JP2010148794A - Optical measurement apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical measurement apparatus obtaining accurate received light quantity information. <P>SOLUTION: The optical measurement apparatus is characterized in that a probe 12 irradiates the surface of a subject with light and makes the light to be incident from the surface. A control part 20 obtains first received light quantity information from a forward route by transmitting the light from a light emitting part 2 through an optical transmission line 13 to a first probe 12 and receiving the light from a second probe 12 in a photodetection part 3 through the optical transmission line 13, obtains second received light quantity information from an inverse route by transmitting the light from the light emitting part through the optical transmission line 13 to the second probe 12 and receiving the light from the first probe 12 in the photodetection part 3 through the optical transmission line 13, and calculates the received light quantity information relating to a measurement part by using the first received light quantity information and the second received light quantity information. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical measurement device that obtains received light amount information about a measurement site inside a subject using light, and more particularly to an optical brain functional imaging device that measures brain activity non-invasively.

In recent years, in order to observe the activity state of the brain, an optical brain functional imaging apparatus has been developed that performs noninvasive measurement using light. Such an optical brain functional imaging apparatus includes a light transmitting probe and a light receiving probe. As a result, in the optical brain functional imaging apparatus, near-infrared light of two different wavelengths λ ₁ and λ ₂ (for example, 780 nm and 830 nm) is applied to the brain by a light transmission probe arranged on the surface of the subject's scalp. While irradiating, the intensity (received light amount information) A (λ ₁ ) and A (λ ₂ ) of near-infrared light of each wavelength emitted from the brain is detected by a light receiving probe arranged on the scalp surface.
The near-infrared light of each wavelength λ ₁ and λ ₂ is transmitted through the scalp tissue and bone tissue, and oxyhemoglobin and deoxyhemoglobin have different spectral absorption spectrum characteristics from visible light to the near-infrared region. In particular, it is absorbed by either oxyhemoglobin or deoxyhemoglobin in the blood.

Then, from the received light quantity information A (λ ₁ ) and A (λ ₂ ) thus obtained, the concentration / optical path length product [oxyHb] of oxyhemoglobin in the cerebral blood flow and the concentration / optical path length of deoxyhemoglobin In order to obtain the product [deoxyHb], for example, the simultaneous equations shown in the relational expressions (1) and (2) are created using the Modified Beer Lambert rule, and the simultaneous equations are solved (for example, Non-Patent Document 1). reference). Furthermore, the concentration / optical path length product of total hemoglobin ([oxyHb] + [deoxyHb]) is calculated from the concentration / optical path length product [oxyHb] of oxyhemoglobin and the deoxyhemoglobin concentration / optical path length product [deoxyHb]. Yes.
A (λ ₁ ) = E _O (λ ₁ ) × [oxyHb] + E _d (λ ₁ ) × [deoxyHb] (1)
A (λ ₂ ) = E _O (λ ₂ ) × [oxyHb] + E _d (λ ₂ ) × [deoxyHb] (2)
E _O (λm) is an absorbance coefficient of oxyhemoglobin in light having a wavelength λm, and E _d (λm) is an absorbance coefficient of deoxyhemoglobin in light having a wavelength λm.

Here, the relationship between the distance (channel) between the light transmitting probe and the light receiving probe and the measurement site will be described. FIG. 4A is a cross-sectional view showing a relationship between a pair of light transmitting probe and light receiving probe and a measurement site, and FIG. 4B is a plan view of FIG.
The light transmitting probe 61 is pressed against the light transmitting point T on the surface of the subject's scalp, and the light receiving probe 62 is pressed against the light receiving point R on the surface of the subject's scalp. Then, light is emitted from the light transmitting probe 61 and light emitted from the scalp surface is incident on the light receiving probe 62. At this time, among the light irradiated from the light transmission point T on the scalp surface, the light passing through the banana shape (measurement region) reaches the light receiving point R on the scalp surface. As a result, in the measurement region, the light transmitting point T and the light receiving point R, particularly from the midpoint M of the line L connecting the light transmitting point T and the light receiving point R at the shortest distance along the surface of the subject's scalp. Received light quantity information A (λ ₁ ) and A (λ ₂ ) relating to the part S of the subject having a depth L / 2 which is half the distance of the line connecting the shortest distances along the scalp surface of the subject. can get.

In the optical brain functional imaging system, oxyhemoglobin concentration / optical path length product [oxyHb], deoxyhemoglobin concentration / optical path length product [deoxyHb], and total hemoglobin concentration / optical path length product for multiple measurement sites of the brain ( In order to measure [oxyHb] + [deoxyHb]), for example, a near-infrared spectrometer (hereinafter abbreviated as NIRS) is used (for example, see Patent Document 1).
In such an optical brain functional imaging apparatus, a holder is used in order to bring a plurality of light transmitting probes and a plurality of light receiving probes into close contact with the scalp surface of the subject in a predetermined arrangement. As such a holder, for example, a molded holder molded into a scissors shape according to the shape of the scalp surface is used. The molding holder is provided with (S + T) through holes, and S light transmitting probes and T light receiving probes are inserted into the through holes.
FIG. 5 is a diagram illustrating an example of a positional relationship between four light transmitting probes and five light receiving probes, and a light emitting unit and a light detecting unit. The light transmitting / receiving unit 60 is a hemispherical shape in which light transmitting probes 61a to 61d and light receiving probes 62a to 62e are arranged in a square lattice so as to alternate in the row direction and the column direction. And the light transmission / reception part 60 is mounted | worn with a test subject's head.

The light transmitting probes 61a to 61d and the light receiving probes 62a to 62e are connected to a cylindrical optical fiber (optical transmission line) 13 having an elongated diameter of about 1.5 mm. One end of the optical fiber 13 is connected to the scalp of the subject. The surface can be contacted.
The other end of the optical fiber 13 connected to the light transmitting probes 61 a to 61 d is connected to the light emitting unit 2. The light emitting unit 2 emits near infrared light. As a result, near-infrared light emitted from the light emitting unit 2 enters one of the other end portions of the optical fiber 13. The near infrared light incident from the other end of the optical fiber 13 passes through the optical fiber 13 and is emitted from one end of the optical fiber 13.
The other end of the optical fiber 13 connected to the light receiving probes 62 a to 62 e is connected to the light detection unit 3. The light detection unit 3 detects near-infrared light intensities A (λ ₁ ) and A (λ ₂ ). As a result, near-infrared light incident from one end of the optical fiber 13 passes through the optical fiber 13 and exits from the other end of the optical fiber 13. Then, near-infrared light emitted from the other end of the optical fiber 13 enters the light detection unit 3.

Using such a light transmitting / receiving unit 60, light is emitted from the light transmitting probes one by one in order, and light emitted from the scalp surface is incident on the five light receiving probes 62a to 62e, so that 20 points can be obtained. The received light amount information A _n (λ ₁ ), A _n (λ ₂ ) (n = 1, 2,..., 20) is obtained. Further, from the received light quantity information A _n (λ ₁ ), A _n (λ ₂ ) at 20 measurement sites, the simultaneous equations as described above are created, and the oxyhemoglobin concentration / optical path length product [oxyHb], Deoxyhemoglobin concentration and optical path length product [deoxyHb] are calculated.

However, in the light transmitting / receiving unit 60 as described above, in order to obtain received light amount information A _n (λ ₁ ), A _n (λ ₂ ) (n = 1, 2,..., 20) regarding 20 measurement sites. Since it is necessary to arrange a total of nine probes including four light transmitting probes 61a to 61d and five light receiving probes 62a to 62e on the scalp surface, nine probes are arranged in a narrow range in the scalp surface. Even if it is going to arrange | position, since arrangement | positioning becomes difficult, there existed a problem that many measurement site | parts could not be set in a narrow range.

Therefore, the light emitting function and the light incident function are separately provided such that the light emitting probes 61a to 61d have a function of emitting light and the light receiving probes 62a to 62e have a function of incident light. An optical brain functional imaging apparatus including a probe having both a function of emitting light and a function of entering light has been developed (for example, see Patent Document 2).
FIG. 6 is a diagram illustrating an example of a positional relationship of probes having both a function of emitting light and a function of entering light, and a light emitting unit and a light detecting unit. FIG. 7 is a cross-sectional view showing the relationship between a pair of probes and a measurement site.
The light transmitting / receiving unit 70 is hemispherical in which probes 71a to 71i are arranged in the row direction and the column direction. The probe 71 is connected to a cylindrical optical fiber (light transmission path) 72 having an elongated diameter of about 3 mm, and one end of the optical fiber 72 can be brought into contact with the surface of the subject's scalp.

The optical fiber 72 includes a quartz single-core fiber 72a having a diameter of about 1.5 mm, a multi-component bundle fiber 72b that covers the outer peripheral surface of the quartz single-core fiber 72a, and a covering portion (not shown) that covers the outer peripheral surface of the multi-component bundle fiber 72b. ). The quartz single-core fiber 72a and the multi-component bundle fiber 72b are branched in the middle as shown in FIG. 8, and the other end of the quartz single-core fiber 72a is connected to the light emitting unit 2 and the multi-component. The other end of the bundle fiber 72b is connected to the light detection unit 3.
The quartz single-core fiber 72a can transmit near-infrared light in the axial direction, and near-infrared light incident from the other end passes through the inside and exits from one end. The multi-component bundle fiber 72b can transmit near infrared light in the axial direction, and near infrared light incident from one end passes through the inside and exits from the other end.

Using such a light transmitting / receiving unit 70, light is emitted from the probes one by one in order, and light emitted from the scalp surface is incident on eight probes other than the probe irradiated with near infrared light. Thus, the received light quantity information A _n (λ ₁ ), A _n (λ ₂ ) (n = 1, 2,..., 36) regarding the total (9 × 8) / 2 measurement sites is obtained. That is, even when nine probes are used as in the case of the light transmitting / receiving unit 60, 36 measurement sites can be set.
JP 2006-109964 A JP-A-10-148611 Factors affecting the accuracy of near-infrared spectroscopy concentration calculations for focal changes in oxygenation parameters, NeuroImage 18, 865-879, 2003

However, as shown in FIG. 7, among the light irradiated from the light transmission point T on the scalp surface, the light that has passed through the banana shape reaches the light receiving point R on the scalp surface. Therefore, even if the position of the light transmitting point T and the position of the light receiving point R are reversed, the received light amount information A _n (λ ₁ ) and A _n (λ ₂ ) having the same value must be obtained. However, the received light amount information A _n (λ ₁ ), A _n (λ ₂ ) having different values is obtained. That is, since the inside of the head has an inhomogeneous structure, light that has actually passed through a more complicated shape than the banana shape reaches the light receiving point R. For example, as shown in FIG. 9A, if the frontal sinus A exists immediately below the light transmission probe 71, in practice, most of the light emitted from the light transmission point T It will be reflected by frontal sinus A. On the other hand, as shown in FIG. 9B, since cerebrospinal fluid exists if the frontal sinus A does not exist immediately below the light transmission probe 71, most of the light emitted from the light transmission point T is present. This light will be transmitted through the cerebrospinal fluid.

In order to solve the above-mentioned problems, the present inventors have studied to obtain accurate received light amount information. Therefore, by irradiating light from the light transmission point T and making light incident at the light reception point R, not only the first light reception amount information from the forward path is obtained, but also the light reception point R is used as the light transmission point T. , And the second light reception amount information from the forward path and the reverse path is obtained by making the light incident with the light transmission point T as the light reception point R, and the first light reception amount information and the second light reception amount information are obtained. It was found that the received light amount information on the measurement site was calculated using
In addition, when calculating the concentration / optical path length product [oxyHb] of oxyhemoglobin, the light transmitting / receiving unit 70 not only treats the center of one end of the optical fiber 72 as the light transmitting point T but also as the light receiving point R. In practice, one end of the multi-component bundle fiber 72b has a cylindrical shape formed between an inner circumference circle having a diameter of about 1.5 mm and an outer circumference circle having a diameter of about 3 mm. No near-infrared light is incident from R. Therefore, in order to calculate the received light amount information regarding the measurement site using the first received light amount information and the second received light amount information, it is more preferable to adopt a configuration in which light is accurately incident from the light receiving point R. I found it.

  That is, the optical measurement device of the present invention includes a light transmitting / receiving unit having a plurality of probes arranged on the surface of a subject, a light emitting unit that emits light, a light detecting unit that detects light, and one light detecting unit. An optical transmission line group to which the probe and one end of one optical transmission line are respectively connected, and light is transmitted from the light emitting part to the probe through the optical transmission line, and light is emitted from the probe by the light detection part. And a control unit that obtains received light amount information regarding a plurality of measurement sites inside the subject by controlling to receive light through a transmission path, wherein the probe includes the probe It is possible to irradiate light on the surface of the subject or to enter light from the surface, and the control unit transmits light from the light emitting unit to the first probe via the optical transmission path. At the same time, the light from the second probe passes through the optical transmission line. The first light receiving amount information from the forward path is obtained by receiving the light at the light detecting unit, and light is transmitted from the light emitting unit to the second probe through the optical transmission path, and from the first probe. By receiving light at the light detection unit via the optical transmission path, the second received light amount information from the forward path and the reverse path is obtained, and using the first received light amount information and the second received light amount information, The received light amount information relating to the measurement site is calculated.

  According to the light measurement apparatus of the present invention, first, light is transmitted from the light emitting unit to the first probe via the optical transmission path, and the light from the second probe is transmitted to the first probe via the optical transmission path. The first received light amount information from the forward path is obtained by receiving the light. Next, the light is transmitted from the light emitting unit to the second probe through the optical transmission path, and the light from the first probe is received by the light detection unit through the optical transmission path. The second received light amount information is obtained. That is, not only the first received light amount information is obtained by irradiating light from the light transmitting point T and entering light at the light receiving point R, but also irradiating light with the previous light receiving point R as the light transmitting point T. The second received light amount information is obtained by making the light incident with the previous light transmitting point T as the light receiving point R. Thereby, the received light amount information relating to the measurement site is calculated using the first received light amount information and the second received light amount information.

  As described above, according to the light measurement device of the present invention, accurate light reception amount information can be obtained without being affected by the forward path or the reverse path.

(Means and effects for solving other problems)
In addition, the optical measurement device of the present invention includes an optical path switching unit connected to the other end of the optical transmission path and connected to the light emitting unit and the light detection unit, and the optical path switching unit includes the light emitting unit. The light path is switched so that the light emitted from the light transmission path is incident on the other end of the light transmission path or the light emitted from the other end of the light transmission path is incident on the light detection section. The control unit transmits light from the light emitting unit to the at least one probe selected from the plurality of probes via the optical transmission path and transmits the light. You may make it control the said optical path switching part so that the light from all the probes other than a probe may be received by the light detection part via an optical transmission path.
According to the light measurement device of the present invention, it is possible to obtain second received light amount information that is accurately reverse to the forward path from which the first received light amount information was obtained.

In the optical measuring device of the present invention, the optical path switching unit may be an optical switch group connected to one optical switch and the other end of one optical transmission path.
Furthermore, in the light measurement device of the present invention, the control unit may calculate an average value of the first received light amount information and the second received light amount information as the received light amount information.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment, It cannot be overemphasized that various aspects are included in the range which does not deviate from the meaning of this invention.

FIG. 1 is a block diagram showing a configuration of an optical brain function imaging apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of the positional relationship of the probe, the light emitting unit, and the light detecting unit.
The optical brain functional imaging apparatus 1 includes a light transmission / reception unit 11, a light emitting unit 2, a light detection unit 3, an optical path switching unit 5, an optical fiber (optical transmission path) group 14, and an overall control of the optical brain functional imaging apparatus 1. It is comprised with the control part (computer) 20 which performs.
The light transmitting / receiving unit 11 has nine probes 12a to 12i, and is a hemispherical shape in which the nine probes 12a to 12i are arranged in the row direction and the column direction. The shortest distance between the probes is 30 mm.
The probes 12a to 12i are connected to a cylindrical optical fiber (optical transmission line) 13 having an elongated diameter of about 1.5 mm so that one end of the optical fiber 13 can contact the scalp surface of the subject. It has become.
The optical fiber 13 includes a multi-component bundle fiber 13a and a covering portion (not shown) that covers the outer peripheral surface of the multi-component bundle fiber 13a. The multi-component bundle fiber 13a can transmit near-infrared light in the axial direction, and near-infrared light incident from one end passes through the inside and exits from the other end or enters from the other end. The near-infrared light that has passed through the inside passes through the inside and exits from one end.

The light emitting unit 2 emits near-infrared light having one set wavelength selected from two set wavelengths according to a drive signal input from the computer 20. For example, 780 nm (λ ₁ ) and 850 nm (λ ₂ ) are used as the set wavelength.
The light detection unit 3 outputs the received light amount information A _n (λ _m ) to the computer 20 by detecting the intensity of near infrared light.

The optical path switching unit (optical switch group) 5 includes nine optical switches (for example, trade name: IOTech, NIR model, etc.) 5a to 5i.
The optical switch 5 a is connected to the other end of the optical fiber 13 connected to the probe 12 a, connected to the light emitting unit 2, and connected to the light detecting unit 3. The optical switch 5a includes, for example, a mirror (not shown), and makes near infrared light emitted from the light emitting unit 2 incident on the other end of the optical fiber 13 by the mirror or the like. The near infrared light emitted from the end portion can be switched so as to be incident on the light detection unit 3. Such control of the mirror or the like is performed by a drive signal input from the computer 20.
Similarly to the optical switch 5a, the optical switches 5b to 5i are also connected to the other end of the optical fiber 13 connected to the probes 12b to 12i, connected to the light emitting unit 2, and connected to the light detecting unit 3, respectively. Is done. The optical switches 5b to 5i also cause the near-infrared light emitted from the light emitting unit 2 to enter the other end of the optical fiber 13 or the near-infrared light emitted from the other end of the optical fiber 13 as light. It can be switched so as to be incident on the detection unit 3. Such mirror control is also performed by a drive signal input from the computer 20.

The computer 20 includes a CPU 21, and further includes a memory 25, a display device 23 having a monitor screen 23 a and the like, and a keyboard 22 a and a mouse 22 b that are input devices 22.
Further, the functions processed by the CPU 21 will be described in the form of blocks. The CPU 21 includes a light emitting / receiving unit control unit 4 that controls the light emitting unit 2, the light detection unit 3, and the optical path switching unit 5, and a brain activity calculation unit 31. Furthermore, the memory 25 includes a received light amount information storage area 51 that stores received light amount information A _n (λ _m ), and an optical path switching timing storage area 52 that stores an optical path switching timing table that indicates the timing for switching the optical path.

The light transmission / reception unit control unit 4 receives the light reception amount information A _n (λ _m ) from the light emission control unit 42 that outputs a drive signal to the light emission unit 2 and the light detection unit 3, thereby receiving the light reception amount information A _n (λ _m ) is stored in the received light amount information storage area 51, and the optical path switching control unit 44 outputs a drive signal to the optical path switching unit 5.
Based on the optical path switching timing table stored in the optical path switching timing storage area 52, the light emission control unit 42 emits near-infrared light having one set wavelength selected from two types of set wavelengths. Is output to the light emitting unit 2. For example, first, a drive signal is output to the light emitting unit 2 such that near-infrared light of 780 nm is emitted, and then that near-infrared light of 850 nm is emitted at a predetermined interval.

Based on the optical path switching timing table stored in the optical path switching timing storage area 52, the optical path switching control unit 44 performs control to output drive signals to the nine optical switches 5a to 5i. For example, first, a drive signal for causing near-infrared light emitted from the light emitting unit 2 to enter the other end of the optical fiber 13 is output to the optical switch 5a, and other optical fibers 13 are supplied to the optical switches 5b to 5i. A drive signal that causes near-infrared light emitted from the end portion to enter the light detection unit 3 is output. That is, near infrared light is transmitted to one probe 12a, and light is received from eight probes 12b to 12i other than the probe 12a that has transmitted near infrared light.
Next, a drive signal for causing near-infrared light emitted from the light emitting unit 2 to enter the other end of the optical fiber 13 is output to the optical switch 5b, and from the other end of the optical fiber 13 to the optical switch 5a. A drive signal that causes the emitted near-infrared light to enter the light detection unit 3 is output. That is, near-infrared light is transmitted to one probe 12b, and light is received from eight probes 12a and 12c to 12i other than the probe 12b that transmitted near-infrared light.
In this way, near infrared light is irradiated from the probes one by one in order, and near infrared light emitted from the scalp surface is incident on eight probes other than the probe irradiated with the near infrared light.

The light detection control unit 43 receives the light reception amount information A _n (λ _m ) from the light detection unit 3 to perform control for storing the light reception amount information A _n (λ _m ) in the light reception amount information storage area 51. For example, when the optical switch 5a outputs a drive signal that causes the near-infrared light emitted from the light emitting unit 2 to enter the other end of the optical fiber 13, the light detection unit 3 receives eight pieces of received light amount information _An. Since (λ _m ) is received, eight received light amount information A _n (λ _m ) is stored in the received light amount information storage area 51. Next, when a driving signal for causing near-infrared light emitted from the light emitting unit 2 to enter the other end of the optical fiber 13 is output to the optical switch 5b, eight received light quantity information A from the light detecting unit 3 is output. _{Since n} (λ _m ) is received, eight received light amount information A _n (λ _m ) is stored in the received light amount information storage area 51. After the near-infrared light is transmitted to all nine probes 12a to 12i, a total of 9 × 8 received light amount information A _n (λ ₁ ), A _n (λ ₂ ) (n = 1, 2... 72) is obtained.

Based on the received light amount information A _n (λ ₁ ), A _n (λ ₂ ) (n = 1, 2,... 72) stored in the received light amount information storage area 51, the brain activity calculating unit 31 Control is performed to obtain received light amount information regarding 36 measurement sites inside the specimen.
By the way, 72 received light quantity information A _n (λ ₁ ) and A _n (λ ₂ ) are stored in the received light quantity information storage area 51, but not 36 received light quantity information regarding 72 measurement sites. Only the received light amount information related to the measurement site is obtained, that is, two received light amount information of the first received light amount information from the forward path and the second received light amount information from the reverse path is obtained for one measurement site. ing.
Therefore, first, the light is transmitted to the probe 12a, the first received light amount information obtained by receiving the light from the probe 12b is obtained, the light is transmitted to the probe 12b, and the light from the probe 12a is also transmitted. Second received light amount information obtained by receiving light is obtained. And the average value of 1st received light quantity information and 2nd received light quantity information is calculated as received light quantity information regarding a 1st measurement site | part.
Next, the light is transmitted to the probe 12b, the first received light amount information obtained by receiving the light from the probe 12c is obtained, the light is transmitted to the probe 12c, and the light from the probe 12b is obtained. The second received light amount information obtained by receiving the light is obtained. And the average value of 1st received light quantity information and 2nd received light quantity information is calculated as received light quantity information regarding a 2nd measurement site | part.
In this way, for each measurement site, two pieces of received light amount information, that is, the first received light amount information from the forward path and the second received light amount information from the reverse path are obtained, An average value with the received light amount information is calculated as received light amount information regarding the nth measurement site.
Finally, the simultaneous equations as described above are created, and the oxyhemoglobin concentration / optical path length product [oxyHb] and the deoxyhemoglobin concentration / optical path length product [deoxyHb] are calculated.

Next, a measurement method using the optical brain function imaging apparatus 1 will be described. FIG. 3 is a flowchart for explaining an example of the measurement method by the optical brain function imaging apparatus 1.
First, in the process of step S101, the light transmitting / receiving unit 11 is arranged on the scalp surface of the subject.
Next, in the process of step S102, the probe number parameter n = 0 indicating the probe that irradiates near-infrared light is set.

Next, in the process of step S103, the optical path switching control unit 44 outputs drive signals to the nine optical switches 5a to 5i based on the optical path switching timing table. Specifically, the optical switch 5a corresponding to the probe of n = 0 outputs a drive signal for causing near infrared light emitted from the light emitting unit 2 to enter the other end of the optical fiber 13, and the optical switch 5b to 5i, a drive signal for causing near-infrared light emitted from the other end of the optical fiber 13 to enter the light detection unit 3 is output.
Next, in the process of step S104, the light emission control unit 42 outputs a drive signal to the light emitting unit 2 based on the optical path switching timing table, and the light detection control unit 43 receives the received light amount information A from the light detection unit 3. By receiving _n (λ _m ), the received light amount information A _n (λ _m ) is stored in the received light amount information storage area 51.

Next, in the process of step S105, it is determined whether or not the probe number parameter n = 8. When it is determined that the probe number parameter n = 8 is not satisfied, n = n + 1 is set in the process of step S106.
Next, in the process of step S107, the optical path switching control unit 44 outputs drive signals to the optical switches 5a to 5i based on the optical path switching timing table. Specifically, a driving signal for causing near-infrared light emitted from the light emitting unit 2 to enter the other end of the optical fiber 13 is output to an optical switch corresponding to a probe with n = n, and n = n. A drive signal for causing near-infrared light emitted from the other end of the optical fiber 13 to enter the optical detection unit 3 is output to the optical switch corresponding to the probe -1.
And when the process of step S107 is complete | finished, it returns to the process of step S104.

On the other hand, when it is determined in the process of step S105 that the probe number parameter n = 8, in the process of step S108, the brain activity calculating unit 31 receives the received light amount information A _n (λ ₁ ), A _n (λ ₂ ). Based on (n = 1, 2,..., 72), light reception amount information regarding 36 measurement sites inside the subject is obtained. Then, the simultaneous equations as described above are created, and the concentration / optical path length product [oxyHb] of oxyhemoglobin and the concentration / optical path length product [deoxyHb] of deoxyhemoglobin are calculated.
Next, in the process of step S109, it is determined whether or not to end the measurement. If it is determined not to end the measurement, the process returns to step S102.
On the other hand, when it is determined that the measurement is finished, this flowchart is finished.

As described above, according to the optical brain functional imaging apparatus 1, accurate light reception amount information A _n (λ ₁ ), A _n (λ ₂ ) (n = 1, ₂ ) is not affected by the forward path or the reverse path. ,..., 36) can be obtained.

(Other embodiments)
(1) In the optical brain functional imaging apparatus 1 described above, the light transmitting / receiving unit 11 having the nine probes 12a to 12i is shown. However, the light transmitting / receiving unit having a different number, for example, 18 probes may be used.
(2) In the optical brain function imaging apparatus 1 described above, the configuration including the optical path switching unit 5 is shown. Also good.
(3) In the optical brain functional imaging apparatus 1 described above, the brain activity calculation unit 31 calculates the average value of the first received light amount information and the second received light amount information as the received light amount information regarding the nth measurement site. However, the first received light amount information and the second received light amount information may be used to calculate a numerical value other than the average value to obtain the received light amount information regarding the nth measurement site. .

  INDUSTRIAL APPLICABILITY The present invention can be used for an optical brain functional imaging apparatus that non-invasively measures brain activity.

It is a block diagram which shows the structure of the optical brain functional imaging apparatus which is one Embodiment of this invention. It is a figure which shows an example of the positional relationship of a probe, a light emission part, and a light detection part. It is a flowchart for demonstrating an example of the measuring method by an optical brain functional imaging apparatus. It is a figure which shows the relationship between a pair of light transmission probe and light reception probe, and a measurement site | part. It is a figure which shows an example of the positional relationship of four light transmission probes and five light reception probes, and a light emission part and a photon detection part. It is a figure which shows an example of the positional relationship of the conventional probe, a light emission part, and a light detection part. It is a figure which shows the relationship between a pair of probe and a measurement site | part. It is a perspective view which shows an example of the conventional optical fiber. It is a figure which shows the relationship between a pair of probe and a measurement site | part.

Explanation of symbols

1: Optical brain functional imaging device (light measurement device)
2: Light emitting unit 3: Light detecting unit 4: Light transmitting / receiving unit control unit 5: Optical path switching unit 11, 60, 70: Light transmitting / receiving unit 12, 71: Probe 13: Optical fiber (optical transmission path)
14: Optical fiber (optical transmission line) group 20: Control unit (computer)

Claims (4)

A light transmitting / receiving unit having a plurality of probes arranged on the surface of the subject;
A light emitting unit for emitting light;
A light detection unit for detecting light;
An optical transmission line group to which one probe and one end of one optical transmission line are respectively connected;
By transmitting light from the light emitting unit to the probe via an optical transmission path and controlling the light detection unit to receive light from the probe via the optical transmission path, a plurality of light sources inside the subject can be obtained. A light measurement device comprising a control unit for obtaining received light amount information on a measurement site of a location,
The probe is capable of irradiating light on the surface of the subject or entering light from the surface,
The control unit transmits light from the light emitting unit to the first probe via the optical transmission path, and receives light from the second probe via the optical transmission path by the light detection unit. Obtain the first received light amount information from the route,
Light is transmitted from the light emitting unit to the second probe through the optical transmission path, and light from the first probe is received by the light detection unit through the optical transmission path, so that the forward path and the reverse path are transmitted. The second received light quantity information of
An optical measurement device that calculates received light amount information relating to the measurement site using the first received light amount information and the second received light amount information. An optical path switching unit connected to the other end of the optical transmission path and connected to the light emitting unit and the light detection unit,
Whether the optical path switching unit causes the light emitted from the light emitting unit to be incident on the other end of the optical transmission path, or whether the light emitted from the other end of the optical transmission path is incident on the optical detection unit It is possible to switch the optical path so that either
The control unit transmits light from the light emitting unit to the at least one probe selected from the plurality of probes via the optical transmission path, and from all probes other than the probe that transmits the light. The optical measurement apparatus according to claim 1, wherein the optical path switching unit is controlled so that light is received by the light detection unit via an optical transmission path.   The optical measurement device according to claim 2, wherein the optical path switching unit is an optical switch group connected to each of one optical switch and the other end of one optical transmission path.   The said control part calculates the average value of said 1st received light amount information and 2nd received light amount information as received light amount information, The light measuring device in any one of Claims 1-3 characterized by the above-mentioned.

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