JPH0686780A - Living body optical measuring instrument - Google Patents

Abstract

PURPOSE:To easily control gain value adjustment of a photodetector and integrating frequency adjustment of a measurement by a measuring person in the living body optical measuring instrument for measuring the function of a living body by using light and making it into image. CONSTITUTION:Light from a light source part 1 containing plural wavelength is made incident on an examinee 5, and also, the light which passes through the examinee 5 is caught by an optical fiber from plural parts to introduce into a multichannel photodetecting part 7. In this case, a gain value of the detector and an integrating frequency of a measurement by the photodetecting part 7 are inputted in advance by a measuring person by an input part 11. In such a way, the measurement set with a condition corresponding to a measuring condition is enabled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a living body optical measuring device for measuring information inside a living body using light.

[0002]

2. Description of the Related Art A biological optical measuring device, which is a so-called optical CT device, which measures and images a biological function by using light having a wavelength in the visible to near infrared region is disclosed in, for example, Japanese Patent Laid-Open No. 57-1152.
32 or JP-A-60-72542. It is known that light in the visible to near-infrared wavelength region has relatively good biological permeability. Furthermore, by using these lights, the oxygen partial pressure in the living body that reflects the biological function can be measured by using hemoglobin in the blood or cytochrome in the cell.
It is known that it can be determined from the amount of light absorbed by mua ₃ or myoglobin in muscle. However, in the case of an optical CT device, the path of light that has passed through the living body spreads through the living body due to the strong scatterer of light, so such light is removed in order to obtain a CT image. It is necessary to extract straight light. Japanese Patent Application No. 02-031
In the optical CT device described in No. 567, a living body is irradiated with ultrashort pulsed light (pulse width 10 to 100 ps) as incident light,
Time-resolved measurement of the light intensity transmitted through the living body. As a result, the light that spreads in the living body and is delayed in time is removed, and the light that travels straight in the living body is extracted.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Conventionally, there has been a problem that it is necessary to detect light whose intensity is remarkably reduced after passing through a living body of several cm to ten and several cm. Therefore, in order to improve the S / N ratio of the measurement light, it is necessary to lengthen the measurement time to increase the number of integrations of the measurement, or to use a photodetector with high sensitivity. However, increasing the measurement time is not preferable because it causes pain to the subject. Further, regarding the use of the high-sensitivity photodetector, the biological optical measurement device has the following problems.
If the detector has high sensitivity, it will be affected by weak stray light, resulting in a decrease in the S / N ratio of the measurement light. In order to eliminate the influence of this faint stray light, it is necessary to make the measurement environment a completely dark room as much as possible, but in a completely dark room it causes psychological fear to the subject, and as a result accurate biological function This causes a problem that measurement becomes difficult. In a completely dark room, the subject cannot recognize the direction of evacuation in an emergency, which is dangerous. Therefore, it is necessary to install the emergency light indicating the exit with the minimum required light intensity.

On the other hand, if the detection sensitivity is lowered, it is possible to eliminate the influence of such stray light, but in this case, the measurement time is increased in order to improve the S / N ratio of the measurement light. Creates the problem of having to. The ideal measurement is to maintain a high S / N ratio in a short time,
In the biological optical measurement device, it is essentially difficult to make them compatible for the above reasons. Therefore, in order to efficiently perform practical measurement, it is necessary to select the measurement in which either the high S / N ratio or the short time measurement is prioritized according to the situation. For example, when a large number of measurements are required in a short time, such as in mass screening, high-sensitivity short-time measurement is performed by prioritizing short-time measurement over high S / N ratio measurement. Since it is necessary to give priority to the high S / N ratio of, it is desirable to perform low-sensitivity long-time measurement. An object of the present invention is to provide a biological optical measurement device that can easily set measurement conditions according to the measurement situation and purpose.

[0005]

Means for Solving the Problems Light emitted from a light source unit and having at least one or more wavelengths in the visible to near-infrared wavelength region is guided to a living body by a light transmitting means, and is irradiated with the living body at a plurality of parts of the living body. In a living body optical measurement device that guides and detects light that has passed through a light detection unit by at least one or more light transmission means, and measures the form or function of a living body from the detected light, the sensitivity and measurement of the light detector The number of times of integration is arbitrarily controlled externally, the sensitivity of the detector is automatically reduced each time the measurement is completed, and the amount of light emitted from the light source unit is automatically reduced each time the measurement is completed.

[0006]

[Function] On the operation panel corresponding to the input section of the measurement condition,
Set a variable switch that can simultaneously set the gain value of the detector and the number of times of measurement integration. This allows the measurer to arbitrarily and easily control these measurement conditions according to the situation and purpose at the time of measurement.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of a biological optical measurement device showing an embodiment of the present invention. The light source unit 1 has a wavelength of 500 nm to 1
Light of a plurality of wavelengths between 500 nm is sequentially emitted. The emitted light is introduced into the multi-input / multi-output optical switch 3 by the optical fiber 2 and any one of the optical fibers 4-1 to 4-n in contact with a plurality of parts around the subject 5 is inspected. Connected to one optical fiber. Assuming that the optical fiber connected to the optical fiber 2 is the optical fiber 4-1 here, the subject 5 is irradiated with the light by the optical fiber 4-1. The subject 5 is at rest in the shaded examination room 12. The light that has passed through the subject 5 is the optical fiber 4-2.
4 to 4n are captured and introduced into the optical switch 3 again. Further, these optical fibers 4-2 to 4-n are connected to the optical fiber 6-1 inside the multi-input / multi-output optical switch 3.
To 6-m are connected one to one. The other ends of the optical fibers 6-1 to 6-m are introduced into the multi-channel photodetector 7, and the light intensity of each optical fiber is measured independently. These light detection intensities are shown in Fig. 1.
The data is stored in the data storage unit 8 and is processed by the computer 9.

When this series of measurements is completed with light of one wavelength, the light source section 1 is controlled by the computer 9 to change the measurement wavelength. When the same measurement is completed for all wavelengths, the computer 9 then multi-inputs.
By controlling the multi-output optical switch 3, multi-input from the light source unit 1
The optical fiber 2 introduced into the multi-output optical switch 3 is connected to, for example, the optical fiber 4-2, and light irradiation to the subject 5 is performed from a position different from the previous time. At this time, the light that has passed through the subject 5 is the optical fiber 4-1 and the optical fiber 4-3.
4 to 4-n, and are connected to the optical fibers 6-1 to 6-m one to one by the multi-input / multi-output optical switch 3 controlled by the computer 10. In this way, the light irradiation position on the subject 5 is sequentially changed and the measurement is repeated, and finally the computer 9 performs arithmetic processing and image processing of the measurement result at each wavelength to obtain an image relating to biological functions. It is displayed on the display unit 10. In order to carry out this series of measurements more effectively according to the measurement situation, the measurer preliminarily measures the measurement mode, for example, the low-sensitivity high integration count mode and the high-sensitivity low integration count mode. And input from the input unit 11. The number of measurement modes can be set to two or more as required.

Here, inside the examination room 12, there is a ramp 15.
Is installed, and the lamp is turned on when the subject enters the examination room and when the subject leaves the examination room after the measurement is completed. Of course, this lamp 15 is turned off during measurement. Further, the entrance / exit 13 of the examination room 12 is designed to be opened simply by pushing from the inside so that the subject can easily escape in an emergency. Further, inside the entrance / exit 13, an emergency light 14 with a built-in power source, which indicates the exit, is installed with the minimum necessary brightness, and this lights up even during measurement. When a series of measurements is completed, the gain value of the detector is automatically set to the lowest level and the output of the light source unit is set to the lowest level, respectively, to prolong the life of the light detection unit and the light source unit. In this way, by setting a variable switch that can simultaneously set the gain value of the detector and the number of times the measurement is integrated on the operation panel corresponding to the input section of the measurement conditions, the measurer can adjust to the situation and purpose at the time of measurement. It is possible to control these measurement conditions arbitrarily and easily.

In the present invention, the operator arbitrarily controls the sensitivity (gain value) of the detector and the number of times the measurement is integrated to perform efficient measurement according to the measurement situation. confirmed. This experiment was conducted with the apparatus configuration shown in FIG. Wavelength 812nm, pulse width 80ps
Light from the semiconductor laser 21 is applied to the scatterer sample 23 by the optical fiber 22. The scatterer sample 23 is prepared by placing diluted milk simulating biological light scattering characteristics in an optical container having a cell optical path length of 30 mm. The light transmitted through this sample is captured by the optical fiber 24, and finally detected by the light intensity time-resolved measuring instrument 25. FIG. 3 shows the time dependence of the amount of detected light at a certain gain value of the detector (this is referred to as G) and a certain number of times of integration (assumed to be N times).
The horizontal axis represents the sample transmission time when the time when the peak of the incident pulsed light is incident on the sample is the origin. The vertical axis shows the relative value of the amount of transmitted light. Next, in FIG. 4, the gain value of the detector is set to 10 G to improve the sensitivity 10 times as compared with FIG.
The result is shown in the case of shortening by 0.1 times compared to.
As is clear from FIGS. 3 and 4, it can be understood that the result of FIG. 3 shows that the measurement time is 10 times longer, but the S / N ratio of the measurement light is better than that of FIG. In this model experiment, the gain value is 1
The measurement of 0 G and the number of integration times N was impossible due to the lack of the storage capacity of the detector. From this point of view, it is understood that such control of the gain value and the number of integrations is effective under the limited storage capacity of the detector.

[0011]

EFFECTS OF THE INVENTION In a living body optical measuring apparatus for measuring the function of a living body by using light and imaging, the adjustment of the gain value of the photodetector and the adjustment of the number of times of measurement can be easily controlled by the measurer. It is possible to measure according to.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a model experiment configuration diagram for confirming the effect of the present invention.

FIG. 3 is a diagram showing a model experiment result.

FIG. 4 is a diagram showing a model experiment result.

[Explanation of symbols]

1 ... Light source part, 2 ... Optical fiber, 3 ... Multi-input / multi-output optical switch, 4-1 to 4-n ... Optical fiber, 5 ... Subject, 6
-1 to 6-m ... Optical fiber, 7 ... Multi-channel photodetector, 8 ... Data storage, 9 ... Computer, 10 ...
Display part, 11 ... Input part, 12 ... Examination room, 13 ... Doorway,
14 ... emergency light, 15 ... lamp, 21 ... semiconductor laser, 2
2 ... Optical fiber, 23 ... Sample, 24 ... Optical fiber, 25
… Light intensity time-resolved measuring instrument.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumio Kawaguchi 1-280 Higashi Koikeku, Kokubunji City, Tokyo Metropolitan Research Laboratory, Hitachi, Ltd. (72) Inventor Yukito Shinohara 143 Shimokasuya, Isehara City, Kanagawa School of Education (72) Inventor Shigeharu Takagi, 143 Shimokasuya, Isehara City, Kanagawa Prefectural School of Medicine Tokai University School of Medicine (72) Nobuaki Shinohara 143, Shimokasuya, Isehara City, Kanagawa Prefectural School of Medicine Tokai University

Claims (3)

[Claims] 1. Light that has been emitted from a light source unit and has at least one wavelength in the visible to near-infrared wavelength region guided to a living body by a light transmitting means and irradiated therewith, and has passed through the living body at a plurality of parts of the living body. In a living body optical measurement apparatus that guides and detects the light to a light detection unit by at least one or more light transmission means, and measures the form or function of the living body from the detected light, the sensitivity of the light detector and the number of times of integration of the measurement. A biological optical measurement device, which is characterized in that the device is controlled from the outside. 2. The biological optical measurement device according to claim 1, wherein the sensitivity of the detector is automatically reduced every time measurement is completed. 3. The amount of light emitted from the light source unit is automatically reduced every time the measurement is completed.
The optical measurement device for living body according to.