JP4356954B2 - Biological light measurement device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biological light measurement device, and more particularly to a technique that is effective when applied to confirmation of the mounting state of a measurement probe attached to a living body.
[0002]
[Prior art]
Conventionally, an apparatus for measuring the inside of a living body simply and without causing harm to the living body has been eagerly desired in the fields of clinical medicine and brain science. In response to this demand, an apparatus for measuring the inside of a living body by irradiating the living body with light having a wavelength from visible to infrared and detecting the light passing through the living body is disclosed in, for example, Japanese Patent Laid-Open No. 9-98972 (hereinafter referred to as “ Reference 1 ”) or JP-A-9-149903 (hereinafter referred to as“ Reference 2 ”).
[0003]
The “biological light measuring device” described in these documents includes a signal processing device that generates light of different modulation frequencies, and generates and displays a biological passing light intensity image (topography image) from the living body passing light, and a signal processing device And a measurement probe that irradiates the light generated by the light to the living body, collects the light that has passed through the living body, and outputs the collected light to the signal processing device.
[0004]
The signal processing device reflects light corresponding to the wavelength and the irradiation position from an electrical signal indicating the intensity of light passing through the living body output from a photodiode to which the collected light is incident (hereinafter referred to as a “biological passing light intensity signal”). A lock-in amplifier that separates light intensities, an A / D converter that converts the output of the lock-in amplifier into a digital signal, and an oxidized and reduced hemoglobin concentration at each measurement point from the light intensity signal passing through the living body after A / D conversion The relative change amount is calculated, and the relative change amount is displayed as a living body passing light intensity image (topography image).
[0005]
The measurement probe includes an irradiation optical fiber that guides light of different modulation frequencies emitted from the signal processing device to a living body and irradiates the light to different positions, and a detection optical fiber that collects light passing through the living body and guides it to a photodiode. And an optical fiber fixing member that alternately arranges the tips of the irradiation optical fiber and the detection optical fiber in a lattice pattern, and a fixing belt that fixes the optical fiber fixing member to a living body. For example, the optical fiber fixing member is formed by forming a base of a thermoreversible plastic sheet having a thickness of about 3 mm in a quadrilateral shape into a curved shape so as to follow the shape of a measurement part of a living body, or a base of a thermoreversible plastic sheet Various types are prepared according to the measurement site, such as forming a helmet or cap shape. Further, the optical fiber fixing member has a hole at each of a plurality of positions where light is irradiated / detected on the living body, and an optical fiber folder is disposed in the hole. This optical fiber folder is composed of a hollow holder main body, a nut screw, and an optical fiber fixing screw, and the holder main body is fixedly attached to the optical fiber fixing member by the nut screw. An irradiation optical fiber or a detection optical fiber was inserted into the holder body, and the optical fiber was lightly brought into contact with the surface of the living body and fixed with an optical fiber fixing screw.
[0006]
On the other hand, the signal processing device has a mode in which the positions of the optical fibers for irradiation and detection attached to the living body, the measurement position of the light passing through the living body, and the like are displayed on the display device, and the biological light passing light intensity signal level after A / D conversion There were a mode for directly displaying on a display device in series, and a mode for displaying an image of light intensity passing through a living body calculated from the relative change amount of oxidized and reduced hemoglobin concentration at each measurement point. However, the measurement position of the light passing through the living body in the biological light measurement device is an adjacent position between the irradiation optical fiber and the detection optical fiber.
[0007]
[Problems to be solved by the invention]
As a result of examining the prior art, the present inventor has found the following problems.
In the conventional biological light measuring device, based on the type of the optical fiber fixing member to be used and the position of the irradiation optical fiber and the detection optical fiber arranged on the optical fiber fixing member, the signal processing device also has a signal processing device before starting the measurement. The type information of the optical fiber fixing member, the irradiation optical fiber arranged on the optical fiber fixing member, and the detection optical fiber position information are set. The signal processing apparatus performs irradiation during or after measurement based on the type information of the optical fiber fixing member set before the start of measurement, and the irradiation optical fiber and detection optical fiber position information arranged on the optical fiber fixing member. Display of optical fiber position for detection and detection, measurement position of passing light through living body, display in time series of relative change amount of oxidized and reduced hemoglobin concentration at each measuring point, and display of living body passing light intensity image .
[0008]
For this reason, in the conventional biological light measurement device, whether or not the optical fiber fixing member is attached to the living body in the direction set in the signal processing device depends on, for example, the positions of the irradiation and detection optical fibers and the attachment of the fixing belt. Since it was only performed from the position or the like, it was necessary to carefully attach the measurement probe to the living body, and there was a problem that much time was required for the attachment and confirmation after the attachment. For this reason, there has been a problem that the diagnostic efficiency is lowered.
[0009]
Further, in the conventional biological light measurement device, when measuring a change in hemodynamics caused by a load, a biological light intensity signal, which is a measurement signal measured during a period in which the load is applied to the living body, The signal of hemodynamics when not applied and the signal of hemodynamics resulting from applying a load to the living body were added. However, blood dynamics are known to change due to biological fluctuations such as changes in blood pressure, pulse waves, respiratory movements and changes in cerebrospinal fluid of the subject. The passing light intensity also changed greatly.
[0010]
On the other hand, in the conventional biological light measurement device, the biological passage light intensity signal level after A / D conversion is calculated from the biological passage light intensity signal in the mode in which the level is directly displayed on the display device or after A / D conversion. In the mode in which the relative change level of the oxidized and reduced hemoglobin concentration at each measurement point is directly displayed on the display screen in time series, the biological light intensity signal level or the relative change level of oxidized and reduced hemoglobin concentration is displayed in time series. Since it was only displayed, there was a problem that it was not possible to determine whether the displayed level change was due to hemodynamic changes due to load or due to biological fluctuations .
[0011]
An object of the present invention is to provide a technique capable of facilitating mounting and confirmation after mounting.
[0012]
Another object of the present invention is to provide a technique capable of easily specifying a change location of hemodynamics caused by applying a load to a living body.
Another object of the present invention is to provide a technique capable of improving diagnostic efficiency.
The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.
[0013]
[Means for Solving the Problems]
Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.
[0014]
(1) A measurement probe that irradiates a living body with light of a plurality of wavelengths guided by an optical fiber from a light source and detects light that has passed through the living body, and a storage that stores position information of an optical fiber that can be placed on the measurement probe A reference position for the measurement probe in the living body light measurement apparatus comprising: means; a means for generating a living body light intensity image of the living body from the detected passing light; and a display means for displaying the living body light intensity image. reference mark indicated are denoted, said storage means stores a location information of each measurement probe that describes the reference mark indicating the reference position, the display means, the shape information imitating a measurement site of the living body And the arrangement position of the optical fiber of the measurement probe and the reference mark are displayed.
[0015]
(2) The display means includes a measurement period in a load state in which a load is applied to the living body and an unloaded state in which no load is applied, together with the intensity of the light passing through the living body or the intensity image of the light passing through the living body. Indicates the measurement period .
[0016]
According to the means (1) described above, the measurement probe is marked with a mark indicating the reference position. In addition, the storage means stores information for each measurement probe with a mark indicating the reference position. Here, the display means displays a mark indicating the reference position stored in the storage means together with the arrangement position of the optical fiber of the measurement probe. Since it is possible to easily compare the state of the measurement probe set in the signal processing means, which is a means for generating a living body passage light intensity image from the passed light, the measurement probe is attached to the living body in a desired orientation. Alternatively, it is possible to easily confirm whether or not the state of the measurement probe is accurately set in the means for generating a living body passage light intensity image from the collected passing light. Therefore, diagnosis efficiency can be improved.
[0017]
According to the above-mentioned means (2), the display means together with the intensity of the passing light passing through the living body or the living body passing light intensity image, the measurement period in the load state where the load is applied to the living body, and the no load that does not apply the load By indicating the measurement period in the state, it is possible to easily identify the change location of the hemodynamics caused by applying the load to the living body in the display mode of the intensity of the passing light or the passing light intensity image of the living body.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings together with embodiments (examples) of the invention.
[0019]
Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment of the invention, and the repetitive description thereof is omitted.
[0020]
FIG. 1 is a diagram for explaining a schematic configuration of a biological light measurement apparatus according to an embodiment of the present invention. 1 is a light source unit, 2 is an optical module, 3 is a semiconductor laser, 8 is an irradiation optical fiber, 9 is a living body, 10 is a detection optical fiber, 11 is a photodiode, 12 is a lock-in amplifier module, 16 is an A / D converter, 17 is a control unit, 18 is a recording unit, 19 is a processing unit, and 20 is an input / output Indicates the part. However, other configurations excluding measurement value processing in the control unit 17 use known means and mechanisms.
[0021]
In the present embodiment, for example, an embodiment in which light is emitted from the skin surface of the head of the living body 9 and the inside of the cerebrum is imaged from the passing light detected on the skin surface of the head, the number of measurement channels, that is, A case where the measurement position is 12 will be described. Of course, the present invention is not limited to the head as a measurement target, and can be applied to other parts, and to a living body other than a human body or a living body other than a living body. Further, by further increasing the number of light irradiation positions and light detection positions, the number of measurement channels can be increased, and the measurement area can be expanded.
[0022]
In FIG. 1, the light source unit 1 is composed of four optical modules 2. Each optical module 2 includes two semiconductor lasers 3 that respectively emit light having a plurality of wavelengths, for example, two wavelengths of 780 nm and 830 nm, in a visible to infrared wavelength region. These two wavelength values are not limited to 780 nm and 830 nm, and the number of wavelengths is not limited to two wavelengths. For the light source unit 1, a light emitting diode may be used instead of the semiconductor laser 3. All of the eight semiconductor lasers included in the light source 1 are modulated by oscillation units each composed of an oscillator (not shown) having different oscillation frequencies. However, as this modulation, the present embodiment shows a case of analog modulation using a sine wave, but the present invention is not limited to this, and digital modulation using rectangular waves at different time intervals may be used. The optical module 2 includes an optical fiber coupler (not shown) that introduces light having wavelengths of 780 nm and 830 nm emitted from the respective semiconductor lasers into one optical fiber (irradiation optical fiber 8). Yes.
[0023]
Therefore, the light obtained by mixing the two-wavelength light emitted from the light source unit 1 is irradiated to the head of the living body 9 to be measured from the tip portions of the four irradiation optical fibers 8 connected to each optical module 2. The At this time, each irradiation optical fiber 8 is fixed to an optical fiber fixing member of a measurement probe (not shown) and irradiates light to different positions. However, in the present embodiment, the tip portions of the irradiation optical fiber 8 and the detection optical fiber 10 are alternately arranged on a square lattice. The details of the measurement probe are described in JP-A-9-149903.
[0024]
The light that has passed through the head, that is, the light passing through the living body, is condensed by five detection optical fibers 10 fixed to optical fiber fixing members of a measurement probe (not shown) and connected to the other end of each detection optical fiber 10. It is detected by a photodiode 11 which is a photodetector. As this photodiode 11, for example, a well-known avalanche photodiode capable of realizing highly sensitive optical measurement is desirable. Further, as the photodetector, any other photoelectric conversion element such as a photomultiplier tube may be used.
[0025]
The living body passing light is converted into an electrical signal (biological passing light intensity signal) by these photodiodes 11, and then a modulation signal selective detection circuit, for example, a lock-in amplifier module 12 composed of a plurality of lock-in amplifiers. The modulation signal corresponding to the irradiation position and wavelength is selectively detected. At this time, the modulation signal output from the lock-in amplifier module 12 is separated into a biological passage intensity signal corresponding to the wavelength and the irradiation position. However, in this embodiment, since measurement is performed at 12 measurement positions using light of two wavelengths, the number of signals to be measured is 12 × 2 = 24. Therefore, the lock-in amplifier module 12 of the present embodiment uses a total of 24 lock-in amplifiers (not shown). However, when digital modulation is used, a digital filter or a digital signal processor is used for detection of the modulation signal.
[0026]
The biological passage light intensity signal analog-output from the lock-in amplifier module 12 is converted into a digital signal by a 24-channel A / D converter (analog / digital converter) 16. Each digital signal is a biological light intensity signal for each wavelength and irradiation position. These measurements are controlled by the control unit 17.
[0027]
The living body passage light intensity signal converted into the digital signal is recorded by the recording unit 18. The living body passage light intensity signal recorded in the recording unit 18 is read out by the processing unit 19, and the processing unit 19 changes and removes oxygenated hemoglobin concentration accompanying brain activity determined from the living body passage light intensity signal at each detection position. The oxygenated hemoglobin concentration change, and further, the total amount of these hemoglobin concentrations are calculated and displayed on a display screen (not shown) of the input / output unit 20 as time-dependent information at a plurality of measurement positions. In addition, time-lapse information of a plurality of measurement positions may be stored in the recording unit 18. The method for calculating the oxygenated and deoxygenated hemoglobin concentration change and the total hemoglobin concentration from the in-vivo light intensity signal at each detection position is described in Document 1 and Document 2, and detailed description thereof is omitted. .
[0028]
At this time, in the biological light measurement device of this embodiment, the recording unit 18 stores in advance information on the types of optical fiber fixing members that can be used in the biological light measurement device. As the optical fiber type information, various shapes of optical fiber fixing members prepared according to the measurement site such as a curved surface shape or a helmet or cap shape along the shape of the measurement site of the living body of the application (measurement) site. Information, information on the reference position written on each optical fiber fixing member, information on the number of irradiation and detection optical fibers 8 and 10 that can be used for each optical fiber fixing member, and measurement part of the intensity of light passing through the living body The shape information imitating The stored information of the optical fiber fixing member includes 1 to n irradiation and detection optical fibers 8 and 10 that can be used for each optical fiber fixing member, and a predetermined optical fiber fixing member. The positions of the optical fibers 8 and 10 for irradiation and detection may be stored. Here, n represents the number of irradiation optical fibers 8 and 10 for detection.
[0029]
Therefore, when measuring the biological light intensity signal using the biological light measurement device of the present embodiment, information related to the measurement probe used for biological light measurement is set in the signal processing device from the input / output unit 20. There is a need. Specifically, the process is performed according to the following steps 1 to 3. First, it is used for measurement from the recording unit 18 before the start of measurement. That is, the optical fiber fixing member to be attached to the living body is selected (step 1). Next, information relating to the optical fiber fixing member selected in step 1 is read from the recording unit 18 of the signal processing means (step 2). According to the positions of the irradiation and detection optical fibers 8 and 10 with respect to the reference position marked on the optical fiber fixing member to be used, the positions of the irradiation and detection optical fibers 8 and 10 are set on the optical fiber fixing member read out in step 2. Set (step 3). Based on the position and orientation of the optical fiber fixing member to be attached to the measurement site, the position and orientation of the optical fiber fixing member are set to shape information imitating the measurement site (step 4). However, the setting of the positions of the irradiation and detection optical fibers 8 and 10 in step 3 and the setting of the arrangement and orientation of the optical fiber fixing member in the shape information imitating the measurement site in step 4 are performed in step 2, for example. The reference position described in the read optical fiber fixing member information is matched with the reference position of the optical fiber fixing member to be used.
[0030]
After step 4, by attaching the measurement probe to a desired measurement site in a preset orientation, the state of the measurement probe attached to the living body and the state of the measurement probe set in the signal processing device are different. This can be prevented. Needless to say, the measurement probe may be attached to the living body before step 1 described above or during steps 1 to 3.
[0031]
2 is a diagram for explaining the relationship between the optical fiber fixing member and the irradiation and detection optical fibers and the measurement position of the light passing through the living body when the measurement probe of the present embodiment is attached to the living body. FIG. 4 is a diagram when the positions of optical fibers for irradiation and detection attached to a living body and the measurement position of light passing through the living body are displayed on the display screen in the signal processing apparatus according to the present embodiment.
[0032]
As shown in FIG. 2, 22 reference marks are marked on 21 and 23 optical fiber fixing members. A state in which the optical fiber fixing member is actually mounted on the head is shown in 24. Reference numerals 24 and 25 denote a light irradiation fiber fixing portion and a light detection fiber fixing portion, respectively.
[0033]
At this time, for example, in order to confirm whether the attachment direction and position of the measurement unit lobe are normally formed, the positions of the irradiation and detection optical fibers attached to the living body from the input / output unit 20 and the measurement position of the light passing through the living body Etc. are set to a mode for displaying them on the display screen of the input / output unit 20. With this mode setting, as shown in FIG. 3, the signal processing apparatus displays shape information 32 imitating the measurement site of the living body passage light intensity and the arrangement position 33 of the measurement probe, and the measurement position of the living body passage light and The reference mark 31 is displayed. Accordingly, the examiner can easily check whether the measurement probe is attached to a desired measurement site by confirming the relationship between the shape information 32 and the arrangement position 33 of the measurement probe and the measurement probe position attached to the living body. Can be confirmed. Further, by comparing the relationship between the measurement position of the light passing through the living body and the reference mark 31 and the relationship between the direction of the living body and the reference mark of the measurement probe attached to the living body, the measurement probe can be easily set in a desired direction. You can check if it is installed.
[0034]
Therefore, as shown in FIG. 4, even when the mode is set to check the signal level of the detection light of the irradiation and detection optical fibers in the measurement probe attached to the living body, for example, the signal displayed in red It becomes easy to specify the optical fiber position 41 whose level does not fall within a preset value. In the present embodiment, the optical fiber position 42 where the signal level falls within a preset value is displayed in green.
[0035]
However, the reference mark 31 may be displayed together with the irradiation and detection optical fiber positions shown in FIG. 4, and by displaying the reference mark 31, the irradiation and detection optical fiber positions on the display screen and the living body are displayed. There is an effect that it is possible to easily grasp the positions of the irradiation and detection optical fibers in the measurement probe attached to the lens.
[0036]
FIG. 5 shows a mode in which the living body passing light intensity signal level after A / D conversion in the signal processing apparatus in the present embodiment when no load is applied to the living body is directly displayed on the display screen in time series. Is an example of the display.
[0037]
In normal biological light measurement, as shown in FIG. 5, by displaying 24 (24 channels) measurements at two wavelengths for each measurement position, the biological light intensity signal for each measurement position is displayed. To monitor. At this time, when measuring the relative change in the concentration of oxidized and reduced hemoglobin related to the application of a specific load on the living body, that is, the change in hemodynamics caused by the load, the light intensity signal level passing through the living body after A / D conversion is calculated. In the mode of directly displaying on the display screen in time series, as shown in FIG. 6, the region 61 indicating the application period of the load is displayed together with the biological passage light intensity signal level in the elapsed time direction, so that the living body by the load application is displayed. It becomes easy to observe the change in the passing light intensity signal level and the change in the biological light intensity signal level measured during the period when the load is applied to the living body.
[0038]
FIG. 7 shows the relative change amount level of the oxidized and reduced hemoglobin concentration at each measurement point calculated from the light intensity signal passing through the living body after A / D conversion in the signal processing apparatus of the present embodiment in a time series directly on the display screen. It is an example of the display in the mode to display.
[0039]
As is apparent from FIG. 7, in this embodiment, the region 71 indicating the load application period is displayed together with the relative change amount level of the oxidized and reduced hemoglobin concentration at each measurement point, so that each measurement point by load application is displayed. It is easy to observe the relative change level change of the oxidized and reduced hemoglobin concentration and the relative change level change of the oxidized and reduced hemoglobin concentration at each measurement point measured during the period when the load is applied to the living body. As shown in FIG. 8, the load application period is displayed in the biological light intensity passing through the living body in a mode in which the biological light intensity image calculated from the relative change in the oxidized and reduced hemoglobin concentration at each measurement point is displayed. A region 81 indicating the load application period is displayed together with the image, and it can be determined, for example, based on the position of the time display bar 82 whether or not the currently displayed biological passage light intensity image is in the application period 83. The time display bar 82 can be moved by a time display bar moving button 81.
[0040]
The invention made by the present inventor has been specifically described based on the embodiment of the invention, but the invention is not limited to the embodiment of the invention and does not depart from the gist of the invention. Of course, various changes can be made.
[0041]
【The invention's effect】
The effects obtained by the representative ones of the inventions disclosed in the present application will be briefly described as follows.
[0042]
(1) It becomes easy to check after mounting.
(2) It is possible to easily identify the change location of hemodynamics caused by applying a load to the living body.
(3) The diagnostic efficiency can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a schematic configuration of a biological light measurement apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining a relationship between an optical fiber fixing member, an irradiation and detection optical fiber, and a measurement position of living body passing light when the measurement probe of the present embodiment is attached to a living body.
FIG. 3 is a diagram when the irradiation and detection optical fiber positions attached to the living body and the measurement position of the light passing through the living body are displayed on the display screen in the signal processing apparatus according to the present embodiment.
FIG. 4 is an example of a display in a mode for confirming signal levels of detection light of irradiation and detection optical fibers in a measurement probe mounted on a living body.
FIG. 5 is a mode in which the living body passing light intensity signal level after A / D conversion in the signal processing apparatus in the present embodiment when no load is applied to the living body is directly displayed on the display screen in time series. It is an example of the display in.
FIG. 6 is a mode in which a living body passing light intensity signal level after A / D conversion in the signal processing apparatus of the present embodiment when a load is applied to a living body is directly displayed on a display screen in time series. Is an example of the display.
FIG. 7 shows the concentration of oxidized and reduced hemoglobin at each measurement point calculated from the light intensity signal passing through the living body after A / D conversion in the signal processing apparatus of the present embodiment when a load is applied to the living body. It is an example of the display in the mode which displays a relative variation | change_quantity level directly on a display screen in time series.
FIG. 8 is an example of display in a mode in which a living body passing light intensity image is directly displayed on a display screen in the signal processing device of the present embodiment when a load is applied to the living body.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Light source part, 2 ... Optical module, 3 ... Semiconductor laser, 8 ... Optical fiber for irradiation, 9 ... Living body, 10 ... Optical fiber for detection, 11 ... Photodiode, 12 ... Lock-in amplifier module, 16 ... A / D Converter: 17 ... Control unit, 18 ... Recording unit, 19 ... Processing unit, 20 ... Input / output unit, 31 ... Reference mark, 32 ... Shape information imitating measurement site of light passing through body, 33 ... Placement of measurement probe Position, 41... Optical fiber position where signal level does not fall within preset value, 42... Optical fiber position where signal level falls within preset value, 61, 71, 81.

Claims (2)

A measurement probe that irradiates a living body with light of a plurality of wavelengths guided by an optical fiber from a light source, detects light that has passed through the living body, and storage means that stores position information of an optical fiber that can be placed on the measurement probe; In the biological light measurement apparatus, comprising: means for generating a living body light intensity image of the living body from the detected passing light; and display means for displaying the living body light intensity image.
A reference mark indicating a reference position is written on the measurement probe, and the storage means stores position information for each measurement probe indicating a reference mark indicating the reference position,
The living body light measurement apparatus , wherein the display means displays shape information imitating a measurement site of the living body and an arrangement position of the optical fiber of the measurement probe, and displays the reference mark .   The display means includes a measurement period in a load state in which a load is applied to the living body and a measurement period in a no-load state in which a load is not applied, together with the intensity of the passing light that has passed through the living body or the biological light intensity image. The biological light measurement device according to claim 1, wherein:

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