JPH06165784A - Optical laminagraphic imaging device - Google Patents

Abstract

PURPOSE:To obtain an optical laminagraphic imaging device capable of imparting functional information, such as a degree of oxygen saturation, in a vital tissue. CONSTITUTION:Lights having two different wavelengths lambda1, lambda2 generated in a light generation part 5 are emitted to a sample 13 as a vital tissue through optical fibers 11a, 11b. The lights reflected within the sample 13 are made to interfere with a light reflected by a mirror 22 with the movement of the mirror 22. The lights are separated in the depth direction of the sample 13 and detected by an interference light detection part 2. In an arithmetic operation device 36, the output signals of PDs 31a, 31b are operated between different depth components and different wavelength components in the reflected lights. The lights are processed as an image forming a laminagpahic image by a computer 37 to be displayed on a display 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical tomographic imaging apparatus which obtains a distribution image with respect to a concentration of an object by using light having a plurality of wavelengths.

[0002]

2. Description of the Related Art In recent years, in the case of diagnosing a living tissue, an optical CT apparatus has been proposed which can obtain optical information inside the tissue in addition to an imaging apparatus which obtains optical information about the surface state of the tissue. .

As an optical CT apparatus, there is a conventional example in which a picosecond-order optical pulse is used to detect information inside a living body and obtain a tomographic image. FIG. 13 shows a schematic configuration of this conventional example.

A picosecond-order optical pulse generated by the optical pulse generator 201 is reflected by a mirror 202, passes through a lens 203 and a half mirror 204, and passes through the optical fiber 20.
5 is incident on one end surface of the optical fiber 5, is transmitted to the other end surface (front end surface) by the optical fiber 205, and is further emitted from this front end surface to the living body 207 side through the lens 206.

A scanning means 208 is provided near the tip surface, and the tip surface is scanned by the scanning means 208 as indicated by an arrow. The light reflected on the living body 207 side is the lens 2
It is condensed by 06 and is incident on the front end surface of the optical fiber 205. A part of this light is reflected by the half mirror 204, is condensed by the lens 209, and is incident on the streak camera 211 via the optical fiber 210.

The streak camera 211 detects an optical pulse in time division, and the detected signal is output to the computer 212. The computer 212 obtains the reflectance intensity in the depth direction of the living body 207 at each position in the direction optically scanned by the scanning unit 208 from the time-divided signal, converts it into a video signal and outputs it to the monitor 213. Display a tomographic image on the monitor screen.

On the other hand, recently, an interference type OCT (Optical Coherence Tomography) for obtaining a tomographic image of a subject by using low coherence light has been used, for example, in Science.
ceVol. 254, 1178 (1991).

The structure of this interference type OCT is shown in FIG.
An ultra-high brightness light emitting diode (hereinafter abbreviated as SLD) 221 as a light source with low coherence has, for example, a coherence length of 17 μm.
Light having a wavelength of 830 nm is generated at a wavelength of about m, the light is incident from one end face of the single mode optical fiber 222a, is transmitted to the other end face (tip face) side, and is transmitted from the tip face to the sample 224 through the lens 223. It is emitted to the side.

The single mode optical fiber 222a is optically coupled to the other single mode optical fiber 22b by a coupler 225 on the way. Therefore, the coupler 25 is branched into two and transmitted. The tip side of the single mode optical fiber 222a (from the coupler 34) is a lead zirconate ceramic (abbreviated as PZT) 2
It is wound around a piezoelectric element such as 26, and a drive signal is applied from an oscillator (not shown) to vibrate the optical fiber 222a to form a modulator that modulates the transmitted light.

Therefore, the modulated light is transmitted to the optical fiber 222.
The light is emitted from the front end surface of a to the sample 224 side. The tip end surface of the optical fiber 222a is moved together with the lens 223. The light reflected on the sample 224 side is the optical fiber 2
It is incident on the front end surface of 22a, is further moved to the other optical fiber 222b by the coupler 225, and is detected by the detector 227.

The detector 227 has an optical fiber 222b.
The light of the SLD 221 reflected by the mirror 229 through the lens 228, that is, the reference light is also incident from the front end surface of the light source, that is, the measurement light reflected by the sample 224 and the reference light reflected by the mirror 229 are incident on the detector 227. It is incident. The mirror 229 is moved in the direction in which the optical path length is changed as indicated by the arrow, and the optical path length of the light reflected on the sample 224 side and the light of which the optical path length is almost equal to the optical path length reflected by the mirror interfere with each other.

The output of the detector 227 is input to the demodulator 231, the signal of the light that is demodulated and interfered is extracted, converted into a digital signal by the AD converter 232, and then input to the computer 233 to correspond to the tomographic image. The generated image data is generated and displayed on a monitor (not shown).

[0013]

In the conventional example shown in FIGS. 13 and 14, since a tomographic image is obtained with light of a single wavelength, only structural information can be obtained. That is, there is a problem in that it is not possible to obtain functional information such as oxygen saturation in living tissue.

The present invention has been made in view of the above points, and an object thereof is to provide an optical tomographic imaging apparatus capable of obtaining functional information such as oxygen saturation in living tissue.

[0015]

Means and Actions for Solving the Problems Irradiation means for irradiating a subject with light of at least two different wavelengths, and the light reflected inside the subject in the light with which the subject is irradiated, in the depth direction. Reflected light detecting means for separating and detecting the first and second detecting means for performing calculation between different depth components in the output signal of the reflected light detecting means, and different wavelength components in the output signal of the reflected light detecting means. By providing a second computing means for performing computation between the two and an imaging means for constructing a tomographic image using the output results of the first and second computing means, light of two or more wavelengths is provided. The influence of discontinuity in the refractive index or scattering from the reflected light is canceled to obtain functional information such as oxygen saturation in the living tissue.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an optical tomographic imaging apparatus according to the first embodiment of the present invention. The optical tomographic imaging apparatus 1 according to the first embodiment generates light of two wavelengths, and an optical interference unit 2 that detects a signal in which measurement light and reference light are interfered with each other, and is output from the optical interference unit 2. A signal processing unit 3 that performs signal processing on the signal to generate a video signal corresponding to the optical tomographic image, and a display device 4 that displays the video signal output from the signal processing unit 3.
Composed of and.

The light generating section 5 provided in the light interference section 2 has SLDs 6a and 6b for respectively generating low coherent light having wavelengths λ1 and λ2 different from each other. The light from the SLDs 6a and 6b is guided to one end face of the single mode optical fiber 11a via the lenses 7a and 7b, the dichroic mirror or the half mirror 8 and the lens 9, respectively, and from the other end face (referred to as a tip face). The light passes through the lens 12 and is emitted to the sample 13 side where concentration measurement, which is noticeable as a biological tissue, is performed.

This optical fiber 11a is a PANDA on the way.
The other single mode optical fiber 11b by the coupler 14
Is optically coupled to. Therefore, this coupler 14
It is divided into two parts and transmitted. This optical fiber 1
The tip side of 1a (from the coupler 14) is wound around a piezoelectric element such as a PZT 15.

A drive signal is applied from the oscillator 16 to the PZT 15, and the PZT 15 forms a modulator 17 that modulates the transmitted light by vibrating the optical fiber 11a. The frequency of this drive signal is, for example, 5 to 20 KHz. The modulated light is emitted from the tip surface of the optical fiber 11a toward the sample 13 side. The front end surface of the optical fiber 11a and the lens 12 arranged so as to face the front end surface are attached to a scanning mechanism 18, and by driving the scanning mechanism 18, light is orthogonal to the emission direction (X direction in FIG. 1). The scanning is performed in the direction (for example, the Z direction).

The light reflected on the sample 13 side is the lens 1
After passing through 2, the light is incident on the tip surface of the optical fiber 11a. Almost half of this light is transferred to the optical fiber 11b by the coupler 14 and guided to the interference light detection unit 21. The optical fiber 11b also transmits the light reflected by the mirror 22 arranged to face the tip surface (reference light obtained by branching the light from the SLD 6a, 6b side to the optical fiber 11b side by the coupler 14), and Michelson interference. It is led to the meter-type interference light detection unit 21.

That is, the light guided to the interference light detector 21 is a mixture of the measurement light reflected on the sample 13 side and the reference light reflected on the mirror 22. It should be noted that the lens 2 is provided between the mirror 22 and the tip surface of the optical fiber 11b.
3 are arranged. Further, the mirror 22 can change the optical path length of the reference light by the mirror moving mechanism 24, and the reference light having the optical path length equal to the optical path length of the measuring light set by the mirror moving mechanism 24 interferes.

A compensating ring 26 is provided between the tip of the optical fiber 11b and the coupler 14, for example, the optical path length of the optical fiber 11a for guiding the measurement light and the optical fiber for guiding the reference light. The optical path length of 11b is compensated to an almost equal optical path length.

The light emitted from the rear end face of the optical fiber 11b to the interference light detecting section 21 side is collimated by the lens 27, and is divided into the transmitted light and the reflected light by the dichroic mirror 28 according to the wavelength. , 29b, and a photodiode (abbreviated as PD) as a photodetector 3
The light is received by each of 1a and 31b.

The dichroic mirror 28 is shown in FIG.
When light having wavelengths λ1 and λ2 is incident from the rear end surface of the optical fiber 11b as shown in FIG.
Since the setting is as shown in (b), the light of wavelength λ1 is transmitted and the light of wavelength λ2 is reflected.

That is, the dichroic mirror 28 is shown in FIG.
As shown in (b), the one whose transmittance intensity changes by almost 100% at the wavelength between the two wavelengths λ1 and λ2 is used.
In this embodiment, almost 100% of the light from the short wavelength side to the wavelength λs between the wavelengths λ1 and λ2 is transmitted, and this wavelength λs
Light on the longer wavelength side is reflected almost 100%. The dichroic mirror 28 efficiently separates the light emitted from the end face of the optical fiber 11b toward the interference light detection unit 21 side.

The signals photoelectrically converted by the PDs 31a and 31b are preamplifiers 32a and 32 in the signal processing unit 3, respectively.
2 channel lock-in amplifier 3 after being amplified in b
3 is input from the signal input terminal.

A drive signal of the oscillator 16 or a signal having the same phase as the reference signal is input to the reference signal input terminal of the lock-in amplifier 33 as a reference signal, and the preamplifiers 32a and 32b are provided.
The signal component having the same phase as the reference signal in the signal passed through is extracted, demodulated, and amplified.

The outputs of the lock-in amplifier 33 are converted into digital signals by the A / D converters 34a and 34b, respectively, and temporarily stored in the memory 35. The signal stored in the memory 35 is transferred to the arithmetic unit 36, and will be described later, for example, from the reflection intensity data obtained by scanning the two wavelengths λ1 and λ2 and the depth direction (10).
Concentration data of Hb (also referred to as Hb; the same applies to others), Mb, cytochrome, etc. are obtained by arithmetic processing of the equation.

The density data calculated by the calculation of the data obtained between the different wavelengths and the different depths by the calculation device 36 is input to the computer 37 together with the reflectance data, and the tomographic image of the reflectance and the density A process of generating a video signal corresponding to a distribution image or the like is performed and output to the display device 4, and a tomographic image of reflectance and a distribution image (for example, in the depth direction) of the density (at which the biological tissue is of interest) ( (In other words, a density tomographic image)
Is displayed.

The computer 37 sends a control signal to the controller 38 to control the driving of the scanning mechanism 18 and the mirror moving mechanism 24. In response to the driving of the scanning mechanism 18 and the mirror moving mechanism 24 by the control device 38, the control device 38 sends a signal to the memory 35 to instruct to change the address for storing the data. Next, it will be described that the concentration (at a certain depth) of a certain substance contained in a scattering substance such as a living body can be obtained from reflectance data of two wavelengths.

First, for simplification, the reflected light intensity in the case of one wavelength will be described with reference to FIG. In this FIG. 3, a certain wavelength of light having an intensity Io is irradiated to a certain concentration of scattering material,
The reflectance at the depth x measured from the surface of this scattering material is R
(x), the reflected light intensity reflected at the depth x is represented by IR (x).

When the scattering substance is irradiated with light of intensity Io, the extinction degree at the depth x1 is expressed by log Io / I (x1) = Co1 × x1 × ε + Is (1) according to the Beer-Lambert law. Where Co1 is the average concentration up to depth x1, Is
Is the extinction degree due to scattering, and ε is the molecular extinction coefficient. Furthermore, when the depth is x1 and the reflectance is R (x1), the extinction on returning is log {R (x1) ・ Io / I (x1)} = Co1 ・ x1 ・ ε + Is' (2) .

Here, Is' represents a decrease due to scattering. Similarly, the extinction at depth x2 is log {R (x2) · Io / I (x2)} = 2 (Co1 · x1 + 2ΔC · ΔD) ε + Is ′ + ΔIs (3). Where ΔC is the concentration between depths x1 and x2 and ΔD is x2
-x1 and ΔIs represents the scattering at 2ΔD. And
Taking the difference between Eqs. (2) and (3), log {R (x2) ・ Io / I (x2)}-log {R (x1) ・ Io / I (x1)} = 2 ΔC ・ ΔDε + ΔIs (4 ). In summary, log {R (x2) I (x1) / R (x1) I (x2)} = 2ΔC · ΔDε + ΔIs (5).

Next, expanding equation (5) into two wavelengths of λ1 and λ2, log {R (x2) · Iλ1 (x1) / R (x1) · Iλ1 (x2)} = 2ΔCΔDελ1 + ΔIs (6) log {R (x2) · Iλ2 (x1) / R (x1) · Iλ2 (x2)} = 2ΔCΔDελ2 + ΔIs (7)

Here, ελ1 and ελ2 are wavelengths λ, respectively.
1, the molecular absorption coefficient of λ2. Here, it is assumed that R (x) and ΔIs do not depend on the wavelength. Further, by taking the difference between the equations (6) and (7), log {Iλ1 (x1) / Iλ1 (x2) -log Iλ2 (x1) / Iλ2 (x2)} = 2ΔCΔDΔελ1-λ2 (8). In addition, Δελ1-λ2 represents ελ1−ελ2.

Here, log Iλ1 (x1) / Iλ1 (x2) is the dimming degree
ODλ1 (x1-x2), log Iλ2 (x1) / Iλ2 (x2)
If λ2 (x1-x2), then ODλ1 (x1-x2) -ODλ2 (x1-x2) = Δελ1-λ2 · 2ΔC · ΔD (9). When transformed, ΔC = {ODλ1 (x1-x2) -ODλ2 (x1-x2)} / {2Δελ1-λ2 · ΔD} (10).

Therefore, the concentration ΔC between x1 and x2 can be obtained from the equation (10). In the case of one wavelength, the effect of reflection and scattering cannot be eliminated, so the substance concentration C cannot be obtained. In the case of living tissue, the concentration of Hb, Mb, and cytochrome can be determined by using near infrared light, but the method using two wavelengths can determine the concentration of only one of these substances.

Therefore, by increasing the wavelength to 3 to 4 wavelengths,
Many substances can be identified. USP as this method
Learn more about 4223680. Also, examples of transmitted light and reflected light will be described later. In other words, the equation (10) can be used to measure the concentration of more substances by calculating it at a plurality of wavelengths.

Two different wavelengths are required to determine the concentration of one substance, three different wavelengths are required to determine the concentration of two substances, and the concentration of the substance is determined using these wavelengths. Will be described below.

For example, to obtain the oxygen saturation of Hb, H
Since two concentrations of bO2 and Hb have to be determined, three different wavelengths are needed. However, at this time,
It is necessary to select wavelengths in which the three wavelengths are not (or are less likely to be) affected by substances other than Hb due to the state change. Such three different wavelengths λ1, λ
For example, λ3 and λ3 are selected from, for example, 650 to 1000 nm with reference to the absorption (absorption) characteristics of HbO2 and Hb of the living body with respect to the wavelength as shown in FIG.

As shown in FIG. 4, HbO2 at depths x1 to x2
The density of Hb and Hb is represented by [Hbo] x12 and [Hb] x12, and the extinction degree at depths x1 to x2 for light of wavelength λ is described as ODλ (x12). ODλ1 (x12),
By subtracting ODλ2 (x12), ODλ1 (x12)-ODλ2 (x12) = {(εHbλ1-εHbλ2) ・ 2 ・
[Hb] x12 + (εHboλ1-εHboλ2) ・ 2 ・ [Hbo] x12} ・
It becomes ΔD. Here, εHbλ represents the molecular extinction coefficient of Hb at the wavelength λ.

Similarly, extinction ODλ2 for wavelengths λ2 and λ3
(x12), ODλ3 (x12) to ODλ2 (x12)-ODλ3 (x12) = {(εHbλ2-εHbλ3) ・ 2 ・
[Hb] x12 + (εHboλ2-εHboλ3) ・ 2 ・ [Hbo] x12} ・
It becomes ΔD. By transforming these equations, (εHbλ1-εHbλ2) ・ 2 ・ [Hb] x12 + (εHboλ1-εHboλ
2) ・ 2 ・ [Hbo] x12 = (ODλ1 (x12) -ODλ2 (x12)) / ΔD (εHbλ2-εHbλ3) ・ 2 ・ [Hb] x12 + (εHboλ2-εHboλ
3) ・ 2 ・ [Hbo] x12 = (ODλ2 (x12)-ODλ3 (x12)) / ΔD.

Here, εHbλ1-εHbλ2 = ΔεHbλ12, ε
Hboλ1-εHboλ2 = ΔεHboλ12, εHbλ2-εHbλ3 = ΔεH
Putting bλ23, εHboλ2-εHboλ3 = ΔεHboλ23, and rewriting them by multiplying both sides of the above two equations by a common factor, ΔεHbλ12 · ΔεHboλ23 · 2 · [Hb] x12 + ΔεHboλ12
・ ΔεHboλ23 ・ 2 ・ (Hbo) x12 = (ODλ1 (x12)-ODλ2 (x
12)) ・ ΔεHboλ23 / ΔD ΔεHbλ23 ・ ΔεHboλ12 ・ 2 ・ [Hb] x12 + ΔεHboλ23
・ ΔεHboλ12 ・ 2 ・ (Hbo) x12 = (ODλ2 (x12)-ODλ3 (x
12)) · ΔεHboλ12 / ΔD.

Subtracting these two equations yields 2 (ΔεHbλ12 · ΔεHboλ23-ΔεHbλ23 · ΔεHboλ12)
[Hb] x12 = {(ODλ1 (x12) -ODλ2 (x12)) ・ ΔεHboλ23-
(ODλ2 (x12) -ODλ3 (x12)) · ΔεHboλ12} / ΔD.

From this equation, [Hb] x12 = {(ODλ1 (x12) -ODλ2 (x12)) ΔεHboλ23- (OD
λ2 (x12) -OD λ3 (x12)) ΔεHboλ12} / {2ΔD (ΔεHbλ1
2 · ΔεHboλ23-ΔεHbλ23 · ΔεHboλ12)} can be obtained.

[Hbo] x12 = {(ODλ1 (x12) -ODλ2 (x12)) ΔεHbλ23- (OD
λ2 (x12) -OD λ3 (x12)) ΔεHbλ12} / {2ΔD (ΔεHboλ1
2 · ΔεHbλ23-ΔεHboλ23 · ΔεHbλ12)} can be obtained.

The oxygen saturation degree SaO2 is SaO2 = [Hbo] x12 · 100 / {[Hb] x12 + [Hbo] x12}. Here, Blood Volum = [Hb] x12 + [Hbo] x12 represents the concentration of hemoglobin in blood at x12.

According to the first embodiment, the reflected light intensity is obtained by using the two wavelengths, and the calculation device 36 further calculates the concentration such as the oxygen saturation which becomes the functional information of the living tissue and displays it. Since it is possible to display a distribution image of the concentration with the device 4, for example, it is possible to easily identify how different the oxygen saturation of the lesion area is from the oxygen saturation of normal tissue. There are merits such that it becomes easy to diagnose the degree of lesion, the state of lesion, and the range of lesion, and it is possible to easily grasp the progress of lesion and the status of healing from changes over time.

When a density distribution image such as oxygen saturation is displayed, different color signals may be generated according to the density value and displayed in pseudo color.

FIG. 6 shows the structure of the photo-detecting section 21 in a modification of the first embodiment. In this modification, the half mirror 4 is used instead of the dichroic mirror 28 in the first embodiment.
The photodetection unit 21 is formed by using bandpass filters 42a and 42b that respectively transmit light of wavelengths 1 and λ1 and λ2. The other structure is the same as that of the first embodiment. The effect of this modification is almost the same as that of the first embodiment (S / N is better in the first embodiment).

FIG. 7 shows an optical tomographic imaging apparatus 51 according to the second embodiment of the present invention. The titanium sapphire laser 52 is excited by the Ar laser 53 and has a wavelength of 700 to 900 nm.
A pulsed light having a pulse width of about 1 ps can be arbitrarily generated between them, and the generation timing of this pulsed light and the wavelength of the generated pulsed light are controlled by the controller 54.

The pulsed light generated by the titanium sapphire laser 52 is reflected at a right angle by the mirror 55, and about 50% is transmitted by the half mirror 56, and the optical fiber 57 is used.
It is incident on one end face of the optical fiber 57 and is transmitted to the other end face (tip face) of the optical fiber 57.
8 is emitted.

The tip of the optical fiber 57 has a scanning mechanism 59.
And is scanned under the control of the control device 54 in a direction Z orthogonal to the emission direction X of the pulsed light. Part of the pulsed light reflected by the sample 58 is incident on the front end surface of the optical fiber 57 and transmitted to the rear end surface side,
The pulsed light emitted from the rear end face and reflected by the half mirror 56 enters the streak camera 61.

The reflected light is time-divisionally detected by the streak camera 61 and becomes a signal which is temporarily stored in the memory 62. The signal similarly input from the streak camera 61 to the memory 62 while the scanning position is moved by the scanning mechanism 59 is stored at a different address by the change signal from the control device 54. It should be noted that the reflected light is measured at the same scanning position using optical pulses of a plurality of wavelengths. In this case, for example, 800n
pulsed light of two wavelengths of m and 830 nm are generated alternately,
The reflected light intensity data is stored in the memory 62.

The reflected light intensity data measured using a plurality of wavelengths stored in the memory 62 is transferred to the arithmetic unit 63, where the depth and wavelength of the sample 58 are calculated and the concentration of interest is calculated. Is done. This arithmetic unit 63
The density data obtained in step 1 is output to the monitor 64 together with the reflection intensity data, and a distribution image of the density in the depth direction and an optical tomographic image can be displayed on the monitor screen. The effect of the second embodiment is almost the same as that of the first embodiment.

FIG. 8 shows an optical tomographic imaging apparatus 71 according to the third embodiment of the present invention. This embodiment uses light of three wavelengths. Therefore, the light generator 5 has SLDs 6a, 6b, 6c for respectively generating low coherent light of three different wavelengths λ1, λ2, λ3. Three wavelengths λ
1, λ2, λ3 are, for example, 760 nm, 790 nm, 8
40 nm.

The light from the SLDs 6a, 6b and 6c is reflected by the lenses 7a, 7b and 7c and the polarizers 10a, 10b and 10 respectively.
The light is guided to one end face of the single mode optical fiber 11a through the c, the dichroic mirror 8 and the lens 9.
A part of the light guided to the optical fiber 11a is transferred to the other single mode optical fiber 11b by the coupler 14,
The rest is reflected by the mirror 72 attached to the other end face (tip face).

The light transferred to the other optical fiber 11b by the coupler 14 is wound around the PZT 15 and is modulated by the modulator 17 formed by supplying the oscillation output (driving signal) from the oscillator 16 and the tip surface. The light is emitted to the sample 13 side through the lens 12. The oscillator 16 is, for example,
It oscillates at 6 kHz.

The tip of this optical fiber 11b and the lens 1
2 is attached to the scanning mechanism 18 and controlled by the biaxial control unit 73. The scanning mechanism 18 moves the light in the direction (Z direction) orthogonal to the light emission direction (X direction in FIG. 7). The light reflected on the sample 13 side passes through the lens 12 and is incident on the tip end surface of the optical fiber 11b, and this light is guided to the interference light detector 74 side. Further, the reference light reflected by the mirror 72 on the front end surface of the optical fiber 11a and moved to the optical fiber 11b by the coupler 14 is also guided to the interference light detection unit 74 side. Optical fiber 11 between mirror 72 and coupler 14
A compensation ring 26 is provided at a.

The light emitted from the rear end face of the optical fiber 11b is collimated by the lens 75, and split into reflected light and transmitted light by the half mirror 76. The reflected light is reflected by the mirror 77, and the light transmitted through the half mirror 76 is incident on the dichroic mirror 78.

The light incident on the dichroic mirror 78 is separated according to its wavelength, and the analyzers 79a, 79
b, 79c side, and each polarizer 10a, 10b, 10
The light components respectively polarized by c are extracted, and the lens 29
PDs 31a, 31b, 31c through a, 29b, 29c
Is received by.

On the other hand, the light transmitted through the half mirror 76 is
It is reflected by the mirror 81. This mirror 81 is mounted on a moving stage 82 for changing the optical path length, and a motor 83
Is moved in the direction X'that changes the optical path length, and the optical path length of each reference light at the time of movement becomes equal to the optical path length reflected in the depth direction inside the sample 13, And the interference light is measured. The rotation of the motor 83 is controlled by the biaxial control unit 73. The motor 83 moves the mirror 81 at a speed of 112 μm / s, for example.

The distance between the half mirror 76 and the mirror 77 and the distance between the half mirror 76 and the mirror 81 are deviated from each other by at least the interference distance of light having low coherence so that the measuring light itself is reflected by the half mirror 76. The reflected component and the transmitted component are prevented from being detected as interference light. The signals detected by the PDs 31a, 31b, 31c are respectively amplified by the preamplifiers 32a, 32b, 32c and then input from the signal input terminals of the lock-in amplifiers 33 of three channels.

A drive signal of the oscillator 16 for oscillating the PZT 15 or a signal having the same phase as this is input to the reference signal input terminal of the lock-in amplifier 33 as a reference signal, and the reference signal in the signal passed through the preamplifiers 32a, 32b, 32c. A signal component having the same phase as is extracted. In this case, heterodyne detection is performed with the reference signal and the local oscillation output synchronized, and an intermediate frequency component of, for example, 270 Hz is extracted, detected, and amplified.

The outputs of the lock-in amplifier 33 are converted into digital signals by the A / D converters 34a, 34b, 34c, respectively, and temporarily stored in a memory (not shown) in the computer 37. The signal stored in the memory is transferred to a calculation unit (not shown) in the computer 37, and a process of calculating concentration data such as oxygen saturation and cytochrome from the reflection intensity data obtained by the three wavelengths λ1, λ2, and λ3 is calculated. To do.

The calculated density data is output to the display device 4 together with the reflectance data, and the tomographic image of the reflectance and the distribution image of the density are displayed. The computer 37 sends a control signal to the biaxial control unit 73 to control the driving of the motor 83 that moves the scanning mechanism 18 and the mirror 81. This example has 2
There is a merit that more concentration data (of different types) can be obtained than when wavelength is used.

FIG. 9 shows an optical tomographic imaging apparatus 85 according to the fourth embodiment of the present invention. In this embodiment, light of four wavelengths is used. The optical tomographic imaging apparatus 85 generates light of four wavelengths, detects an optical interference portion 86 that detects the measurement light and the reference light as interference signals, and a signal output from the optical interference portion 86. A signal processing unit 87 that performs processing to generate a video signal corresponding to the optical tomographic image, and a display device 4 that displays the video signal output from the signal processing unit 87.
Composed of and.

The light generating portion 88 in the light interference portion 86 has SLDs 6a, 6b, 6c and 6d which respectively generate low coherent light of four different wavelengths λ1, λ2, λ3 and λ4. The light from the SLDs 6a and 6b is reflected by the lenses 7a and 7
The light is guided to one end face of the single mode optical fiber 11a through the b, the dichroic mirrors 8a and 89, the polarizer 10, and the lens 9.

The light from the SLDs 6c and 6d passes through the lenses 7c and 7d, the dichroic mirrors 8b and 89, the polarizer 10 and the lens 9, respectively, and the single mode optical fiber 1
The light is guided to one end surface of 1a. The dichroic mirror 8a reflects light of wavelength λ1 and transmits light of wavelength λ2. Further, the dichroic mirror 89 has a characteristic of reflecting the light of the wavelengths λ1 and λ2 and transmitting the light of the wavelengths λ3 and λ4. Dare dichroic mirror 8b
Indicates a characteristic of reflecting light of wavelength λ4 and transmitting light of wavelength λ3.

The light guided to the optical fiber 11a is modulated by the modulator 17 using the PZT 15 as in the first embodiment, and emitted from the tip end surface of the optical fiber 11a to the sample 13 side. The tip of this optical fiber 11a and the lens 1
2 is scanned by the scanning mechanism 18 in a direction orthogonal to the light emission direction).

The light reflected on the sample 13 side is the lens 1
After passing through 2, the light is incident on the tip surface of the optical fiber 11a. Almost half of this light moves to the optical fiber 11b by the coupler 14 and is guided to the interference light detection unit 91. The optical fiber 11b also transmits the reference light reflected by the mirror 22 arranged so as to face the tip end surface and guides it to the interference light detector 91. That is,
The light guided to the interference light detection unit 91 side is a mixture of the measurement light light reflected on the sample 13 side and the reference light reflected on the mirror 22.

A lens 23 is arranged between the tip surface of the optical fiber 11b and the mirror 22. The mirror 22 can change the optical path length of the reference light by a mirror moving mechanism 24. Also, the optical fiber 11
A compensating ring 26 is provided between the tip of b and the coupler 14 so that the optical path length of the optical fiber 11a that guides the measurement light and the optical path length of the optical fiber 11b that guides the reference light are substantially equal. I am compensating to become.

The light emitted from the end face of the optical fiber 11b to the interference light detecting portion 91 side is collimated by the lens 27,
Only the light component polarized by the polarizer 10 is transmitted by the analyzer 92, and the wavelengths λ1 and λ2 are transmitted by the dichroic mirror 93.
Light is reflected, and light having wavelengths λ3 and λ4 is transmitted.

The light reflected by the dichroic mirror 93 is further transmitted by the dichroic mirror 28a to a wavelength λ1.
Light is reflected, light of wavelength λ2 is transmitted, and is received by PDs 31a and 31b via lenses 29a and 29b, respectively. The light transmitted through the dichroic mirror 93 is reflected by the dichroic mirror 28b at the wavelength λ3,
The light of wavelength λ4 is transmitted, and the lenses 29c and 29 are respectively
The light is received by the PDs 31c and 31d via d.

The signals photoelectrically converted by the PDs 31a, 31b, 31c, 31d are amplified by the preamplifiers 32a, 32b, 32c, 32d in the signal processing section 87, respectively, and then the signals of the lock-in amplifiers 33a, 33b of two channels. It is input from the input terminal. This lock-in amplifier 33
The drive signal of the oscillator 16 or a signal having the same phase as that of the drive signal of the oscillator 16 is input to the reference signal input terminals of a and 33b as a reference signal,
The signals from the preamplifiers 32a, 32b, 32c, and 32d are subjected to heterodyne detection, etc., and amplified and detected.

The outputs of the lock-in amplifiers 33a and 33b are A / D converters 34a, 34b and 34, respectively.
These are converted into digital signals by c and 34d and temporarily stored in the memory 35. The signal stored in the memory 35 is transferred to the arithmetic unit 36, and the four wavelengths λ1, λ2,
From the reflection intensity data obtained by scanning in the depth direction with λ3 and λ4, concentration data such as Hb and cytochrome are calculated.

The concentration data calculated by the calculation device 36 is
Along with the reflectance data, the data is input to the computer 37, processed to generate a video signal corresponding to the tomographic image of reflectance and the density distribution image, and output to the display device 4 to display the tomographic image of reflectance and density. The distribution image is displayed.

The computer 37 sends a control signal to the control device 38 to control the driving of the scanning mechanism 18 and the mirror moving mechanism 24. In response to the driving of the scanning mechanism 18 and the mirror moving mechanism 24 by the control device 38, the control device 38 sends a signal to the memory 35 to instruct to change the address for storing the data. According to this embodiment, more concentration measurement data can be obtained.

FIG. 10 shows the structure in the vicinity of the light generator in the first modification of the fourth embodiment. In this modification, SLD6
Lights having wavelengths λ1 and λ2 of a and 6b are collimated by 7a and 7b, respectively, and further condensed by lenses 9a and 9b.
The light enters the optical fibers 95a and 95b, respectively.

The light from the optical fibers 95a and 95b is partly transferred to the optical fiber 95b by the coupler 96a and mixed with the light from the wavelength λ2. Similarly SLD6
Lights having wavelengths λ3 and λ4 of c and 6d are collimated by 7c and 7d, respectively, and further condensed by lenses 9c and 9d,
The light enters the optical fibers 11a and 95d, respectively.

The light of the optical fibers 11a and 95d is partly transferred to the optical fiber 11a by the coupler 96b and mixed with the light of the wavelength λ3. Optical fiber 95b
Of the wavelengths λ1 and λ2 of the optical fiber 11 by the coupler 97.
Part of the light moves to a and is mixed with light having wavelengths λ3 and λ4.
This light is guided to the coupler 14 side.

FIG. 11 shows the structure in the vicinity of the interference light detector in the second modification of the fourth embodiment. In this modification, a rotary filter 98 is used as the wavelength separating means. The light emitted from the end face of the optical fiber 11b is collimated by the lens 27, passes through the rotary filter 98 rotated by the motor 99, is condensed by the lens 31, and is received by the PD 31 as a photodetector.

In the circumferential direction of the rotary filter 98, the wavelength λ1,
Four filters 98a, 98b, 98c, 98d having characteristics of respectively transmitting light of λ2, λ3, λ4 are arranged at regular intervals.

FIG. 12 shows an optical tomographic imaging apparatus 101 according to the fifth embodiment of the present invention. This embodiment is applied to an endoscope. The optical tomographic imaging apparatus 101 includes an endoscope 102 capable of observing an arbitrary part in a body cavity, a light source device 103 for supplying illumination light to the endoscope 102, and low interference provided in the endoscope 102. Optical interferometer 104 for generating light and signal detection for optical tomographic imaging, and a video signal corresponding to the optical tomographic image from the signal from the optical interferometer 104, to which a light guide member for guiding the light having optical property is connected. And a monitor 106 as a display device for displaying the video signal output from the signal processing unit 105.

The endoscope 102 has an elongated and flexible insertion portion 108 and a wide operation portion 109 provided at the rear end of the insertion portion 108, and a side portion of the operation portion 109. A cable for transmitting a signal or illumination light is extended from the outside.

A light guide 110 is inserted into the insertion portion 108, and the connector at the end on the near side is connected to the light source device 103.
Can be detachably attached to. In this mounted state, the white illumination light of, for example, the xenon lamp 111 inside the light source device 103 is condensed by the condenser lens 112, and the light guide 1
The illumination light is supplied to the end portion of 10, and is transmitted, and emitted from the other end surface fixed to the illumination window of the tip portion 113 of the insertion portion 108 to the front of the insertion portion 108.

By the illumination light emitted from the illumination window, the observed region of interest such as the internal organ 114 in the body cavity is illuminated by the objective lens 116 disposed inside the glass plate 115 of the observation window adjacent to the illumination window. It is tied to the focal plane.
The front end surface of the image guide 117 is arranged at the position of this focal plane, and the formed optical image is transmitted to the rear end surface on the operation unit 109 side. Objective lens 116 and image guide 11
Dichroic mirror 1 on the optical path between the tip surface of 7
18 are arranged.

An image forming lens 119 is arranged so as to face the rear end surface of the image guide 117, and the optical image transmitted to the rear end surface is formed on the CCD 120. This CCD 120 is connected via a signal line 121 to a video processor (hereinafter referred to as VP) 122 as a video signal processing means, and V
When the CCD drive signal is applied from the CCD drive circuit 121 in the P 122, the photoelectrically converted signal is read out and input to the signal processing circuit in the VP 122.

The output signal of the VP 122 is output to the monitor 106 via the superimpose circuit 123, and CC
The endoscopic image captured in D120 is displayed. A bending operation mechanism (not shown) is provided in the operation unit 109, and by operating the bending operation knob, the bending portion formed at the rear end of the tip end portion 113 can be bent in any of vertical and horizontal directions. It has become. An optical fiber 125 for transmitting light with low coherence is inserted through the endoscope 102.

The tip of this optical fiber 125 is the tip 11
A fixed member is attached to the movable plate 126 inside the optical disc 3, and a prism 127 is attached to face the front end surface of the optical fiber 125 in the movable plate 126. This prism 12
Reference numeral 7 reflects the light emitted from the end surface of the optical fiber 125 to guide it to the dichroic mirror 117 side, and
The light reflected by the dichroic mirror 117 is reflected and guided to the tip end side of the optical fiber 125.

A rack is formed on the back surface of the movable plate 126, and this rack meshes with a pinion gear 130 attached to the tip of a shaft 129 connected to the rotary shaft of a stepping motor 128 housed in the operation unit 109, for example. By rotating the stepping motor 128, the movable plate 126 is moved in a direction parallel to the optical axis of the objective lens 116, that is, in the longitudinal direction of the insertion portion 108.

For example, from the state of FIG. 12, the movable plate 126
Is moved rearward, the prism 127 is also moved rearward, so that the light reflected by the prism 127 is guided as shown by the dotted line. Therefore, by moving the prism 127, light is vertically scanned on the organ 114 side, and a tomographic image corresponding to this scanning direction is obtained.

The rear end side of the optical fiber 125 is connected to the front end surface of the optical fiber 11a of the optical interference device 104, and the light from the light generating section 88 is guided to the optical fiber 125 side via the optical fiber 11a. It This light generator 88 is shown in FIG.
As described above, for example, four wavelengths λ1, λ2, λ3,
It is configured to generate light of λ4. SLD6i (i
The light of (= a, b, c, d) is incident from one end face of the single mode optical fiber 11a via the polarizer 10, the lens 9 and the like, and is transmitted to the other end face side.

This single-mode optical fiber 11a is a coupler 14 in the middle of the other single-mode optical fiber 1
Optically coupled to 1b. The tip side of the optical fiber 11a (from the coupler 14) is wound around a piezoelectric element such as a PZT 15 to form a modulator 17.

The modulated light is emitted from the front end surface of the optical fiber 11a, and comes into contact with the front end surface of the optical fiber 125.
Is transmitted to the end face on the side of the tip 113, and from this end face, the prism 127, the dichroic mirror 118,
It is emitted to the organ 114 side through the objective lens 116 and the glass plate 115. The dichroic mirror 118 has a property of transmitting light in the visible region and reflecting light of the infrared region (low coherence) generated by the SLD 6i.

The low coherent light reflected by the organ 114 is incident on the dichroic mirror 118 via the glass window 115 and the objective lens 116. The light emitted by the SLD 6i is reflected by the dichroic mirror 118,
Further, the light is reflected by the prism 127 and is incident on the tip surface of the optical fiber 125.

The light is incident on the front end surface of the optical fiber 11a from the rear end surface of the optical fiber 125. This light is coupler 1
In step 4, almost half of them are moved to the optical fiber 11b,
It is guided to the interference light detection unit 131 side together with the reference light reflected by the mirror 22 arranged to face the tip surface of 1b. This mirror 22 is an X-stage 24 that constitutes a mirror moving mechanism.
The X-stage 24a is mounted on a and is driven by a stepping motor 24b so as to change the optical path length. The rotation of the motor 24b and the motor 128 is controlled by the computer 132.

The interference light detector 131 has a structure in which an analyzer 92 is arranged between the lens 27 and the rotary filter 98 in the structure described with reference to FIG. PD31
The signal detected in (1) is amplified by the preamplifier 32 and then input to the lock-in amplifier 33. The lock-in amplifier 33 refers to the oscillation signal of the oscillator 16 to demodulate and outputs it to the computer 132.

This computer 132 is the memory 3 of FIG.
5. It incorporates an arithmetic unit 36 and the like, performs the same processing as in FIG. 9, and outputs a video signal corresponding to the density distribution of the tomographic image and hemoglobin to the monitor 106 via the superimpose circuit 123. Therefore, the monitor 106 has a CCD
An endoscopic image (captured image) of the surface of the organ 114 captured by 120 and an optical tomographic image or a tomographic image of concentration distribution can be displayed at the same time.

Further, the computer 132 displays a cursor 135 indicating the area where the tomographic image is measured in the endoscopic image as shown in FIG. By this display, the region where the tomographic image is obtained can be known on the observed image, which is convenient for diagnosis. The cursor 135 can be erased when not needed.

In this embodiment, an arbitrary site in the body cavity can be observed with visible light, and a tomographic image of the inside of the observed site can be obtained, and further a concentration distribution image can be obtained.

[0102]

As described above, according to the present invention, irradiation means for irradiating a subject with light of at least two different wavelengths, and light reflected inside the subject among the light radiated to the subject. Of the reflected light detecting means for separately detecting the reflected light in the depth direction, a first calculating means for calculating between different depth components in the output signal of the reflected light detecting means, and an output of the reflected light detecting means. Since the second arithmetic means for performing arithmetic operation between different wavelength components in the signal and the imaging means for constructing a tomographic image using the output results of the first and second arithmetic means are provided, It becomes possible to obtain functional information of the biological tissue, which cannot be obtained by using the wavelength of.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an optical tomographic imaging apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of splitting light by a dichroic mirror.

FIG. 3 is an explanatory diagram showing how light is reflected and returns inside a scattering substance having a certain concentration.

FIG. 4 is an explanatory diagram for obtaining oxygen saturation in the case of Hb and HbO2.

FIG. 5 is a characteristic diagram showing the absorption coefficient with respect to wavelength in the case of Hb and HbO 2.

FIG. 6 is a configuration diagram of a photodetector in a modification of the first embodiment.

FIG. 7 is a configuration diagram showing an optical tomographic imaging apparatus according to a second embodiment of the present invention.

FIG. 8 is a configuration diagram showing an optical tomographic imaging apparatus according to a third embodiment of the present invention.

FIG. 9 is a configuration diagram showing an optical tomographic imaging apparatus according to a fourth embodiment of the present invention.

FIG. 10 is a configuration diagram of the vicinity of a light generating portion in a first modification of the fourth embodiment.

FIG. 11 is a configuration diagram of the vicinity of an interference light detection unit in a second modification of the fourth embodiment.

FIG. 12 is a configuration diagram showing an optical tomographic imaging apparatus according to a fifth embodiment of the present invention.

FIG. 13 is a configuration diagram of a conventional example.

FIG. 14 is a configuration diagram of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical tomographic imaging apparatus 2 ... Optical interference part 3 ... Signal processing part 4 ... Display device 5 ... Light generation part 6a, 6b ... SLD 8 ... Dichroic mirror 11a, 11b ... Optical fiber 13 ... Sample 14 ... Coupler 16 ... Oscillator 17 Modulator 18 Scanning mechanism 21 Interference light detection unit 22 Mirror 24 Mirror moving mechanism 26 Compensation ring 28 Dichroic mirror 31a, 31b Photodiodes (PD) 32a, 32b Preamplifier 33 Lockin amplifier 34a, 34b ... A / D converter 35 ... Memory 36 ... Arithmetic device 37 ... Computer 38 ... Control device

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[Procedure amendment]

[Submission date] March 11, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The single mode optical fiber 222a is optically coupled to the other single mode optical fiber 22b by a coupler 225 on the way. Accordingly, the transmission is split into two in the coupler 2 2 5 parts. Single mode optical fiber 222a (from coupler 225 )
The tip side is wound around a piezoelectric element such as lead zirconate ceramics (abbreviated as PZT) 226 and a drive signal is applied from an oscillator (not shown) to vibrate the optical fiber 222a to modulate the transmitted light. Forming a vessel.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

That is, the light guided to the interference light detector 21 is a mixture of the measurement light reflected on the sample 13 side and the reference light reflected on the mirror 22. It should be noted that the lens 2 is provided between the mirror 22 and the tip surface of the optical fiber 11b.
3 are arranged. Further, the mirror 22 can change the optical path length of the reference light by the mirror moving mechanism 24, and the measuring light having the optical path length equal to the optical path length of the reference light set by the mirror moving mechanism 24 interferes.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

When the scattering substance is irradiated with light of intensity Io, the extinction degree at the depth x1 is expressed by log Io / I (x1) = Co1 × x1 × ε + Is (1) according to the Beer-Lambert law. Where Co1 is the average concentration up to depth x1, Is
Is the extinction degree due to scattering, and ε is the molecular extinction coefficient. Furthermore, when the depth is x1 and the reflectance is R (x1), the extinction upon returning is log {R (x1) ・ Io / I (x1)} = 2 (Co1 ・ x1 ・ ε) + Is' ( 2)

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

For example, to obtain the oxygen saturation of Hb, H
Since two concentrations of bO2 and Hb have to be determined, three different wavelengths are needed. However, at this time,
It is necessary to select wavelengths in which the three wavelengths are not (or are less likely to be) affected by substances other than Hb due to the state change. Such three different wavelengths λ1, λ
2, the absorption of HbO2 and Hb of the living body with respect to the wavelength as shown to λ3 in Figure 5 if e Example (absorption) properties with reference to the example 6
Select from 50 to 1000 nm.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0069

[Correction method] Change

[Correction content]

The light from the SLDs 6c and 6d passes through the lenses 7c and 7d, the dichroic mirrors 8b and 89, the polarizer 10 and the lens 9, respectively, and the single mode optical fiber 1
The light is guided to one end surface of 1a. The dichroic mirror 8a reflects light of wavelength λ1 and transmits light of wavelength λ2. Further, the dichroic mirror 89 has a characteristic of reflecting the light of the wavelengths λ1 and λ2 and transmitting the light of the wavelengths λ3 and λ4. The dichroic mirror 8b on of al
Indicates a characteristic of transmitting light of wavelength λ4 and reflecting light of wavelength λ3.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0082

[Correction method] Change

[Correction content]

FIG. 11 shows the structure in the vicinity of the interference light detector in the second modification of the fourth embodiment. In this modification, a rotary filter 98 is used as the wavelength separating means. The light emitted from the end face of the optical fiber 11b is collimated by the lens 27, passes through the rotary filter 98 rotated by the motor 99, is condensed by the lens 29 , and is received by the PD 31 as a photodetector.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0088

[Correction method] Change

[Correction content]

An image forming lens 119 is arranged so as to face the rear end surface of the image guide 117, and the optical image transmitted to the rear end surface is formed on the CCD 120. This CCD 120 is connected via a signal line 121 to a video processor (hereinafter referred to as VP) 122 as a video signal processing means, and V
By CCD driving circuit or et CCD drive signal P 122 is applied, converted signal photoelectrically read out, is input to the signal processing circuit VP 122.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0097

[Correction method] Change

[Correction content]

The light is incident on the front end surface of the optical fiber 11a from the rear end surface of the optical fiber 125. This light is coupler 1
In step 4, almost half of them are moved to the optical fiber 11b,
It is guided to the interference light detection unit 131 side together with the reference light reflected by the mirror 22 arranged to face the front end surface of 1b. This mirror 22 is an X-stage 24 that constitutes a mirror moving mechanism.
The X-stage 24a is mounted on a and is driven by a stepping motor 24b so as to change the optical path length. The rotation of the motor 24b is controlled by the computer 132.

[Procedure Amendment 9]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure Amendment 10]

[Document name to be corrected] Drawing

[Correction target item name] Figure 8

[Correction method] Change

[Correction content]

[Figure 8]

[Procedure Amendment 11]

[Document name to be corrected] Drawing

[Correction target item name] Figure 9

[Correction method] Change

[Correction content]

[Figure 9]

[Procedure Amendment 12]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 11

[Correction method] Change

[Correction content]

FIG. 11

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kuniaki Kamami 2-43-2, Hatagaya, Shibuya-ku, Tokyo Within Olympus Optical Co., Ltd. (72) Inventor Oka ▲ saki ▼ 2nd birth Hatagaya, Shibuya-ku, Tokyo 43-2 Olympus Optical Co., Ltd. (72) Inventor Tetsumaru Kubota 2-chome, Hatagaya, Shibuya-ku, Tokyo 43-2 Olympus Optical Co., Ltd. (72) Inventor Koji Yasunaga 2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Industry Co., Ltd. 43-72 (72) Inventor Atsushi Osawa Hatagaya, Shibuya-ku, Tokyo 2-43 Olympus Optical Co., Ltd. (72) Inventor Kaiji Ohashi Hatagaya, Shibuya-ku, Tokyo 2-43-2 Olympus Optical Co., Ltd. (72) Inventor Yoshinao Daimei 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olin Scan Optical Industry Co., Ltd. in

Claims (1)

[Claims] 1. An irradiation unit for irradiating a subject with light of at least two different wavelengths, and the light reflected inside the subject in the light with which the subject is irradiated is separated and detected in the depth direction. Reflected light detecting means, first computing means for computing between different depth components in the output signal of the reflected light detecting means, and computing between different wavelength components in the output signal of the reflected light detecting means An optical tomographic imaging apparatus comprising: a second calculation means; and an imaging means that constructs a tomographic image using the output results of the first and second calculation means.