JP3801172B2 - Biological light measurement device - Google Patents

Description

  The present invention relates to a biological light measurement device, and more particularly, to a biological light measurement device that non-invasively measures and images a change in concentration of a light-absorbing substance inside a living body using light.

  An apparatus for measuring the inside of a living body simply and non-invasively is desired in clinical medicine. To meet this demand, living body light measurement is very effective. The first reason is that the oxygen metabolism function in the living body corresponds to the concentration of a specific pigment (hemoglobin, cytochrome aa3, myoglobin, etc.) in the living body, that is, a light-absorbing substance. This is because it is obtained from the amount of absorption in the outer region). The second and third reasons that optical measurement is effective include that light is easy to handle with an optical fiber, and that it does not harm the living body when used within the range of safety standards.

  Utilizing the advantages of the above-mentioned optical measurement, a biological optical measuring device that irradiates a living body with light of visible to near-infrared wavelength and measures the inside of the living body from reflected light at a position about 10 to 50 mm away from the irradiation position. For example, it describes in Unexamined-Japanese-Patent No. 63-277038 and Unexamined-Japanese-Patent No. 5-3000887.

JP-A 63-277038

JP-A-5-300887

  In living body measurement using light, the irradiated light spreads greatly in the living body due to the strong light scattering characteristics of the living body (scattering coefficient = about 1.0 [1 / mm]). A wide range of absorbent concentrations will be included. In particular, the spatial characteristics of detection sensitivity have a problem in that the sensitivity of the shallow part of the living body close to the light irradiation and detection position is larger than the sensitivity of the deep part of the living body. For this reason, it is difficult to accurately measure the concentration change of the absorbent in the deep part of the living body. For example, when measuring the hemodynamic change of the living brain from the scalp, there is a problem in that the hemodynamic change of the skin or the skull is largely reflected in the measurement value for the above reason.

  Hereinafter, an example in which the relative sensitivity distribution of the concentration change of the absorbing substance in the deep part of the living body is obtained using the above-described conventional technique will be described. The surface of the living body is assumed to be a plane, a plane parallel to the surface of the living body is defined as an XY plane, light is irradiated from the position of x = 32.5 mm and y = 17.5 mm on the surface of the living body, and 30 mm from the light irradiation position. FIG. 11 shows the relative sensitivity distribution at the position of depth 2.5 mm in the case where light is condensed at the position x = 32.5 mm and y = 47.5 mm away from each other. FIG. 12 shows the sensitivity distribution, and FIG. 13 shows the relative sensitivity distribution at a depth of 12.5 mm. In these figures, the influence of the surface of the living body is very large, and it is difficult to measure the concentration change of the absorbing substance in the deep part of the living body with high accuracy.

  An object of the present invention is to provide a biological light measurement device that measures the concentration change of an absorbing substance in a deep part of a living body with high accuracy.

  In order to achieve the above object, the irradiation light emitted from a plurality of irradiation units is condensed at a plurality of detection positions of the subject as transmitted light that has passed through the subject, and the irradiation light emitted from each irradiation unit is collected. Sensitivity for condensing transmitted light so that the respective optical paths overlap and improving the sensitivity of detecting the optical parameter of the first predetermined region of the subject, or detecting the optical parameter of the second predetermined region of the subject Is characterized by a biological light measurement device that performs processing of the intensity of transmitted light. Hereinafter, the features of the present invention will be described in more detail. A light irradiating means having a plurality of irradiating portions for irradiating a plurality of wavelengths of irradiation light to a plurality of irradiation positions of the subject; and a plurality of collections for collecting the transmitted light transmitted through the subject at a plurality of detection positions of the subject. A light condensing unit having a plurality of condensing units for condensing transmitted light so that respective optical paths of irradiation light emitted from the respective irradiation units overlap each other, and a plurality of light irradiation positions from the transmitted light And detecting means for detecting the light intensity of the transmitted light for each wavelength and the sensitivity for detecting the optical parameter of the first predetermined region of the subject, or detecting the optical parameter of the second predetermined region of the subject. The biological light measuring device has an arithmetic processing means for arithmetically processing the intensity of transmitted light by reducing the sensitivity of the transmitted light. It is possible to apply intensity modulation of different frequencies to the irradiated light and detect light of a predetermined intensity modulation frequency from the transmitted light, or calculate the intensity of light of a predetermined intensity modulation frequency from the transmitted light May be. Further, the transmitted light may be dispersed for each wavelength, and light having a predetermined intensity modulation frequency may be detected from the dispersed transmitted light, or light having a predetermined intensity modulation frequency may be detected from the dispersed transmitted light. The intensity may be calculated. The optical parameter is an absorption coefficient.

  A photoelectric conversion unit for converting transmitted light having an intensity modulation frequency or transmitted light having a predetermined wavelength having a predetermined intensity modulation frequency into a transmitted light intensity signal having the predetermined intensity modulation frequency by photoelectric conversion and a transmitted light intensity signal are input. A signal corresponding to the intensity modulation frequency applied to the light of a predetermined wavelength at the light irradiation position, and the output signal from the phase detector is modulated to a predetermined intensity. It is detected as the intensity of transmitted light having a frequency. Alternatively, it has an analog-to-digital conversion unit to which a transmitted light intensity signal is input, and the transmitted light intensity signal is input to the analog-to-digital conversion unit and subjected to Fourier transform to obtain a biological transmitted light intensity signal in the frequency space for light irradiation. A predetermined reference frequency is obtained by inputting a signal corresponding to the intensity modulation frequency given for each predetermined wavelength of the position or for each predetermined light irradiation position to the analog-digital conversion unit and performing Fourier transform, and the predetermined reference frequency May be calculated as the intensity of transmitted light having a predetermined intensity modulation frequency.

  The irradiating unit and the condensing unit are on at least one circle centered on a point where a straight line passing through the approximate center of the first predetermined region and the surface of the subject intersect, and on a circle having a predetermined diameter The irradiation unit and the condensing unit are arranged at point-symmetrical positions that are arranged at equal intervals and the center of the circle is the point-symmetrical center, and the transmitted light intensity for each of a plurality of wavelengths from each of the light irradiation positions Detected at each condensing position, and selects the transmitted light intensity for each wavelength from the irradiation position that is in point symmetry with the condensing position from the transmitted light intensity for each wavelength from each of the light irradiation positions. The transmitted light intensity detected on the same circle is selected from the light intensities, and calculation processing is performed by multiplying or integrating the transmitted light intensity of transmitted light having a predetermined wavelength detected on the same circle. . Furthermore, the transmitted light collected by the condensing unit installed on the circle having a small diameter is used as information on the shallow part of the subject, and the transmission light collected by the condensing unit installed on the circle having a large diameter is used. The transmitted light is processed using light as information on the deep part of the subject.

  The irradiating unit and the condensing unit are arranged in a square lattice shape, and each of the irradiating unit and the condensing unit is arranged in a square lattice row in which the irradiating unit is arranged on a grid point of each of a plurality of predetermined rows of the square lattice. And a square lattice row in which the light condensing portions are arranged are alternately arranged. Or an irradiation part and a condensing part are arrange | positioned at a regular hexagonal grid | lattice form, and are alternately arrange | positioned at each lattice point of a regular hexagonal grid.

  The irradiation light is light having a wavelength near 805 nm, and the total hemoglobin concentration change calculated from the sum of the oxygenated hemoglobin concentration change, the reduced hemoglobin concentration change, and the oxygenated hemoglobin concentration change and the reduced hemoglobin concentration change from the intensity of the transmitted light. It is obtained, and the time change of the total hemoglobin concentration change is displayed. Alternatively, the total hemoglobin concentration change may be obtained from the intensity of transmitted light, and the irradiation light may be irradiation light having at least two wavelengths from a range of 700 nm to 1100 nm.

  The total hemoglobin concentration change calculated from the sum of the oxyhemoglobin concentration change and the reduced hemoglobin concentration change, the time change of the oxyhemoglobin concentration change or the reduced hemoglobin concentration change is calculated from the sum of the oxyhemoglobin concentration change and the reduced hemoglobin concentration change. The color, the type of line, or the thickness of the line is displayed for each change in total hemoglobin concentration, oxyhemoglobin concentration change, or reduced hemoglobin concentration change. The change in oxyhemoglobin concentration may be displayed in red or orange, the change in reduced hemoglobin concentration in blue, indigo or green, and the change in total hemoglobin concentration in black or brown. Also, an image of total hemoglobin concentration change, oxygenated hemoglobin concentration change or reduced hemoglobin concentration change calculated from the sum of oxygenated hemoglobin concentration change and reduced hemoglobin concentration change may be displayed in color or brightness corresponding to the concentration change. When the density change is positive, the larger the absolute value of the density change value, the darker red or higher luminance is displayed. When the density change is negative, the lower the absolute value of the density change value, the darker blue or lower You may display with a brightness | luminance.

  The transmitted light intensity of transmitted light having a predetermined wavelength detected on the same circle is rotated through a predetermined range region of the predetermined depth of the subject on the perpendicular passing through the center of the circle and perpendicular to the surface of the subject or the perpendicular. It is considered to reflect the total hemoglobin concentration change, oxyhemoglobin concentration change, or deoxyhemoglobin concentration change calculated from the sum of the oxyhemoglobin concentration change and the reduced hemoglobin concentration change in the predetermined range area of the predetermined rotating body at the center. It is characterized in that the calculation is carried out in a short time, and the diameter of the circle is 25 mm to 35 mm, and the depth is 12 mm to 25 mm. By covering the contact surface between the irradiation unit or the light collecting unit and the subject using a flexible and highly transmissive member of the irradiation light, the stimulation given to the subject by the irradiation unit or the light collecting unit can be eased.

  A plurality of irradiation units and condensing units are arranged on a circle with a predetermined diameter so that the respective optical paths of the irradiation light emitted from the irradiation unit overlap, and the living body transmitted light from the irradiation unit at a position opposite to the condensing unit It is possible to improve the sensitivity at a predetermined depth from the position of the center of the circle by selectively detecting only the light and multiplying the transmitted light intensity of the detected transmitted light.

  According to the present invention, it is possible to accurately measure the concentration of an absorbing substance at a predetermined depth in a living body.

  An embodiment based on the present invention will be described. In the present embodiment, a case where two wavelengths are used as irradiation wavelengths for the purpose of measuring changes in oxidized and reduced hemoglobin concentrations in a living body and two light irradiation positions and two light detection positions are set will be described. It is easy to increase the position and the light detection position. Further, by increasing the number of wavelengths, in addition to changes in oxidized and reduced hemoglobin concentration, changes in the concentration of other light absorbing substances such as cytochrome and myoglobin can be measured.

  FIG. 1 shows an apparatus configuration according to the present invention.

  Light of a specific wavelength is emitted from the light sources 1-1, 1-2, 1-3, and 1-4 and is incident on the optical fibers 2-1, 2-2, 2-3, and 2-4, respectively. Here, the wavelength from the light sources 1-1 and 1-3 is λ1, and the wavelength from the light sources 1-2 and 1-4 is λ2, which is selected from the range of 400 nm to 2400 nm. In particular, when measuring hemodynamics in a living body, it is desirable to select a wavelength difference within a range of 50 nm from a range of 700 nm to 1100 nm. The light sources 1-1, 1-2, 1-3, and 1-4 have different frequencies f1 and f2 between 100 Hz and 10 MHz by the light source driving circuits 4-1, 4-2, 4-3, and 4-4, respectively. , F3, and f4. The frequency signals from the light source drive circuits 4-1, 4-2, 4-3, and 4-4 are respectively supplied to the phase detectors 10-1, 10-2, 10-3, and 10-4 as reference frequency signals. Have been entered.

  The optical fibers 2-1 and 2-2 are connected to the optical directional coupler 3-1, and the optical fibers 2-3 and 2-4 are connected to the optical directional coupler 3-2. -2 is mixed and incident on the irradiation optical fiber 5-1, and the light from the light sources 1-3 and 1-4 is mixed and incident on the irradiation optical fiber 5-2. The irradiation optical fibers 5-1 and 5-2 and the condensing optical fibers 8-1 and 8-2 are fixed by an optical fiber holder 6.

  The subject 7 is irradiated with light from the irradiation optical fibers 5-1 and 5-2, and the living body transmitted light is collected by the condensing optical fibers 8-1 and 8-2. Here, the irradiation optical fibers 5-1 and 5-2 and the condensing optical fibers 8-1 and 8-2 are arranged on the circle of the optical fiber holder 6 at equal intervals, and the irradiation optical fibers 5-1 and 5-2. The concentrating optical fibers 8-1 and 8-2 are arranged at positions opposite to. The optical fiber holder 6 is preferably covered with a black material or a black material to improve the light shielding property and have a hollow structure. Further, it is desirable that the irradiation optical fibers 5-1 and 5-2 and the condensing optical fibers 8-1 and 8-2 are also covered with a black material other than the subject contact surface. Further, irradiation of the subject contact surfaces of the irradiation optical fibers 5-1 and 5-2 and the condensing optical fibers 8-1 and 8-2, such as vinyl resin, is performed for the purpose of reducing pain due to contact. Cover with a material that is transparent to the wavelength.

  The biologically transmitted light collected by the condensing optical fibers 8-1 and 8-2 is incident on the photodetectors 9-1 and 9-2, respectively, and the biologically transmitted light at each condensing position is photoelectrically converted and amplified. The For the photodetectors 9-1 and 9-2, a photomultiplier tube or an avalanche photodiode is used. The output signal from the photodetector 9-1 is distributed into two and then input to the phase detectors 10-1 and 10-2, and the output signal from the photodetector 9-2 is distributed into two. Then, it inputs into the phase detectors 10-3 and 10-4.

  The signals input to the respective phase detectors are mixed with the irradiated biologically transmitted light of all wavelengths, but the phase detectors 10-1, 10-2, 10-3, and 10-4 each have a light source driving circuit. Since the reference frequencies are input from 4-1, 4-2, 4-3, and 4-4, the phase detector 10-1 uses the phase detector 10-2 to determine the transmitted light intensity from the light source 1-1. Shows the intensity of the transmitted light from the light source 1-2, the intensity of the transmitted light from the light source 1-3 at the phase detector 10-3, and the intensity of the transmitted light from the light source 1-4 at the phase detector 10-4. Separate detection.

  Each biological transmitted light intensity signal (biologically transmitted light intensity of the same wavelength λ1 irradiated from the opposite position) detected by the phase detectors 10-1 and 10-3 is input to the multiplier 11-1 and multiplied, and phase detection is performed. Each of the living body transmitted light intensities detected by the devices 10-2 and 10-4 (the transmitted light intensity of the wavelength λ2 irradiated from the opposite position) is input to the multiplier 11-2 and multiplied, and the multipliers 11-1, The output signals from 11-2 are input to log amplifiers 12-1 and 12-2, respectively. Further, output signals from the log amplifiers are input to analog-digital converters (hereinafter abbreviated as A / D converters) 13-1 and 13-2, converted into digital signals, and then taken into the arithmetic unit 14.

  The arithmetic unit 14 calculates the sum of the change in the oxygenated hemoglobin concentration, the change in the reduced hemoglobin concentration, the change in the oxygenated hemoglobin concentration representing the blood volume, and the change in the reduced hemoglobin concentration from the captured time series signal of the transmitted light intensity of the two wavelengths. Then, it is displayed on the display device 15 as a time series graph. Further, when multipoint measurement is performed with the same device, the image is displayed on the display device 15 as an image. When displaying changes in each hemoglobin concentration as a time-series graph, if the display device can display a color, it will change the color for each change in hemoglobin concentration, and if the display device cannot display a color The line type or line thickness is changed for each change in hemoglobin concentration. For example, a change in oxyhemoglobin concentration is displayed in red or orange, a change in reduced hemoglobin concentration is displayed in blue, indigo or green, and a change in total hemoglobin concentration is displayed in black, gray or brown. Further, when displaying an image, it may be displayed as a contour image, or may be displayed by changing the color or brightness in accordance with the change in the density change value. For example, the larger the absolute value of the positive density change value, the darker red or darker gray, and the larger the absolute value of the negative density change value, the darker blue or lighter white.

  As the apparatus configuration of the present invention, various combinations of the data collection unit from the photodetector 9 to the arithmetic unit 14 shown in FIG. FIG. 2 to FIG. 6 show device configuration examples related to the data collection unit from the photodetector 9 to the arithmetic device 14.

  FIG. 2 shows a first example of a device configuration relating to the data collection unit. In the figure, symbols A, B, C, and D with circles represent reference frequency signals as in the device configuration example shown in FIG. For simplicity, the light source 1 to the condensing optical fiber 8 in FIG. Device configuration examples related to the data collection unit include photodetectors 9-1 and 9-2, phase detectors 10-1, 10-2, 10-3, and 10-4, and an A / D converter 13-1. , 13-2, 13-3, 13-4 and the arithmetic unit.

  Each phase detector 10-1, 10-2, 10-3, 10-4 is the same as the configuration shown in FIG. 1, but each phase detector 10-1, 10-2, 10-3, 10 -4 are converted into digital signals by A / D converters 13-1, 13-2, 13-3, and 13-4, respectively, and then input to the arithmetic unit 14. The computing device 14 multiplies the input biological transmitted light signals of the same wavelength and performs the multiplication result by natural logarithm calculation, or performs natural logarithm calculation after natural logarithm calculation of the biological transmitted light signals of the same wavelength. Add the operation results. Here, the combination of the biologically transmitted optical signals having the same wavelength is obtained by combining the output signals from the A / D converter 13-1 and the A / D converter 13-3, the A / D converter 13-2, and the A / D. There are two sets of output signals from the D converter 13-4.

FIG. 3 shows a second example of the device configuration relating to the data collection unit. In the figure, symbol A with a circle
, B, C, and D represent reference frequency signals as in the device configuration example shown in FIG. For simplicity, the light source 1 to the condensing optical fiber 8 in FIG. Device configuration examples related to the data collection unit include photodetectors 9-1 and 9-2, phase detectors 10-1, 10-2, 10-3, and 10-4, and multipliers 11-1 and 11-. 2, A / D converters 13-1 and 13-2, and an arithmetic unit 14. The multipliers 11-1, 11-2, 11-3, and 11-4 are the same as those shown in FIG. 1, but the output signals from the multipliers 11-1 and 11-2 are assigned to each A. The signal is converted into a digital signal by the / D converter 13-1 and the A / D converter 13-2 and then input to the arithmetic unit 14. The arithmetic unit 14 performs natural logarithm calculation on the signals from the A / D converters 13-1 and 13-2.

  FIG. 4 shows a third example of the apparatus configuration relating to the data collection unit. In the figure, symbols A, B, C, and D with circles represent reference frequency signals as in the device configuration example shown in FIG. For simplicity, the light source 1 to the condensing optical fiber 8 in FIG. Device configuration examples related to the data collection unit include photodetectors 9-1 and 9-2, phase detectors 10-1, 10-2, 10-3, and 10-4, and log amplifiers 12-1 and 12-. 2, 12-3, 12-4, adders 16-1 and 16-2, A / D converters 13-1 and 13-2, and an arithmetic unit 14. The phase detectors 10-1, 10-2, 10-3, and 10-4 are the same as the configuration shown in FIG. 1, but the phase detectors 10-1, 10-2, 10-3, 10- 4 are input to log amplifiers 12-1, 12-2, 12-3, and 12-4, respectively. Each biological transmitted light intensity signal from the log amplifier 12-1 and the log amplifier 12-3 (biological transmitted light intensity of the same wavelength λ1 irradiated from the opposite position) is input to the adder 16-1 and added to the log amplifier. Each biological transmitted light intensity signal (biologically transmitted light intensity of the same wavelength λ2 irradiated from the opposing position) from 12-2 and the log amplifier 12-4 is input to the adder 16-2 and added, and each adder 16 is added. -1 and 16-2 are input to A / D converters 13-1 and 13-2, respectively. Each of the A / D converters 13-1 and 13-2 is converted into a digital signal and then input to the arithmetic unit 14.

  FIG. 5 shows a fourth example of the apparatus configuration relating to the data collection unit. In the figure, symbols A, B, C, and D with circles represent reference frequency signals as in the device configuration example shown in FIG. For simplicity, the light source 1 to the condensing optical fiber 8 in FIG. Device configuration examples related to the data collection unit include photodetectors 9-1 and 9-2, phase detectors 10-1, 10-2, 10-3, and 10-4, and log amplifiers 12-1 and 12-. 2, 12-3, 12-4, A / D converters 13-1, 13-2, 13-3, 13-4, and an arithmetic unit 14. The phase detectors 10-1, 10-2, 10-3, and 10-4 are the same as those shown in FIG. 1 except that each of the phase detectors 10-1, 10-2, 10-3, 10-. 4 are input to log amplifiers 12-1, 12-2, 12-3, and 12-4, respectively. After the output signals from the log amplifiers 12-1, 12-2, 12-3, and 12-4 are converted into digital signals by the A / D converters 13-1, 13-2, 13-3, and 13-4, respectively. Input to the arithmetic unit 14. In the arithmetic unit 14, the input biological transmitted light signals of the same wavelength are added. Here, the combination of the biologically transmitted optical signals having the same wavelength is obtained by combining the output signals from the A / D converter 13-1 and the A / D converter 13-3, the A / D converter 13-2, and the A / D. There are two sets of output signals from the D converter 13-4.

  FIG. 6 shows a fifth example of the device configuration relating to the data collection unit. In the figure, symbols A, B, C, and D with circles represent reference frequency signals in the same manner as the apparatus configuration example shown in FIG. For simplicity, the light source 1 to the condensing optical fiber 8 in FIG. Device configuration examples related to this data collection unit include photodetectors 9-1 and 9-2 and A / D converters 13-1, 13-2, 13-3, 13-4, 13-5, and 13-6. And the arithmetic unit 14. The photodetectors 9-1 and 9-2 are the same as those shown in FIG. 1, but output signals from the photodetectors 9-1 and 9-2 are converted into A / D converters 13, respectively. -1 and A / D converter 13-2. Output signals from the A / D converters 13-1 and 13-2 are input to the arithmetic unit 14. Further, the reference frequency signals A, B, C and D given to the irradiation light are inputted to the A / D converters 13-3, 13-4, 13-5 and 13-6, converted into digital signals, and then operated. Input to the device 14. In the arithmetic unit, the signals from the A / D converters 13-1, 13-2, 13-3, 13-4, 13-5, and 13-6 are subjected to Fourier transform. The signals from the A / D converters 13-3, 13-4, 13-5, and 13-6 are Fourier-transformed, and the obtained highest intensity frequencies are defined as f 1, f 2, f 3, and f 4, respectively. From the result of Fourier transform of the signal from the A / D converter 13-1, the signal intensities corresponding to the frequencies f1 and f2 are I (f1) and I (f2), and from the A / D converter 13-2. The signal intensity corresponding to the frequencies f3 and f4 is defined as I (f3) and I (f4) from the result of Fourier transform of the signal. Here, since I (f1) and I (f3) are biologically transmitted optical signals of the same wavelength (light from the light sources 1-1 and 1-3 in FIG. 1) irradiated from the opposite positions, they are multiplied by each other. Thus, natural logarithm calculation is performed, and I (f2) and I (f4) are biologically transmitted optical signals of the same wavelength (light from the light sources 1-2 and 1-4 in FIG. 1) emitted from the opposite positions. The natural logarithm calculation is performed by multiplying each other.

  The case where two irradiation optical fibers and two condensing optical fibers are arranged on one circle has been described above. Hereinafter, an embodiment in which a large number of irradiation optical fibers and condensing optical fibers are arranged will be described.

  FIG. 7 shows a first example of the arrangement of the irradiation optical fiber and the condensing optical fiber. In this arrangement example, three irradiation optical fibers and three collection optical fibers are arranged on each concentric circle on a double concentric circle. However, the irradiation optical fibers and the collection optical fibers are multiplexed on the concentric circles. By providing them, it is possible to increase the sensitivity of measurement at various predetermined depth positions.

The irradiation optical fibers 5-1, 5-2, and 5-3 are arranged on the concentric circle 17-1 at every 120 degrees, and the condensing optical fibers 8-1 and 8-2 are arranged at positions facing the respective irradiation optical fibers. , 8-3. Irradiation optical fibers 5-4, 5-5, and 5-6 are arranged at intervals of 120 degrees on the concentric circle 17-2 provided inside the concentric circle 17-1, and are opposed to each irradiation optical fiber (180 degrees). The condensing optical fibers 8-4, 8-5, and 8-6 are arranged in the above. Such an arrangement position fixing means is performed by using the optical fiber holder 6. The multiplied biological transmitted light intensity detected on the concentric circle 17-1 is assigned as the deep portion information to calculate the hemoglobin concentration change inside the living body, and the multiplied biological transmitted light intensity detected on the concentric circle 17-2 is calculated. The change in the hemoglobin concentration inside the living body can be calculated by assigning it as shallow information. Further, the multiplication detected on the concentric circle 17-1 is obtained by multiplying the hemoglobin concentration change calculated from the multiplied biological transmitted light intensity detected on the concentric circle 17-2 by a predetermined weighting factor estimated from the sensitivity distribution. By subtracting from the change in hemoglobin concentration calculated from the transmitted light intensity of the living body, it is possible to further improve the relative sensitivity of the deep part of the predetermined depth.

  FIG. 8 shows a second example of the arrangement of the irradiation optical fiber and the condensing optical fiber. This arrangement example shows an efficient arrangement example in the case where measurement is performed at various positions of a living body based on the present invention. In this example, an arrangement example of two sets of irradiation optical fibers and condensing optical fibers is shown on one circle.

  When two sets of optical fiber for irradiation and optical fiber for condensing are arranged on one circle and the measurement area is expanded, the optical fiber for irradiation and the optical fiber for condensing are arranged on the apex of the square lattice as shown in FIG. It arrange | positions and it arrange | positions so that the optical fiber for irradiation and the optical fiber for condensing may be located mutually in the diagonal direction of each grating | lattice. Here, when nine measurement positions, that is, nine circles 18-1 to 18-9 are set, as shown in FIG. 8, from the irradiation optical fiber 5-1 to the irradiation optical fiber 5-12, The condensing optical fiber 8-1 to the condensing optical fiber 8-12 are arranged on the apex of the square lattice. With this arrangement, the irradiation optical fibers and the condensing optical fibers arranged at the intersections of different circles function with the same number of measurement positions as the number of circular intersections, so that measurement with a smaller number of optical fibers is possible. In addition, since a wider area is measured, it is easy to increase the measurement position. An image of hemodynamics in the deep part of the living body can be obtained from the result obtained by widening the measurement region.

  FIG. 9 shows a second example of the arrangement of the irradiation optical fiber and the condensing optical fiber. This arrangement example shows an efficient arrangement example in the case where measurement is performed at various positions of a living body based on the present invention. In this example, an arrangement example of three sets of irradiation optical fibers and condensing optical fibers is shown on one circle.

  When three sets of optical fiber for irradiation and optical fiber for condensing are arranged on one circle and the measurement area is expanded, as shown in FIG. 9, the optical fiber for irradiation and the optical fiber for condensing are placed on the apex of a regular hexagonal lattice. An optical fiber is arranged, and an irradiation optical fiber and a condensing optical fiber are arranged at the apexes of the opposing positions of the lattice apexes. Here, when four measurement positions, that is, four circles 18-1 to 18-4 are set, as shown in FIG. 8, from the irradiation optical fiber 5-1 to the irradiation optical fiber 5-8, The condensing optical fiber 8-1 to the condensing optical fiber 8-8 are arranged on the regular hexagonal lattice apex. With this arrangement, the irradiation optical fibers and the condensing optical fibers arranged at the intersections of different circles function with respect to the same number of measurement positions as the number of circular intersections, so that measurement with a small number of optical fibers is possible. In addition, since a wider area is measured, it is easy to increase the measurement position. A biological hemodynamic image can be obtained from the result obtained by widening the measurement area.

  FIG. 10 shows another apparatus configuration according to the present invention.

  Light having a continuous wavelength spectrum is emitted from the white light sources 19-1 and 19-2, passes through the glass filters 20-1 and 20-2, a wavelength range necessary for measurement is selected, and the lens 21-1 , 21-2 is incident on the irradiation optical fibers 5-1, 5-2. Here, the wavelengths from the light source 19-1 and the light source 19-2 are in the range of 400 nm to 2400 nm. In particular, when measuring hemodynamics in a living body, it is desirable to select the glass filter 20-1 and the glass filter 20-2 so as to be in the range of 700 nm to 1100 nm. The light sources 19-1 and 19-2 are intensity-modulated at different frequencies f1 and f2 between 100 Hz and 10 MHz by the light source drive circuit 4-1 and the light source drive circuit 4-2, respectively. The frequency signals from the light source driving circuits 4-1 and 4-2 are respectively input to the phase detectors 10-1, 10-2, 10-3 and 10-4 as reference frequency signals. The irradiation optical fiber 5-1 and the irradiation optical fiber 5-2 are fixed by the optical fiber holder 6 together with the condensing optical fiber 8-1 and the condensing optical fiber 8-2.

  The subject 7 is irradiated with light from the irradiation optical fibers 5-1 and 5-2, and the living body transmitted light is collected by the condensing optical fibers 8-1 and 8-2. Here, the irradiation optical fibers 5-1 and 5-2 and the condensing optical fibers 8-1 and 8-2 are arranged on the optical fiber holder 6 at equal intervals on the circle, and the irradiation optical fibers 5-1 and 5-2. The concentrating optical fibers 8-1 and 8-2 are arranged at positions facing each other.

  The living body transmitted light collected by the condensing optical fibers 8-1 and 8-2 is incident on the spectroscopes 22-1 and 22-2, respectively, and is dispersed for each predetermined wavelength. Here, the wavelength λ1 and the wavelength λ2 are selected from the plurality of dispersed wavelengths. Biologically transmitted light of wavelength λ1 from the spectroscope 22-1 is sent to the photodetector 9-1, biologically transmitted light of wavelength λ2 from the spectroscope 22-1 is sent to the photodetector 9-2, and from the spectroscope 22-2. The biologically transmitted light having the wavelength λ1 is input to the photodetector 9-3, and the biologically transmitted light having the wavelength λ2 from the spectroscope 22-2 is input to the photodetector 9-4, and is photoelectrically converted and amplified by each photodetector. The As the photo detectors 9-1, 9-2, 9-3, 9-4, photomultiplier tubes or avalanche photodiodes are used. The output signal from the photodetector 9-1 is input to the phase detector 10-1, the output signal from the photodetector 9-2 is input to the phase detector 10-2, and the output from the photodetector 9-3. The output signal is input to the phase detector 10-3, and the output signal from the photodetector 9-4 is input to the phase detector 10-4.

  The signals input to the phase detectors are mixed with biologically transmitted light having the same wavelength and different intensity modulation frequencies, but each of the phase detectors 10-1, 10-2, 10-3, 10-4 has Since the reference frequencies are respectively input from the light source drive circuits 4-1 and 4-2, the phase detector 10-1 calculates the intensity of the biologically transmitted light having the wavelength λ 1 from the light source 19-1 by the phase detector 10-2. Then, the biological transmitted light intensity of wavelength λ2 from the light source 19-1, the biological transmitted light intensity of wavelength λ1 from the light source 19-2 in the phase detector 10-3, and the light source 19-2 from the phase detector 10-4. It is possible to separate and detect the transmitted light intensity of the living body having the wavelength λ2.

  Each biological transmitted light intensity signal detected by the phase detector 10-1 and the phase detector 10-3 (biological transmitted light intensity of wavelength λ1 irradiated from the opposite position) is input to the multiplier 11-1 and multiplied, Each biological transmitted light intensity detected by the phase detector 10-2 and the phase detector 10-4 (the biological transmitted light intensity of the wavelength λ2 irradiated from the opposite position) is input to the multiplier 11-2 and multiplied. The output signal from the multiplier is input to the log amplifier 12-1 and the log amplifier 12-112-2, respectively. Further, output signals from the respective log amplifiers are inputted to the analog-digital converters 13-1 and 13-2, converted into digital signals, and taken into the arithmetic device 14.

  The arithmetic unit 14 calculates the sum of the change in the oxygenated hemoglobin concentration, the change in the reduced hemoglobin concentration, the change in the oxygenated hemoglobin concentration representing the blood volume and the change in the reduced hemoglobin concentration from the time-series signal of the transmitted two-wavelength transmitted light intensity. It calculates and displays on the display device 15 as a time series graph.

In the apparatus configuration shown in FIG. 1, a set of irradiation optical fibers and condensing optical fibers may be further installed in the optical fiber holder 6. For example, FIG. 14, FIG. 15 and FIG. 16 show the measurement results obtained by providing four sets of irradiation optical fibers and condensing optical fibers. Assuming that the surface of the living body is a plane, a plane parallel to the surface of the living body is defined as an XY plane, on the surface of the living body, on a circle with a center of x = 32.5 mm and y = 32.5 and a diameter of 30 mm. Four sets of irradiation optical fibers and condensing optical fibers were arranged so that the center of the circle was a point-symmetrical center. The measurement results are the relative sensitivity distribution at a depth of 2.5 mm (FIG. 14), the relative sensitivity distribution at a depth of 7.5 mm (FIG. 15), and the relative sensitivity distribution at a depth of 12.5 mm. (FIG. 16). Measurement results according to the conventional example (FIGS. 11, 12 and 13) and measurement results of the present invention (FIG. 14)
15 and 16), it was possible to improve the measurement sensitivity in a predetermined deep part of the living body.

  In the present embodiment, the configuration has been described in which all the transmitted light intensities from opposite positions on a predetermined circle are multiplied for each same wavelength. Similarly, in the device configuration in which all are added for each same wavelength. Although the physical meaning is lowered, it is possible to improve the relative sensitivity in the deep part. Moreover, the sensitivity of the target measurement region may be improved by using an apparatus configuration that performs four arithmetic operations on the transmitted light intensity measured at a plurality of positions. In addition, according to the present invention, as a measurement that requires a sensitivity distribution in the deep part, a change in hemodynamics accompanying brain function activity can be measured from the scalp.

The figure which shows the structure of the optical measuring device which concerns on this invention. The other block diagram of the data collection part in the optical measuring device which concerns on this invention. The other block diagram of the data collection part in the optical measuring device which concerns on this invention. The other block diagram of the data collection part in the optical measuring device which concerns on this invention. The other block diagram of the data collection part in the optical measuring device which concerns on this invention. The other block diagram of the data collection part in the optical measuring device which concerns on this invention. The figure which shows arrangement | positioning of the optical fiber for irradiation in the optical measuring device which concerns on this invention, and the optical fiber for condensing. The figure which shows other arrangement | positioning of the optical fiber for irradiation in the optical measuring device which concerns on this invention, and the optical fiber for condensing. The figure which shows other arrangement | positioning of the optical fiber for irradiation in the optical measuring device which concerns on this invention, and the optical fiber for condensing. The figure which shows the other structure of the optical measuring device which concerns on this invention. The figure which shows the sensitivity distribution in the biological body depth 2.5mm by a prior art. The figure which shows the sensitivity distribution in the biological body depth 7.5mm by a prior art. The figure which shows the sensitivity distribution in the biological body depth of 12.5 mm by a prior art. The figure which shows the sensitivity distribution in the biological body depth of 2.5 mm calculated | required with the apparatus of this invention. The figure which shows the sensitivity distribution in the biological body depth 7.5mm calculated | required with the apparatus of this invention. The figure which shows the sensitivity distribution in the biological body depth of 12.5 mm calculated | required with the apparatus of this invention.

Explanation of symbols

1-1, 1-2, 1-3, 1-4 ... light source, 2-1, 2-2, 2-3, 2-4 ... optical fiber, 3-1, 3-2 ... optical directional coupler, 4-1, 4-2, 4-3, 4-4, light source driving device, 5-1, 5-2, 5-3, 5-4, 5-5, 5-6, 5-7, 5- DESCRIPTION OF SYMBOLS 8 ... Optical fiber for irradiation, 6 ... Optical fiber holder, 7 ... Subject, 8-1, 8-2 ... Optical fiber for condensing, 9-1, 9-2 ... Photo detector, 10-1, 10-2, 10-3, 10-4 ... Phase detectors, 11-1, 11-2 ... Multipliers, 12-1, 12-2 ... Log amplifiers, 13-1, 13-2, 13-3, 13-4 ... Analog-to-digital converter, 14 ... arithmetic unit, 15 ... display device, 16-1, 16-2 ... adder, 17-1, 17-2 ... concentric circles, 18-1, 18-2, 18-3, 18 -4, 18-5, 18 6, 18-7, 18-8, 18-9 ... circle, 19-1, 19-2 ... white light source, 20-1, 20-1 ... glass filter, 21-1, 211-1 ... lens, 22- 1, 22-2 ... Spectroscope.

Claims (4)

Having first and second light sources emitting continuous wavelength spectrum light;
The first output light of the first light source is intensity-modulated at a first frequency f1, and the second output light of the second light source is intensity-modulated at a second frequency f2 (where f1 ≠ f2). And
The first output light before SL is irradiated to the first analyte head inside the irradiation position of the head of the subject surface, before Symbol second output light to the first irradiation position the head of the subject surface Is irradiated into the subject's head from a different second irradiation position,
A first photodetector that detects the first output light transmitted through the subject head at a first detection position, and the second output light transmitted through the subject head is second. A second photodetector for detecting at a detection position of
An optical path of the first transmitted light from the first irradiation position to the first detection position and an optical path of the second transmitted light from the second irradiation position to the second detection position are The first and second irradiation positions and the first and second detection positions are positioned so as to overlap in a specific area inside the specimen head;
The first straight line connecting the first irradiation position and the first detection position and the second straight line connecting the second irradiation position and the second detection position are non-parallel,
A first spectroscope for acquiring light of wavelength λ1 and wavelength λ2 (λ1 ≠ λ2) by making the first output light received by the first light detector incident thereon, and the second light detection; A second spectroscope for acquiring the light of wavelength λ1 and wavelength λ2 (λ1 ≠ λ2) by making the second output light received by the instrument incident
Of the biologically transmitted light of wavelength λ1 and wavelength λ2 separated by the first spectrometer, light whose intensity is modulated at the frequency f1 is separated and detected, and the wavelength λ1 separated by the second spectrometer and Separating and detecting light intensity-modulated at the frequency f2 from the living body transmitted light of wavelength λ2,
Multiplying or adding the light intensity-modulated by f1 and f2 separately detected from the light of wavelength λ1 dispersed by the first and second spectrometers, respectively, by the first and second spectrometers. A biological light measurement apparatus comprising: an arithmetic unit that multiplies or adds light that has been separately detected and intensity-modulated with f1 and f2 out of the divided light having the wavelength λ2.   The first optical filter for selecting a predetermined wavelength range from the first output light, and the second optical filter for selecting a predetermined wavelength range from the second output light. The biological light measurement device according to 1.   The arithmetic unit calculates a change in oxyhemoglobin concentration and a change in deoxyhemoglobin concentration from a time-series signal of transmitted light intensity for each wavelength multiplied or added for each of the wavelengths λ1 and λ2. Item 2. The biological optical measurement device according to Item 1.   The living body optical measurement device according to claim 3, further comprising a display device that displays a change in the oxyhemoglobin concentration and a change in the reduced hemoglobin concentration.

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