JP4071506B2 - Biological light measurement device - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
This invention irradiates a living body with light, detects light reflected on the surface of the living body, or passing through the vicinity of the surface, obtains biological information such as blood circulation, hemodynamics, hemoglobin change, etc. from the light quantity and images it. The present invention relates to a biological light measurement device, and more particularly to a biological light measurement device suitable for measurement in a relatively wide area.
[0002]
[Prior art]
The living body light measuring device irradiates the living body with wavelengths in the visible to infrared region, detects light reflected from the living body or light passing through the living body (hereinafter collectively referred to as transmitted light), and measures the inside of the living body. Therefore, biological information such as hemodynamics inside the living body can be obtained simply and non-invasively with low restraint on the subject. An apparatus capable of measuring a wide area by using a probe in which the tips of a plurality of optical fibers are arranged as a light irradiator and a light receiver is being applied in clinical practice (Japanese Patent Laid-Open No. 57-115232, Japanese Patent Laid-Open No. 57-115232). Sho-63-275323 etc.).
[0003]
As a measurement method using such a biological light measurement device, event mode measurement that detects sudden changes such as epileptic seizures by tracking changes in signals over time, and a predetermined load (task) ) Is repeatedly given, and there is a measurement method (hereinafter referred to as load mode or stimulus mode measurement) in which the active state of the brain at the time of task load is observed. The load mode measurement is described in, for example, Japanese Patent Application Laid-Open No. 9-98972. In this measurement, the biological light measurement is performed while repeatedly applying predetermined loads (tasks) such as light stimulation and exercise to the subject at regular intervals. From the obtained results, a relative change in the hemoglobin concentration at the time of task load (change with respect to no load) is obtained. At this time, a method of adding statistical data obtained by repetition to increase the statistical reliability is also employed (referred to as addition mode measurement).
[0004]
[Problems to be solved by the invention]
However, since the measurement of the amount of change in hemoglobin concentration in the conventional addition mode is performed after the measurement is completed, it is necessary to determine whether the measurement site is appropriate, whether the load is applied properly, and the number of repetitions is appropriate until the measurement is completed. I didn't. Therefore, after data analysis, for example, when it is found that the number of repetitions is not appropriate, the number of repetitions considered to be appropriate must be set again and measured again.
In addition, the subject may move during the measurement, and noise may be mixed in. However, since the noise is also reflected in the addition result, there is a possibility that the accuracy of the measurement is lowered.
[0005]
Therefore, the present invention can display a measurement result in real time for each measurement in one task unit in the biological light measurement in the addition mode, and thereby can perform measurement under appropriate conditions by one measurement. An object is to provide an apparatus. It is another object of the present invention to provide a biological light measurement device capable of preventing noise from being mixed into an addition result and performing highly accurate measurement.
[0006]
[Means for Solving the Problems]
The living body light measuring device of the present invention that achieves the above object includes a measuring probe that arranges a plurality of irradiation optical fibers and detecting optical fibers on the body surface of the living body, and the amount of light received by the detecting optical fiber for each measuring position. A biological light measurement apparatus comprising: an optical measurement means for detecting the information; and a signal processing means for calculating biological information of the subject based on a signal corresponding to the detected light quantity, and forming and displaying a biological information image. The signal processing means includes means for storing measurement data for each predetermined time unit (for example, a relative change in hemoglobin concentration) and means for displaying the measurement data for the time unit in real time during measurement. is there.
[0007]
According to such a biological light measurement device, the measurement result can be observed in real time at the time of the biological light measurement at the time of task load. Conditions can be set. In addition, according to the present invention, since the presence / absence of noise generation and the characteristics of noise can be grasped in real time, measurement data mixed with noise can be removed accordingly, and an accurate measurement result can be obtained.
[0008]
In the biological light measurement apparatus of the present invention, the signal processing means includes means for adding measurement data in units of time, and the display means displays the added measurement data in real time. In order to realize real-time display, the biological light measurement device of the present invention includes, for example, a clock that controls the time unit of measurement, and the signal processing means performs measurement for each time unit based on an operation signal from the clock. Data division, addition processing and display are time-division processing or parallel processing.
[0009]
Furthermore, in the biological light measurement device of the present invention, the signal processing means includes means for selecting time-unit measurement data to be removed from the addition target among the time-unit measurement data, and the addition means is selected by the selection means. The addition is performed using measurement data in units of time that have not been performed.
[0010]
According to this biological light measurement device, it is possible to display in real time a measurement result whose statistical significance has been enhanced by the addition process. Further, by eliminating data in a section in which noise is mixed in the addition process, a highly accurate measurement result can be obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the biological light measurement device of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 is a diagram showing an overall outline of the biological light measurement device of the present invention. This biological light measurement device mainly includes a light source unit 10 that irradiates a living body with near-infrared light, and light from the light source unit 10 that is transmitted through the living body or reflected or scattered from the living body (hereinafter collectively referred to as transmitted light). Optical measurement unit 20 that measures and converts it into an electrical signal, and signal processing that calculates biological information, specifically blood hemoglobin concentration change, based on the signal from optical measurement unit 20, and displays the result Part 30. Further, this living body light measurement device brings the tip of the optical fiber that guides the light from the light source unit 10 into contact with the measurement position of the subject, and guides the transmitted light from the subject to the light measurement unit 20 In order to bring the optical fiber into contact with the measurement position of the subject, a mounting tool (referred to as a measurement probe together with the optical fiber tip) 40 to which these optical fiber tips are fixed is provided.
[0013]
The light source unit 10 includes a semiconductor laser 11 that emits a plurality of wavelengths in a wavelength region from visible light to infrared, for example, 780 nm and 830 nm, and modulation for modulating these two wavelengths of light at a plurality of different frequencies. It comprises a plurality of optical modules 12 provided with a vessel and an optical fiber 13 for light irradiation. The two-wavelength light emitted from the semiconductor laser 11 is mixed, then modulated to a different frequency for each optical module, and irradiated to the examination site of the subject through the optical fiber 13.
[0014]
The optical measurement unit 20 is connected to the detection optical fiber 21 and converts a light guided by the detection optical fiber 21 into an electric signal corresponding to the light amount. A lock-in amplifier 23 for inputting a signal and selectively detecting a modulation signal corresponding to the irradiation position and wavelength, and an A / D converter 24 for A / D converting the signal from the lock-in amplifier 23. . The lock-in amplifier 23 includes at least the same number of lock-in amplifiers as the number of signals to be measured.
[0015]
In the probe 40, a socket for connecting an optical fiber is arranged in a matrix of an appropriate size such as 3 × 3, 4 × 4 so that the tip of the irradiation optical fiber and the tip of the detection optical fiber are alternately arranged. It is. The light detected by the detection optical fiber is a mixture of the light irradiated from the four adjacent irradiation optical fibers and transmitted through the living body, and the modulation signal varies depending on these irradiation optical fibers by the lock-in amplifier 23. By selectively detecting, it is possible to obtain information on a point (measurement point) between the tip of the detection optical fiber and the tip of the adjacent irradiation optical fiber. These measurement points correspond to the channels detected by the lock-in amplifier 23. For example, in a 4 × 4 matrix probe, the number of measurement points between the light irradiation position and the detection position is 24, and light measurement with 24 channels is performed. be able to.
[0016]
The signal processing unit 30 includes a control unit 34 that controls the entire apparatus, a storage unit 31 that stores a voltage signal (digital signal) sent from the optical measurement unit 20, and stores data after signal processing, and a storage unit 31. The processing unit 32 that processes the voltage signal stored in the signal, converts it into a signal representing biological information, specifically, a hemoglobin signal representing the hemoglobin concentration of the measurement site, and creates a topography image, and displays the processing result. In addition, an input / output unit 33 for inputting instructions necessary for measurement and signal processing to the control unit 34 is provided. Further, the signal processing unit 30 includes a clock that controls the time unit of measurement in the load mode measurement described later. Based on the operation signal from the clock, the measurement and the data acquisition of the time unit are performed, and the image is calculated using the data. And display.
[0017]
In the biological light measurement apparatus having such a configuration, the biological optical measurement is performed by irradiating light modulated at different frequencies by the irradiation optical fiber 13 from a probe attached to the biological body and transmitting through the living body to detect the optical fiber. The light induced by 21 is converted into an electrical signal by each photodiode 22, detected at each measurement point that is the intermediate point between the irradiation position and the detection position, and the hemoglobin signal converted into the blood hemoglobin concentration at the measurement site Done by getting. The information obtained by this measurement is generally oxygenated hemoglobin concentration (Oxy-Hb), deoxygenated hemoglobin concentration (Deoxy-Hb), and total hemoglobin (Total-Hb), but absorbed in the near infrared A substance other than hemoglobin, such as cytochrome, can be used as a measurement target if it is an in vivo substance.
[0018]
Next, the operation in the case of measuring the hemoglobin concentration in the load mode (stimulation mode) using the biological light measurement device will be described. FIG. 2 is a diagram showing an embodiment of the biological light measurement by the biological light measurement device of the present invention. In this measurement, first, a preliminary measurement is performed before the task load is performed, and then a certain section including the task load. The above measurement is repeated, and the relative change in the hemoglobin concentration in the section is measured. One section includes a time pre before loading a task, a task loading time task, a relaxation time relaxation after task loading, and a subsequent time post. Relaxation is the time required for the biological reaction due to the load to return to its original state. Here, pre, relaxation, and post are referred to as rests, and one task and the accompanying rest are measured as one task unit, and this is repeated a plurality of times. The start of each section and each time in the section are controlled so as to be constant in each repetition in accordance with a clock (not shown) provided in the apparatus.
[0019]
FIG. 3 shows the measurement procedure. As shown in the figure, first, preliminary measurement is performed before task loading (step 301), and the measurement state in a state where no task is loaded is checked (step 302). Next, measurement is performed in units of one task, and the relative change of the hemoglobin Hb in the section, that is, the change with respect to the reference data is measured (step 303). The task unit measurement is repeated a preset number of times (N).
[0020]
For each measurement, the raw data is displayed on the display unit of the input / output unit 33 in a time course (step 304). The measured data is stored in the memory of the storage means 31 for each measurement for each task (step 305). As shown in FIG. 4, the measurement data for each task includes four data of pre, task, relaxation, and post for each channel (measurement point).
[0021]
FIG. 5 shows an example of a display displayed on the display unit. In the figure, (c) is a display of the time course of raw data (voltage data ). Here, measurement data of 24 channels are displayed in the time course for two types of measurement wavelengths (780 nm and 830 nm). This is displayed, for example, every measurement of 0.1S. The data between the two vertical lines is the data at task load. Further, (a) is an ID column for displaying the ID, name, and measurement date and time of the subject, and (b) shows the number and position of the measurement channel.
[0022]
On the other hand, the processing means 32 obtains an approximate straight line or approximate curve connecting pre and post of the task unit for the data of one task unit, and takes the difference between the approximate straight line or approximate curve and the data at the time of task load , to calculate the relative concentration of hemoglobin (step 306). Then, the calculated relative density is displayed on the display unit as shown in FIG. 5 (d) (step 309).
[0023]
Similarly, for the measurement of the second task unit, the measurement raw data is displayed on the display unit, and the relative concentration of hemoglobin is calculated by taking the difference from the approximate line or approximate curve connecting pre and post of the task unit. (Step 306). The processing means 32 further obtains an average value of the second data and the data measured before that (first data) and displays it on the display unit (steps 308 and 309). Thereafter, the processing from step 303 to step 309 is repeated until the set number of times N, and finally a graph of relative density, which is an average value of N times of task unit measurement, is obtained. Although FIG. 5 shows an example in which the relative density is displayed as a graph, the topography showing the relative density of each measurement point as a contour image on the measurement region is displayed instead of the graph display or together with the graph display. It is also possible.
[0024]
The series of processing from step 303 to step 309 uses the foreground of the processing means 32 and the background, which is its free time, as shown in FIG. 6, for example, by an operation signal from a clock that controls measurement in units of tasks. And done in real time. That is, for example, measurement is performed every 0.1 second and data is fetched (steps 303 to 305) in the foreground, and when the measurement for each task is completed, the background is started and the image for each task is calculated. Thereafter, the processing is performed in the background until the calculation of the image for each task and the display of the result are completed. At this time, the measurement display is processed as a high priority job after the measurement. Thus, an image can be displayed in real time in parallel with the measurement. Note that these processes can be performed in parallel by a plurality of processing means instead of time-sharing by the single processing means 32.
[0025]
As described above, according to the present embodiment, when performing biological measurement while repeatedly performing a task load, the average value of the measurement results of one task unit can be sequentially displayed in real time simultaneously with the measurement. Etc., it is possible to judge whether the measurement conditions (how to apply load and the number of repetitions of measurement) are appropriate during measurement. If necessary, change the conditions and continue or end the measurement. Is possible. In this case, as shown in the flow B and the subsequent steps in FIG. 3, for example, it is determined whether or not to continue further after the preset number of repetitions N (after step 310) (step 311). Via the output unit 33, selection of continuation or termination of measurement and setting of conditions for continuation are performed (step 312). When a new condition is set, preliminary measurement (from step 301) or task unit measurement (from step 303) is resumed depending on the condition.
[0026]
Moreover, in the above-mentioned biological light measurement, since the generation of noise can be known in real time by observing the raw data displayed in the time course, the measurement data mixed with noise can be deleted from the subsequent processing. Is possible. Such determination can be made manually by looking at the measurement result displayed in real time, but can also be automatically determined by the processing means 32 . Such automatic determination is shown as step 307 in FIG. In that case, a threshold value of relative density (or signal value) at the time of task load is set in advance, and when the measurement data exceeds the threshold value, it is considered that a large noise has occurred, and the data is excluded from the calculation. At the same time, the measurement is not counted as the number of repetitions.
[0027]
As described above, the biological light measurement in the load mode in which the measurement is performed while repeatedly applying one kind of load has been described. However, the biological light measurement device of the present invention is not limited to such a load mode, for example, a method of applying the load is different. It can also be applied to measurement while giving different tasks. Such an embodiment is shown in FIG. In this embodiment, for example, three types of tasks T1, T2, and T3 having different loads are cyclically repeated to observe a biological reaction.
[0028]
Also in this biological light measurement, the relative value of the hemoglobin concentration for each task unit from the point of displaying the raw data as a time course for each measurement and the difference between the measured raw data and the approximate straight line or approximate curve connecting pre and post for each task unit The point of calculating the change is the same as in the above embodiment. However, in this embodiment, the addition of the measurement data for each task is performed between the same task types. That is, in the second and subsequent measurements following the measurement for the third task T1, T2, T3 load, the measurement data for the first task T1 load and the measurement data for the second task T1 load are added. Display in real time.
[0029]
As another embodiment, it is possible to measure by changing loads one after another without adding data for each task unit, and find an optimum load or perform another test.
[0030]
【The invention's effect】
According to the present invention, the measurement result can be observed in real time during the measurement of biological light at the time of task load. Therefore, it is possible to instantaneously determine whether the measurement is appropriate and to continue measurement or set new conditions. Can do. In addition, according to the present invention, since the presence / absence of noise generation and the characteristics of noise can be grasped in real time, measurement data mixed with noise can be removed accordingly, and an accurate measurement result can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall outline of a biological light measurement device of the present invention. FIG. 2 is a diagram illustrating measurement of a load mode using the biological light measurement device of the present invention. FIG. 4 is a flowchart showing an example of measurement using a measurement device. FIG. 4 is a diagram showing an example of measurement data stored in a storage means. FIG. 5 is a diagram showing an example of display of the biological light measurement device of the present invention. FIG. 7 is a diagram showing the state of processing in the processing means. FIG. 7 is a diagram showing another embodiment of measurement using the biological light measuring device of the present invention.
10 ... Light source
13 ... Optical fiber for irradiation
20 ... Optical measurement unit
21 ... Optical fiber for detection
30 ... Signal processing section
31 ... Storage means
32 ... Processing means
40 ... Probe

Claims (3)

Corresponding to the detected light quantity, a measuring probe that arranges a plurality of optical fibers for irradiation and optical fibers for detection on the body surface of the living body, an optical measuring means that detects the amount of light received by the optical fiber for detection at each measurement position A biological light measurement device comprising signal processing means for calculating biological information of the subject based on a signal to be formed and forming and displaying a biological information image;
The signal processing means includes
A storage unit that performs measurement to acquire measurement data for each predetermined task, and stores the measurement data for each measurement ;
A calculation means for calculating an average value of measurement data acquired by the measurement for each measurement ,
Display means for displaying the average value calculated by the calculating means ;
Selecting means for selecting measurement data to be removed from the average value calculation target among the measurement data acquired for each measurement;
The selection means selects the measurement data as the measurement data to be removed when the measurement data exceeds a predetermined threshold value,
The calculating means calculates the average value using measurement data in units of tasks not selected by the selecting means ;
A biological light measuring device characterized by the above. The biological light measurement device according to claim 1,
Further comprising a counting means for counting the number of measurements performed,
When the measurement data is selected by the selection means, the counting means does not count the measurement that acquired the measurement data.
A biological light measuring device characterized by the above . The biological light measurement device according to claim 1 or 2,
The measurement is performed under a plurality of different conditions,
The calculation means calculates the average value between measurement data acquired by measurement performed under the same conditions.
A biological light measuring device characterized by the above .

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