JP2004290226A - Glucose concentration measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a glucose concentration measuring apparatus which is not invasive along with a higher measuring accuracy. <P>SOLUTION: Herein employed are an optical fiber 5 which is disposed on the surface S1 of a living body to irradiate inside the living body S with far infrared rays L1, a PbS sensor 6 which detects the rays L2 diffused into the living body S or passing therethrough outside the living body S, an arithmetic part 18 which determines the concentration of glucose in the living body S based on the received signals detected by the PbS sensor 6 and a pump 20 which applies a negative pressure to the surface S1 of the living body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a glucose concentration measuring device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, blood glucose concentration has been measured to determine diabetes, and glucose concentration has been measured particularly to test a blood sugar level that determines the insulin dose of a diabetic patient. The measurement of the glucose concentration is generally performed by directly analyzing blood collected from a finger or an arm. Since the glucose concentration in blood in the body of a patient changes depending on measurement conditions such as before and after a meal and after exercise, frequent measurements are required to obtain an accurate blood glucose level.
However, in the above method of directly analyzing the collected blood, blood must be collected by puncturing an injection needle or the like every time the glucose concentration is measured, and there is a problem that the burden on the patient is large.
[0003]
To solve this problem, fingers, arms, and earlobes are irradiated with near-infrared light from the outside and diffused in the living body to detect non-invasive light emitted outside the living body. A glucose concentration measuring method has been proposed (for example, see Patent Document 1 below). According to the method disclosed in Patent Document 1, an optical fiber bundle formed by bundling a plurality of light emitting fibers and a plurality of light receiving fibers is prepared, and the distal end surface of each optical fiber constituting the optical fiber bundle is brought into contact with the surface of a living body. Place it in a state where Then, near-infrared light enters the living body from the distal end face of each light emitting fiber, and further, light that is diffused in the living body and returns from the surface of the living body to the outside of the living body is received by each light receiving fiber, and the spectrum of the received light is received. Is analyzed to calculate the glucose concentration.
[0004]
[Patent Document 1]
Japanese Patent Application No. 2000-131322 (FIG. 3, etc.)
[0005]
[Problems to be solved by the invention]
However, there is a problem that the S / N ratio is low because light returned from the living body and received by the light receiving fiber includes diffused light in the epidermal tissue or the like that does not contribute to the glucose concentration.
The method disclosed in Patent Document 1 uses a large number of light-emitting fibers and light-receiving fibers, thereby increasing the amount of irradiation light and the amount of detected light, and increasing the information amount of the detected glucose concentration. However, such a method has a problem that the S / N ratio is not improved because the noise also increases at the same time.
[0006]
The present invention has been made in view of the above circumstances, and has as its object to provide a glucose concentration measuring device that is noninvasive and has high measurement accuracy.
[0007]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
That is, the glucose concentration measuring device according to claim 1 is arranged on the surface of a living body, and detects a light irradiating unit that irradiates near-infrared light into the living body, and detects light diffused or transmitted in the living body outside the living body. It is characterized by comprising a detector, a calculating means for obtaining a glucose concentration in a living body based on a light receiving signal detected by the detector, and a suction means for applying a negative pressure to the surface of the living body.
[0008]
According to the glucose concentration measuring device according to the first aspect, in a state in which the suction means is activated and a negative pressure is applied to the surface of the living body as compared with a state in which the suction means is stopped, the suction portion in the living body is Blood flow increases. In addition, even when the suction force is increased or decreased while the suction means is activated, the blood flow increases when the suction force is strong as compared to when the suction force is weak.
Therefore, when irradiating the living body with near-infrared light from the light irradiating unit and detecting the light returning outside the living body with the detector, the measurement results when the blood flow rate was increased by the suction means, These differences can also be obtained by subtracting the measurement results when the blood flow is low. This difference is obtained by subtracting a noise component from all measurement information obtained by irradiating the living body with near-infrared light.
[0009]
The glucose concentration measuring device according to claim 2 is the glucose concentration measuring device according to claim 1, wherein the glucose concentration measuring device has a recess into which the living body surface sucked by the suction means enters, and the irradiation direction of the near-infrared light. The light irradiation unit and the detector are arranged so as to be inclined such that the light receiving direction of the detector and the light receiving direction of the detector are oblique to each other in the recess.
[0010]
According to the glucose concentration measuring apparatus of the second aspect, the surface of the living body sucked by the suction means has a convex shape that is partially raised so as to fill the inside of the recess. The light irradiating section irradiates near-infrared light to the raised portion and the detector receives the light, so that scattering from the light irradiating section can be suppressed. Therefore, it is possible to increase the light receiving intensity while suppressing the influence of the scattering.
[0011]
A glucose concentration measuring device according to a third aspect is the glucose concentration measuring device according to the second aspect, wherein the irradiation direction of the near-infrared light and the light receiving direction of the detector intersect. .
[0012]
According to the glucose concentration measuring device according to the third aspect, a light path having a substantially “<” shape is formed from the light irradiation unit to the detector. By setting the shape of the light path in this way, scattering can be suppressed as compared with the case where the irradiation direction of near-infrared light and the light receiving direction of the detector are parallel in the same direction, so that the received light intensity can be increased. it can.
[0013]
A glucose concentration measuring device according to a fourth aspect is the glucose concentration measuring device according to the first aspect, wherein the glucose concentration measuring device has a recess that sandwiches the living body surface and communicates with the suction unit, and sandwiches the recess. Wherein the light irradiation section and the detector are arranged.
[0014]
According to the glucose concentration measuring device according to the fourth aspect, the living body surface is sandwiched in the recess, and the light irradiating section irradiates near-infrared light and the detector receives light to the sandwiched portion. Thereby, scattering from the light irradiation unit can be suppressed. Therefore, it is possible to increase the light receiving intensity while suppressing the influence of the scattering.
[0015]
The glucose concentration measuring device according to claim 5 is the glucose concentration measuring device according to claim 4, wherein the irradiation direction of the near-infrared light and the light receiving direction of the detector are directly opposed. I do.
[0016]
According to the glucose concentration measuring device according to the fifth aspect, a linear light path penetrating the living body is formed from the light irradiation unit to the detector. By suppressing the scattering, the received light intensity can be increased.
[0017]
The glucose concentration measurement device according to claim 6, which is disposed on the surface of the living body, a light irradiation unit that irradiates the living body with near-infrared light, and a detector that detects light diffused in the living body outside the living body, It is characterized by comprising a calculating means for obtaining a glucose concentration in a living body based on a light receiving signal detected by the detector, and a pressurizing means for applying a positive pressure to the surface of the living body.
[0018]
According to the glucose concentration measuring device according to the sixth aspect, compared to a state where a positive pressure is not applied to the surface of a living body, in a state where a positive pressure is applied by the pressurizing means, a blood flow rate of the pressurized portion is reduced. Decrease. Further, even when the positive pressure is increased or decreased, the blood flow decreases when the positive pressure is high as compared to when the positive pressure is low.
Therefore, when irradiating near-infrared light into the living body from the light irradiating unit and detecting the light returning outside the living body with the detector, the blood pressure is increased by applying the positive pressure based on the measurement result without applying the positive pressure. These differences can be obtained by subtracting the measurement result when the value is reduced. This difference is obtained by subtracting a noise component from all measurement information obtained by irradiating the living body with near-infrared light.
[0019]
The glucose concentration measuring device according to claim 7 is the glucose concentration measuring device according to claim 6, wherein a plurality of the detectors are provided, and at least one of these detectors projects more than the other detectors. It has a light receiving end, and the light receiving end forms the pressurizing means.
[0020]
According to the glucose concentration measuring apparatus of the seventh aspect, in order to measure the glucose concentration using the glucose concentration measuring device, first, the light irradiation unit and each light receiving end are pressed against the surface of the living body. At this time, the detector having the protruding light receiving end presses the surface of the living body more strongly than the other detectors by the protruding amount. This reduces the amount of blood circulation in the vicinity of the compression part.
Therefore, when irradiating near-infrared light into the living body from the light irradiating unit and detecting light returning outside the living body with each detector, pressure is applied by the protruding light-receiving end to reduce blood flow. By subtracting the measurement result at the above from other measurement results, these differences can be obtained. This difference is obtained by subtracting a noise component from measurement information obtained by irradiating near-infrared light into a living body.
[0021]
The glucose concentration measuring device according to claim 8 is the glucose concentration measuring device according to any one of claims 1 to 7, further comprising a temperature controller that adjusts a temperature of the surface of the living body. And
[0022]
According to the glucose concentration measuring device of the eighth aspect, by heating or cooling the living body surface by the temperature controller, it is possible to promote or suppress blood circulation at the measurement site. That is, when a configuration is adopted in which the negative pressure by the suction means is applied to the surface of the living body for measurement, by heating at the time of the measurement with the negative pressure applied, blood circulation at the measurement site can be promoted. Further, at this time, by performing cooling at the time of measurement without applying a negative pressure, blood circulation can be suppressed.
On the other hand, when a configuration is adopted in which pressure is applied by the pressurizing means to the surface of a living body and measurement is performed, by heating at the time of measurement without applying a positive pressure, blood circulation at the measurement site can be promoted. Further, at this time, blood circulation can be suppressed by performing cooling at the time of measurement in which a positive pressure is applied.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Each embodiment of the glucose concentration measuring device of the present invention will be described below with reference to the drawings, but it is needless to say that the present invention is not limited to these. First, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the glucose concentration measuring device 1 of the present embodiment is schematically configured to include a measuring head 2 and a measuring device main body 3 to which the measuring head 2 is connected at the tip.
[0024]
The measuring head 2 is disposed opposite to the living body surface S1 when measuring the glucose concentration, and irradiates the living body S with near-infrared light, and light diffused or transmitted in the living body S. Sensor 6 (detector) for detecting PbS outside the living body S, and a head main body 7 that accommodates the optical fiber 5 and the PbS sensor 6.
[0025]
As shown in FIG. 2, the head main body 7 has a measurement end face 7a which is applied to the living body surface S1 at the time of measurement, and a concave portion 7b is formed at the center of the measurement end face 7a. Further, a suction path 7c communicating with the recess 7b is formed in the head main body 7.
The optical fiber 5 has, for example, a circular cross section with a diameter of 1 mm, and is arranged such that the distal end surface 5a is flush with the inner wall surface of the recess 7b. A mask 5b for blocking light is formed on the outer peripheral surface of the optical fiber 5. The mask 5b makes it possible to prevent light from leaking from the inside of the optical fiber 5 to the outside and prevent light from the outside from entering the inside of the optical fiber 5. Therefore, the light propagating in the optical fiber 5 is emitted only from the distal end face 5a.
[0026]
The PbS sensor 6 is formed in a cylindrical shape having a circular cross section with a diameter of, for example, 7 mm, and its light receiving surface 6a faces the space inside the recess 7b through a through hole 7a1 formed on the inner wall surface of the recess 7b. Are located in
The PbS sensor 6 and the optical fiber 5 emit the near-infrared light L1 emitted from the optical fiber 5 and the light receiving direction of the PbS sensor 6 that receives the light L2 returning from the inside of the living body S to the outside of the living body. However, the relative arrangement of the PbS sensor 6 and the optical fiber 5 is determined such that the PbS sensor 6 and the optical fiber 5 cross each other obliquely in the recess 7b. More specifically, when the measuring head 2 is viewed in a cross section shown in FIG. 2, the tip of the optical fiber 5 and the PbS sensor 6 are arranged on this cross section, and the near infrared light L1 and the light L2 Thus, a light path that bends in the shape of a "ku" is formed.
[0027]
As shown in FIG. 1, the measuring device main body 3 includes a light source 10 such as a halogen lamp, a collimating lens 11 for collimating the light emitted from the light source 10, and a polarization direction of the collimated light in a certain polarization direction. And an acousto-optic tunable wavelength filter that splits light polarized by the polarizer 12 according to the frequency of the input ultrasonic wave, and further polarizes and emits only light of a specific wavelength (near infrared light). (AOTF: Acoustic-Optical Tunable Filter) 13, a filter control unit 14 that supplies and controls ultrasonic waves to the acousto-optic tunable wavelength filter 13, and a light having a specific wavelength polarized by the acousto-optic tunable wavelength filter 13. An analyzer 15 to pass therethrough, and a light beam passing through the analyzer 15 is condensed and incident on the optical fiber 5. A condenser lens 16, an amplifier 17 for receiving and amplifying an output signal from the PbS sensor 6, an arithmetic unit 18 for calculating a glucose concentration based on the output signal amplified by the amplifier 17, and an arithmetic unit 18 The display unit 19 includes a display unit 19 that is connected and displays the calculation result, and a pump 20 (suction unit) that suctions the inside of the recess 7b via the suction path 7c.
[0028]
When the light emitted from the light source 10 is incident on the acousto-optic tunable filter 13, the light in a specific frequency range from the incident light, that is, in the present embodiment, according to the frequency of the input ultrasonic wave, The light in the near infrared region is spectrally output.
The filter control unit 14 synchronizes with supplying an ultrasonic wave of a specific frequency to the acousto-optic tunable wavelength filter 13 and, in synchronization with the frequency, outputs a wavelength signal of light emitted from the acousto-optic tunable wavelength filter 13. Is supplied to the calculation unit 18. In addition, the filter control unit 14 can sequentially change the frequency of the ultrasonic wave supplied to the acousto-optic tunable wavelength filter 13 and perform scanning.
[0029]
The arithmetic unit 18 calculates the spectral distribution of the output signal obtained from the output signal (light receiving signal) obtained from the PbS sensor 6 via the amplifier 17 and the wavelength signal corresponding to each output signal obtained from the filter control unit 14. Based on this, the glucose concentration is calculated from an output signal value in a specific wavelength region, for example, a region near a wavelength of 1.5 μm.
The display unit 19 is a display connected to the calculation unit 18 and displays the glucose concentration value output from the calculation unit 18.
[0030]
The pump 20 applies a negative pressure to the living body surface S1 by sucking the inside of the recess 7b, and sucks and enters the living body surface S1 into the recess 7b. The operation of turning on / off or increasing or decreasing the suction force by the pump 20 may be performed manually or may be performed automatically. Although not shown, a signal indicating the operation state (ON / OFF or strength) of the pump 20 is taken into the arithmetic unit 18 in real time. Thereby, the calculation unit 18 can recognize the operation state of the pump 20 at the same time as receiving the electric signal from the PbS sensor 6 in association with each other. Reference numeral 20a in FIG. 1 denotes a pipe connecting between the pump 20 and the suction path 7c.
[0031]
The operation of the glucose concentration measuring device 1 according to the present embodiment having the configuration described above will be described below.
First, the measurement end face 7a of the measurement head 2 is brought into close contact with the living body S, for example, the surface of a fingertip. In this state, the pump 20 is started to generate a negative pressure in the recess 7b. Then, the living body surface S1 partially rises and is sucked into the recess 7b. In this state, the light source 10 and the acousto-optic tunable filter 13 are operated to split the near-infrared light from the light emitted from the light source 10 and make it incident on the optical fiber 5. The near-infrared light that is incident on the optical fiber 5 and propagates enters the living body S from the distal end surface 5a of the optical fiber 5.
[0032]
The near-infrared light L1 that has entered the living body S collides with the living tissue and is diffused while traveling in the living body S along the incident direction. At this time, light of a specific wavelength is absorbed according to the components of the living tissue or body fluid passing through. Therefore, the amount of light that is diffused in the living body S and returns to the outside of the living body S has a reduced light amount in a specific wavelength region according to the passed biological tissue or body fluid. Then, the light emitted outside the living body S in this way is detected by the PbS sensor 6, and an output signal from the PbS sensor 6 is input to the arithmetic unit 18. Hereinafter, the measurement result at this time is referred to as measurement result A.
Subsequently, the same measurement is performed in a state where the pump 20 is stopped or its suction force is weakened, and the output signal from the PbS sensor 6 is taken into the arithmetic unit 18. Hereinafter, the measurement result at this time is referred to as measurement result B.
[0033]
As described above, both the measurement result A when the suction force (negative pressure) is applied to the living body surface S1 and the measurement result B when the suction force is stopped or weakened are taken into the calculation unit 18. It is. The calculation unit 18 obtains a glucose concentration value by subtracting the measurement result B from the measurement result A, so that a measurement result with a small noise component can be obtained.
That is, at the time of measuring the measurement result A, the suction force applied to the living body surface S1 is stronger than that at the time of measuring the measurement result B, so that the blood flow rate of the suction portion in the living body S is increased.
Therefore, the difference can be obtained by subtracting the measurement result B when the blood flow is lower than the measurement result A when the blood flow is increased by the pump 20. This difference is obtained by subtracting a noise component from all measurement information obtained by irradiating the living body S with the near-infrared light L1.
The glucose concentration value thus obtained is displayed on the display unit 19.
[0034]
The glucose concentration measuring device 1 of the present embodiment described above has a configuration that includes the optical fiber 5, the PbS sensor 6, the arithmetic unit 18, and the pump 20, and non-invasively measures the glucose concentration. According to this configuration, when the glucose concentration is measured, the suction force by the pump 20 is raised and lowered to obtain the difference between the measurement results A and B, so that all of the living body S obtained by irradiating the near-infrared light L1 is obtained. , A difference obtained by subtracting a noise component can be obtained. Since this difference is close to the result when purely blood is measured, it is possible to measure glucose concentration with high measurement accuracy.
[0035]
Further, the glucose concentration measuring device 1 of the present embodiment has a recess 7b into which the sucked body surface S1 enters, and the irradiation direction of the near-infrared light L1 and the light receiving direction of the PbS sensor 6 are within the recess 7b. An intersecting configuration was adopted. According to this configuration, the light path from the optical fiber 5 to the PbS sensor 6 can be formed in a “<” shape. By setting the shape of the light path in this way, scattering can be suppressed and the light receiving intensity can be increased as compared with the case where the irradiation direction of the near infrared light L1 and the light receiving direction of the PbS sensor 6 are made parallel. Can be. Therefore, it is possible to increase the amount of information that can be detected by the PbS sensor 6 and improve the S / N ratio.
[0036]
Subsequently, a description of a second embodiment of the present invention will be described below with reference to FIG. Note that the present embodiment is characterized by the structure of the distal end portion of the measuring head 2, and therefore the description will be focused on this characteristic point, and the description of other points will be omitted because they are the same as in the first embodiment.
[0037]
The measurement head 2 according to the present embodiment has a recess 21 that partially sandwiches the living body S and communicates with the suction path 7c, and the irradiation direction of the near-infrared light L1 emitted from the optical fiber 5 and the PbS sensor 6. The feature is that the optical fiber 5 and the PbS sensor 6 are arranged so that the light receiving direction is directly opposed in the recess 21. Further, the measuring head 2 of this embodiment is also characterized in that a heater (temperature controller) 22 for heating the sandwiched living body surface S1 is provided in the recess 21.
[0038]
In the measurement of the present embodiment, first, the living body S is partially sandwiched in the recess 21. Then, the heater 22 is turned on and the pump 20 is started to generate a suction force in the recess 21 (hereinafter referred to as a measurement state S1). The measurement is performed on two conditions, that is, the state in which the suction force is reduced or the state in which the suction force is reduced (hereinafter, this state is referred to as a measurement state S2).
In any of these measurement states S1 and S2, the optical fiber 5 irradiates the near-infrared light L1 to the sandwiched portion of the living body S and the PbS sensor 6 receives the light L2, thereby transmitting the living body S. A linear light path is formed. By suppressing the scattering, the received light intensity can be further increased. Therefore, it is possible to increase the amount of information that can be detected by the PbS sensor 6 and improve the S / N ratio.
[0039]
Further, in the measurement state S1, in addition to the fact that the negative pressure of the pump 20 is applied to the measurement site, the measurement site is heated by the heater 22, so that the blood circulation of the measurement site is higher than in the measurement state S2. It has been promoted. Accordingly, in the measurement state S1, the ratio of the blood information amount in the light L2 detected by the PbS sensor 6 is larger than that in the measurement state S2. Therefore, since the difference in blood flow at the time of measurement can be made more prominent, it is possible to further increase the S / N ratio when obtaining the glucose concentration.
[0040]
In the present embodiment, the heater 22 is used to promote blood circulation of the living body S, but instead, a temperature controller (not shown) capable of switching between heating and cooling of the living body surface S1 is used. May be provided.
In this case, by heating or cooling the living body surface S1 by the temperature controller, blood circulation at the measurement site can be promoted or suppressed. That is, in the measurement state S1 in which the negative pressure is applied, by heating the measurement site by the temperature controller, blood circulation at the measurement site can be promoted as described above. Further, in the measurement state S2 in which no negative pressure is applied, blood circulation can be suppressed by cooling the measurement site with the temperature controller. In this way, it is possible to further increase the difference between the measurement result when the blood flow is high and the measurement result when the blood flow is low. This makes it possible to further increase the S / N ratio by increasing the ratio of the information amount due to blood.
[0041]
Subsequently, a description of a third embodiment of the present invention will be described below with reference to FIGS.
As shown in FIG. 4, the glucose concentration measuring apparatus 101 of the present embodiment is schematically configured to include a measuring head 102 and a measuring instrument main body 103 connected to the tip of the measuring head 102.
[0042]
The measuring head 102 is arranged to face the living body surface S1 when measuring the glucose concentration, and irradiates the living body S with near-infrared light, and captures light diffused in the living body S. A plurality of optical fibers 106, light receiving elements 107 connected to each of the optical fibers 106, and a head body 108 that accommodates these optical fibers 105 and 106 and each light receiving element 107 are provided.
[0043]
As shown in FIG. 5B, the head main body 108 has a flat measurement end surface 108a that is applied to the living body surface S1 during measurement.
The optical fiber 105 has, for example, a circular cross section with a diameter of 1 mm, and is arranged such that the distal end surface 105a is flush with the measurement end surface 108a. Further, a mask for blocking light is formed on the outer peripheral surface of the optical fiber 105. With this mask, it is possible to prevent light from leaking from the inside of the optical fiber 105 to the outside and prevent light from the outside from entering the inside of the optical fiber 105. Therefore, the light propagating in the optical fiber 105 is emitted only from the distal end face 105a.
[0044]
Each optical fiber 106 is annularly arranged around the optical fiber 105 as shown in FIG. 5A, and when viewed in a cross section including the axis of the optical fiber 105 as shown in FIG. 5B. Are arranged parallel to each other with respect to this axis.
Each of the optical fibers 106 has a distal end surface 106a, which is a light receiving end, protruding every other one. That is, in the measurement end surface 108a of the measurement head 102, portions corresponding to every other position of each of the optical fibers 106 arranged circularly form projections 108a1 protruding in a cylindrical shape. Each optical fiber 106 is arranged so as to protrude so that the end face 106a and the end face 106a are flush with each other. These projections 108a1 constitute a pressing means for applying a positive pressure to the living body surface S1 during measurement.
[0045]
Since each of the light receiving elements 107 constitutes a set of detectors in combination with the optical fiber 106 connected to the light receiving element 107, the light receiving end 107 is substantially flush with the measuring end face 108 around the optical fiber 105. A detector having a (tip surface 106a) and a detector having a light-receiving end (tip surface 106a) protruding therefrom are arranged in an annular arrangement every other unit.
[0046]
Further, a mask for blocking light is formed on the outer peripheral surface of the optical fiber 106. With this mask, it is possible to prevent light from leaking from the inside of the optical fiber 106 to the outside and to prevent light from the outside from entering the inside of the optical fiber 106. Therefore, the light taken into the optical fiber 106 is only from the distal end surface 106a.
[0047]
As shown in FIG. 4, the measuring device main body 103 includes a light source 110 such as a halogen lamp, a collimating lens 111 for collimating the light emitted from the light source 110, and polarizing the collimated light in a certain polarization direction. And an acousto-optic tunable wavelength filter that splits light polarized by the polarizer 112 according to the frequency of the input ultrasonic wave, further polarizes only light of a specific wavelength (near-infrared light), and emits it. (AOTF: Acoustic-Optical Tunable Filter) 113, a filter control unit 114 for supplying and controlling ultrasonic waves to the acousto-optic tunable wavelength filter 113, and a light of a specific wavelength polarized by the acousto-optic tunable wavelength filter 113. Analyzer 115 that passes therethrough, and light that has passed through the analyzer 115 A condenser lens 116 for entering the optical fiber 105, an amplifier 117 for receiving and amplifying output signals from the respective light receiving elements 107, and an arithmetic unit for calculating a glucose concentration based on the output signal amplified by the amplifier 117 118, and a display unit 119 connected to the calculation unit 118 to display the calculation result. Reference numeral 107b in the figure indicates a wiring connecting between each light receiving element 107 and the amplifier 117.
[0048]
The filter control unit 114 synchronizes with supplying an ultrasonic wave of a specific frequency to the acousto-optic tunable wavelength filter 113 and, according to the frequency, outputs a wavelength signal of light emitted from the acousto-optic tunable wavelength filter 113. Is supplied to the calculation unit 118. In addition, the filter control unit 114 can change the frequency of the ultrasonic wave supplied to the acousto-optic tunable wavelength filter 113 in order to perform scanning.
[0049]
The arithmetic unit 118 calculates the spectrum of an output signal obtained from each output signal (light receiving signal) obtained from each light receiving element 107 via the amplifier 117 and a wavelength signal corresponding to each output signal obtained from the filter control unit 114. Based on the distribution, a glucose concentration is calculated from an output signal value in a specific wavelength region, for example, a region near a wavelength of 1.5 μm. That is, the arithmetic unit 118 knows whether the light receiving end of the optical fiber 106 connected to each light receiving element 107 is protruding, and receives the light through the light receiving end flush with the measurement end surface 108a. A difference is obtained by subtracting the light receiving signal of the light receiving element 107 that receives light through the light receiving end projecting from the light receiving signal of the element 107. Then, the difference is subjected to frequency analysis, and the glucose concentration is calculated according to the light amount in a region near a specific wavelength, for example, 1.5 μm.
[0050]
The operation of the glucose concentration measuring device 101 of the present embodiment having the above-described configuration will be described below.
First, the measurement end surface 108a of the measurement head 102 is pressed against the living body S, for example, the surface of a fingertip. Then, since the optical fiber 106 having the protruding light receiving end strongly presses against the living body surface S1 as compared with the other optical fibers 106, the blood circulation amount in the vicinity of the light receiving end decreases. On the other hand, in the other optical fiber 106 having the light receiving end flush with the measurement end face 108a, the amount of pressure is small, so that a normal blood circulation amount is secured.
In this state, the light source 110 and the acousto-optic tunable wavelength filter 113 are operated to split the near-infrared light from the light emitted from the light source 110 and make it incident on the optical fiber 105. The near-infrared light that is incident on the optical fiber 105 and propagates enters the living body S from the distal end surface 105a of the optical fiber 105.
[0051]
The near-infrared light La that has entered the living body S collides with the living tissue and is diffused while traveling in the living body S along the incident direction. At this time, light of a specific wavelength is absorbed according to the components of the living tissue or body fluid passing through. Therefore, the amount of light that is diffused in the living body S and returns to the outside of the living body S has a reduced light amount in a specific wavelength region according to the passed biological tissue or body fluid. Then, the light emitted outside the living body S in this way is detected by each light receiving element 107 via each optical fiber 106. At this time, the light receiving element 107 connected to the optical fiber 106 having the protruding light receiving end has a smaller blood circulation amount than the light receiving element 107 connected to the optical fiber 106 having the light receiving end flush with the measuring end face 108a. A light receiving signal in a small state is obtained.
[0052]
Then, the output signal emitted from each light receiving element 107 is amplified by the amplifier 117 and then input to the arithmetic unit 118.
The operation unit 118 calculates the measurement result of the portion where the compression is stronger (the measurement result of the optical fiber 106 having the protruding light receiving end) based on the measurement result of the portion where the compression is small (the measurement result of the optical fiber 106 having the non-projecting light receiving end). By subtracting (measurement result), these differences can be obtained. This difference is obtained by subtracting a noise component from measurement information obtained by irradiating near-infrared light into a living body.
The glucose concentration value thus obtained is displayed on the display unit 119.
[0053]
According to the glucose concentration measuring apparatus 101 of the present embodiment described above, in measuring the glucose concentration, a difference obtained by subtracting the measurement result of the low blood flow from the measurement result of the normal blood flow can be obtained. Since this difference is close to the result when purely blood is measured, it is possible to measure glucose concentration with high measurement accuracy.
[0054]
In the present embodiment, the projection 108a1 is provided on each of the optical fibers 106 that project the light receiving end (the distal end surface 106a). However, it is only necessary to apply a partial pressure on the living body surface S1. May be employed.
[0055]
For example, in FIGS. 6A to 6C, a ring-shaped annular projection 108a2 centered on the optical fiber 105 is used when the measurement end face 108a is viewed from the opposite side. In this example, the optical fibers 106 are arranged on the annular protrusion 108a2 in an annular shape so as to be flush with the tip thereof, and the optical fibers 106 are arranged in an annular shape so as to be flush with the measurement end surface 108a. And it is divided into two. Therefore, when the measurement is performed by pressing the measurement end face 108a against the living body surface S1, the annular protrusion 108a2 presses the living body surface S1 to reduce the amount of blood circulation in this portion, so that the optical fiber 106 is flush with the measurement end face 108a. By subtracting the measurement result of the optical fiber 106 disposed on the annular projection 108a2 from the measurement result of the above, a difference similar to that obtained in the third embodiment can be obtained. This difference is obtained by subtracting a noise component from all measurement information obtained by irradiating the living body S with near-infrared light, and is close to the result when purely blood is measured. It is possible to measure glucose concentration with high accuracy.
[0056]
It should be noted that the glucose concentration measuring devices of the first and third embodiments are combined with the heater 22 and the temperature controller described in the second embodiment to obtain a measurement result in a state where the blood flow is large and a state in which the blood flow is small. A configuration in which the difference from the measurement result is further increased can be adopted. Also in this case, it is possible to further increase the S / N ratio by increasing the ratio of the information amount due to blood.
However, when the temperature controller is used in combination with the third embodiment, a portion having a protruding light receiving end for applying a positive pressure is heated to promote blood circulation, and a portion having another non-protruding light receiving end. Then, it is preferable to suppress the blood circulation by cooling.
[0057]
【The invention's effect】
The glucose concentration measuring device according to claim 1 of the present invention has a configuration in which a light irradiating unit, a detector, a calculation unit, and a suction unit are provided, and the glucose concentration is measured noninvasively. According to this configuration, when measuring the glucose concentration, the difference in the measurement results is obtained by raising and lowering the suction force by the suction means, so that all the measurement information obtained by irradiating the living body with near-infrared light is obtained. , The difference obtained by subtracting the noise component can be obtained. Since this difference is close to the result when purely blood is measured, it is possible to measure glucose concentration with high measurement accuracy.
[0058]
Further, the glucose concentration measuring device according to claim 2 has a concave portion into which the sucked biological surface enters, and the irradiation direction of the near-infrared light and the light receiving direction of the detector are not parallel in the concave portion. It was adopted. According to this configuration, the entire length of the light path formed by the irradiation path of the near-infrared light and the path of the light diffused in the living body and returned to the outside of the living body can be relatively shortened, and the light receiving intensity can be increased. It can be done. Therefore, it is possible to increase the amount of information that can be detected by the detector and improve the S / N ratio.
[0059]
Further, the glucose concentration measuring device according to claim 3 employs a configuration in which the irradiation direction of near-infrared light and the light receiving direction of the detector intersect. According to this configuration, the overall length of the light path can be made shorter, and the light receiving intensity of the detector can be further increased. This makes it possible to increase the amount of information that can be detected by the detector and further improve the S / N ratio.
[0060]
Further, the glucose concentration measuring device according to claim 4 has a recess that sandwiches the surface of the living body and communicates with the suction unit, and the light irradiation unit and the detector are arranged so as to sandwich this recess. Configuration was adopted. According to this configuration, it is possible to shorten the entire length of the light path formed by the irradiation path of the near-infrared light and the path of the light diffused in the living body and returned to the outside of the living body, thereby increasing the light receiving intensity. Has become. Therefore, it is possible to increase the amount of information that can be detected by the detector and improve the S / N ratio.
[0061]
Further, the glucose concentration measuring device according to claim 5 employs a configuration in which the irradiation direction of near-infrared light and the light receiving direction of the detector are directly opposed. According to this configuration, the light receiving intensity of the detector can be further increased by minimizing the overall length of the light path. This makes it possible to increase the amount of information that can be detected by the detector and further improve the S / N ratio.
[0062]
Further, the glucose concentration measuring device according to claim 6 has a configuration in which a light irradiating unit, a detector, an arithmetic unit, and a pressurizing unit are provided, and the glucose concentration is measured noninvasively. According to this configuration, when measuring the glucose concentration, the positive pressure is increased or decreased by the pressurizing means and the difference between the measurement results is obtained, whereby all the measurement information obtained by irradiating the living body with near-infrared light is obtained. From the difference, a difference obtained by subtracting a noise component can be obtained. Since this difference is close to the result when purely blood is measured, it is possible to measure glucose concentration with high measurement accuracy.
[0063]
Further, in the glucose concentration measuring device according to claim 7, the plurality of detectors are provided, at least one of these detectors has a light receiving end protruding from other detectors, and this light receiving end is The configuration that forms the pressurizing means is employed. According to this configuration, when measuring the glucose concentration, it is possible to reliably measure the glucose concentration with high measurement accuracy.
[0064]
In addition, the glucose concentration measuring device according to claim 8 employs a configuration including a temperature controller that adjusts the temperature of the surface of the living body. According to this configuration, by heating or cooling the surface of the living body in accordance with the measurement configuration, it is possible to increase the difference between the measurement result when the blood flow is high and the measurement result when the blood flow is low. This makes it possible to increase the S / N ratio by increasing the ratio of the information amount due to blood.
[Brief description of the drawings]
FIG. 1 is a device configuration diagram showing a first embodiment of a glucose concentration measuring device of the present invention.
FIG. 2 is a diagram showing a main part of the glucose concentration measuring device, and is an enlarged sectional view of a tip portion of a measuring head.
FIG. 3 is a view showing a second embodiment of the glucose concentration measuring device of the present invention, and is an enlarged sectional view corresponding to FIG. 2;
FIG. 4 is an apparatus configuration diagram showing a third embodiment of the glucose concentration measuring apparatus of the present invention.
5A and 5B are diagrams showing the same glucose concentration measuring device, wherein FIG. 5A is a front view of a tip portion of a measuring head, FIG. 5B is a right half of FIG. The left half is a sectional view taken along line BB of FIG.
6A and 6B are diagrams showing a modification of the glucose concentration measuring device, wherein FIG. 6A is a front view of a tip portion of a measuring head, FIG. 6B is a cross-sectional view taken along line CC of FIG. It is DD sectional drawing of (a).
[Explanation of symbols]
1,101 ... glucose concentration measuring device
5,105 ・ ・ ・ Optical fiber (light irradiation part)
6,106 ... PbS sensor (detector)
7, 107 ... light receiving element (detector)
7b, 7c ... recess
18, 118... Arithmetic means
20 ... suction means
22 ... heater (temperature controller)
108a1... Protrusion (pressing means)
108a2 ··· Annular protrusion (pressing means)
S: living body
S1: Body surface

Claims (8)

A light irradiator arranged on the surface of a living body and irradiating near-infrared light to the inside of the living body, a detector for detecting light diffused or transmitted in the living body outside the living body, and a light reception signal detected by the detector. An apparatus for measuring glucose concentration, comprising: means for calculating glucose concentration in a living body based on the information; and suction means for applying a negative pressure to the surface of the living body. The glucose concentration measuring device according to claim 1,
Having a recess into which the living body surface sucked by the suction means enters,
Glucose concentration measurement, wherein the light irradiating section and the detector are arranged obliquely such that the irradiation direction of the near-infrared light and the light receiving direction of the detector are oblique to each other in the recess. apparatus. The glucose concentration measuring device according to claim 2,
A glucose concentration measuring device, wherein an irradiation direction of the near infrared light and a light receiving direction of the detector intersect. The glucose concentration measuring device according to claim 1,
Having a recess that sandwiches the body surface and communicates with the suction means,
The glucose concentration measuring device, wherein the light irradiator and the detector are arranged so as to sandwich the recess. The glucose concentration measuring device according to claim 4,
A glucose concentration measuring device, wherein an irradiation direction of the near-infrared light and a light receiving direction of the detector are directly opposed. A light irradiation unit that is arranged on the surface of the living body and irradiates the living body with near-infrared light, a detector that detects light diffused in the living body outside the living body, and a light reception signal detected by the detector. An apparatus for measuring glucose concentration, comprising: means for calculating glucose concentration in a living body; and pressurizing means for applying a positive pressure to the surface of the living body. The glucose concentration measuring device according to claim 6,
A plurality of the detectors are provided,
At least one of these detectors has a light receiving end protruding from other detectors, and the light receiving end forms the pressurizing means. The glucose concentration measuring device according to any one of claims 1 to 7,
A glucose concentration measuring device comprising a temperature controller for adjusting the temperature of the living body surface.

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