modified embodiment, we will continue the explanation of the case where relative concentration and oxygen saturation are applied as an example of tissue oxygen dynamics. The derivation unit 114 derives relative concentration and oxygen saturation based on the acquired information indicating the first received light intensity, the second received light intensity, the first received light intensity, and the second received light intensity. Here, we will explain a method for measuring tissue oxygen dynamics using near-infrared light absorption. Known methods for measuring tissue oxygen dynamics include the MBL (Modified Beer-Lambert) method, time-resolved spectroscopy (TRS), and spatially resolved spectroscopy (SRS).

[0039] The MBL method uses continuous light as a light source and calculates the change in density from the detected light intensity. The MBL method requires information on the optical path length for quantification. Time-resolved spectroscopy is a method that uses short-pulse light of 1 ns or less as a light source and calculates the absolute concentration and oxygen saturation from the temporal spread at the light-receiving point. Spatial-resolved spectroscopy is a method that uses continuous light as a light source and calculates relative concentration and oxygen saturation from the difference in the amount of light detected at two light-receiving points. Figure 6 is a diagram illustrating spatially resolved spectroscopy. The interprobe distance between the light-transmitting probe 103 and the first light-receiving probe 104 is denoted as ρ1, and the interprobe distance between the light-transmitting probe 103 and the second light-receiving probe 105 is denoted as ρ2. In spatially resolved spectroscopy, the relative concentration and oxygen saturation are calculated from the difference between the detected light intensity at the first light-receiving probe 104 and the detected light intensity at the second light-receiving probe 105. In a modified embodiment, as an example, the case in which relative concentration and oxygen saturation are calculated by spatially resolved spectroscopy will be described. In this case, the derivation unit 114 derives the relative absorption coefficients at the first and second wavelengths based on the first received light quantity, the second received light quantity, the first received light quantity, and the second received light quantity, and derives the oxygen saturation based on the derived relative absorption coefficients.

[0040] The detected light intensity A(ρ) is expressed as shown in equation (5).

number

number

[0041] The relative absorption coefficient is expressed as in Equation (7). [Formula] The relative absorption coefficient is expressed as in Equation (8). [Formula] Here, [Formula] is.

[0042] Figure 7 is a diagram showing an example of the relationship between wavelength and absorption coefficient. In Figure 7, the horizontal axis represents wavelength [nm], and the vertical axis represents absorption coefficient [cm -1 mM -1 . Figure 7 shows the relationship between wavelength and absorption coefficient for hemoglobin (Hb) and oxyhemoglobin (HbO2). According to Figure 7, it can be seen that the absorption coefficient of hemoglobin (Hb) and the absorption coefficient of oxyhemoglobin (HbO2) are equal near the wavelength of 800 nm. It can also be seen that on the shorter wavelength side than about 800 nm, the absorption coefficient of hemoglobin (Hb) is larger than the absorption coefficient of oxyhemoglobin (HbO2). Further, it can be seen that on the longer wavelength side than about 800 nm, the absorption coefficient of oxyhemoglobin (HbO2) is larger than the absorption coefficient of hemoglobin (Hb).

[0043] The tissue oxygen saturation StO2 is expressed as in Equation (9). [Formula] In Equations (5) to (9), ρ is the inter-probe distance, and μs ' is the decay scattering coefficient, μ a λ is the absorption coefficient, k is the proportionality constant, h is the slope of the linear regression of the decay scattering coefficient, λ is the wavelength, Coxy is the relative oxygenated hemoglobin concentration, Cdeoxy is the relative deoxygenated hemoglobin concentration, and ε is the molecular extinction coefficient of hemoglobin.

[0044] The derivation unit 114 acquires information indicating the first received light intensity, information indicating the second received light intensity, information indicating the second received light intensity, and information indicating the second received light intensity from the data acquisition unit 112. Based on the acquired information indicating the first received light intensity, information indicating the second received light intensity, information indicating the second received light intensity, and information indicating the second received light intensity, the derivation unit 114 uses the interprobe distances ρ1 and ρ2 to derive the relative absorption coefficients for the wavelengths λ1 of the first and second light, respectively. The derivation unit 114 solves the simultaneous equations of the two derived relative absorption coefficients to derive the relative concentration in equation (9), and uses the solution to derive the oxygen saturation expressed in equation (10).

[0045] The derivation unit 114 derives the relative metabolic rate of oxygen (rMRO2) based on the derived blood flow velocity index and relative concentration / oxygen saturation. For example, the derivation unit 114 derives the relative metabolic rate of oxygen (rMRO2) from equation (10).

number

[0046] The output unit 116 obtains the tissue oxygen metabolic rate (rMRO2) from the derivation unit 114 and outputs the obtained tissue oxygen metabolic rate (rMRO2). For example, the output unit 116 may output by voice or by displaying on a display unit (not shown). In addition to the tissue oxygen metabolic rate (rMRO2), or instead of the tissue oxygen metabolic rate (rMRO2), the output unit 116 may output either or both of the blood flow velocity index (BFI) and relative concentration / oxygen saturation.

[0047] All or part of the data acquisition unit 112, the derivation unit 114, the output unit 116, and the signal detection unit 117 are functional units (hereinafter referred to as software functional units) that are realized by a processor such as a CPU (Central Processing Unit) executing a program stored in the memory unit 118. Furthermore, all or part of the data acquisition unit 112, the derivation unit 114, the output unit 116, and the signal detection unit 117 may be implemented by hardware such as an LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), or FPGA (Field-Programmable Gate Array), or by a combination of software functions and hardware.

[0048] (Operation of the measuring device) Figure 8 shows an example of the operation of a measuring device 100a according to a modified embodiment. The operation from the second detection unit 107 detecting the second received first light quantity and the second received second light quantity, to the first detection unit 106 detecting the first received first light quantity and the first received second light quantity, is the same as in Figure 3. However, the first detection unit 106 detects the first received first light quantity and the first received second light quantity after a predetermined time has elapsed since detecting an artifact triggered by an artifact in the analog signal detected by the signal detection unit 117. The second detection unit 107 detects the second received first light quantity and the second received second light quantity after a predetermined time has elapsed since detecting an artifact triggered by an artifact in the analog signal detected by the signal detection unit 117. This section describes the operation after the second detection unit 107 detects the second received first light quantity and the second received second light quantity, and the first detection unit 106 detects the first received first light quantity and the first received second light quantity. (Step S1-2) The second detection unit 107 detects the second received first light quantity based on the second received first light from the second light receiving probe 105. (Step S2-2) The first detection unit 106 detects the first amount of first received light based on the first received light from the first light receiving probe 104. (Step S3-2) The data acquisition unit 112 collects information indicating the second received first light quantity detected by the second detection unit 107.

[0049] (Step S4-2) The data acquisition unit 112 collects information indicating the first light intensity of the first light received, which is detected by the first detection unit 106. (Step S5-2) The output unit 114 acquires information indicating the second received first light quantity from the data acquisition unit 112. (Step S6-2) The derivation unit 114 acquires information indicating the first received light intensity from the data acquisition unit 112. (Step S7-2) The second detection unit 107 detects the second amount of second received light based on the second received light from the second light receiving probe 105.

[0050] (Step S8-2) The first detection unit 106 detects the first received 21st light quantity based on the first received 2nd light from the first light receiving probe 104. (Step S9-2) The data acquisition unit 112 collects information indicating the second light intensity of the second received light detected by the second detection unit 107. (Step S10-2) The data acquisition unit 112 collects information indicating the first received second light quantity detected by the first detection unit 106. (Step S11-2) The derivation unit 114 acquires information indicating the second received light quantity from the data acquisition unit 112. (Step S12-2) The derivation unit 114 acquires information indicating the first received second light quantity from the data acquisition unit 112.

[0051] (Step S13-2) The derivation unit 114 inputs the wavelength λ1 of the first light into equation (4) based on the acquired information indicating the first received light intensity, and αD B By deriving the first received first photoblood flow velocity index, the first light received first photoblood flow velocity index is derived. Based on the acquired information indicating the second received first light quantity, the derivation unit 114 inputs the wavelength λ1 of the first light into equation (4) and αD B By deriving this, the second photon-first photon blood flow velocity index is derived. The derivation unit 114 inputs the wavelength λ2 of the second light into equation (4) based on the acquired information indicating the first received second light quantity, and αD B By deriving the first received second photoblood flow velocity index, the first received second photoblood flow velocity index is derived. Based on the acquired information indicating the second received second light quantity, the derivation unit 114 inputs the wavelength λ2 of the second light into equation (4) and αD B By deriving this, the second photon-receiving second photon blood flow velocity index is derived. (Step S14-2) The derivation unit 114 acquires information indicating the first received light intensity, information indicating the second received light intensity, information indicating the first received light intensity, and information indicating the second received light intensity from the data acquisition unit 112. Based on the acquired information indicating the first received light intensity, information indicating the second received light intensity, information indicating the first received light intensity, and information indicating the second received light intensity, the derivation unit 114 derives the oxygen saturation.

[0052] (Step S15-2) The output unit 114 derives the tissue oxygen metabolic rate rMRO2 based on one of the derived first photoreceiving first photoblood flow velocity index, second photoreceiving first photoblood flow velocity index, first photoreceiving second photoblood flow velocity index, and second photoreceiving second photoblood flow velocity index, along with oxygen saturation. (Step S16-2) The output unit 116 obtains blood flow velocity index, relative concentration, oxygen saturation, and tissue oxygen metabolic rate (rMRO2) from the output unit 114. (Step S17-2) The output unit 116 outputs the acquired blood flow velocity index, relative concentration, oxygen saturation, and tissue oxygen metabolic rate (rMRO2). The process then returns to step S1-2 and is repeated.

[0053] An example of the application of the measuring device 100a will be described. As an example, the case of measuring the tissue oxygen metabolic rate (rMRO2) of the forearm FA during exercise will be described. Figure 9 shows an example of the analysis timing of a measuring device according to a modified embodiment. Figure 9 shows the on / off timing of the first light source 101 and the second light source 102, the timing of muscle contraction and relaxation of the forearm FA detected by the signal detection unit 117 using analog signals, and the blood flow velocity. MA shown for blood flow velocity is a change in blood flow (motion artifact) caused by the deformation of blood vessels due to the physical movement of the muscle, and is not a change in physiological blood flow. An example of the analysis range is the period from when the first light source 101 is turned on, turned off, and then turned on again. In other words, it is the period from when the second light source 102 is turned off, turned on, and then turned off again.

[0054] Figure 10 is a diagram illustrating muscle contraction and relaxation. In Figure 10, the left diagram shows muscle contraction, and the right diagram shows muscle relaxation. Blood flow changes as the forearm (FA) contracts and relaxes. This change in blood flow is not physiological. When muscles contract, capillaries are compressed, so blood flow velocity increases at the start of contraction as blood is pushed out of the vessels, but then decreases as blood inflow is inhibited. Conversely, when muscles relax, the compression of capillaries is removed, and stagnant blood flows into the vessels as relaxation begins, increasing blood flow velocity. After that, the velocity increases or decreases physiologically due to the innervation of the blood vessels by nerves and humoral factors. Return to Figure 9 and continue the explanation. The measuring device 100a performs a 1-second analysis at the timing after the consecutive on-off of the first light source 10 and the second light source 102, as shown in the analysis time range (1) to analysis time range (6) when the subject is at rest. During exercise, the measuring device 100a records changes in momentum (grip strength, pressure, tension) as analog signals. The measuring device 100a determines the timing for analysis based on the analog signals and the on-off timing of the first light source 101 and the second light source 102. Specifically, when the timing of blood flow velocity measurements is switched, motion noise is introduced, and during muscle contraction, tremors and other phenomena occur, making it difficult to observe physiological responses. Therefore, measurements (analysis) for one second are performed in a natural vasodilation / constriction state after relaxation, where motion noise is minimal, and at a timing immediately following the continuous switching on of the first light source 101 and the second light source 102. In Figure 9, this corresponds to analysis time range (4) to analysis time range (6).

[0055] Figure 11 shows an example of the analysis timing of the measuring device 100a according to a modified embodiment. In Figure 11, the horizontal axis is time [s] and the vertical axis is blood flow velocity index (BFI). The figures show the case without a trigger, with a trigger during contraction, and with a trigger during relaxation. Figure 11 shows an example of simultaneous measurement of blood flow dynamics and oxygen dynamics in the gastrocnemius (calf) muscle. The measurement was performed after a 2-minute heel-raising / lowering exercise using maximum voluntary contraction force. After the measurement, the blood flow index (BFI) was calculated during muscle relaxation and relaxation based on the analog signals from the pressure sensor. Figure 11 shows that without a trigger, the variability of BFI is greater compared to when the trigger is during contraction or during relaxation. When triggering during contraction or relaxation, motion artifacts caused by the movement of muscle tissue can be reduced compared to when there is no trigger. Triggering during contraction and relaxation allows for more accurate blood flow velocity calculation in measurements where the activity of the target muscle can be separated into relaxation / contraction phases. In other words, it is possible to detect blood flow velocity at specific phases of muscle movement using analog signals such as grip strength or pressure as trigger timing.

[0056] Figure 12 shows an example of a comparison of measurement results from a measurement device 100a according to a modified embodiment. The oxygen metabolic rate rMRO2 derived by the measurement device 100a was compared with the oxygen metabolic rate rVO2 derived by the NIRS method. The subjects were two adult males and three adult females (age 22.3 ± 0.37 years) with no muscle injury in the forearm FA. The measurement site was the superficial flexor muscles of the non-dominant hand. Maximum grip strength (MVC) was 38.0 ± 4.0 kg for the males and 19.3 ± 3.3 kg for the females. The measured indices were blood flow velocity index (BFI), oxygenated hemoglobin concentration (OxyHb), oxygen saturation (StO2), oxygen uptake rate (rOEF), and oxygen metabolic rate (rMRO2).

[0057] Figure 12 shows an example of a measurement protocol. Tests were conducted using methods (1) and (2). Method (1) is a 6-minute rest test. In Method (1), the minimum value of oxygenated hemoglobin concentration (OxyHb) at the time of tourniquet application was defined as 0, and the average value of oxygenated hemoglobin concentration (OxyHb) at rest was defined as 1. In Method (1), the slope from immediately after the start of tourniquet application for 360 seconds was approximated by a straight line, and the slope was defined as S1. In Method (1), the Delfi PTSii tourniquet system (Zimmer Biomet) was used for tourniquet application. Method (2) involves a 5-minute gripping exercise followed by a 1-minute resting tourniquet test (HG test). In Method (2), gripping exercises were performed at 0.25 Hz for 5 minutes at exercise intensities of 0% maximum grip strength (MVC), 20% maximum grip strength (MVC), 35% maximum grip strength (MVC), and 50% maximum grip strength (MVC). In Method (2), the oxygenated hemoglobin concentration (OxyHb) was normalized using the minimum and average values ​​obtained in Method (1). In Method (2), the slope during the 20-second period of tourniquet application immediately after exercise was approximated by a straight line, and the slope was defined as S².

[0058] Figures 13A to 13D show an example of measurement results from a measurement device 100a according to a modified embodiment. For four types of measurement indices, blood flow velocity index BFI, oxygenated hemoglobin concentration OxyHb, oxygen uptake rate rOEF, and oxygen metabolic rate rMRO2, outliers greater than three times the local central absolute deviation were removed, and resampling was performed at 1 Hz. Figure 13A shows the time-series average waveform for all conditions regarding blood flow velocity index BFI, Figure 13B shows the time-series average waveform for all conditions regarding oxygenated hemoglobin concentration (rOxyHb), Figure 13C shows the time-series average waveform for all conditions regarding oxygen uptake rate (rOEF), and Figure 13D shows the time-series average waveform for all conditions regarding oxygen metabolic rate (rMRO2).

[0059] As shown in Figures 13A to 13D, the slope (S2) of the blood flow velocity index BFI, oxygen uptake rate rOEF, oxygen metabolic rate rMRO2, and oxygenated hemoglobin concentration rOxyHb immediately after blood entry increased with increasing exercise intensity. The oxygen metabolic rate rVO2 (=S2 / S1) was estimated from the slope of the oxygenated hemoglobin concentration OxyHb measured by methods (1) and (2). The average value of the oxygen metabolic rate rMRO2 in the 20 seconds immediately preceding the end of exercise was calculated. The responses of rVO2 and oxygen metabolic rate rMRO2 to each exercise intensity were compared and the correlation was examined. Figure 14 shows an example of measurement results from the measuring device 100a according to a modified embodiment. Figure 14 shows the relationship between oxygen metabolic rate rVO2 and oxygen metabolic rate rMRO2. According to Figure 14, it can be seen that there is a correlation between oxygen metabolic rate rVO2 and oxygen metabolic rate rMRO2. The correlation value r was 0.73 and the P value was 0.0004. This confirms that the measuring device 100a can non-invasively measure muscle oxygen metabolism without requiring ischemia.

[0060] According to the modified measurement device 100a of the embodiment, the measurement device 100a can simultaneously derive blood flow velocity by diffusion correlation spectroscopy and tissue oxygen dynamics by near-infrared spectroscopy. In other words, blood flow velocity and tissue oxygen dynamics can be measured simultaneously with the same device. In conventional methods, blood flow velocity and tissue oxygen dynamics could only be measured alternately with a time difference between them, using separate devices. Therefore, the measurement device 100a can derive oxygen metabolism in local tissues by combining the derived blood flow velocity and tissue oxygen dynamics. In other words, it becomes possible to simultaneously measure blood flow dynamics, oxygen dynamics, oxygen uptake rate, and oxygen metabolic rate in living tissues. Furthermore, it can perform dynamic measurements taken while the subject is exercising. Traditionally, oxygen metabolic rate was measured by examining whole-body oxygen intake using methods such as exhaled gas analysis. The measuring device 100a can acquire information on muscle oxygen metabolic rate, enabling functional evaluation of local muscle tissue. In addition to basic research in exercise physiology, it has clinical applications such as evaluating age-related decline in exercise function and muscle atrophy (frailty) due to cardiovascular disease.

[0061] Furthermore, in the measuring device 100a, after the input to the light transmitting probe 103 is switched between the first and second light, the timing of measurement can be determined based on the timing of movement (muscle contraction and muscle relaxation). By configuring it in this way, noise caused by movement can be reduced, and thus the measurement accuracy can be improved.

[0062] <Example Configuration> As an example configuration, a first light source that generates first light having a first wavelength, a second light source that generates second light having a second wavelength different from the first wavelength, a light transmitting probe that switches between receiving the first light generated by the first light source and the second light generated by the second light source and irradiates the living body with the first light and the second light, a first receiving probe that is positioned apart from the light transmitting probe and receives first light from the living body when the first light is irradiated on the living body, and receives second light from the living body when the second light is irradiated on the living body, and a position positioned apart from the light transmitting probe and the first receiving probe The measuring device comprises: a second light-receiving probe that is installed to receive a second light, which is light from the living body, when a first light is irradiated onto the living body, and a second light, which is light from the living body, when a second light is irradiated onto the living body; a first detection unit that detects the amount of the first light based on the first light received by the first light-receiving probe and detects the amount of the second light based on the second light; and a second detection unit that detects the amount of the first light based on the second light received by the second light-receiving probe and detects the amount of the second light based on the second light. As an example configuration, the system further includes a retrieval unit that derives oxygen saturation and blood flow velocity based on the first and second light intensity levels detected by the first detection unit and the second light intensity levels detected by the second detection unit, and derives tissue oxygen metabolic rate based on the derived oxygen saturation and blood flow velocity. As an example configuration, the derivation unit derives the first received first light autocorrelation function and the second received first light autocorrelation function from the time changes of the first received first light quantity and the second received first light quantity, respectively, and derives the first received first light blood flow velocity and the second received first light blood flow velocity from the time changes of the first received second light quantity and the second received second light quantity, respectively, and derives the first received second light blood flow velocity and the second received second light blood flow velocity from the time changes of the first received second light quantity and the second received second light quantity, respectively, and derives the first received second light blood flow velocity and the second received second light blood flow velocity from the derived first received second light autocorrelation function and the second received second light autocorrelation function. As an example configuration, the derivation unit uses the first wavelength to derive the first photon blood flow velocity and the second photon blood flow velocity in the diffusion correlation equation, and uses the second wavelength to derive the first photon blood flow velocity and the second photon blood flow velocity. As an example configuration, the derivation unit derives the relative absorption coefficients at the first and second wavelengths based on the first received light intensity, the second received light intensity, the first received light intensity, and the second received light intensity, and derives the oxygen saturation based on the derived relative absorption coefficients. As one example configuration, the derivation unit derives oxygen saturation based on the distance between the light-transmitting probe and the first light-receiving probe, and the distance between the light-transmitting probe and the second light-receiving probe. As one example configuration, the output unit derives tissue oxygen saturation based on oxygen saturation, and derives tissue oxygen metabolic rate based on the blood flow velocity and tissue oxygen saturation. As an example configuration, the system further includes a signal detection unit that detects signals generated when a living organism contracts or relaxes its muscles. The first detection unit detects a first light intensity and a second light intensity based on the signal detected by the signal detection unit, and the second detection unit detects a first light intensity and a second light intensity based on the signal detected by the signal detection unit. As one example configuration, the system further includes a control unit that switches between inputting the first light generated by the first light source 101 and the second light generated by the second light source 102 to the light transmitting probe.

[0063] Although embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. Furthermore, the aforementioned measuring devices 100 and 100a have internal computers. The processes of each of the aforementioned devices are stored in program form on a computer-readable recording medium, and the above processes are performed by reading and executing this program on the computer. Here, a computer-readable recording medium refers to a magnetic disk, magneto-optical disk, CD-ROM, DVD-ROM, semiconductor memory, etc. Alternatively, this computer program may be distributed to a computer via a communication line, and the computer that receives this distribution may execute the program. Furthermore, the above program may be intended to implement some of the functions described above. Furthermore, the aforementioned functions may be implemented in combination with programs already recorded in the computer system, such as so-called differential files (differential programs). [Explanation of Symbols]

[0064] 100, 100a... Measuring device, 101... First light source, 102... Second light source, 103... Transmitting probe, 104... First light receiving probe, 105... Second light receiving probe, 106... First detection unit, 107... Second detection unit, 110... Information processing device, 112... Data acquisition unit, 114... Data output unit, 116... Output unit, 118... Storage unit

Claims

1. A first laser that generates first coherent light having a first wavelength, A second laser that generates a second coherent light having a second wavelength different from the first wavelength, A control unit that switches the first laser and the second laser such that the second laser is turned off when the first laser is on, and the first laser is turned off when the second laser is on, A light-transmitting probe connected to the first laser and the second laser, which receives the first coherent light generated by the first laser and the second coherent light generated by the second laser in a switchable manner, and irradiates the same location on a living organism with the first coherent light and the second coherent light, A first light receiving probe is installed at a distance from the light transmitting probe and receives a first received light, which is light from the living organism when the first coherent light is irradiated onto the living organism, and receives a first received light, which is light from the living organism when the second coherent light is irradiated onto the living organism. A second light-receiving probe is installed at a distance from the light-transmitting probe and the first light-receiving probe, and receives a second light-receiving first beam, which is light from the living body, when the living body is irradiated with the first coherent light, and receives a second light-receiving second beam, which is light from the living body, when the living body is irradiated with the second coherent light. A first detection unit includes a first photon counter, which detects a first received light quantity based on the result of the first photon counter counting the number of photons of the first received light received by the first light receiving probe, and detects a first received light quantity second based on the result of the first photon counter counting the number of photons of the first received light second. A second detection unit includes a second photon counter, which detects the second received first light quantity based on the result of the second photon counter counting the number of photons of the second received first light received by the second light receiving probe, and detects the second received second light quantity based on the result of the second photon counter counting the number of photons of the second received second light, An output unit that derives oxygen saturation by near-infrared spectroscopy based on the first light intensity and the first second light intensity detected by the first detection unit and the second first light intensity and the second second light intensity detected by the second detection unit, derives blood flow velocity by diffusion correlation spectroscopy, and derives tissue oxygen metabolic rate based on the derived oxygen saturation and blood flow velocity, Equipped with, The aforementioned derivation section is, Based on the time integral values ​​of the first received light intensity, the first received light intensity, the second received light intensity, and the second received light intensity, relative absorption coefficients are derived for each of the first and second wavelengths using the distance between the light transmitting probe and the first receiving probe and the distance between the light transmitting probe and the second receiving probe, and the oxygen saturation is derived based on the derived relative absorption coefficients for each of the first and second wavelengths. A measuring device that derives the time correlation of light intensity based on the time changes of the first received light intensity, the first received light intensity, the second received light intensity, and the second received light intensity, and derives the blood flow velocity from the decay characteristics of the derived autocorrelation function.

2. A probe holder for fixing the light transmitting probe, the first light receiving probe, and the second light receiving probe to the living body. The measuring device according to claim 1, further comprising:

3. The first wavelength is 775 nm to 795 nm, and the second wavelength is 820 nm to 840 nm, The first light-receiving probe is attached to the living organism at a distance of 2 cm to 4 cm from the light-transmitting probe. The measuring device according to claim 1, wherein the second light-receiving probe is attached to the living body at a distance of 1 cm to 2 cm from the light-transmitting probe.

4. The measuring device according to claim 1, wherein the derivation unit derives a first received first light autocorrelation function and a second received first light autocorrelation function from the time changes of the first received first light quantity and the second received first light quantity, respectively, and derives a first received first light blood flow velocity and a second received first light blood flow velocity based on the derived first received first light autocorrelation function and the second received first light autocorrelation function, respectively, and derives a first received second light autocorrelation function and a second received second light autocorrelation function from the time changes of the first received second light quantity and the second received second light quantity, respectively, and derives a first received second light blood flow velocity and a second received second light blood flow velocity based on the derived first received second light autocorrelation function and the second received second light autocorrelation function, respectively.

5. The measuring device according to claim 4, wherein the derivation unit derives the first received first photoblood flow velocity and the second received first photoblood flow velocity in the diffusion correlation equation using the first wavelength, and derives the first received second photoblood flow velocity and the second received second photoblood flow velocity using the second wavelength.

6. The measuring device according to claim 1, wherein the output unit derives tissue oxygen saturation based on the oxygen saturation, and derives tissue oxygen metabolic rate based on the blood flow velocity and the tissue oxygen saturation.

7. Signal detection unit that detects signals generated when the living organism undergoes muscle contraction or muscle relaxation. Furthermore, The first detection unit detects the first light intensity and the first light intensity based on the signal detected by the signal detection unit. The measuring device according to claim 1, wherein the second detection unit detects the second received first light quantity and the second received second light quantity based on the signal detected by the signal detection unit.

8. A first laser that generates first coherent light having a first wavelength, a second laser that generates second coherent light having a second wavelength different from the first wavelength, a control unit that switches the first laser and the second laser so that when the first laser is on, the second laser is off, and when the second laser is on, the first laser is off, and a device connected to the first laser and the second laser that switches the first coherent light generated by the first laser and the second coherent light generated by the second laser into input, and the first coherent light A light transmitting probe that irradiates the first coherent light and the second coherent light to the same position on a living organism; a first light receiving probe that is spaced apart from the light transmitting probe and receives a first received light, which is light from the living organism when the first coherent light is irradiated to the living organism, and receives a first received light, which is light from the living organism when the second coherent light is irradiated to the living organism; and a light receiving probe that is spaced apart from the light transmitting probe and the first light receiving probe and receives a second received light, which is light from the living organism when the first coherent light is irradiated to the living organism, and the first coherent light A first detection unit includes a second light receiving probe that receives a second light, which is light from the living organism, when a second coherent light is irradiated; a first photon counter that detects a first light quantity based on the result of the first photon counter counting the number of photons of the first light received by the first light receiving probe, and a second light quantity based on the result of the first photon counter counting the number of photons of the second light received; and a second photon counter that includes a second photon counter that counts the number of photons of the first light received by the second light receiving probe. The system comprises: a second detection unit that detects the second received first light quantity based on the counting results and detects the second received second light quantity based on the counting results of the second photon counter; and a derivation unit that derives oxygen saturation by near-infrared spectroscopy and blood flow velocity by diffusion correlation spectroscopy based on the first received first light quantity and the first received second light quantity detected by the first detection unit and the second received second light quantity detected by the second detection unit, and derives tissue oxygen metabolic rate based on the derived oxygen saturation and blood flow velocity.A measurement method performed by a measuring device, The derivation unit derives a relative absorption coefficient for each of the first and second wavelengths, based on the time integral values ​​of the first received light quantity, the first received light quantity, the second received light quantity, the second received light quantity, and the second received light quantity, using the distance between the light transmitting probe and the first receiving probe and the distance between the light transmitting probe and the second receiving probe, and derives the oxygen saturation based on the derived relative absorption coefficients for each of the first and second wavelengths. A measurement method for deriving the time correlation of light intensity based on the time changes of the first received light intensity, the first received light intensity, the second received light intensity, and the second received light intensity, and deriving the blood flow velocity from the decay characteristics of the derived autocorrelation function.

9. A first laser that generates first coherent light having a first wavelength, a second laser that generates second coherent light having a second wavelength different from the first wavelength, a control unit that switches the first laser and the second laser so that when the first laser is on, the second laser is off, and when the second laser is on, the first laser is off, and a device connected to the first laser and the second laser that switches the first coherent light generated by the first laser and the second coherent light generated by the second laser into input, and the first coherent light A light transmitting probe that irradiates the same position on a living organism with the first coherent light and the second coherent light; a first light receiving probe that is positioned apart from the light transmitting probe and receives the first received light, which is light from the living organism when the first coherent light is irradiated on the living organism, and receives the first received light, which is light from the living organism when the second coherent light is irradiated on the living organism; and a second light receiving probe that is positioned apart from the light transmitting probe and the first light receiving probe and receives the first received light, which is light from the living organism when the first coherent light is irradiated on the living organism, and irradiates the front of the living organism The first detection unit includes a second light receiving probe that receives the second light, which is light from the living organism, when the second coherent light is irradiated, and a first photon counter which detects the first light quantity based on the result of the first photon counter counting the number of photons of the first light received by the first light receiving probe, and detects the first light quantity based on the result of the first photon counter counting the number of photons of the second light received, and a second photon counter which includes the second photon counter which counts the number of photons of the first light received by the second light receiving probe The system comprises: a second detection unit that detects the second received first light quantity based on the counting results and detects the second received second light quantity based on the counting results of the second photon counter; and a derivation unit that derives oxygen saturation by near-infrared spectroscopy, blood flow velocity by diffusion correlation spectroscopy, and tissue oxygen metabolic rate based on the derived oxygen saturation and blood flow velocity.In the computer of the measuring device, Based on the time integral values ​​of the first received light intensity, the first received light intensity, the second received light intensity, and the second received light intensity, relative absorption coefficients are derived for each of the first and second wavelengths using the distance between the light transmitting probe and the first receiving probe and the distance between the light transmitting probe and the second receiving probe, and oxygen saturation is derived based on the derived relative absorption coefficients for each of the first and second wavelengths. A program that derives the time correlation of light intensity based on the time changes of the first received light intensity, the first received light intensity, the second received light intensity, and the second received light intensity, and derives the blood flow velocity from the decay characteristics of the derived autocorrelation function.

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