JP2006026015A - Optical tomographic image acquisition system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently acquire optical tomographic images of a desired scanning region. <P>SOLUTION: A fluorescent diagnostic image 31 inside a celom 1 generated by a fluorescent image unit 11 is displayed on a monitor 182. An observer searches a lesion of a cancer, or the like, on the basis of the fluorescent diagnostic image 31 and specifies a scanning start specifying point A1 and a scanning end specifying point A2 on the fluorescent diagnostic image 31 with a pen-like input part 183. A scanning region setting part 15 rotates, slides and moves the coating tube 173 of an OCT (optical coherence tomography) probe 13 by a scanning control part 176 so as to match the luminescent spot of aiming light L2 displayed on the fluorescent diagnostic image 31 with the specifying point A1 and the specifying point A2. A region from the irradiation point of the aiming light L2 when the luminescent spot matches with the specifying point A1 to the irradiation point of the aiming light L2 when the luminescent spot matches with the specifying point A2 is set as the scanning region. By signal waves L4, the scanning region is scanned, and the optical tomographic images are acquired by an OCT acquisition part 12 and displayed on the monitor 181. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention scans a scanning region in a living body observation section with scanning light, and uses interference between reflected light from a predetermined depth of the scanning region and reference light having a slight frequency difference from the scanning light. The present invention relates to an optical tomographic image acquisition system for acquiring an optical tomographic image.

  In recent years, development of an optical tomographic image acquisition apparatus for acquiring an optical tomographic image of a living body or the like has been advanced. As a method for acquiring these optical tomographic images, a method using optical interference by frequency-swept coherence light, a method using optical interference by low-coherence light, and the like are known.

  In particular, an OCT (Optical Coherence Tomography) apparatus that acquires an optical tomographic image of a measurement unit by measuring the light intensity of low coherence interference light by heterodyne detection is being put into practical use.

  This OCT apparatus divides low-coherence light emitted from a light source such as an SLD (Super Luminescent Diode) into scanning light and reference light, and slightly shifts the frequency of the reference light or scanning light by a piezo element or the like. The light is incident on the measurement unit, the reflected light reflected at a predetermined depth of the measurement unit and the reference light are caused to interfere, the light intensity of the interference light is measured by heterodyne detection, and tomographic information is obtained. Information at the depth of the measurement unit where the optical path length of the reference light and the optical path length of the scanning light coincide by slightly moving the movable mirror, etc., placed on the optical path of the reference light and slightly changing the optical path length of the reference light Can be obtained. Further, by repeating the measurement while slightly shifting the incident point of the scanning light, an optical tomographic image of a predetermined scanning region can be acquired.

If such an OCT apparatus is used, it becomes possible to diagnose the depth of invasion of early cancer. Therefore, the OCT probe that can be inserted into the forceps opening of the endoscope apparatus guides the scanning light and the reflected light of the scanning light. Thus, development of a method for acquiring an optical tomographic image in a body cavity has been promoted (see, for example, Non-Patent Document 1). In this Non-Patent Document 1, an OCT probe including an optical fiber that guides scanning light and a mirror that is disposed at the tip of the optical fiber and reflects the scanning light at a right angle is inserted through a forceps port of an endoscope. An OCT apparatus that displays an optical tomographic image of a body cavity wall by inserting it into a body cavity and rotating a mirror at the tip is described. Further, an OCT apparatus combined with an endoscope apparatus has been proposed by the present applicant (see Patent Document 1).
OPTICS LETTER Vol.24, No19 P1358〜P1360 by Andrew M Rollins and Rujchai Ung-arunyawee JP2002-200037

  However, a predetermined time is required to acquire the optical tomographic image, and acquiring the optical tomographic image in a large number of scanning regions has a problem that the inspection time is prolonged. In particular, when an optical tomographic image acquisition probe, such as an OCT probe, is inserted into the forceps port of an endoscope apparatus and examination is performed under the endoscope, the endoscope is inserted into the body of the subject for a long time. It is not desirable to insert, as it will cause pain to the subject.

  The present invention has been made in view of the above problems, and an object thereof is to provide an optical tomographic image acquisition system that can efficiently acquire an optical tomographic image of a desired scanning region.

The optical tomographic image acquisition system of the present invention irradiates an observation unit with excitation light, captures an image of fluorescence emitted from the observation unit irradiated with the excitation light, and captures fluorescence based on the captured image of fluorescence Fluorescence image acquisition means for generating an image;
Fluorescence image display means for displaying the fluorescence image generated by the fluorescence image acquisition means;
An optical tomographic image acquisition unit that scans a scanning region in the observation unit with scanning light and acquires an optical tomographic image of the scanning region is provided.

  Here, the fluorescence image based on the captured fluorescence image may be any image as long as it is an image based on the captured fluorescence image. For example, a fluorescence image that reflects the fluorescence intensity of the captured fluorescence image, or a fluorescence diagnostic image in which a pseudo color is set based on the ratio of the light intensity in a different wavelength band for each pixel of the captured fluorescence image is there. Furthermore, a fluorescence diagnostic image generated in combination with the light intensity of the reflected image obtained by irradiating the observation part with near infrared light can also be used. Note that such a fluorescent image may be superimposed on a normal image captured by a normal endoscope system. For example, a fluorescence diagnostic image of pseudo color can be superimposed on a black and white normal image. Further, a translucent fluorescent image in which abnormal tissue is emphasized may be superimposed on a normal color image by performing special image processing.

  Further, the “scanning region” may have any shape as long as it is a scannable region, and includes, for example, a line-shaped region on the observation unit and a region on the surface.

  Further, when “scanning the scanning region”, any scanning method may be used. For example, the reflection direction of the scanning light emitted from the light source or from the tip end of the light guide unit can be controlled. Any scanning method that can acquire an optical tomographic image by scanning light, such as a method of scanning by reflecting with a mirror or the like, a method of scanning by moving the emission end of the scanning light, etc. may be used.

  The optical tomographic image acquisition means scans a scanning region in the observation unit with scanning light that is low-coherence light, reflected light from a predetermined deep portion of the scanning region, and reference light having a slight frequency difference from the scanning light. OCT means for acquiring an optical tomographic image of the scanning region using interference with the scanning region. “Low coherence light” means that the coherence length is 50 μm or less. The coherence length is preferably 25 μm or less, more preferably 10 μm or less.

A position designating unit for designating any one or more designated points on the fluorescent image displayed on the fluorescent image display unit;
Scanning area setting means for setting a scanning area of the scanning light based on a designated point designated by the position designation means.

  For example, if there is one designated point, a single straight line having a predetermined length passing through a point on the observation portion corresponding to the designated point may be set as the scanning region, or an observation corresponding to the designated point. Two or more straight lines passing through the points on the part, or a polygonal area or a circular area having a predetermined area centered on the point on the observation part corresponding to the designated point may be designated as the scanning area. If two points are designated as designated points, a straight line between the two points on the observation unit corresponding to the designated points may be set as the scanning region.

Further, if the position specifying means specifies three or more specified points,
The scanning area setting means sets an area surrounded by points on the observation unit corresponding to three or more designated points designated by the position designation means as a scanning area,
The optical tomographic image acquisition means acquires a plurality of optical tomographic images in the scanning region,
You may further provide the three-dimensional optical tomographic image generation means which produces | generates a three-dimensional optical tomographic image based on the several optical tomographic image acquired by the said optical tomographic image acquisition means.

  In addition, “setting an area surrounded by points on the observation portion corresponding to three or more designated points as a scanning area” means that if three points are designated by the position designation means, for example, An area surrounded by three points on the observation unit corresponding to the three designated points designated by the designation means may be set as the scanning area.

Superimposed image generating means for generating a superimposed image in which the fluorescent image is superimposed on the optical tomographic image;
You may have a superimposed image display means to display this superimposed image.

  If the observation unit is a living body observation unit to which a fluorescent reagent having affinity for abnormal tissue is administered, the fluorescence may be emitted from the fluorescent reagent.

  The position specifying means and the three-dimensional position specifying means may be any means as long as an arbitrary point can be specified. For example, the point specifying means by touching the screen with a pen, or the coordinates of the points There are those that input a position and those that input a point using a mouse that operates a cursor.

 In the optical tomographic image acquisition system according to the present invention, since the fluorescent image based on the captured fluorescence image is displayed on the fluorescent image display means, the observer observes the fluorescent image to detect a lesion site such as cancer or the like. An optical tomographic image of a desired scanning area can be efficiently acquired by efficiently finding a desired part such as a suspicious part such as cancer and setting a scanning area to those parts. Based on the acquired optical tomographic image, the observer can observe the depth of cancer in a desired entire section such as a lesion site such as cancer or a suspected site such as cancer.

  The optical tomographic image acquisition means scans a scanning region in the observation unit with scanning light that is low coherence light, and reflected light from a predetermined depth of the scanning region and reference light having a slight frequency difference from the scanning light. If it is OCT means which acquires the optical tomographic image of the said scanning area | region using interference, the optical tomographic image which has high spatial resolution corresponding to the coherence length of low coherence light can be acquired.

  By setting the scanning area based on the designated point specified on the fluorescent image, there is no trouble of guiding the scanning light to the scanning area by manual operation, and a tomographic image of the desired scanning area is acquired more efficiently. be able to. In addition, a desired scanning area can be easily set.

 Further, an area surrounded by points on the observation unit corresponding to three or more designated points designated on the fluorescence image is set as a scanning area, and a plurality of optical tomographic images in the scanning area are acquired, When generating a three-dimensional optical tomographic image based on the plurality of optical tomographic images, it is possible to acquire a three-dimensional optical tomographic image of a desired scanning region only with a simple manual operation. Based on the acquired three-dimensional optical tomographic image, the observer can observe the depth of cancer in a cross section of the entire lesion site such as cancer or the entire site suspected of cancer.

  Furthermore, by displaying a superimposed image obtained by superimposing the fluorescent image on the optical tomographic image, the fluorescent image and the optical tomographic image in a desired scanning region can be simultaneously viewed. For example, when the scanning region is an early cancer site, the degree of extension and depth of advance of the early cancer can be visually recognized only by observing one image.

  If the observation part is a living body observation part to which a fluorescent reagent having affinity for abnormal tissue is administered and fluorescence is emitted from the fluorescent reagent, the observer can easily observe the abnormal tissue when observing the fluorescence image. Can be found.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing an entire embodiment of an optical tomographic image acquisition system of the present invention. The optical tomographic image acquisition system is an apparatus incorporated in an endoscope, which irradiates an observation part in a body cavity 1 of a subject with excitation light L6 and generates fluorescence L7 emitted from the observation part with a CCD image sensor. The fluorescence diagnostic image corresponding to the relative ratio of the signal intensity in the predetermined wavelength band is generated from the captured fluorescent image, displayed on the monitor, and the optical tomographic image of the scanning region designated on the fluorescent diagnostic image is displayed. The optical tomographic image is obtained by using the OCT means and displayed side by side with the fluorescence diagnostic image.

  The optical tomographic image acquisition system acquires an optical tomographic image of a linear scanning region between two specified points when acquiring an optical tomographic image.

  The optical tomographic image acquisition system includes an endoscope insertion unit 10 inserted into a body cavity 1 of a subject, a fluorescence image unit 11 that acquires a fluorescence diagnostic image 31 of an observation unit in the body cavity 1, and a body cavity 1. An OCT acquisition unit 12 that acquires an optical tomographic image of a scanning region in the inner region, an OCT probe 13 that is inserted into a forceps port 71 provided in the insertion unit 10, a fluorescence diagnostic image 31, and an optical tomographic image of the scanning region are displayed. A display unit 22 and a scanning region setting unit 15 that sets a scanning region for acquiring an optical tomographic image based on a designated point designated on the fluorescence diagnostic image 31 are provided.

  The insertion unit 10 includes a forceps port 71 that passes through the insertion unit 10, and a CCD cable 201 and a light guide 202 that extend to the tip. A CCD image sensor 205 on which a mosaic filter 204 in which minute band filters are combined in a mosaic pattern is connected to the tip of the CCD cable 201 is connected to the CCD image sensor 205, and a prism 206 is attached to the CCD image sensor 205. . As shown in FIG. 5, the mosaic filter 204 includes a narrowband filter 204a that transmits light in a wavelength band of 430 nm to 530 nm and a wideband filter 204b that transmits light in a wavelength band of 430 nm to 700 nm alternately. The band-pass filter has a one-to-one correspondence with the pixels of the CCD image sensor 205.

  The light guide 202 is made of a multi-component glass fiber, and an illumination lens 75 is provided at its distal end, that is, the distal end of the insertion portion 10. The other end of the light guide 202 is connected to the fluorescence image unit 11. In addition, an imaging lens 76 is provided at the distal end portion of the insertion portion 10, and the above-described prism 206 is provided inside the imaging lens 76. The prism 206 reflects the fluorescence L7 emitted from the observation unit and collected by the imaging lens 76, and makes it incident on the CCD image sensor 205.

  The CCD cable 201 is an output line for reading out signal charges from the CCD image sensor 205, and one end thereof is connected to an image processing unit 230 described later.

  The fluorescence image unit 11 includes an excitation light unit 210 including a light source that emits excitation light for capturing a fluorescent image, and image processing for displaying the fluorescence image as a pseudo color image corresponding to a relative ratio of signal intensities in a predetermined wavelength band. And an image processing unit 230 for performing

  The excitation light unit 210 includes a GaN-based semiconductor laser 211 that emits excitation light L6 for imaging a fluorescent image and a lens 212 that collects the excitation light L6 emitted from the semiconductor laser 211.

  The image processing unit 230 includes a signal processing circuit 231 that performs process processing of a signal imaged by the CCD image sensor 205, an A / D conversion circuit 232 that digitizes an image signal obtained by the signal processing circuit 231, and the A / D An image memory 233 that stores the image signal output from the D conversion circuit 232 for each corresponding optical filter of the mosaic filter 204, and the image signal of the narrow-band fluorescent image and the image signal of the broadband fluorescent image stored in the image memory 233 A fluorescence image generation circuit 234 that generates a fluorescence diagnosis image signal that is a pseudo color image signal, and a video signal processing circuit 235 that converts the fluorescence diagnosis image signal output from the fluorescence image generation circuit into a video signal and outputs the video signal. .

  The OCT acquisition unit 12 includes a light source unit 100 that emits low coherence light L1 having a central wavelength of 800 nm and a coherence length of 10 μm, an aiming light source unit 110 that emits aiming light L2 that is visible light, and a low coherence light L1. A fiber coupling optical system 120 that combines the aiming light L2 and splits and combines the low-coherence light L1 into the reference light L3 and the scanning light L4, and the optical path of the reference light L3. An optical path delay unit 130 that changes the length, a balance difference detection unit 150 that detects the intensity of the interference light L5 between the scanning light L4a reflected at a predetermined depth in the scanning region and the reference light L3, and a balance difference detection unit 150 And a signal processing unit 160 that performs heterodyne detection for obtaining the intensity of the scanning light L4a reflected by a predetermined surface of the scanning region from the detected light intensity of the interference light L5, and generates optical tomographic image data.

  The light source unit 100 of the OCT acquisition unit 12 includes an SLD (Super Luminescent Diode) 101 that emits low-coherence light L1 and a lens 102 that collects the low-coherence light L1 emitted from the SLD 101.

  The aiming light source unit 110 includes a semiconductor laser 111 that emits green laser light as the aiming light L2, and a lens 112 that collects the aiming light L2 emitted from the semiconductor laser 111.

  The fiber coupling optical system 120 divides the low coherence light L1 emitted from the light source unit 100 into the scanning light L4 and the reference light L3, and also refers to the scanning light L4a that is reflected light from the scanning region of the scanning light L4. A fiber coupler 121 that combines the light L3 and obtains the interference light L5, a fiber coupler 122 and a fiber coupler 123 provided between the light source unit 100 and the fiber coupler 121, and a piezo that causes a slight frequency shift in the reference light L3. The element 124, the fiber 125 that connects the light source unit 100 and the fiber coupler 122, the fiber 126 that connects the aiming light source unit 110 and the fiber coupler 123, and the optical path delay unit 130 and the balance difference detection unit 150 via the fiber couplers 121 and 122. , And a fiber 128 that connects the OCT probe 130 and the balance difference detector 150 via a fiber coupler 121. Fibers 125, 127 and 128 are single mode optical fibers.

  The optical path delay unit 130 converts the reference light L3 emitted from the fiber 127 into parallel light, and the lens 131 that makes the reflected reference light L3 incident on the fiber 127, and the reference light by moving in the horizontal direction in FIG. A prism 132 that changes the optical path length of L3 and a drive unit 133 that moves the prism in the horizontal direction are provided.

  The balance difference detection unit 150 adjusts the input balance between the detection values of the photodetectors 151 and 152 that measure the light intensity of the interference light L5, the detection value of the photodetector 151 and the detection value of the photodetector 152, and detects noise components and drifts. And a differential amplifier 153 that amplifies the difference after canceling out the components.

  The OCT probe 13 includes a coating tube 173 that can be inserted into the forceps port 71 of the insertion portion 10 and a fiber 172 that penetrates the coating tube 173. The scanning light L4 emitted from the fiber 172 is collected at the tip of the fiber 172, and the scanning light L4a that is reflected light from the scanning region of the scanning light L4 emitted from the fiber 172 is fed back to the fiber 172. A lens 174 is provided, and a prism 175 that reflects the scanning light L4 and the scanning light L4a at a right angle is provided at the distal end of the lens 174, that is, at the distal end of the OCT probe 13. A lens 171 for condensing the scanning light L4 emitted from the fiber 128 and introducing it into the fiber 172 and returning the scanning light L4a to the fiber 128 is provided at the rear end of the fiber 172, that is, at the connection with the fiber 128. I have. The fiber 172, the lens 174, and the prism 175 are incorporated in a state of being fixed in the cladding tube 173. A scanning control unit 176 that rotates and slides the cladding tube 173 is attached to the base portion of the cladding tube 173. The scanning control unit 176 is connected to the scanning region setting unit 15, and slides and rotates the cladding tube 173 based on the scanning region set in the scanning region setting unit 15 to perform scanning with the scanning light L4. .

  The display unit 22 includes a monitor 181 that displays the optical tomographic image output from the OCT acquisition unit 12, a monitor 182 that displays the fluorescent diagnostic image 31 output from the fluorescent image unit 11, and a desired on the fluorescent diagnostic image 31. And a pen-type input unit 183 as position specifying means for specifying a pixel position. Each part is connected to a controller (not shown) and the operation timing is controlled.

  Next, the operation of the OCT apparatus of the present invention will be described. The observer first inserts the insertion portion 10 into the body cavity of the subject, and displays the fluorescence diagnostic image 31 on the monitor 182.

  Hereinafter, an operation for acquiring a fluorescent diagnostic image will be described. First, excitation light L6 having a wavelength of 410 nm is emitted from the GaN-based semiconductor laser 211. The excitation light L6 passes through the lens 212, enters the light guide 202, is guided to the distal end of the insertion unit 10, and is irradiated from the illumination lens 75 to the observation unit.

  By irradiating the excitation light L6, fluorescence L7 is emitted from the observation part. The fluorescence L7 is collected by the condenser lens 76, reflected by the prism 206, transmitted through the mosaic filter 204, and formed on the CCD image sensor 205 as a fluorescent image.

  In the CCD image sensor 205, the fluorescent image is received, photoelectrically converted, converted into an image signal corresponding to the intensity of light, and output to the fluorescent image unit 11. The image signal is processed by the signal processing circuit 231 of the image processing unit 230, converted into a digital signal by the A / D conversion circuit 232, and transmitted through the narrowband filter 204a and the narrowband image signal and the wideband filter. It is divided into wideband image signals that have passed through 204b and stored in the storage area of the image memory 233. The fluorescence image generation circuit 234 calculates the ratio of the signal intensity of the narrowband image signal and the broadband image signal for each adjacent pixel, creates a fluorescence diagnostic image signal to which a pseudo color is applied based on the ratio, and displays it at the display timing. At the same time, the data is output to the video signal processing circuit 235. The video signal processing circuit 235 converts the fluorescence diagnostic image signal into a video signal and outputs it to the monitor 182 of the display unit 22. The monitor 182 displays a fluorescence diagnostic image 31 that is a pseudo color image.

  The fluorescence diagnostic image 31 is displayed in a pseudo color in which the display color changes in accordance with the change in the relative ratio between the signal intensity in the wide wavelength band and the signal intensity in the narrow wavelength band. It is preferable to set a pseudo color so that the display color difference between the fluorescence emitted from the normal tissue and the fluorescence emitted from the diseased tissue becomes clear. For example, the fluorescence emitted from the normal tissue becomes white, and the diseased tissue By displaying the pseudo color so that the fluorescence emitted from the light becomes pink or other colors, the observer can easily recognize the diseased tissue.

  While observing the fluorescence diagnostic image 31 displayed on the monitor 182, the observer moves the position of the insertion unit 10 by manual operation and guides it to the desired site, and observes the desired site. When a lesion tissue is recognized in the displayed fluorescence diagnostic image 31, a scanning region is designated and an optical tomographic image is acquired.

  Hereinafter, an operation when acquiring the optical tomographic image 33 will be described. When acquiring an optical tomographic image, the observer inserts the OCT probe 13 into the forceps port 71 of the insertion unit 10 in advance. While observing the fluorescence diagnostic image 31 displayed on the monitor 182, the scanning start designated point A1 and the scanning end designated point A2 for acquiring the optical tomographic image are displayed on the monitor 182 using the pen-type input unit 183. Specify on the diagnostic image 31.

  At the same time, the green aiming light L2 is emitted from the semiconductor laser 111 of the aiming light source unit 110, collected by the lens 112, and introduced into the fiber 126. The aiming light L2 is guided through the fiber 126, the fiber coupler 123, the fiber 125, the fiber coupler 122, the fiber 127, the fiber coupler 121, and the fiber 128, and is introduced into the fiber 172 by the lens 171. The aiming light L2 emitted from the fiber 172 is condensed by the lens 174, reflected by the prism 175, and irradiated into the body cavity 1 as green spot light. The reflected light of the aiming light L2 is also displayed as a bright spot on the fluorescent diagnostic image 31 displayed on the monitor 182.

  In the scanning region setting unit 15, first, the relative position between the scanning start designated point A1 designated on the fluorescence diagnostic image 31 and the bright spot obtained by imaging the reflected light of the aiming light L2 is calculated, and the scanning control unit 176 calculates the cladding tube. 173 is slid and rotated to match the bright spot of the aiming light L2 with the designated point A1. The scanning start point in the body cavity 1 when the optical tomographic image is acquired by the above operation is set. Thereafter, similarly, the bright spot of the aiming light L2 is matched with the scanning end designated point A2. The scanning end point in the body cavity 1 when the optical tomographic image is acquired by the above operation is set. Thereafter, an optical tomographic image between the scanning start point and the scanning end point is acquired by an operation described later.

  When the scanning start point is set, the low-coherence light L1 having a center wavelength for optical tomographic image acquisition of about 800 nm and a coherence length of 10 μm is emitted from the SLD 101, and this low-coherence light L1 is collected by the lens 102, Introduced into fiber 125.

  The low-coherence light L1 transmitted through the fiber 125 is introduced into the fiber 127 by the fiber coupler 122, and further, the reference light L3 traveling in the direction of the optical path delay unit 130 through the fiber 127 and the fiber 128 Is divided into scanning light L 4 traveling in the direction of the OCT probe 13.

  The reference light L3 is modulated by the piezo element 124 provided on the optical path, and a slight frequency difference Δf is generated between the reference light L3 and the scanning light L4.

  The scanning light L 4 is incident on the scanning start point in the body cavity 1 through the lens 171, the fiber 172, the lens 174 and the prism 175 of the OCT probe 13. Of the scanning light L4 incident on the scanning start point, the scanning light L4a reflected at a predetermined depth at the scanning start point is returned to the fiber 128 via the prism 175, the lens 174, the fiber 172, and the lens 171. The scanning light L4a fed back to the fiber 128 is combined with the reference light L3 fed back to the fiber 127 described later in the fiber coupler 121.

  On the other hand, the reference light L3 after being modulated by the piezo element 124 passes through the fiber 127, enters the prism 132 via the lens 131 of the optical path delay unit 130, is reflected by the prism 132, and passes through the lens 131 again. Then, it is returned to the fiber 127. The reference light L3 fed back to the fiber 127 is combined with the scanning light L4a described above by the fiber coupler 121.

  The scanning light L4a combined with the fiber coupler 121 and the reference light L3 are overlapped on the same axis again, and the scanning light L4a and the reference light L3 interfere with each other under a predetermined condition to form an interference light L5 and generate a beat signal. To do.

  Since the reference light L3 and the scanning light L4a are low-coherence light L1 with a short coherence distance, the scanning light L4a reaches the fiber coupler 121 after the low-coherence light L1 is divided into the scanning light L4 and the reference light L3. When the optical path length is approximately equal to the optical path length until the reference light L3 reaches the fiber coupler 121, both lights interfere with each other, and a beat signal that repeats strength with the frequency difference (Δf) of the both interfering lights is appear.

  The interference light L5 is split by the fiber coupler 121, one of which is input to the photodetector 151 of the balance difference detection unit 150 via the fiber 127, and the other is input to the photodetector 152 via the fiber 128.

  The photodetectors 151 and 152 detect the light intensity of the beat signal from the interference light L5, the differential amplifier 153 obtains the difference between the detection value of the photodetector 151 and the detection value of the photodetector 152, and performs signal processing. To the unit 160. Note that the differential amplifier 153 has a function of adjusting the balance of the DC component of the input value, so that even if the low coherence light L1 emitted from the light source unit 100 is drifted, By amplifying the difference after adjusting the balance, the drift component is canceled out and only the beat signal component is detected.

  At this time, the prism 132 is moved in the optical axis direction (horizontal direction in the figure) by the drive unit 133. For this reason, the optical path length until the reference light L3 reaches the fiber coupler 121 changes. Since the optical path length of the scanning light L4 that interferes with the reference light L3 also changes, the depth at which tomographic information is acquired also changes.

  By the above operation, tomographic information up to a desired depth, for example, 2 mm from the surface at the scanning start point in the body cavity 1 is acquired. When the measurement at the scanning start point is completed, the scanning control unit 176 slightly rotates or slides the cladding tube 173, and at the point slightly shifted from the scanning start point toward the scanning end point, the scanning control unit 176 similarly reaches the predetermined depth. Acquire fault information. Such an operation is repeated until the scanning point reaches the scanning end point while repeating a slight movement.

  The signal processing unit 160 performs heterodyne detection for obtaining the intensity of the scanning light L4a reflected by a predetermined surface at each scanning point from the light intensity of the interference light L5 detected by the balance difference detection unit 150, and converts it to an optical tomographic image. Output to the monitor 181.

  The monitor 181 displays the optical tomographic image 33 output from the signal processing unit 160. By such an operation, it is possible to display the optical tomographic image 33 in the scanning region between the scanning start point and the scanning end point.

  By the operation as described above, the scan start designated point A1 and the scan end designated point A2 are designated on the fluorescence diagnosis image 31, and the interval between the scan start point and the scan end point in the body cavity 1 corresponding to these two designated points. Is set as the scanning area, and this scanning area is scanned with the scanning light L4 to obtain an optical tomographic image. Therefore, there is no need to manually guide the scanning light L4 to the desired scanning area, and the optical tomography can be performed quickly. Since an image can be acquired, an optical tomographic image of a desired scanning region can be acquired efficiently. In addition, an optical tomographic image of a desired part can be acquired accurately.

 Further, based on the acquired optical tomographic image, the observer can observe the depth of cancer in the entire desired cross section, for example, if the scanning region is a site such as cancer.

  In addition, the scanning region was scanned with scanning light L4, which is low-coherence light with a coherence length of 10 μm, and an optical tomographic image was acquired, so an optical tomographic image with a spatial resolution of about 10 μm can be acquired, and the tomographic shape of the tissue It can be easily visually recognized.

  Next, a second specific embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a schematic configuration diagram showing an entire second embodiment of the OCT apparatus of the present invention, and FIG. 4 is an explanatory diagram of a displayed image. Similar to the first embodiment, this OCT apparatus is also incorporated in the endoscope apparatus, and has four designated points designated on the fluorescence diagnostic image 31 that is an image in the body cavity 1 of the subject. The three-dimensional optical tomographic image 35 of the area surrounded by is acquired and displayed.

  The OCT apparatus includes an insertion unit 10 that is inserted into a body cavity of a subject, a fluorescence image unit 11 that acquires a fluorescence diagnostic image 31 in a body cavity 1 of a living body, and an OCT that acquires an optical tomographic image in the body cavity 1. An acquisition unit 12, an OCT probe 13 inserted into a forceps port 71 provided in the insertion unit 10, and a scanning region setting unit 20 for setting a scanning region based on a designated point designated on the fluorescence diagnostic image 31; A three-dimensional optical tomographic image generation unit 21 that generates a three-dimensional optical tomographic image from a plurality of optical tomographic images, a display unit 22 that displays a fluorescence diagnostic image 31 and a three-dimensional optical tomographic image 35 in the body cavity 1; And a superimposed image generating unit 23 that generates a superimposed image 36 in which the fluorescence diagnostic image 31 is superimposed on the three-dimensional optical tomographic image 35. The same elements as those in the first specific embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted unless particularly necessary.

  When acquiring a three-dimensional optical tomographic image, the scanning region setting unit 20 sets a region surrounded by points on the observation unit corresponding to the four specified designated points as a scanning region.

  The three-dimensional optical tomographic image generation unit 21 has a storage unit (not shown) that stores a plurality of optical tomographic images output from the OCT acquisition unit 12, and stores the plurality of optical tomographic images stored in the storage unit. Based on this, a three-dimensional optical tomographic image is generated and output to the display unit 22.

  The display unit 22 includes a monitor 181 that displays a three-dimensional optical tomographic image 35 output from the three-dimensional optical tomographic image generation unit 21 or a superimposed image 36 in which a part of the fluorescence diagnostic image is superimposed on the three-dimensional optical tomographic image; A monitor 182 for displaying the fluorescent diagnostic image 31 and a pen-type input unit 183 for designating a desired pixel position on the fluorescent diagnostic image 31 are provided. Each part is connected to a controller (not shown) and the operation timing is controlled.

  Next, the operation of the endoscope apparatus according to the second specific embodiment of the present invention will be described. As in the first embodiment, first, the fluorescence diagnostic image 31 is acquired and displayed on the monitor 182 of the display unit 22. While observing the fluorescence diagnostic image 31 displayed on the monitor 182, the observer moves the position of the insertion portion 10 by manual operation to guide it to a desired site, and observes the desired site.

  An operation when acquiring a three-dimensional optical tomographic image will be described. The observer observes the fluorescence diagnostic image 31 displayed on the monitor 182 and, as shown in FIG. 3, four designated points A3, A4, A5, and A6 that designate a scanning region for acquiring a three-dimensional optical tomographic image. Is designated on the fluorescence diagnostic image 31 displayed on the monitor 182 using the pen-type input unit 183.

  The aiming light L2 is irradiated into the body cavity 1 and is also displayed as a bright spot on the fluorescence diagnostic image 31 displayed on the monitor 182.

  The scanning area setting unit 20 first calculates the relative position between the designated point A3 designated on the fluorescence diagnostic image 31 and the bright spot of the aiming light L2, and the scanning control unit 176 slides and rotates the cladding tube 173. The bright spot of the aiming light L2 is made to coincide with the designated point A1. The scanning control unit 176 stores the angle and slide position of the cladding tube 173 corresponding to the irradiation position of the aiming light L2 at that time. Similarly, the angle and slide position of the cladding tube 173 when the designated points A4, A5 and A6 coincide with the bright spot of the aiming light L2 are stored, and then the body cavity 1 surrounded by the points corresponding to each designated point Are set as scanning areas.

  Next, the scanning control unit 176 slides the cladding tube 173 within the scanning region at one end of the scanning region, acquires the optical tomographic image by the OCT acquisition unit 12, and stores it in the three-dimensional optical tomographic image generation unit 21. To do. Next, the scanning control unit 176 slightly rotates the cladding tube 173, slides the cladding tube 173 again in the scanning region, acquires an optical tomographic image by the OCT acquisition unit 12, and generates a three-dimensional optical tomographic image. Store in unit 21. A similar operation is repeated until the other end of the scanning area is reached. The three-dimensional optical tomographic image generation unit 21 generates a three-dimensional optical tomographic image 35 from these stored optical tomographic images and outputs it to the monitor 181 of the display unit 22. The monitor 182 displays a three-dimensional optical tomographic image 35 as shown in FIG.

  By observing the displayed three-dimensional optical tomographic image 35, the observer can observe the depth of cancer in a cross section of the entire lesion site such as cancer or the entire site suspected of cancer. As the three-dimensional optical tomographic image 35, a pseudo 3D image subjected to volume rendering processing or the like may be used instead of a normal three-dimensional optical tomographic image. If the optical tomographic image is made three-dimensional in this way, a desired part can be observed from an arbitrary direction by rotating the image.

  When the observer selects the superimposed image display, the superimposed image generation unit 23 generates a superimposed image 36 in which the fluorescence diagnostic image 31 is superimposed on the three-dimensional optical tomographic image 35 and displays it on the monitor 182. As shown in FIG. 4, the superimposed image 36 is an image in which the image of the region surrounded by the designated points A3, A4, A5 and A6 in the fluorescence diagnostic image 31 is superimposed on the surface portion of the three-dimensional optical tomographic image 35. It is.

  In the optical tomographic image acquisition system according to the present embodiment, it is possible to acquire a three-dimensional optical tomographic image of a desired scanning region only with a simple manual operation. Further, by displaying the superimposed image 36, the fluorescence diagnostic image and the optical tomographic image in the desired scanning region can be viewed at the same time. For example, when the scanning region is an early cancer site, the degree of extension and depth of advance of the early cancer can be visually recognized only by observing one image.

  When the OCT probe 13 is inserted into the forceps port 71 of the endoscope and used as in the above embodiments, the distal end of the OCT probe 13 is affected by the movement of the observation unit, the breathing of the subject, and the like. May be blurred. When scanning the OCT probe 13, the scanning region setting unit always detects the position of the bright spot of the aiming light L2, and controls the position of the OCT probe 13 by the scanning control unit so as to match the set scanning region. For example, it is possible to reduce the influence of the fluctuation of the tip position of the OCT probe 13 and accurately acquire an optical tomographic image of a desired scanning region.

  In each of the above embodiments, since the wavelength of the low-coherence light is 800 nm, the scanning light L4 has desirable transparency and scattering properties in the scanning region, so that a desired optical tomographic image can be acquired. it can.

  In addition, although green visible light is used as the aiming light L2, the scanning light L4 can be used as the aiming light if an image pickup device capable of imaging light with a wavelength of 800 nm is used as the CCD image pickup device 205. A light source part becomes unnecessary and the structure of the OCT acquisition part 12 can be simplified.

  In each embodiment, the pen-like input unit 183 is used to designate a designated point for setting a scanning region. However, the present invention is not limited to this. For example, while observing the fluorescence diagnostic image 31, the irradiation position of the aiming light is moved by a manual operation such as a mouse operation, and when the bright spot of the aiming light displayed on the fluorescence diagnostic image 31 comes to a desired position, a click or the like The designated point for setting the scanning region may be designated by manual operation.

  In each embodiment, if a fluorescent reagent having an affinity for abnormal tissue is administered to a subject in advance, an abnormal tissue can be easily found by observing a fluorescent image obtained by imaging fluorescence emitted from the fluorescent reagent. Can do. In this case, an excitation light cut filter for cutting the excitation light may be provided between the CCD image pickup element 205 and the prism 206 instead of the mosaic filter.

  Each embodiment is limited to an image using a fluorescence diagnostic image as a fluorescence image in which a pseudo color is set based on a ratio of light intensities in different wavelength bands for each pixel of the captured fluorescence image. is not. For example, a fluorescence diagnostic image generated by combining the pseudo color with the light intensity of the reflected image obtained by irradiating the observation part with near infrared light can be used. In addition, when the above-described fluorescent reagent is used, a fluorescent image reflecting the fluorescence intensity of the captured image can also be used. Further, such a fluorescent image may be superimposed on a normal image captured by a normal endoscope system, for example, a pseudo-color fluorescent diagnostic image may be superimposed on a black and white normal image. Alternatively, a translucent fluorescent image in which abnormal tissue is emphasized may be superimposed on a normal color image by performing special image processing.

1 is a schematic configuration diagram of an optical tomographic image acquisition system according to a first embodiment of the present invention. Illustration of mosaic filter Schematic configuration diagram of an optical tomographic image acquisition system according to a second embodiment of the present invention Illustration of superimposed image

Explanation of symbols

1 body cavity
10 Insertion section
11 Fluorescence image unit
12 OCT acquisition department
13 OCT probe
15,20 Scanning area setting section
21 3D optical tomographic image generator
22 Display
23 Superimposed image generator
71 Forceps port
100 Low coherence light source
110 Aiming light source
120 Fiber coupling optics
130 Optical path delay
150 Balance difference detector
160 Signal processor
176 Scan control unit
181,182 monitor
183 Input section
201 CCD cable
202 Light Guide
205 CCD image sensor
210 Excitation light unit
230 Image processing unit
L1 Low coherence light
L2 aiming light
L3 reference beam
L4 scanning light
L5 interference light
L6 excitation light
L7 fluorescence

Claims (6)

Fluorescence image acquisition means for irradiating an observation part with an excitation light, capturing an image of fluorescence emitted from the observation part irradiated with the excitation light, and generating a fluorescence image based on the image of the captured fluorescence;
Fluorescence image display means for displaying the fluorescence image generated by the fluorescence image acquisition means;
An optical tomographic image acquisition system comprising: an optical tomographic image acquisition unit configured to scan a scanning region in the observation unit with scanning light and acquire an optical tomographic image of the scanning region. The optical tomographic image acquisition means scans a scanning region in the observation unit with scanning light that is low coherence light, and reflected light from a predetermined depth of the scanning region and reference light having a slight frequency difference from the scanning light. The optical tomographic image acquisition system according to claim 1, wherein the optical tomographic image acquisition system is an OCT unit that acquires an optical tomographic image of the scanning region using interference with the scanning region. Position designation means for designating any one or more designated points on the fluorescence image displayed on the fluorescence image display means;
The optical tomographic image acquisition system according to claim 1, further comprising: a scanning region setting unit that sets a scanning region of the scanning light based on a designated point designated by the position designation unit. The position specifying means specifies three or more specified points;
The scanning area setting means sets an area surrounded by points on the observation unit corresponding to three or more designated points designated by the position designation means as a scanning area,
The optical tomographic image acquisition means acquires a plurality of optical tomographic images in the scanning region;
4. The light according to claim 3, further comprising three-dimensional optical tomographic image generation means for generating a three-dimensional optical tomographic image based on a plurality of optical tomographic images acquired by the optical tomographic image acquisition means. Tomographic image acquisition system. Superimposed image generating means for generating a superimposed image in which the fluorescent image is superimposed on the optical tomographic image;
5. The optical tomographic image acquisition system according to claim 1, further comprising a superimposed image display unit configured to display the superimposed image. 6. The observation unit is a living body observation unit to which a fluorescent reagent having affinity for abnormal tissue is administered, and the fluorescence is emitted from the fluorescent reagent. The optical tomographic image acquisition system described.

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