JP4259319B2 - Optical measuring device - Google Patents

Description

  The present invention irradiates light from a light transmission terminal to a subject and reflects and / or transmits the light within the subject (used to include both cases of reflection and transmission). The present invention relates to an apparatus for detecting light received by a light receiving terminal.

  Hemoglobin plays a role in transporting oxygen by binding to and leaving oxygen in the blood. Since hemoglobin contained in blood increases or decreases according to the expansion and contraction of blood vessels, it is known that the expansion and contraction of blood vessels can be detected by measuring the amount of hemoglobin in the tissue. In addition, by utilizing the fact that the hemoglobin concentration corresponds to the oxygen metabolism function inside the living body, living body measurement is also known that can measure the inside of the living body simply and non-invasively using light.

  The concentration of hemoglobin is determined from the amount of light absorbed by irradiating the living body with light having a wavelength in the near-infrared region from visible light and transmitting through the living body. In addition, even if oxygen is used in the brain due to brain activity, more than the necessary amount of oxygen is normally supplied to sites activated by blood flow redistribution. The amount of oxyhemoglobin bound to is increased. Therefore, measurement of fluctuations in oxyhemoglobin and deoxyhemoglobin from which oxygen has been eliminated can be applied to observation of brain activity.

  In general, the shape of the absorption spectrum of hemoglobin differs depending on whether hemoglobin is combined with oxygen to form oxyhemoglobin or oxygen is separated to form deoxyhemoglobin. Non-invasive quantitative measurement of oxyhemoglobin and deoxyhemoglobin using this spectral shape difference has been developed.

  In this way, the optical measurement device can measure changes in the blood volume of the brain and the activation state of oxygen metabolism, and can be applied to the measurement of brain functions such as movement, sensation, and thought, and displays the measurement results as an image. As a result, the applicability to the medical field such as the diagnosis of brain function in the living body and the diagnosis of cardiovascular disorders can be enhanced.

  The optical measurement device can measure a plurality of locations on the subject with a configuration including a plurality of light transmission terminals for irradiating the subject with light and a plurality of light receiving terminals for receiving light emitted from the subject. Further, by changing the position and combination of the light transmitting terminal and the light receiving terminal, it is possible to change the measurement point on the subject and change the depth direction of the obtained data (see Patent Document 1).

  FIG. 5A shows the arrangement of terminals in the conventional method. As an example, an arrangement of a total of 12 terminals including 6 light transmitting terminals (white circles) and 6 light receiving terminals (black circles) is taken up. As shown in the figure, the terminals are generally arranged in a square lattice so that adjacent terminals are of different types, and data collection is performed between adjacent terminals. The measurement point is the midpoint between the light transmission terminal 4 and the light receiving terminal 6 that receives light from the light transmission terminal 4, and the measurement point in this arrangement is indicated by a white circle in FIG. Seventeen sets of data are collected. The measurement point is a position inside the subject depending on the distance between the light transmission terminal and the light reception terminal, but in this specification, it is treated as a position projected on the same plane as the light transmission terminal and the light reception terminal. In FIG. 5 (B) and the examples described later, the measurement points are represented by ellipses, and the major axis indicates the measurement direction.

Spatial resolution is defined as the distance between measurement points on the same plane as the light transmitting terminal and the light receiving terminal. In the case of FIG. 5, the distance X between the light transmitting terminals and the light receiving terminals and the distance D between the adjacent terminals are equal, and the spatial resolution P is equal to X and D.
JP 2001-337033 A

  However, since the distance X between the light transmitting terminals and the light receiving terminals is related to the distance in the depth direction obtained from the subject, for example, in the case of the brain, in order to obtain data of a predetermined depth from the scalp, an adult transmits The distance X between the optical terminals and the light receiving terminals is 30 mm. Therefore, the spatial resolution is also 30 mm, and the resolution is low.

In general, if the measurement data at a deep position is obtained, it is necessary to increase the distance X between the light transmitting terminals and the light receiving terminals. Therefore, measurement data at a deep position cannot be obtained with high resolution.
SUMMARY OF THE INVENTION An object of the present invention is to provide an optical measurement apparatus that can obtain measurement data at a deep position with high resolution.

The present invention includes a plurality of light transmitting terminals that irradiate a subject with light and a plurality of light receiving terminals that receive and detect light emitted to the outside after being transmitted and / or reflected through the subject. In an optical measurement device, the distance between the light transmitting terminal and the light receiving terminal is such that the distance between the light transmitting terminal that performs the light irradiation operation and the light receiving terminal that receives light from the light transmitting terminal is longer than the distance between the adjacent terminals. When controlling the operation so that data is measured at, and measuring the intermediate position between the light transmitting terminal that performs the light irradiation operation and the light receiving terminal that receives light from the light transmitting terminal, the adjacent measurement The light transmitting terminal and the light receiving terminal are arranged so that the distance between the points is equal to the distance between adjacent terminals.

In one embodiment , the light transmitting terminals and the light receiving terminals are arranged in a lattice pattern, the column (or row) direction is composed of the same type of terminals, and the row (or column) direction is alternately arranged with different types of terminals in units of two rows. Thus, the types of the terminals are different between the diagonal terminals with a distance between the two terminals, and the light receiving terminals at the diagonal positions with the distance between the two terminals from the light transmitting terminal are operated with respect to the light transmitting terminals that perform the light irradiation operation. The operation of the light transmitting terminal and the light receiving terminal is controlled.

In another embodiment , the light transmitting terminals and the light receiving terminals are arranged in a grid pattern, and different terminals are arranged alternately in units of four terminals in the column (or row) direction, and terminals having the same arrangement are arranged in the row (or column) direction. Two rows (or two columns) are arranged adjacent to two rows (or columns) and are arranged with different terminal types across two rows (or two columns) where terminals are not arranged. ) Arranged and different in the row direction and the column direction at intervals of 4 terminals, and with respect to the light transmission terminal that performs the light irradiation operation, the light reception at the position of the 4 terminals interval from the light transmission terminal in the row direction or the column direction. The operation of the light transmitting terminal and the light receiving terminal is controlled so as to operate the terminal.

In the present invention, with equal to the distance between adjacent terminals the distance between adjacent measurement points, between the light-sending terminal receiving inter-terminal distance is received and sending terminal to be longer than the distance between adjacent terminals terminal in controlling the operation to perform measurement of data, it is possible to obtain measurement data of a deep position by increasing the distance between the sending terminal receiving terminal.

  FIG. 1 schematically shows an example of a multi-channel optical measurement apparatus to which the present invention is applied. A light transmission terminal 4 for irradiating light to a subject and an external after passing through and / or reflecting through the subject. A probe 12 in which a plurality of light receiving terminals 6 for receiving light emitted by the light receiving terminal 6 are arranged on the arrangement surface, and a data processing device 18 for analyzing based on the light received by the light receiving terminals 6 of the probe 12. I have.

  Reference numeral 14 denotes a light source for each light transmission terminal that supplies light for measurement to each light transmission terminal 4, and a light emitting element such as an LED (light emitting diode) or an LD (laser diode) can be used. Light from each light source 14 is guided to each light transmission terminal 4 via a light guide such as an optical fiber. In this case, the light transmission terminal 4 becomes the light transmission end face of the light guide.

  Reference numeral 16 denotes a detector that detects the light received by each light receiving terminal 6, and a photomultiplier tube or the like can be used in addition to a light receiving element such as a photodiode or a phototransistor. Light from each light receiving terminal 6 is guided to each detector 16 via a light guide such as an optical fiber.

The light source 14 and the detector 16 turn on the light source 14 connected to the light transmitting terminal 4 at a position where data is to be acquired, and a detector connected to the light receiving terminal 6 that is intended to receive light emitted from the light transmitting terminal 4. The operation timing is controlled so that each detector 16 detects data at a predetermined position such that each detector 16 is operated. Such operation of the light source 14 and the detector 16 is also controlled by the data processor 18. In the present invention, the operations of the light source 14 and the detector 16 are described as the operations of the light transmitting terminal 4 and the light receiving terminal 6.
Reference numeral 20 denotes a display device that displays data processed by the data processing device 18.

Next, an embodiment of specific arrangement and operation of the light transmitting terminal 4 and the light receiving terminal 6 will be described in detail with reference to the drawings.
[ Reference example ]
FIG. 2 is a diagram showing a reference example , (A) is an arrangement diagram showing the arrangement of light transmitting terminals and light receiving terminals, and (B) is a diagram showing the measurement points.
The light transmitting terminal 4 and the light receiving terminal 6 of this reference example are 12 types of light transmitting terminals and 8 light receiving terminals, as shown by way of example in FIG. ) Are arranged in a square lattice shape.

  In (A), the hollow mark represents the light transmitting terminal 4, and the hatched mark represents the light receiving terminal 6. In this apparatus, as indicated by a bowed arrow, the light transmission terminal is arranged such that the light reception terminal 6 adjacent to the side of the light reception terminal 6 adjacent to a certain light transmission terminal 4 becomes the light reception point of the light transmission terminal 4. The light transmission operation from 4 and the detection operation by the light receiving terminal 6 are controlled. The measurement point is the midpoint between the light transmitting terminal 4 and the light receiving terminal 6 that are operated, that is, the midpoint between the measurement terminals.

The measurement points in this reference example are as shown in (B), and the distance between adjacent measurement points (spatial resolution) P is smaller than the distance D between adjacent terminals, and the spatial resolution is shown in FIG. Higher than the ones. Moreover, the distance X between measurement terminals is larger than the distance D between adjacent terminals. The relationship between D, X, and P is expressed as follows.
D = √2 · P
X = √10 · P = 3.16 · P

The relationship among the spatial resolution P, the distance D between adjacent terminals, and the distance X between measurement terminals is shown in Table 1 as numerical values. Spatial resolution refers to the distance P between adjacent measurement points. The shorter the distance P between adjacent measurement points, the higher the resolution (good), and the longer the distance P between adjacent measurement points, the lower (bad) resolution.

  As can be seen from the above, even when the spatial resolution P is increased, the distance X between the measurement terminals is larger than the spatial resolution P, so that data at a deeper position can be obtained with high resolution. Further, even when the spatial resolution P is increased, a sufficient distance D between adjacent terminals can be ensured.

[Example 1 ]
Figure 3 is sending terminal 4 in the first embodiment, and a diagram showing the arrangement and the measurement point of the light receiving terminal 6 shows (A) is arranged, (B) the measurement point. As in FIG. 1, in FIG. 1A, the hollow mark represents the light transmitting terminal 4, and the hatched mark represents the light receiving terminal 6.
In this embodiment, as shown in (A), 13 light transmitting terminals and 13 light receiving terminals are composed of the same kind of terminals in the column direction, and different kinds of terminals are alternately arranged in units of two rows in the row direction. It arrange | positions and is arrange | positioned at the grid | lattice form so that a kind may differ between the diagonal terminals of 2 terminal space | interval. As indicated by the bowed arrow, the light transmitting terminal 4 is operated so as to operate the light receiving terminal 6 that is diagonally spaced from the light transmitting terminal 4 by a distance of 2 terminals with respect to the light transmitting terminal 4 that performs the light irradiation operation. The operation of the light receiving terminal 6 is controlled.
It is the same even if the arrangement of FIG.

Similar to the reference example , the measurement point is the midpoint between the light transmitting terminal and the light receiving point, that is, the midpoint between the measurement terminals. The measurement points in this embodiment are as shown in (B), and the distance D between adjacent terminals and the distance P between adjacent measurement points are equal. The distance X between measurement terminals is larger than the distance D between adjacent terminals. The relationship among the spatial resolution P, the distance D between adjacent terminals, and the distance X between measurement terminals is expressed as follows.
D = P
X = 2 · √2 · P = 2.828P

Table 2 shows the relationship between the spatial resolution P, the distance D between adjacent terminals, and the distance X between measurement terminals in numerical form.

  In this way, even when the arrangement of the light transmitting terminals 4 and the light receiving terminals 6 is changed as shown in FIG. 2A, the distance X between the measurement terminals is larger than the spatial resolution P, so that the deeper position. Can be obtained with high resolution.

[Example 2 ]
FIG. 4 is a diagram showing the arrangement of light transmitting terminals and light receiving terminals and their measurement points in the second embodiment, where (A) shows the arrangement and (B) shows the measurement points. In (A), a hollow mark represents a light transmitting terminal, and a hatched mark represents a light receiving terminal.
In this embodiment, as shown in (A), 16 light transmitting terminals and 16 light receiving terminals are arranged such that different terminals are arranged alternately in units of 4 terminals in the column direction, and terminals having the same arrangement in the row direction. Two rows are arranged adjacent to each other and arranged with different types of terminals across two rows where no terminals are arranged, and the types are different at intervals of four terminals in the row direction and the column direction. Are arranged in a grid pattern. As indicated by the bowed arrow, the light transmitting terminal 4 that performs the light irradiation operation is transmitted so that the light receiving terminal 6 located at a distance of 4 terminals from the light transmitting terminal 4 in the row direction or the column direction is operated. The operation of the terminal 4 and the light receiving terminal 6 is controlled.
It is the same even if the arrangement of FIG.

In this apparatus, as described above, the midpoint between the light transmission terminal and the light receiving point is used as a measurement point.
In this arrangement, the measurement points shown in (B) can be obtained, and the distance D between adjacent terminals and the distance P between adjacent measurement points are equal. The distance X between measurement terminals is larger than the distance D between adjacent terminals. The relationship among the spatial resolution P, the distance D between adjacent terminals, and the distance X between measurement terminals is expressed as follows.
D = P
X = 4 · P
Since the sufficient distance X between the measurement terminals can be maintained even when the spatial resolution P is increased as in the above equation, data at a deeper position can be obtained with high resolution.
The arrangement of the light transmitting terminal and the light receiving terminal is not limited to the embodiment, and the arrangement of the embodiment is merely an example.

  The optical measurement device of the present invention is a device for diagnosing whether a tissue is normal or abnormal from a temporal change of components in a subject such as a living body, for example, a temporal change in blood flow or oxygen in each part of the brain It can be used in the medical field, such as an oxygen monitor that measures changes in supply, and cardiovascular system failure diagnosis.

It is a figure which shows an example of a multichannel optical measuring device roughly. It is a figure which shows a reference example , (A) is a top view which shows arrangement | positioning of a light transmission terminal and a light receiving terminal, (B) is a top view which shows the measurement point. It is a figure which shows one Example , (A) is a top view which shows arrangement | positioning of a light transmission terminal and a light reception terminal, (B) is a top view which shows the measurement point. It is a figure which shows another Example , (A) is a top view which shows arrangement | positioning of a light transmission terminal and a light receiving terminal, (B) is a top view which shows the measurement point. (A) is a top view which shows arrangement | positioning of the light transmission terminal and light reception terminal of the conventional multichannel optical measuring device, (B) is a top view which shows the measurement point.

Explanation of symbols

2 Light Transmitting Terminal 4 Light Receiving Terminal 14 Light Source 16 Detector 18 Data Processing Device 20 Display Device

Claims (2)

An optical measurement apparatus comprising: a plurality of light transmitting terminals for irradiating light to a subject; and a plurality of light receiving terminals for receiving and detecting light emitted to the outside after being transmitted and / or reflected through the subject. ,
The distance between the light transmitting terminal that performs the light irradiation operation and the light receiving terminal that receives light from the light transmitting terminal is longer than the distance between adjacent terminals in the terminal group including both the light transmitting terminal and the light receiving terminal. In addition, when a measurement point is an intermediate position between a light transmitting terminal that performs light irradiation operation and a light receiving terminal that receives light from the light transmitting terminal, the distance between adjacent measurement points is between the adjacent terminals. The terminal arrangement and operation control are performed so as to be equal to the distance.
The light transmitting terminals and the light receiving terminals are arranged in a grid pattern, the column (or row) direction is composed of the same type of terminals, and the row (or column) direction is arranged with different types of terminals alternately arranged in units of two rows. There are different types of terminals between diagonal terminals,
Light and controlling the operation of the light-sending terminal and receiving terminal to operate the receiving terminal from the light-sending terminal to sending terminal for irradiation operation of light at the position of the diagonal of the two-terminal spacing Measuring device. An optical measurement apparatus comprising: a plurality of light transmitting terminals for irradiating light to a subject; and a plurality of light receiving terminals for receiving and detecting light emitted to the outside after being transmitted and / or reflected through the subject. ,
The distance between the light transmitting terminal that performs the light irradiation operation and the light receiving terminal that receives light from the light transmitting terminal is longer than the distance between adjacent terminals in the terminal group including both the light transmitting terminal and the light receiving terminal. In addition, when a measurement point is an intermediate position between a light transmitting terminal that performs light irradiation operation and a light receiving terminal that receives light from the light transmitting terminal, the distance between adjacent measurement points is between the adjacent terminals. The terminal arrangement and operation control are performed so as to be equal to the distance.
The light transmitting terminals and the light receiving terminals are arranged in a lattice pattern, and different terminals are alternately arranged in units of four terminals in the column (or row) direction, and two terminals (or the same arrangement) are arranged in the row (or column) direction. 2) (or 2 columns) of rows (or columns) that are arranged adjacent to each other and are arranged with different types of terminals across 2 rows (or 2 columns) where no terminals are arranged, The types are different at intervals of 4 terminals in the row and column directions.
The operation of the light transmitting terminal and the light receiving terminal is controlled so that the light receiving terminal located at a distance of 4 terminals from the light transmitting terminal in the row direction or the column direction is operated with respect to the light transmitting terminal performing the light irradiation operation. An optical measuring device.

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