JP2006305120A - Optical bioinstrumentation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical bioinstrumentation device in which reliability becomes high when the contribution rate of a biological section directly under the middle point of a light-sending point and a light-receiving point is made high to give data in a measuring point. <P>SOLUTION: Two or more pairs of the light-sending points T1 (T2) and the light-receiving points R1 (R2), in which the measuring point M becomes the same position, are established on a living body, a same measuring point two or more measuring section, which separately performs optical measurement about the measuring point M by using a measuring probe 11 for each pair of the light-sending points and the light-receiving points, and a measuring data calculation section, which computes optical measuring data about the measuring point based on two or more measured results separately optically measured by the same measuring point two or more measuring section, are included, and by performing normalizing treatment, the contribution directly under the light-sending point and the light-receiving point is reduced and the contribution directly under the measuring point is raised. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical biological measurement apparatus that acquires in-vivo information by measuring light transmitted and scattered in a living body, and more specifically, in-vivo information from a plurality of pairs of light transmission points and light receiving points. The present invention relates to an optical biological measurement apparatus that acquires Specifically, the optical biometric device of the present invention is used as, for example, a brain function diagnostic device that measures the distribution of activated sites in the brain or an oxygen monitor that measures changes in oxygen supply.

  Hemoglobin in blood is combined with oxygen to become oxyhemoglobin, and away from oxygen to deoxyhemoglobin. Hemoglobin plays a role of transporting oxygen to various parts of the living body by utilizing the property of being able to bind to and separate from oxygen. Since the amount of hemoglobin contained in blood increases and decreases according to the expansion and contraction of blood vessels, it is known to detect the expansion and contraction of blood vessels by measuring the amount of hemoglobin in the tissue.

Since oxyhemoglobin and deoxyhemoglobin in blood have different spectral absorption spectrum characteristics from visible light to near-infrared light region, for example, light absorption by hemoglobin in blood is measured using near-infrared light By doing so, the oxyhemoglobin concentration and the deoxyhemoglobin concentration can be calculated.
The oxyhemoglobin concentration and deoxyhemoglobin concentration change corresponding to oxygen metabolism in the living body. Therefore, oxyhemoglobin concentration and deoxyhemoglobin concentration in the blood of the brain, various organs, muscles, etc. in the living body are measured non-invasively by optical absorption measurement of near infrared light. An optical measurement method for living bodies has been established that measures changes in oxygen metabolism in each living body part and measures the state of that part.

For example, in the brain, a large amount of oxygen is consumed at the activated site, but it is normal that oxygen supply exceeding the consumed amount of oxygen is performed at the activated site by the blood flow redistribution action. As a result, the oxyhemoglobin concentration tends to increase at the activated site.
Therefore, a plurality of light transmitting points and light receiving points are arranged in a lattice pattern on the head, and light emitted from each light receiving point is guided by the light transmitting probe to the light transmitting points and irradiated into the living body. A multi-channel optical measurement device that observes activated sites in the brain by measuring changes in the oxyhemoglobin concentration and deoxyhemoglobin concentration at multiple different measurement points and measuring the distribution in the brain (See, for example, Patent Document 1).
JP 2001-337033 A

  The optical biological measurement device includes a multi-channel optical measurement device that performs measurement by determining a plurality of pairs of light transmission points and light reception points on a living body so that optical measurement can be performed at a plurality of measurement points, There is a single channel optical measurement device that measures one measurement point by a light transmission point and a light reception point. Whether it is a multi-channel optical measurement device or a single-channel optical measurement device, a pair of light transmission point and light reception point is set corresponding to one measurement point. The biological part immediately below the middle point (that is, on the perpendicular bisector of the light transmitting point and the light receiving point) is regarded as the position of the measurement point. The relationship between the pair of light transmission point and light reception point and the measurement point will be further described.

  FIG. 7A is a diagram showing a configuration of a conventional optical biometric device, and FIG. 7B shows a pair of light transmitting points and light receiving points, and these light transmitting points and light receiving points in the optical biometric device. It is a top view which shows the positional relationship with the measurement point defined by a pair of. The measurement probe 11 of the optical biological measurement apparatus 10 includes a light transmission probe 12 and a light reception probe 13, the light transmission probe end 14 is pressed against the light transmission point T on the living body B, and the light reception probe end 15 is the living body. It is pressed against the light receiving point R spaced apart from the light transmitting point T on B. At this time, the midpoint between the light transmission point T and the light receiving point R is regarded as the measurement point M. In the multi-channel optical measurement device, a plurality of pairs of the same light transmission point T and light reception point R are set, and there are a plurality of measurement points M corresponding to each pair.

  As shown in FIG. 7 (a), the light emitted from the light transmission point T travels randomly while being scattered by the tissue in the living body, and a part of the light reaches the light receiving point R, from here to the outside of the living body. Released. The light emitted from the light receiving point R contains a lot of information on light absorption in a region where transmitted scattered light passes densely in the living body. FIG. 8 is a plan view showing a sensitivity region S (measurement region) by a pair of light transmission point T and light reception point R from above. The sensitivity region S has an elliptical shape, and the light emitted from the light receiving point R contains a lot of information on the light absorption of the sensitivity region S.

  FIG. 9 is a diagram showing the spatial distribution of information relating to light absorption (contribution ratio in the detection light emitted from the light receiving point) in light and shade in a section cut out so as to pass the light transmitting point T and the light receiving point R. It is. The sensitivity region S by the pair of light transmitting point T and light receiving point R extends so as to become a banana-shaped region R. On the other hand, as shown in FIG. 7, the measurement point M defined by the pair of the light transmission point T and the light reception point R is regarded as a midpoint between the light transmission point T and the light reception point R. 3 and the light receiving point R is a measurement region, and as is clear from the comparison between the banana-shaped region R in FIG. 3 and the measurement point M in FIG. It is impossible to regard the information as information from the measurement point M. That is, depending on the depth from the living body surface, the ratio of light absorption information on the perpendicular bisector of the light transmitting point T and the light receiving point R is small. Rather, the light near the light transmitting point T and the light receiving point R is light. The percentage of information on absorption may be large. In particular, in a shallow region, most of the light absorption information near the light transmission point and the light reception point is present.

FIGS. 10 and 11 are diagrams for explaining the distribution of contribution to light absorption at depths d1 and d2 (d1 <d2) when optical measurement is performed using the pair of light transmission points and light reception points shown in FIG.
In the figure, an XY direction indicates a plane direction along the surface of the living body, and a Z direction indicates a large amount of information (contribution rate) of light absorption at a certain depth d.
The calculation of the contribution distribution can be obtained analytically, for example, by a calculation formula introduced in the following paper.
Michael S. Patterson, B. Chance, and BC Wilson, `` Time resolved reflectance and trancemittance for the non-invasive measurement of tissue optical properties '', 15 June (1989), Vol. 28, No. 12, p2331-2336, APPLIED OPTICS

  In a shallow region (depth d1) close to the surface of the living body, as shown in FIG. 10, two steep peaks are generated at positions corresponding to the light transmitting point and the light receiving point, and the tissue immediately below the light transmitting point and the light receiving point. The contribution rate from is high. On the other hand, there is no peak at the position of the depth d1 at the midpoint between the light transmission point and the light receiving point (that is, the position immediately below the measurement point), and the contribution rate is almost zero. For this reason, in the shallow region of the depth d1, the information immediately below the measurement point has little influence on the measurement result.

  On the other hand, in the deep region (depth d2, d1 <d2), as shown in FIG. 11, the two peaks at the positions corresponding to the light transmitting point and the light receiving point are slightly gentler as compared to FIG. However, the contribution ratio is almost the same. In addition, a buttock is generated at the position of the depth d2 at the midpoint, and the contribution rate is about half the peak, but the influence from the position of the depth d2 immediately below the measurement point affects the measurement result. .

  Therefore, although the measurement data obtained by the conventional optical biometric device has some contribution from the living body part immediately below the midpoint regarded as the measurement point, it is not sufficient, and the midpoint can be regarded as the measurement point. Sometimes it was not appropriate. In particular, if a singular point exists in a living body part directly below a light transmitting point or a light receiving point, the influence of the singular point is reflected in a deep color, and thus the data may be low in reliability.

Therefore, an object of the present invention is to provide an optical biometric measuring device in which the contribution rate from the living body part immediately below the midpoint is increased as much as possible to increase the reliability when the data at the measurement point is used. To do.
It is another object of the present invention to provide an optical biological measurement apparatus that averages the contribution ratios immediately below the light transmitting point and the light receiving point as much as possible and diminishes the influence from this part.

  An optical living body measuring apparatus of the present invention made to solve the above-described problem is a light transmitting probe that sets a pair of light transmitting point and light receiving point on a living body and guides and irradiates light source light to the light transmitting point. Using a measuring probe that is paired with a light receiving probe that guides the light emitted from the light receiving point to the photodetector, light transmitted through the living body from the light transmitting point to the light receiving point is detected, and the light transmitting point and the light receiving point are detected. An optical biological measurement apparatus that performs light measurement at a measurement point by regarding the midpoint as a measurement point in this measurement, and sets a plurality of pairs of light transmission points and light reception points at which the measurement points are at the same position on the living body, The same measurement point multiple measurement unit that performs optical measurement separately for each measurement point using a measurement probe for each pair of light transmission point and light reception point, and a plurality of light measurements that are separately measured by the same measurement point multiple measurement unit Based on the measurement result, the optical measurement data for the measurement point So that and a measurement data calculation unit for output.

According to this apparatus, when a living body part to be subjected to optical measurement is determined as a measurement point, a plurality of pairs of light transmission points and light receiving points are set on the living body corresponding to the measurement points. At this time, a plurality of pairs of light transmission points and light reception points are set such that the measurement point is the midpoint position between the light transmission point and the light reception point. The light transmission point and the light reception point may be set by preparing a positioning holder for determining the positional relationship between the light transmission point and the light reception point, and fixing the probe to the holder, or by a plurality of pairs of light transmission probes. Alternatively, a measurement probe in which the light receiving probe is previously positioned may be used.
The same measurement point measurement unit guides the light from the light source to the light transmission point by the light transmission probe and irradiates the living body separately for each pair of the light transmission point and the light reception point. The light passes through the living body while being scattered, and part of the light reaches a pair of light receiving points, and is emitted from the light receiving point outside the living body. Since the emitted light is guided to the photodetector by the light receiving probe, it is detected. The same measurement point measurement unit performs this detection for each pair of a light transmission point and a light reception point, and obtains a plurality of measurement results from different pairs of light transmission points and light reception points for the same measurement point. The data detected for each pair of light transmitting point and light receiving point includes contributions from directly below the measurement point, as well as contributions from directly below the light transmitting point and the light receiving point. Of these, the contribution of the former (just below the measurement point) is common to all pairs, and the contribution of the latter (just below the light transmission point and light reception point) is different in all pairs.
Then, the measurement data measurement unit performs an arithmetic process for removing the influence of the vicinity of the light transmission point and the light reception point, such as an averaging process, based on a plurality of measurement results obtained separately for the same measurement point. Optical measurement data is obtained by amplifying the contribution from directly below. Thereby, about the said measurement point, the measurement result which reduced the influence of the light transmission point and the light reception point vicinity, and enlarged the influence directly under a measurement point is obtained.

Here, the measurement point may be any of the head, trunk, upper limb, and lower limb on the living body. Optical measurement of the brain, various organs, and muscles can be performed according to the measurement position.
Near-infrared light is preferably used as the light source light, but any light source capable of irradiating light having a wavelength capable of detecting an absorption difference due to oxyhemoglobin or deoxyhemoglobin may be used.

  Prepare multiple measuring probes consisting of a light-transmitting probe and a light-receiving probe according to the number of pairs of light-transmitting points and light-receiving points, and fix them to the living body in advance using a holder or the like for fixing the probes to the living body. It is preferable that the measurement can be performed efficiently and stably, but it is also possible to perform measurement by moving one measurement probe to a pair of different light transmission points and light reception points in sequence and using them again. .

According to the present invention, it is possible to obtain measurement data in which the contribution ratio from the living body part directly below the midpoint between the light transmission point and the light reception point can be obtained, so that the midpoint between the light transmission point and the light reception point is defined as the measurement point. When it is considered, the reliability of the measurement result can be increased.
In addition, according to the present invention, the contribution ratios in the vicinity of the light transmission point and the light receiving point are averaged, so that measurement data with less influence from this part can be obtained, and the specific data immediately below the light transmission point and the light receiving point can be obtained. Even if there is a point, the effect can be weakened.

(Means and effects for solving other problems)
In the above invention, it is preferable that the pair of the light transmitting point and the light receiving point be arranged on a concentric circle with the measurement point as the center.
That is, when one light transmission point / light reception point pair is used as a reference, the other light transmission point / light reception point pairs are arranged so as to be rotated around the measurement point. Specifically, when two pairs of light transmission points and light reception points are used, the light transmission points and the light reception points are arranged at positions rotated by 90 degrees. When three pairs of light transmission points and light reception points are used, the light transmission points and the light reception points are arranged at positions rotated by 60 degrees.
According to this, since the banana-shaped region, which is the sensitivity region created by each pair of light transmission point and light reception point, has the same shape and rotates around the measurement point, the light transmission point such as averaging processing Thus, the arithmetic processing for removing the influence of the vicinity of the light receiving point is facilitated.

Hereinafter, the optical biological measurement apparatus of the present invention will be specifically described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a single-channel optical biometric device showing an embodiment of the present invention, and FIG. 1 (a) is a perspective view when a measurement probe of the optical biometric device is set on a biological surface, FIG. 1B is a plan view showing the positional relationship between two pairs of light transmission points and light reception points and measurement points defined by the pairs of light transmission points and light reception points.

  The optical biological measurement apparatus 1 includes an apparatus main body 10 and a measurement probe 11. The measurement probe 11 of the optical biological measurement apparatus 1 includes light transmission probes 12a and 12b and light reception probes 13a and 13b. The light transmission probe ends 14a and 14b are pressed against the light transmission points T1 and T2 on the living body B. Further, the light receiving probe ends 15a and 15b are pressed against the light receiving points R1 and R2 that are separated from the light transmitting points T1 and T2 on the living body. The light transmitting points T1 and T2 and the light receiving points R1 and R2 are arranged at positions rotated 90 degrees on concentric circles. At this time, the midpoint between the light transmission point T1 (T2) and the light receiving point R1 (R2) is regarded as the measurement point M.

The apparatus main body 10 includes a control unit 20 that performs control necessary for optical measurement. If the control which this control part 20 performs is demonstrated for every function, it will be divided into the same point multiple measurement part 21 and the measurement data calculation part.
The same point multiple measuring unit 21 transmits light from a light source (built in the apparatus main body 10) separately for each pair of light transmitting point T1 (T2) and light receiving point R1 (R2) by a light transmitting probe 12a (12b). The light is guided to the light spot T1 (T2) and controlled to irradiate the living body. The light is transmitted while being scattered in the living body, reaches a light receiving point R1 (R2) that is partly paired, and is emitted from the light receiving point to the outside of the living body. Since the emitted light is guided to the photodetector (built in the apparatus main body 10) by the light receiving probe 13a (13b), the same point multiple measuring unit 21 performs control to detect this. Further, the same measurement point measurement unit 21 performs this detection for each pair of the light transmission point and the light reception point, and obtains a plurality of measurement results by using different pairs of the light transmission point and the light reception point for the measurement point M. The data detected for each pair of light transmitting point and light receiving point includes contributions from directly below the measurement point M, as well as contributions from each light transmitting point T1 (T2) and R1 (R2) immediately below each light receiving point. Of these, the former (immediately below the measurement point) contribution is included in the measurement data for all pairs in common, and the latter (immediately below the light transmission and reception points) contribution is included only in the corresponding pair of measurement data. become.

  The measurement data measurement unit 22 performs an averaging process on the basis of a plurality of measurement data separately obtained for the measurement point M, and performs an arithmetic process for removing the influence of the vicinity of the light transmission point and the light reception point, thereby directly below the measurement point. Control to obtain optical measurement data in which the contribution from is amplified.

  As shown in FIG. 1 (a), the light irradiated from the light transmission point T1 (T2) travels randomly while being scattered by the tissue in the living body, and a part of the light reaches the light receiving point R1 (R2). From here, it is released out of the living body. The light emitted from the light receiving point R1 (R2) contains a lot of information on light absorption in a region where transmitted and scattered light in the living body densely passes. FIG. 2 is a diagram in which a sensitivity region due to a pair of light transmission point T1 and light reception point R1 and a sensitivity region due to a pair of light transmission point T2 and light reception point R2 are shown in a plane overlapping from above. The sensitivity region S has a round cross shape in which two elliptical sensitivity regions overlap at the center.

  3 and 4 show optical measurements at the two pairs of light transmission points and light reception points shown in FIGS. 1 and 2, respectively, and the depths d1 and d2 (d1 <d2) when the two measurement data are added together. It is a figure explaining the contribution distribution to light absorption. These are compared with FIGS. 10 and 11 described in the conventional example.

In the shallow region (depth d1) close to the surface of the living body, as shown in FIG. 3, four steep peaks are generated at positions corresponding to the light transmitting point and the light receiving point, and the tissue immediately below the light transmitting point and the light receiving point. The contribution rate from is increasing. On the other hand, there is almost no peak at the position of the depth d1 at the midpoint (that is, the position immediately below the measurement point M), and the contribution rate is almost zero. For this reason, in the shallow region of the depth d1, the information immediately below the measurement point M has little influence on the measurement result, as in FIG.
However, in the deep region (depth d2), as shown in FIG. 4, there are peaks at positions corresponding to the light transmitting point and the light receiving point as compared to FIG. 11, and at the four light transmitting points and the light receiving points. There is a peak of almost the same level in the center of the sandwiched value. That is, it is possible to increase the contribution rate immediately below the midpoint that is the measurement point M, and the midpoint neighborhood influence in the measurement data is strong.

  Next, the measurement operation of the optical biological measurement apparatus 10 using the measurement data by the two pairs of light transmission points and light reception points described above will be described. For the measurement point M, first, optical measurement measurement is performed using a pair of a light transmission point T1 and a light reception point R1. Subsequently, optical measurement measurement is performed using a pair of a light transmission point T2 and a light reception point R2. And the average value (namely, half value of total data) of 2 times optical measurement data is calculated. Thereby, measurement data with an increased contribution rate directly below the measurement point M can be obtained.

  In the above embodiment, two pairs of light transmission points and light reception points are set. However, the present invention is not limited to this. As shown in FIG. 5, three pairs of light transmission points T1 to T3 and light reception points R1 to R3 are used. Thus, the contribution rate directly below the measurement point may be further increased by adding the three measurements. In this case, as shown in FIG. 6, a sensitivity region S having convex portions rounded in six directions is formed. If the number of pairs of light transmission points and light reception points is further increased, the contribution ratio directly under the measurement point can be further increased, but the cost of the apparatus also increases, so the number of pairs can be determined in relation to the cost. That's fine.

  Moreover, although the said embodiment is a single channel optical biometric apparatus which measures about one measurement point, it cannot be overemphasized that this can be applied to a multichannel optical biometric apparatus.

  INDUSTRIAL APPLICABILITY The present invention can be used for an optical biological measurement apparatus that uses light absorption of hemoglobin, such as a brain function diagnostic apparatus or an oxygen monitor.

It is a figure which shows the structure of the optical biological measurement apparatus which is one Embodiment of this invention, Fig.1 (a) is a perspective view in the state which attached the measurement probe to the biological body, FIG.1 (b) is a light transmission point and light reception. It is a figure which shows the positional relationship of a point and a measurement point. It is a figure explaining the sensitivity area | region in the optical biological measurement apparatus of FIG. It is a figure explaining the contribution rate in shallow depth d1 by the optical biological measuring apparatus of FIG. It is a figure explaining the contribution rate in deep depth d2 (d1 <d2) by the optical biological measuring apparatus of FIG. It is a figure which shows the positional relationship of the light transmission point in the optical biological measurement apparatus which is other one Embodiment of this invention, a light receiving point, and a measurement point. It is a figure explaining the sensitivity area | region in the optical biological measurement apparatus of FIG. It is a figure which shows the structure of the conventional optical biological measuring apparatus, Fig.7 (a) is sectional drawing when a probe is attached to the biological body, FIG.1 (b) is a position of a light transmission point, a light receiving point, and a measurement point. It is a figure which shows a relationship. It is a figure explaining the sensitivity area | region in the conventional optical biological measurement apparatus. It is a figure explaining the banana-shaped area | region formed between the light transmission point in a photobiological measuring device, and a light reception point. It is a figure explaining the contribution rate in shallow depth d1 by the optical living body measuring device of FIG. is there. It is a figure explaining the contribution rate in deep depth d2 (d1 <d2) by the optical biological measuring apparatus of FIG.

Explanation of symbols

10: Optical biological measurement device 11: Measurement probe 12a, 12b: Light transmission probe 13a, 13b: Light reception probe T1, T2: Light transmission point R1, R2: Light reception point M: Measurement point S: Sensitivity region

Claims (2)

A pair of a light transmitting point and a light receiving point that are paired on a living body, a light transmitting probe that guides and emits light from the light source to the light transmitting point, and a light receiving probe that guides light emitted from the light receiving point to a photodetector The light transmitted through the living body from the light transmitting point to the light receiving point is detected using a measurement probe consisting of the above, and the midpoint of the light transmitting point and the light receiving point is regarded as the measurement point in this measurement, and light measurement is performed at the measurement point An optical biometric device,
Set multiple pairs of light transmission points and light reception points on the living body where the measurement points are at the same position, and use the measurement probe for each pair of light transmission points and light reception points to perform optical measurement separately for the measurement points. The same measurement point multiple measurement unit to perform,
An optical biological measurement apparatus comprising: a measurement data calculation unit that calculates optical measurement data for the measurement point based on a plurality of measurement results separately measured by the same measurement point multiple measurement unit. The optical biological measurement apparatus according to claim 1, wherein the pair of the light transmission point and the light reception point is arranged on a concentric circle with the measurement point as a center.