JP2007267837A - Biolight measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biolight measuring apparatus which enables the detection of lesion sites deep invivo with a higher precision. <P>SOLUTION: The apparatus includes a light emitting means which emits a plurality of beams of light with different wavelengths varying the intensity hourly, a synthesization means which synthesizes the lights emitted by the light emitting means on the same optical path, an irradiation means which irradiates beams of the light synthesized by the synthesization means, a detection means which detects beams of the light irradiated by the irradiation means, a measurement means which measures the intensity of the beams of light detected by the detection means and an adjustment means which adjusts the intensity of the plurality of beams of light emitted by the light emitting means so as to minimize the hourly variance of the intensity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a living body light measurement apparatus capable of non-invasively obtaining living body internal information using light.

  It is known that optical properties such as biological tissue and blood, for example, values such as light scattering coefficient and absorption coefficient vary depending on physiological conditions. A typical example of this is the change in absorption coefficient due to the oxidation state of hemoglobin present in blood. Specifically, as shown in FIG. 5, oxyhemoglobin has a larger absorption coefficient for light in the vicinity of 900-1000 nm compared to reduced hemoglobin. However, this magnitude relationship is reversed around 800 nm, and the light absorption coefficient on the shorter wavelength side is larger for reduced hemoglobin. Therefore, for example, by irradiating a living body simultaneously with light having a wavelength near 900 nm where the absorption of oxyhemoglobin has a large value and light with a wavelength of 700 nm having a large absorption coefficient of reduced hemoglobin, and measuring the ratio of the amount of absorption, etc. The degree of oxidation of hemoglobin can be estimated. In addition, a measurement device for determining the oxygen saturation of blood flowing on the body surface based on such an idea has already been put into practical use, and an attempt to measure the function of the cerebrum using a similar principle has also been made. Yes. When the living body is irradiated with light such as a laser beam, the light is scattered inside the living body, passes through the skin again, and is emitted outside the living body. This light contains information inside the living body, and recently, it is expected that the emitted light can be used for early diagnosis of cancer.

  An example of the measurement principle at this time is that diagnosis is performed by evaluating the degree of oxidation of the above-described hemoglobin. That is, in general, cancer cells are in a state in which the supply of oxygen is insufficient compared to normal tissues due to abnormal growth of cells. Therefore, cancer tissue has a relatively high amount of reduced hemoglobin compared to surrounding normal tissue, and if such changes in the body can be measured, early detection of cancer becomes possible. .

  Of course, in current cancer diagnosis, methods such as ultrasonic diagnosis and X-ray CT are often used, and have achieved great results in health checkups and the like. However, these diagnoses measure mainly physical characteristics such as tissue acoustic impedance and X-ray transmission. For this reason, such tests can measure the presence or absence of a tissue that is different from the normal state present in normal tissue, but also include knowledge based mainly on chemical information, such as whether the tissue is malignant or benign. Can not get. Therefore, if a medical diagnostic device using light as described above can be realized, it is expected that the diagnostic accuracy can be greatly improved by combining this with an existing diagnostic device. However, in the diagnosis using biological light, the incident efficiency of light into the body varies depending on various factors. Therefore, instead of extracting information based on the absolute intensity of the detected light, the incident position and detection of light Attempts to diagnose the inside of a living body from changes in detection light caused by changing the position of the light passing through the living body from the incident position to the detecting position by changing the position have been advanced.

  However, what is required in scenes such as actual cancer screening is a diagnosis of tissue deep in the living body. The tissue in the deep part of the living body has a negligible effect on the light observed on the surface of the living body. That is, the light observed on the surface of the living body includes light that has repeatedly scattered many times inside the living body and passed through various places. Therefore, in the development of biodiagnosis using light, the intensity of the irradiated light is modulated in order to improve the measurement sensitivity of weak signals, and changes in the observed light intensity modulation are measured with a lock-in amplifier or the like. The method is used.

For example, light having a wavelength λ _{1 with} a significantly different absorption coefficient is prepared for a normal tissue and an abnormal tissue. At this time, the light intensity I ₁ when the intensity of the light of wavelength λ ₁ is subjected to amplitude modulation of frequency ω can be expressed by the following equation. Here, a ₁ and b ₁ are constant DC components.

At this time, it is assumed that the light irradiation point or the measurement point is changed, and the light passing through the cancer tissue existing in the living body is increased. Then, the amount of absorption of the light having the wavelength λ ₁ changes. In general, this amount of change is very small. Assuming that the amount of change is 10 ⁻⁶ , the light intensity I ₁ ′ of the wavelength λ ₁ after the change can be expressed by the following equation.

If I ₁ and I ₁ ′ at this time are expressed in the same scale, the result is as shown in FIG. When a part of FIG. 6a is enlarged, it becomes like FIG. 6b. The light intensities I ₁ ′ and I ₁ are very close, and the difference in amplitude modulation of the light intensity is very small. In order to detect such a minute difference, it is necessary to capture a minute change in a signal having a large absolute value, and the effective number in the measurement must be very large.
Japanese Patent Laid-Open No. 9-19408

  As described above, the influence of the lesion in the deep part of the living body on the reflected light intensity is only a very small change of about 5 to 6 digits in absolute value. On the other hand, the living body consists of a very complex tissue system, and even if the incident light is modulated, the extraordinarily large light that has passed through the area other than the region to be measured is also modulated. It will be superimposed. Therefore, information on the deep part of the living body cannot be obtained unless a minute change in the signal having a large absolute value is captured. Considering the relationship of the dynamic range of the amplifier, it is difficult to detect such a minute change, and there is a problem in the measurement accuracy of the biological optical measurement device. An object of the present invention is to solve the problem of such a conventional configuration, and to provide a living body light measurement device capable of detecting a lesion site in a deep part of a living body with high accuracy.

  Therefore, the present invention provides a light emitting means for emitting a plurality of lights having different wavelengths whose intensity changes over time, a combining means for combining the light emitted by the light emitting means on the same optical path, and a combining means. Irradiating means for irradiating the irradiated light, detecting means for detecting the light irradiated by the irradiating means, measuring means for measuring the intensity of the light detected by the detecting means, and measurement of the light measured by the measuring means Adjusting means for adjusting the intensities of the plurality of lights emitted by the light emitting means so that the temporal change in intensity is minimized.

  The living body light measurement apparatus of the present invention can remove a large signal component that has become an obstacle when measuring a change in detection light, and is necessary without requiring an excessive dynamic range for measurement of a detection signal. Only the signal can be detected. This increases detection sensitivity and enables detection of small lesion sites that have been overlooked in the past, and is effective in the early detection of diseases by combining with existing diagnostic equipment.

  Hereinafter, the biological light measurement device of the present invention will be described.

  FIG. 1 shows the configuration of an embodiment of the biological light measurement device of the present invention.

1. Light emitting means The light emitting means 12 includes a first light source 12 (a) that emits a first light beam and a second light source 12 (b) that emits a second light beam having a wavelength different from that of the first light beam. ) And a third light source 12 (c) that emits a third light beam having a wavelength different from that of the first and second light beams. As the first to third light sources, for example, three different types of semiconductor lasers are used. The semiconductor laser is composed of a head part and a driver part. The head part irradiates a laser as a light source, and the driver part controls the intensity of the light beam emitted from the head part.

For example, when detecting a cancer tissue, light having a wavelength λ ₁ having a large absorption coefficient between a normal tissue and a cancer tissue is prepared as the first light beam emitted from the first light source 12 (a). What is important here is that the optical constant of the first light beam differs between the normal site in the living tissue and the cancer tissue site. Different optical constants mean different scattering coefficients and absorption coefficients. As described above, the amount of reduced hemoglobin is higher in cancer tissues than in normal tissues. Therefore, it is necessary to irradiate light having a wavelength with different light absorption coefficients between a tissue with a large amount of deoxyglobin and a tissue with a small amount of reduced hemoglobin. That is, the first light source 12 (a) that emits the first light beam plays a role as a light source for detection light.

Then, as the light beam emitted from the second light source 12 (b) and the light beam emitted from the third light source 12 (c), two types of wavelengths whose absorption coefficients hardly change between normal tissue and cancer tissue. Prepare light of λ ₂ and λ ₃ . The second light source 12 (b) that emits the second light beam and the third light source 12 (c) that emits the third light beam serve as a light source for reference light.

2. Modulating means The modulating means 11 outputs a control signal for modulating the intensity of the light beam emitted from the first to third light sources. For example, a function generator is used as the modulation means.

The light intensity I ₁ when the intensity of the light of wavelength λ ₁ is modulated at the frequency ω can be expressed by the following equation (1). The state of the periodic change in the light intensity at the wavelength λ ₁ is shown in FIG. Similar to the light at λ ₁ , the light intensities I ₂ and I are obtained by modulating the intensity of the light at λ ₂ and λ _{3 at} the frequency ω and providing a phase difference of 2π / 3 and 4π / 3 with respect to I _{1 3} can be represented by formulas (2) and (3), respectively. The state of the periodic change of the light intensity of the wavelengths λ ₂ and λ ₃ is shown in FIG. 2b.

What is important here is to provide a phase difference so that the periodic changes in the light intensity cancel each other when the two or more lights are superimposed. In the embodiment of FIG. 1, the first to third light beams have the same light intensity (constant a), and the periodic change of the light intensity is shifted by 2π / 3 (ωt, ωt + 2π / 3). , Ωt + 4π / 3). In addition, the optical constants of biological tissues for light having different wavelengths are generally not the same. Therefore, even if the light intensity superimposed at this stage is a constant, the detected light intensity is not a constant. However, the influence of the difference in the optical constant of the biological material depending on the wavelength is mainly to change the ratio of the incident light intensity and the detected light intensity. Therefore, by adjusting a ₁ + a ₂ + a ₃ , the detected light intensity can be expressed as in Expression (4).

3. Combining unit The combining unit 13 includes a mechanism for superimposing the first to third light beams emitted from the first to third light sources.

  When the first to third light beams incident in the above formulas (1) to (3) are superimposed on the same optical path, the periodic modulation of the intensity of each light cancels out in the detection light, and detection is performed. Only the DC component remains in the light. Further, in the measurement, this adjustment is performed, and the detection light changes from this adjustment.

4). Light Irradiation Unit The light irradiation unit 14 is connected to the synthesis unit 13 and includes a mechanism for irradiating the living body with the first to third light beams superimposed by the synthesis unit 13. As the light irradiation means, for example, an optical fiber is used.

  The first to third light beams are irradiated onto the living tissue through the optical fiber 14 for light irradiation while being superposed by the combining unit 13. The first to third light beams irradiated on the living body travel inside the living tissue, a part is absorbed according to the light absorption characteristics of the living tissue, and a part is emitted outside the living body as reflected light. Since the reflected light of the first to third light beams is diffused in the living tissue, in order to obtain information for detecting cancer tissue from the diffused reflected light, a certain interval is provided from the light irradiation means. It is necessary to transmit the reflected light at the fixed position to the light detection means. Accordingly, the optical fiber 14 for light irradiation and the optical fiber 16 for light detection are fixed to the probe 21 at a predetermined interval, and the first diffused by scanning the probe 21 along the surface of the living tissue. The reflected light of the third light beam can be used as information for detecting cancer tissue.

When the probe 21 is scanned along the surface of the living tissue and the cancer tissue is irradiated with the first light beam, the light amount of the first light beam as reflected light emitted outside the living body changes. That is, as described above, since the first light beam is light having a wavelength λ _{1 that} has a large absorption coefficient between normal tissue and cancer tissue, when the first light beam is irradiated to the “normal tissue”. The light intensity of the first light beam as reflected light emitted outside the living body, and the first as reflected light emitted outside the living body when the first cancer beam is irradiated to the “cancer tissue”. A detectable light amount difference is generated between the light intensity of the light beam.

  Note that 15 represents a biological model sample. The biological model sample 15 is composed of a model block 24 and a thin plate 23. The model block 24 is provided with a plurality of grooves 25 for receiving model blood, and a thin plate 23 having the same optical constant as that of fat adheres to the model block 24. It is left still.

5). Photodetection means The photodetection means 17 is connected to the optical fiber 16 for light detection, and detects the reflected light from the living body of the first to third light beams irradiated into the living tissue through the optical fiber 14 for light irradiation. It has a mechanism. The first to third light beams as reflected light emitted outside the living body are received by the optical fiber 16 for light detection fixed at a predetermined interval from the optical fiber 14 for light irradiation, and the received light. Is transmitted to the light detection means 17 through the optical fiber 16. As the light detection means, for example, an OE converter is used.

6). Light intensity measuring means The light intensity measuring means 18 has a mechanism for measuring the light intensity of the first to third light beams as the reflected light emitted outside the living body. As the light intensity measuring means, for example, a lock-in amplifier is used.

The probe 22 is moved along the surface of the living tissue, and the change in the light intensity of the reflected light that changes at the cancer tissue site is detected. Since cancer tissue has a large amount of deoxyhemoglobin, light having a wavelength λ ₁ that has passed through the lesion site is absorbed by the tissue more than when it passes through the normal tissue. On the other hand, the light having wavelengths λ ₂ and λ ₃ has almost no change in the absorption coefficient between normal tissue and cancer tissue, so that the detected emitted light does not change even when passing through the cancer tissue. Thus, by moving the probe 22, when the amplitude modulation on the light intensity of the reflected light detected in the light detecting unit appears, the change is the wavelength lambda ₁ of the light is absorbed strongly reduced hemoglobin intensive cancer tissue It can be presumed to be caused by this.

Assuming that the amount of change is 10 ⁻⁶ , the light intensity I ₁ ′ of the wavelength λ ₁ after the change can be expressed by the following equation.

Here, the value obtained by adding the intensities I ₁ ', I ₂ and I ₃ of the three overlapping lights is

It becomes. At this time, the signal of the constant 3b can be easily removed by passing through a high-pass filter when measuring. The detection intensity after removing the DC component in this way is shown in FIG. That is, it is possible to remove a large signal component that has been an obstacle when measuring a change in detection light by the measurement method of the present invention, and it is necessary without requiring an excessive dynamic range for measurement of the detection signal. Only the signal can be detected.

In the above discussion, it is assumed that the coefficients a ₂ and a ₃ do not change even if the irradiation position or observation position of light is changed. However, in the normal case, the light actually enters the living body in the irradiated light. This assumption is not correct because the amount or the amount of light emitted from the inside of the living body to the outside depends on the condition of the skin surface. However, the frequency dependence of the influence of this on the detected light intensity is small, and the influence on the coefficients a ₁ , a ₂ , and a ₃ can be considered to be multiplied by an overall constant factor having a magnitude of about 1. The change resulting from this is only a factor of about 1 in Equation (4), and the conclusion obtained is unchanged. In addition, it is assumed that the absorption coefficients of the wavelengths λ ₂ and λ ₃ do not change between the cancer tissue and the normal tissue. However, if the absorption coefficient does not change the same as the light of the wavelength λ ₁ , the same conclusion is reached. Is obtained.

7). Adjusting means The adjusting means 19 is based on temporal changes in the light intensity of the first to third light beams as reflected light detected by the light intensity measuring means 18, and the temporal intensity of the light in the modulating means 11. It has a mechanism to adjust.

  A living body is an integral body of a complex tissue system. For example, light emitted from the optical fiber 14 for light irradiation first passes through the skin and reaches the cancer tissue existing therebelow. The light that reaches the cancer tissue is partially absorbed and partially reflected. Here, the skin consists of three layers of the epidermis, dermis, and subcutaneous tissue. The dermis contains a large amount of fiber components, nerve endings, and capillaries, and is also involved in moisturizing and fevering the body surface such as sebaceous glands and sweat glands. There are many organizational systems. A complex tissue system in which cartilage tissue, bone tissue, hematopoietic tissue, muscle tissue, nerve tissue and the like are intertwined is developed inside the subcutaneous tissue.

  As described above, in the present embodiment, the first light beam is used as the detection light and the second and third light beams are used as the reference light depending on the difference in absorption characteristics with respect to deoxyhemoglobin. In order to detect a cancer tissue from within a complex tissue system in a living body, the reflected light obtained from the second and third light beams used as the reference light needs to be substantially constant between the normal tissue and the cancer tissue. There is. However, in the complex tissue system, there exists a tissue in which the light absorption characteristics in the vicinity of the wavelength range of the second or third light beam are significantly different from those in other wavelength ranges. Then, even if the normal tissue is scanned, the amount of absorption of the second and third light beams changes, and as a result, the reflected light obtained from the second and third light beams is changed even in the normal tissue. It will change. When such a change becomes large as the background, it becomes impossible to detect a change in reflected light obtained from the first light beam to be truly detected. Therefore, in order to detect cancer tissue lurking inside a complex tissue system, it is necessary to continually correct the reflected light.

  In the light intensity measurement means 18, when modulation appears in the light intensity due to a decrease in the reflected light of at least one of the second and third light beams, this modulation amount is read, and the adjustment means 19 reads the modulation means 11 and the light emission means 12. Feedback control is performed, and the light intensities of the second and third light beams emitted from the second and third light sources are adjusted in accordance with the modulation. Since the adjusting unit 19 performs feedback control on the modulating unit 11 and the light emitting unit 12, changes in the light intensity of the second and third light beams that change in the normal tissue can be continually corrected. As a result, the combined intensity of the first to third light beams obtained as reflected light from the normal tissue can always be kept at a constant value (DC component only). Thereby, when the probe 22 scans on the cancer tissue, it is possible to detect a minute change amount of the first light beam obtained as reflected light.

  The embodiment of the present invention has been described above with reference to FIG. The embodiment is merely an example of the present invention, and various other aspects can be considered. More simply, the present invention causes periodic light intensity changes and phase differences in two or more lights, and controls the intensity of the two or more lights based on the output of the detected reference light. It is a biological light measuring device provided with a controller.

  For example, although three light beams are used in the above embodiment, the number of lights to be used may be at least two, and the number is not limited. For example, when two lights are used, the periodic change in the light intensity needs to be shifted by π. What is important is that when two or more lights are superimposed, the light intensity that periodically changes is canceled out, and the amount of change in the light intensity is minimized. “The amount of change in light intensity is minimal” means that in practice it is not possible to completely cancel out periodic changes in light intensity, and that this amount of change is made as small as possible. . That is, theoretically, it is sufficient that two or more lights are selected so that periodic changes in the light intensity cancel each other and only the DC component remains.

  Moreover, as long as the requirement of canceling periodic changes in light intensity is satisfied, light having different light intensity (that is, light having a different coefficient a in the above equation) may be used. Furthermore, light having a constant light intensity (that is, light having only a DC component) may be included in the two or more lights to be used.

Example 1
The measurement object was blood, and hemoglobin reductant and hemoglobin oxidant were selected as absorbers. The following model samples were prepared as measurement targets for evaluating the device performance. Using a silicone resin as a base material, a scatterer (10% fat sphere dispersion, product name: Intralipid) and an absorber (colorant for near infrared region, product name: Greenish Green) are dispersed and cured to obtain fat. And the same optical constant (scattering coefficient / absorption coefficient). While a thin plate was prepared by slicing this sample to a thickness of 15 mm, a groove having a width and length of 5 to 25 mm (in increments of 5 mm) and a depth of 5 mm was produced on the block surface. Two types of aqueous solutions were prepared as model blood by selecting pigments each showing a spectrum that matches the absorption spectrum in the near infrared region (around 800 nm) of hemoglobin reductant and hemoglobin oxidant (Model 1: aqueous solution of hemoglobin reductant) Model 2: Aqueous hemoglobin solution). Model blood was injected with care so that no air remained in the groove created in the block (Model 1 in odd-numbered grooves and Model 2 in even-numbered grooves). A thin plate was carefully placed on the block so that no air layer was formed.

  The measurement wavelength is 760 nm, 840 nm, and 970 nm including the hemoglobin reductant, hemoglobin oxidant, and water absorption band, and three near-infrared LDs as light sources (intensity modulated with a continuous wave LD with a sine wave of frequency 500 kHz) I chose. After a sine wave was generated by the function generator, a signal with a phase shift of 120 degrees was input to each LD driver. The modulated light output from each LD was combined on a filter, and the sample was irradiated with light through one optical fiber (quartz single core, 250 μm diameter). On the other hand, the emitted light was transferred by an optical fiber (plastic multi-core, 500 μm diameter), and light was detected by a system (OE detector, which can detect output from sub nW to 10 mW) connected to a logarithmic amplifier with a fast response Si photodiode. . The distance between the two optical fibers was 3 cm. By connecting the OE output to a lock-in amplifier and applying an external trigger with a signal to the LD driver, the output of each LD can be detected independently. In addition, the OE output can be switched to an AC coupling amplifier, and the signal strength is amplified by the main amplifier and then AD converted to be taken into the PC.

  First, the light output from each LD was detected with a lock-in amplifier while the probe was placed on the position where there was no groove, and the light intensity passing through the model without the absorber was measured. The current value supplied to the LD was adjusted so that the three LD outputs were of the same level (10 nW to sub-μW level). In this state, the OE output was connected to an AC coupling amplifier and set as a light intensity reference (output = 0) in the absence of an absorber. The probe was rotated around the position of the source fiber until the probe was over the grooved position (ie, the detector position was changed without changing the position of the light source). It was observed that the output from the AC amplifier attenuated from 0, showed a minimum above the grooved position, then increased again and returned to 0. FIG. 4 shows the relationship between the rotation angle of this probe and the AC coupling amplifier output. When the same rotation operation was performed at a position without a groove, the output from the AC amplifier only moved up and down around 0. As the groove width decreased from 25 mm to 5 mm, the decrease in the amplifier output decreased. However, even when the width was 5 mm, a decrease sufficient to distinguish it from noise could be observed.

  When the probe is installed at a position where the output is minimized and the OE output is reconnected to the lock-in amplifier, the output of 760 nm LD light is attenuated in the case of an odd number of grooves, and the output of 840 nm LD light is output in the case of an even number of grooves. Was decaying. These results are consistent with the fact that the absorber in the odd-numbered groove is a hemoglobin reductant and the absorber in the even-numbered groove is a hemoglobin oxidant.

Comparative Example 1
A similar experiment was conducted as a system for detecting the OE output itself using a DC coupled amplifier instead of an AC coupled amplifier. When the OE output was monitored while installing the probe at each position, it was observed that when the groove width was 15 mm or more, the signal was significantly smaller than the output at the position without the groove. On the other hand, when the groove width was 10 mm or less, the signal intensity was not necessarily reduced, and the absorber could not be detected.

Example 2
Twelve fiber heads were arranged at equal intervals on the circumference with a radius of 3 cm from the center with the light source fiber at the center. The light received by each fiber was detected by a system (OE detector array) in which a logarithmic amplifier was connected to 12 high-speed response Si photodiodes. Determine the reference fiber (number is 0, number 1 to 11 in the clockwise direction below), place this fiber in a groove-free position, and the signal obtained from this is the same as in Example 1. The light intensity of 3LD was adjusted by the above operation and set as the light intensity reference (output = 0) in the absence of the absorber. The signal from each detector obtained from the OE detector array passes through a differential amplifier circuit with reference to number 0, and then AD-converts the signal into a PC.

  When the fiber 0 is installed at a position where there is no groove and the probe is placed so that some fibers are above the position where the groove is located, it is possible to detect a decrease in light intensity due to absorption up to a groove with a width of 5 mm. did it.

Comparative Example 2
On the other hand, when a similar experiment was performed as a system for detecting the OE output itself without using a differential amplifier circuit, the detectable width was up to 15 mm.

The figure which shows the structure of one Embodiment of the biological light measuring device of this invention. State diagram of periodic variation in the wavelength lambda ₁ of the light intensity. The phase diagram of the periodic change of the light intensity of wavelength (lambda) ₂ and (lambda) ₃ . Detection intensity after removing the DC component from the combined light intensity of wavelengths λ ₁ , λ _2, and λ ₃ at the lesion site in the living tissue. The figure which shows the relationship between the rotation angle of a probe, and AC coupling amplifier output. The figure which shows the change of the light absorption coefficient in the oxidation state and reduction state of hemoglobin. FIG. 3 is a phase diagram of periodic changes in the light intensities at wavelengths λ ₁ and λ _{2 having} the light intensities represented by equations A and C. Fig. 6b is an enlarged view of Fig. 6a.

Explanation of symbols

DESCRIPTION OF SYMBOLS ₁ Output light intensity of light of wavelength λ ₁ 2 Output light intensity of light of wavelength λ ₂ 3 Output light intensity of light of wavelength λ ₃ 11 Modulating means 12 Light emitting means 13 Combining means 14 Light irradiation means 15 Biological model sample 16 Light detection Means 17 Photodetection means 18 Light intensity measurement means 19 Adjustment means 20 AC coupled amplifier (+ main amplifier)
21 AD converter + PC
22 Probe 23 Thin plate 24 Model block 25 Model blood slot

Claims (4)

A light emitting means for emitting a plurality of lights having different wavelengths, the intensity of which changes with time,
Combining means for combining light emitted by the light emitting means on the same optical path;
Irradiating means for irradiating light synthesized by the synthesizing means;
Detection means for detecting light emitted by the irradiation means;
Measuring means for measuring the intensity of light detected by the detecting means;
A biological light measuring apparatus comprising: an adjusting unit that adjusts the intensity of a plurality of lights emitted by the light emitting unit so that a temporal change amount of the intensity of the light measured by the measuring unit is minimized.   The biological light measurement apparatus according to claim 1, wherein at least one of the plurality of lights is light having different optical constants between a normal site and a lesion site in the biological tissue. The light emitted by the light emitting means is three lights defined by intensity I ₁ , intensity I ₂ , and intensity I ₃ , and the three lights satisfy the following formulas (1) to (3). The biological light measurement device according to claim 1 or 2.

  The biological light measurement apparatus according to any one of claims 1 to 3, wherein the adjustment of the plurality of lights is performed with each amplitude and phase difference when the intensity of each light is periodic. .

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