JPH07222736A - Method for measuring living body light and device therefor - Google Patents

Abstract

PURPOSE:To measure the oxygen metabolic function of a living body with high accuracy by changing a measuring wavelength region corresponding to the measured size of the living body, and changing measuring wavelength regarding a detecting position near or far from a light irradiating position when light passing the living body is detected at plural positions. CONSTITUTION:A size measuring part 5 supports an incident optical fiber 2 and a detection optical fiber 4, and simultaneously, measures the size of a testee body 3. After the incident optical fiber 2 and the detection optical fiber 4 are set on the testee body 3, a resistance value between an incident optical fiber strut 12 and a detection optical fiber strut 13 is measured, and it is converted to the measured size by a control part 10. The measuring wavelength region is selected by the value of the measured size, and the testee body 3 is irradiated with three kinds wavelengths of light in a corresponding wavelength region from a light source part 1 by the incident optical fiber 2 sequentially. The transmission light quantity of the light passing the testee body 3 is found by a light detecting part 6, and the density of oxygenated hemoglobin and that of deoxygenated hemoglobin are found.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for measuring information inside a living body using light.

[0002]

2. Description of the Related Art Biological measurement using light having a wavelength in the visible to near-infrared region is considered useful in clinical medicine because the oxygen metabolism function of the living body can be measured easily and without harming the living body. . The principle of measuring the oxygen metabolism function by light and its simplicity are described below.

The oxygen partial pressure in the living body that reflects the oxygen metabolism function of the living body depends on the oxygenation state (usually called the oxygen saturation or the degree of oxidation) of a specific pigment (hemoglobin, myoglobin, cytochrome aa ₃ ) in the living body. Correspond. Since the light absorption spectrum of these dyes changes in the visible to near-infrared wavelength region depending on the oxygenation state, the oxygenation state of each dye is determined from the amount of light absorption. Moreover, the light is handled easily by the optical fiber, and further, the light is used within the range of the safety standard, and does not harm the living body.

An apparatus for measuring the oxygen metabolism function of a living body by using light having a wavelength from visible to near-infrared by utilizing such an advantage of the optical measurement is disclosed in, for example, JP-A-57-115232 or JP-A-57-115232.
No. 63-275323. Furthermore, in order to apply this oxygen metabolism function measuring technique to medical diagnosis more effectively, an optical CT device for imaging oxygen metabolism function is disclosed in, for example, Japanese Patent Laid-Open No. 60-72542 or Japanese Patent Laid-Open No. 62-62242. It is described in Japanese Patent No. 231625.

[0005]

As described above, light is very useful for measuring the oxygen metabolism function of a living body, but has the following problems in setting the measurement wavelength. Here, the factors to be considered regarding the wavelength setting are the amount of transmitted light and the measurement accuracy of the oxygenated state of the dye.

First, the amount of transmitted light will be described. Since the living body is both a light absorber and a strong light scatterer, the light applied to the living body is absorbed and scattered in the living body, and the transmitted light becomes extremely weak. This transmitted light quantity is determined by the scattering coefficient and absorption coefficient of the living body, and the measurement size, that is,
It largely depends on the distance between the light incident position on the living body and the light detection position. With respect to all of these factors, the amount of transmitted light becomes weak as the respective values (scattering coefficient, absorption coefficient, and measurement size) increase. Here, since the values of the scattering coefficient and the absorption coefficient change in wavelength, a wavelength having a small value is preferable from the viewpoint of the amount of transmitted light. The wavelength dependence of the scattering coefficient of a living body is, for example,
L. Karagiannes, et al., "Applications of the 1-Diffusion Approximation to the Optics of Tissues and Tissue Simulated Samples"
D diffusion approximation to the optics of tissues
and tissues phantoms) ”, June 15, 1989, Applied Optics, Volume 28, No. 12, 231.
Items 1-2317 (Applied Optics, 28, 12, 2311 (198
9)) and the results are shown in Figure 1 for calf brain tissue.

The main substances that greatly contribute to light absorption in the living body are water and hemoglobin. Regarding the absorption spectrum of water, for example, JGBayly et al. “Absorption spectra of liquid phase H ₂ O, HDO, and D ₂ O from 0.7 μm to 10 μm (The
absorption spectra of liquid phase H ₂ O, HDOa
nd D ₂ O from 0.7 μm to 10 μm) ”, 1963
Year, Infrared Physics, Volume 3, 211-
223 (Infrared Physics, 3, 211 (1963)) and the like. The wavelength dependence of the absorption coefficient of water is shown in FIG.

On the other hand, regarding the light absorption spectrum of hemoglobin, Royal Fangorkum (Roya
L. Vangorcun Ltd., 1970, OW van Assendelft, "Spectrophotometry of Hemoglobin Derivatives (Spectrophoto).
metry of haemoglobin derivatives) ”. Furthermore, the hemoglobin concentration in the adult brain is 0.0
8 mM (mmol / liter) was reported by Fumihiko Sakai et al. “Regional cerebral blood volume and hematocrit in normal human brain measured by single photon emission CT.
measured in normal human volunteers by single-phot
on emission computed tomography) ", 1985, Journal of cerebral blood flow and metabolism, Vol. 5, No. 2, 207-213.
(Journal of Cerebral BloodFlow and Metabolism,
5, 2, 207 (1985)).

Since the hemoglobin absorption spectrum is displayed as an absorption coefficient per unit concentration, the wavelength dependence of the hemoglobin absorption coefficient in the adult brain can be obtained by multiplying the hemoglobin concentration in the adult brain. Is shown in FIG. In FIG. 3, the spectrum of oxygenated hemoglobin is shown by a solid line and the spectrum of deoxygenated hemoglobin is shown by a dotted line in order to show the difference in absorption coefficient due to the difference in oxygenation state of hemoglobin.

The wavelength dependence of the scattering coefficient and the absorption coefficient shown in FIGS. 1, 2 and 3 will be considered next.
First, it can be seen from FIG. 1 that the scattering coefficient monotonically decreases as the wavelength increases. Regarding the absorption coefficient, both water and hemoglobin show complicated spectra, but as a general trend, water increases with increasing wavelength (Fig. 2), while hemoglobin decreases with increasing wavelength. (Fig. 3). However, in the near infrared region, that is, 750
It can be seen that, at a wavelength of 850 nm, both water and hemoglobin have relatively small absorption coefficients. From these results, both the scattering coefficient and the absorption coefficient show small values.
It can be seen that the wavelength range of 50 to 850 nm is an appropriate measurement wavelength for the amount of transmitted light.

On the other hand, regarding the measurement accuracy of the oxygenated state of the dye, the difference between the oxygenated state and the deoxygenated state of the light absorption amount of hemoglobin or the like is important. That is, if this difference is large, a small change in the oxygenated state will appear as a large change in the amount of light absorbed, so that the oxygenated state can be measured accurately. It is easily understood from FIG. 3 that the difference in the light absorption amount is large in hemoglobin in the wavelength range of 500 to 650 nm. The value of this difference is 560 nm for 0.01 (1 / mm) at a wavelength of 780 nm, for example.
Is 0.35, and at 600 nm is 0.20 (1 / mm).
Therefore, for the quantification of oxygenation state, 500 to 6
It turns out that the wavelength range of 50 nm is suitable. Regarding the measurement of such an oxygenated state, the wavelength region of 500 to 650 nm is also suitable for myoglobin and cytochrome aa ₃ .

From the above, the range of wavelength 750 to 850 nm is suitable for the measurement of the transmitted light amount, while the wavelength 500 to 6 of the measurement accuracy of the oxygenation state is suitable.
The 50 nm region is appropriate. As described above, appropriate wavelengths are different from both viewpoints of the amount of transmitted light and measurement accuracy, and it is difficult to judge which one should be selected based only on this condition.

Therefore, the measurement size, which is a factor other than the scattering coefficient and the absorption coefficient related to the amount of transmitted light, is important for this selection. Here, for each wavelength region, the attenuation rate of the transmitted light amount due to the increase in the measurement size is evaluated. This attenuation rate indicates the ratio of the amount of transmitted light to the amount of incident light on the living body. For this evaluation, we use a model that describes light scattering / absorption phenomena in the living body by diffusion theory.

This model irradiates an infinite flat plate having a measurement size (that is, a thickness) dmm with a light having a δ function in terms of time and space as incident light, and calculates the time dependence of the amount of transmitted light. Here, we consider the case where scatterers and absorbers are uniformly present in this infinite plate. The time dependence of the amount of transmitted light in this case is, for example, Michael S. Patterson (Michae
l S. Patterson et al., “Time resolved reflectance and transmittance for non-invasive measurement of tissue optical properties.
frectance and transmission for the noninvasive mea
surement of tissue optical properties) ", 198
June 15, 1997, Applied Optics, Volume 28,
No. 12, 2331 to 2336 (Applied Optics,
28, 12, 2331 (1989)). The time dependency T (t) (t: detection time (ps)) of the transmitted light amount is shown by the equation 1.

[0015]

[Equation 1]

In Equation 1, S is the scattering coefficient, A is the absorption coefficient, and c
Is the speed of light in the living body (0.23 mm / ps of the speed of light in water)
Is approximately equal to), and π indicates the circular constant.

Here, 600 nm is set as a representative wavelength in the wavelength range of 500 to 650 nm, and wavelengths of 750 to 850 are set.
Consider 800 nm as a representative wavelength in the region of nm. As scattering coefficients at wavelengths of 600 and 800 nm, 0.7 and 0.4 (1 / mm) from FIG. 1 are used, respectively, and as absorption coefficients by hemoglobin, from 0.1 to 0.0
2 (1 / mm) is used respectively. Light absorption by water is negligible because it is small at these wavelengths.

The attenuation rate is obtained by integrating the calculation result obtained by the equation 1 in the entire time domain, and the result is shown in FIG. The detection limit of the amount of light transmitted through the living body depends on the light output of the light source, the sensitivity of the detector, and the like, but here, the attenuation rate of 10 digits is assumed to be the detection limit. This 10-digit value is a value that can be sufficiently detected by the current performance of the detector with respect to the light irradiation amount within the safety standard for the living body. This 10-digit attenuation rate is shown by the dotted line in FIG.

From FIG. 4, at a wavelength of 600 nm, if the measurement size is 30 mm or less, the amount of transmitted light above the detection limit is obtained. However, when the measurement size exceeds 30 mm, the amount of transmitted light does not reach the detection limit, so 600 n
It becomes difficult to detect m. Therefore, the measurement size is 30mm
Below, that is, when a sufficient amount of transmitted light is obtained, a wavelength of 600 nm is an appropriate measurement wavelength from the viewpoint of the accuracy of measurement of the oxygenated state. On the other hand, when the measurement size exceeds 30 mm, a sufficient amount of transmitted light cannot be obtained at a wavelength of 600 nm, and therefore 800 nm is an appropriate wavelength in consideration of the amount of transmitted light.

As described above, in biological measurement using light, proper wavelength selection largely depends on the measurement size. However, the conventional biological optical measurement technology does not consider the selection of the measurement wavelength depending on the measurement size. Therefore, for example, 60
Even if a sufficient amount of transmitted light can be obtained at a wavelength near 0 nm, a wavelength near 800 nm is used for measurement to cause a decrease in measurement accuracy of the oxygen metabolism function, or conversely, it is originally 800
6 if a sufficient amount of transmitted light cannot be obtained unless it is in the vicinity of nm
A wavelength near 00 nm is used for measurement, and a weak amount of transmitted light may cause deterioration in measurement accuracy.

An object of the present invention is to provide a method and apparatus for accurately measuring the oxygen metabolism function of a living body by taking into consideration the measurement size and using a wavelength suitable for the measurement target.

[0022]

In the present invention, first, the measurement size of a living body is obtained, and the measurement wavelength region is changed according to the measurement size. When detecting the light passing through the living body at a plurality of positions, the measurement wavelength is changed at the detection position at a short distance and the detection position at a long distance with respect to the light irradiation position.

When the measurement size is not obtained in advance, the living body is irradiated with light having a wavelength in the short wavelength region, for example, near 600 nm, and the amount of light passing through the living body is first detected. Here, if sufficient detection light amount is obtained with light in this short wavelength region, measurement is performed in this wavelength region as it is, and if measurement in this wavelength region is substantially difficult due to the small amount of transmitted light, The measurement is performed with light having a wavelength in the long wavelength region, for example, near 800 nm.

[0024]

[Function] The effect of the difference in the wavelength of irradiation on the living body on the measurement accuracy of transmitted light quantity and oxygen metabolism function, and the relationship with the measurement size of the living body, the accuracy of the oxygen metabolism function is determined by the measurement wavelength according to the measurement size of the living body High measurement is possible.

[0025]

【Example】

(Embodiment 1) A first embodiment of the present invention will be described with reference to the apparatus configuration shown in FIG. The light source unit 1 has a wavelength of 500 to 650.
From the first wavelength region in the range of nm, the appropriate three wavelengths (hereinafter referred to as the first, second and third wavelengths respectively), 750 to 85
It is composed of a total of 6 wavelengths from the second wavelength region in the range of 0 nm to an appropriate 3 wavelengths (hereinafter referred to as the 4th, 5th and 6th wavelengths, respectively). Which wavelength region is used for measurement is determined by the measurement result of the measurement size shown below. The measurement size measuring unit 5 supports the incident optical fiber 2 and the detection optical fiber 4 and simultaneously measures the measurement size of the subject 3.

The structure of the measurement size measuring unit 5 is shown in FIG. In the measurement size measuring unit 5, the rod-shaped electric resistor 11 is used as an axis, and the incident optical fiber support 1 is attached to this axis.
2 and the detection optical fiber column 13 are in contact with each other. In these optical fiber columns, a portion in contact with the electric resistor 11 is made of metal, and a portion close to the subject 3 is made of an insulator, and supports the incident optical fiber 2 and the detection optical fiber 4, respectively. There is. The incident optical fiber support 12 is fixed to the electric resistor 11, but the detection optical fiber support 13
Is slidable on the electric resistor 11. By this slide, the incident optical fiber 2 and the detection optical fiber 3 can be set on the subject of any size.

Here, since it is widely known that the electric resistance value is generally proportional to the distance between the electric resistors, the measurement size of the object 3 is determined by the structure of the measurement size measuring unit 5 between the two fiber struts. One-to-one is derived from the electric resistance value.
Here, the relationship between the resistance value and the measurement size is previously stored in the control unit 10 as data.

After the setting of the incident optical fiber 2 and the detection optical fiber 4 to the subject 3 is completed, the electrical resistance measuring unit 14 measures the resistance value between the incident optical fiber support 12 and the detection optical fiber support 13, The control unit 10 converts the result into a measurement size. If the value of this measurement size is a predetermined value, for example, 30 mm or less, the control unit 10 selects the first wavelength region as the measurement wavelength, and if it is 30 mm or more, the second wavelength region is selected.

After the measurement wavelength region is selected, the light source unit 1 sequentially irradiates the subject 3 with the three wavelengths of light in the corresponding wavelength region through the incident optical fiber 2. The light passing through the subject 3 is transmitted through the detection optical fiber 4 and the amount of transmitted light for each wavelength is obtained by the photodetector 6. The data processing unit 7 obtains the concentrations of oxygenated hemoglobin and deoxygenated hemoglobin, which show the oxygen metabolism function, from the amounts of transmitted light of three wavelengths in this wavelength range. In general, the concentration of the light absorber contained in the light scatterer (test object) is obtained by using a plurality of wavelengths for measurement in this way. The method is, for example, the method described in the book "Two-wavelength spectrophotometry and its application" by Shozo Shibata, etc., published by Kodansha in 1979. The oxygenated hemoglobin concentration and the deoxygenated hemoglobin concentration thus obtained are converted into oxygen saturation indicating the oxygenation state of hemoglobin (the ratio of the oxygenated hemoglobin concentration to the total hemoglobin concentration),
It is displayed on the display unit 8 and stored in the storage unit 9. At this time, the series of measurement is controlled by the control unit 10.

(Embodiment 2) A second embodiment of the present invention is shown in FIG.
A description will be given according to the apparatus configuration shown in FIG. The light source unit 1 has a wavelength of 50
From the first wavelength region in the range of 0 to 650 nm, three appropriate wavelengths (hereinafter referred to as first, second and third wavelengths), respectively, 7
From the second wavelength range of 50 to 850 nm, a suitable 3
It is composed of a total of 6 wavelengths (hereinafter referred to as the 4th, 5th, and 6th wavelengths, respectively). With respect to these wavelengths, first, the light of the first wavelength is emitted from the light source unit 1 to the subject 3 through the incident optical fiber 2. The amount of transmitted light of the light that has passed through the subject 3 is obtained by the photodetector 6 via the detection optical fiber 4.

In this case, if the transmitted light amount of the first wavelength in the first wavelength region has a predetermined SN ratio, for example, 5 or more, the control unit 10 determines that the transmitted light amount sufficient for measurement is obtained, and continues. The same measurement is performed for the second and third wavelengths in the first wavelength region, and the light in the second wavelength region is not used for the measurement. If the SN ratio is less than 5, the control unit 10 determines that the transmitted light amount sufficient for measurement cannot be obtained with the light in the first wavelength region, and the light in the second wavelength region is measured.

From the amounts of transmitted light of three wavelengths in the relevant wavelength range, the concentrations of oxygenated hemoglobin and deoxygenated hemoglobin showing the oxygen metabolism function are obtained by the data processing unit 7 by the same method as in the first embodiment. The oxygenated hemoglobin concentration and the deoxygenated hemoglobin concentration thus obtained are converted into oxygen saturation indicating the oxygenation state of hemoglobin (ratio of oxygenated hemoglobin concentration to total hemoglobin concentration) and displayed on the display unit 8. It is also stored in the storage unit 9.

(Embodiment 3) A third embodiment of the present invention is shown in FIG.
A description will be given according to the apparatus configuration shown in FIG. The light source unit 1 has a wavelength of 50
Appropriate three wavelengths from the first wavelength range of 0 to 650 nm (hereinafter referred to as first, second and third wavelengths, respectively)
And a total of 6 wavelengths of appropriate 3 wavelengths (hereinafter referred to as the 4th, 5th and 6th wavelengths respectively) from the 2nd wavelength range of 750 to 850 nm. From the light source unit 1, for example, lights of the first and fourth wavelengths are simultaneously irradiated onto the subject 3 by the incident fiber 2. This incident optical fiber 2
An optical lens (not shown) is attached to the front end of the device, and irradiates light on the subject 3 in a non-contact and focused manner.

The light that has passed through the inside of the subject 3 is detected by the detection optical fiber 22-1 and the detection optical fiber 22-q arranged at a predetermined distance from the light irradiation position, for example, within 30 mm. The detection is performed by the detection optical fiber 23-r from the fiber 23-1 and the detection optical fiber 24-1 from the detection optical fiber 24-1 arranged at a distance of 30 mm or more from the light irradiation position. The detection optical fiber and the incident optical fiber 2 are attached to the optical fiber support ring 21. An optical lens (not shown) is attached to the tip of each detection optical fiber on the side of the subject 3 as in the case of the incident fiber 2. The other ends of these detection optical fibers are introduced into the multichannel photodetection section 25. As the multi-channel photodetector 25, for example, a photodiode array is used to independently detect the amount of detected light for each detection optical fiber.

FIG. 9 shows an introduction portion of the detection optical fiber to the multi-channel light detection portion 25. Here, a filter 26 is arranged on the end surfaces of the detection optical fiber 22-1 to the detection optical fiber 22-q and the detection optical fiber 23-1 to the detection optical fiber 23-r on the multi-channel photodetector 25 side. . This filter 26 allows light having a wavelength of 500 to 650 nm to pass therethrough, or has a wavelength of 750 nm.
To cut off 850 nm light. On the other hand, a filter 27 is arranged on the end faces of the detection optical fibers 24-1 to 24-s on the multi-channel photodetector 25 side. This filter 27 has a wavelength of 750 to 85.
Passes only 0 nm light, or has a wavelength of 500 nm
To cut light from 600 nm.

Therefore, only the light having a short wavelength (in this case, the first wavelength region) is measured in the detection optical fiber within the distance of 30 mm from the light irradiation position, and the long wavelength is detected in the detection optical fiber at the distance of 30 mm or more from the light irradiation position. Only the light (in this case, the second wavelength region) is measured. When the measurement at the first and fourth wavelengths is completed, the light source unit 1 is then controlled by the control unit 10 to irradiate the subject 3 with the second and fifth measurement wavelengths and measurement is performed in the same manner as above. . When the measurement at the second and fifth measurement wavelengths is completed, the measurement is continued at the third and sixth measurement wavelengths.

From these measurements, the concentrations of oxygenated hemoglobin and deoxygenated hemoglobin showing the oxygen metabolism function were determined from the detected light amounts measured by the respective detection optical fibers.
It is obtained by the method shown in. In this way, the projected image of the density at a plurality of detection positions with respect to one light irradiation position is obtained.

Next, the control unit 10 rotates the optical fiber support ring 21 as a whole by a predetermined angle to irradiate the subject 3 with light from a position different from the previous time, and at the same time, the light passing through the subject is also different from the previous time. Detect from different positions.

After the predetermined light measurement is completed at this irradiation position, the irradiation position is changed again. After repeating this operation, when the measurement for the predetermined light irradiation position is completed,
That is, when a predetermined number of projection images necessary for imaging are obtained, then the concentration distributions of oxygenated hemoglobin and deoxygenated hemoglobin are imaged from these projected images.
The image reconstruction process is performed by, for example, ACADEMIC PRESS, Inc.
GT Herm, issued in 980
an) book "Image reconstruction from projected image (Image reco
nstruction from projections) ”. The image thus obtained is displayed on the display unit 8 and at the same time stored in the storage unit 9.

[0040]

INDUSTRIAL APPLICABILITY In an apparatus for measuring a biological function using light, by changing the measurement wavelength according to the measured size of the biological body, it becomes possible to perform highly accurate measurement of the biological function for an arbitrary measured size. .

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing wavelength dependence of a light scattering coefficient of a living body.

FIG. 2 is a characteristic diagram showing wavelength dependence of a light absorption coefficient of water.

FIG. 3 is a characteristic diagram showing wavelength dependence of a light absorption coefficient of hemoglobin.

FIG. 4 is a characteristic diagram showing the measurement size dependency of the optical attenuation rate of a living body.

FIG. 5 is a block diagram of a first embodiment according to the present invention.

FIG. 6 is an explanatory diagram of a measurement size measuring unit.

FIG. 7 is a block diagram of a second embodiment according to the present invention.

FIG. 8 is a block diagram of a third embodiment according to the present invention.

FIG. 9 is an explanatory diagram showing the introduction of a detection optical fiber into a multi-channel photo detection unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source part, 2 ... Incident optical fiber, 3 ... Subject, 4 ... Detection optical fiber, 5 ... Measurement size measuring part, 6 ... Photodetection part,
7 ... Data processing section, 8 ... Display section, 9 ... Storage section, 10 ... Control section.

Front page continuation (72) Inventor Fumio Kawaguchi 1-280 Higashi Koikekubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Inventor Yoshitoshi Ito 1-280 Higashi Koikeku, Kokubunji, Tokyo Hitachi Central Research Co., Ltd. In-house (72) Inventor Hideaki Koizumi 1-280, Higashi Koigokubo, Kokubunji, Tokyo Inside Hitachi Central Research Laboratory

Claims (8)

[Claims] 1. The wavelength of the light applied to the living body is variable according to the distance between the irradiation position of the light applied to the living body and the detection position for detecting the light passing through the inside of the living body. Measuring method for living body light. 2. With respect to the light having a plurality of wavelengths applied to the living body, the light passing through the inside of the living body is detected at a plurality of detection positions, and the light having a specific wavelength is detected according to the distances from the irradiation positions to the respective detection positions. A living body optical measurement method comprising: 3. The living body optical measurement method according to claim 2, wherein the plurality of detection positions are divided into a plurality of detection position groups according to the distance from the light irradiation position, and the wavelengths to be detected are different for each group. 4. The wavelength 5 for irradiating a living body according to claim 3.
Light having a plurality of wavelengths in the region of 00 to 1400 nm is divided into a plurality of wavelength region groups for each smaller wavelength region, and detection positions having a short distance from the light irradiation position are sequentially arranged from a group of short wavelength regions to a group of long wavelengths A living body optical measurement method comprising measuring light in a wavelength region group corresponding to each detection position group in order from a group to a detection position group having a long distance. 5. A living body light measuring method, which comprises irradiating a living body with light of a plurality of wavelengths and selecting only wavelengths in which the amount of light detected by passing through the living body is equal to or more than a preset amount. 6. A wavelength range from 500 nm to 140 for irradiating a living body
Light of a plurality of wavelengths in the region of 0 nm is divided into a plurality of wavelength region groups for each smaller wavelength region, irradiated to the living body in order from a group of short wavelength regions to a group of long wavelengths, and passes through the living body for detection. A living body optical measurement method, characterized in that light of a wavelength region groove having a predetermined amount of light equal to or more than a preset amount is used for measurement. 7. A light source section in which light of a plurality of wavelengths is further divided into a plurality of wavelength region groups, an irradiation position for irradiating the living body with light from the light source section, and a detection position for detecting light passing through the living body. And a control unit that controls the wavelength region group emitted from the light source unit according to the distance obtained by the measurement size measuring unit. A biological optical measurement device. 8. A light source unit in which light of a plurality of wavelengths is further divided into a plurality of wavelength region groups, and a plurality of detection position groups according to a distance from an irradiation position at which light from the light source unit is applied to a living body. A living body optical measurement device comprising a photodetector that splits a wavelength for each detection position group at each of a plurality of divided positions and detects light that has passed through a living body.