JP2006204430A - Tomographic image acquisition device - Google Patents

Tomographic image acquisition device Download PDF

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Publication number
JP2006204430A
JP2006204430A JP2005018346A JP2005018346A JP2006204430A JP 2006204430 A JP2006204430 A JP 2006204430A JP 2005018346 A JP2005018346 A JP 2005018346A JP 2005018346 A JP2005018346 A JP 2005018346A JP 2006204430 A JP2006204430 A JP 2006204430A
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tomographic image
ultrasonic
light
depth
image acquisition
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Kazuhiro Tsujita
和宏 辻田
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Fuji Photo Film Co Ltd
富士写真フイルム株式会社
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Abstract

PROBLEM TO BE SOLVED: To obtain a tomographic image of a depth region of about several cm from the surface of a test part, and to display an easy-to-see tomographic image when these tomographic images are synthesized and displayed.
An optical tomographic image, an ultrasonically modulated optical tomographic image, and an ultrasonic tomographic image are acquired and stored in a storage unit (not shown). The control unit 52 selects a low-depth tomographic image (from the surface to a depth of about 2 mm and a resolution of several μm) from the optical tomographic image, and selects an ultrasonically modulated optical tomographic image or a medium-depth tomographic image (from a depth of about 2 mm to a depth). Select from 5 mm to 10 mm, resolution of several tens of μm), select ultrasonic tomographic image from high depth tomographic image (depth from 5 mm to 10 mm to 30 mm, resolution of several hundred μm), low depth tomographic image and medium The depth tomographic image and the high depth tomographic image are combined to generate a combined tomographic image, which is output to the monitor 70 and displayed. In this composite tomographic image, the resolution changes stepwise.
[Selection] Figure 1

Description

  The present invention relates to a tomographic image acquisition apparatus, and more particularly to a tomographic image acquisition apparatus that acquires both an optical tomographic image and an ultrasonic tomographic image.

  Conventionally, an ultrasonic tomographic image acquisition apparatus is known as an apparatus for acquiring a tomographic image. Particularly in the medical field, it is widely used because it has many advantages such as less burden on patients and inexpensive equipment. This ultrasonic tomographic image acquisition apparatus irradiates a patient's test part with ultrasonic waves and obtains information inside the body based on the reflected wave reflected from the test part. Many of these ultrasonic tomographic image acquisition apparatuses perform a sector scan or a linear scan to obtain a B-mode image, that is, a two-dimensional tomographic image. Also, in the field of endoscopes, an ultrasonic probe that is inserted through the forceps opening of an endoscope is widely used, and is used for observing a two-dimensional tomographic image of an inner wall in a body cavity. .

  Furthermore, in recent years, an optical tomographic image apparatus that acquires a tomographic image using light such as an OCT (Optical Coherence Tomography) apparatus has been used in the field of medical diagnosis. The OCT apparatus divides low-coherence light emitted from a light source such as an SLD (Super Luminescent Diode) into measurement light and reference light, and slightly shifts the frequency of the reference light or measurement light by a piezo element or the like. Is incident on the test portion, the reflected light reflected at a predetermined depth of the test portion 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. By moving the movable mirror, etc., placed on the optical path of the reference light slightly, and slightly changing the optical path length of the reference light, the optical path length of the reference light and the optical path length of the measurement light coincide with each other at the depth of the test part. Information can be obtained.

  If such an OCT apparatus is used, an optical tomographic image of the test part can be acquired with a high resolution of about several μm. Therefore, since early cancer diagnosis is possible, a method for obtaining an optical tomographic image of a body cavity by guiding measurement light and reflected light of the measurement light with a probe that can be inserted into a forceps port of an endoscope apparatus Development is underway. However, in the OCT apparatus, a tomographic image can be acquired with a high resolution of about several μm. However, when the test part is a living tissue or the like, the depth is only about 1 to 2 mm from the wall surface of the test part. Cannot be imaged.

  In the case of an ultrasonic tomographic image acquisition apparatus, imaging can be performed to a depth of several tens of millimeters from the surface of the test part. However, the frequency of ultrasonic waves that is practically used for diagnosis is about several MHz to several tens of MHz. The resolution can only be increased to about several hundred μm.

  For this reason, the present applicant combines the functions of both an OCT apparatus and an ultrasonic tomographic image acquisition apparatus, and acquires both an optical tomographic image and an ultrasonic tomographic image with a single apparatus. There has been proposed a tomographic image acquisition apparatus that can acquire high-resolution tomographic image information at low depths while acquiring tomographic image information from the surface to a high depth (see Patent Document 1).

On the other hand, an ultrasonic wave and light are simultaneously irradiated onto the test part, and an ultrasonically modulated optical tomographic image of the test part is acquired based on the ultrasonically modulated reflected light reflected by the test part affected by the ultrasonic wave. Development of an ultrasonic modulation optical tomographic image acquisition apparatus has been advanced in recent years (see Non-Patent Document 1). This ultrasonic modulation optical tomographic image acquisition apparatus can acquire a tomographic image from the surface of a test part to a depth of about 5 mm to 10 mm, and the upper limit of resolution is about several tens of μm.
JP 2002-153472 A "Ultrasound-modulated optical computed tomography of biological tissues" by Lihong V. Wang, APPLIED PHYSICS LETTERS, Volume 84, Number 9, page 1597-1599.

  In the tomographic image acquisition apparatus having the functions of both the OCT apparatus and the ultrasonic tomographic image acquisition apparatus, both the optical tomographic image and the ultrasonic tomographic image are acquired from the test portion, and the images are combined and displayed. In this case, the difference between the resolution of the optical tomographic image and the resolution of the ultrasonic tomographic image is large, and the image becomes very difficult to see. Further, when observing a diseased tissue or the like, it is desired to obtain a diagnostic image with a resolution as high as possible with respect to a tomographic image having a depth of about 5 mm to 10 mm from the surface of the test part. There is also a problem that a tomographic image having a depth of about 5 mm to 10 mm cannot be acquired, and the ultrasonic tomographic image acquiring apparatus cannot obtain a sufficient resolution.

  In view of the above problems, the present invention can acquire a tomographic image of a region having a depth of about several centimeters from the surface, and can display an easy-to-see tomographic image when these tomographic images are combined and displayed. An object of the present invention is to provide an image acquisition device.

The tomographic image acquisition apparatus of the present invention irradiates a test part with first light, and acquires an optical tomographic image of the test part based on the reflected light of the first light reflected by the test part. An optical tomographic image acquisition means and an ultrasonic to acquire an ultrasonic tomographic image of the test part based on a reflected wave of the ultrasonic wave reflected by the test part by irradiating the test part with a first ultrasonic wave In a tomographic image acquisition apparatus having a sonic tomographic image acquisition means,
Ultrasound-modulated reflected light of the second light that is irradiated on the test part simultaneously with the second light and the second ultrasonic wave and reflected by the test part that has received the action of the second ultrasonic wave And an ultrasonic modulation optical tomographic image acquisition means for acquiring an ultrasonic modulation optical tomographic image of the test portion.

  Here, the “reflected light of the first light reflected by the test part” means the reflected light of the first light that is specularly reflected or irregularly reflected (diffuse reflected) by the test part, It also includes the scattered light of the first light scattered by the test portion.

  The optical tomographic image acquisition means means for acquiring a high-resolution tomographic image based on reflected light, and specifically includes an OCT apparatus, a confocal microscope, and the like.

  Also, a first light emitting end that emits the first light to the test part, a first ultrasonic emission end that emits the first ultrasonic wave to the test part, and the test part At least one of the second light emitting end for emitting the second light and the second ultrasonic emitting end for emitting the second ultrasonic wave to the test part is an endoscope. It may be incorporated in the inside.

  In addition, a first light emitting end that emits the first light to the test part, a first ultrasonic emission end that emits the first ultrasonic wave to the test part, and the test part A second light emitting end that emits the second light and a second ultrasonic emitting end that emits the second ultrasonic wave to the test portion are integrally fixed, and are inserted into the probe. It may be contained. This probe may be inserted into the forceps port of the endoscope.

  Here, the “light exit end” means the exit end of the light guide means when light is guided to the vicinity of the test part by a light guide means such as a fiber and irradiated to the test part. However, when the light guide means is not used, it means the light source itself. In addition, the ultrasonic emission end means that the ultrasonic wave is guided to the vicinity of the test part by a waveguide means such as an ultrasonic fiber, and if the ultrasonic wave is irradiated to the test part, the emission end of the waveguide means is used. This means that when the waveguide means is not used, the ultrasonic oscillator itself is meant.

  The first light exit end may also serve as the second light exit end. The light source of the first light may also serve as the light source of the second light.

  The first ultrasonic emission end may also serve as the second ultrasonic emission end. The first ultrasonic oscillator may also serve as the second ultrasonic oscillator.

  The tomographic image acquisition apparatus selects, from the optical tomographic image, a low-depth tomographic image that is a tomographic image of a low-depth region of the test part, and the medium-depth region of the test part from the ultrasonically modulated optical tomographic image A medium-depth tomographic image that is a tomographic image of the subject portion, and a high-depth tomographic image that is a tomographic image of a high-depth region of the test portion is selected from the ultrasonic tomographic image, and the low-depth tomographic image and the medium-depth tomographic image are selected A composite tomographic image generation unit that synthesizes an image and the high-depth tomographic image and generates a composite tomographic image of the test portion may be provided.

  Here, the “low depth region” means a region from the surface of the test portion to a depth at which the tomographic image can be acquired with a desired resolution by the optical tomographic image acquisition means. Further, the “medium depth region” means a region from the bottom of the low depth region to a depth at which the tomographic image can be acquired with a desired resolution by the ultrasonic modulated optical tomographic image acquisition means. Means a region from the bottom of the medium depth region to a depth at which the tomographic image can be acquired with a desired resolution by the ultrasonic tomographic image acquisition means.

  In the tomographic image acquisition apparatus according to the present invention, in addition to the optical tomographic image acquisition means and the ultrasonic tomographic image acquisition means, the second light and the second ultrasonic wave are simultaneously irradiated to the test portion, Ultrasound modulated optical tomographic image acquisition means for acquiring an ultrasonically modulated optical tomographic image of the test part based on the ultrasonically modulated reflected light of the second light reflected by the test part subjected to the action of sound waves The tomographic image of the area near the surface of the test part (hereinafter referred to as the low depth area) can be acquired with high resolution by the optical tomographic image acquisition means, and the deep area of the test part (hereinafter referred to as the high depth area and The tomographic image described in the above description) can be acquired by the ultrasonic tomographic image acquisition means although the resolution is low, and a tomographic image of a region slightly deeper than the depth at which the tomographic image can be acquired by the optical tomographic image acquisition means (hereinafter referred to as a medium depth region). Ultrasound cutting by means of ultrasonic modulated optical tomographic image acquisition Since these images can be acquired at a higher resolution than images, when displaying these combined tomographic images, the resolution gradually decreases as the depth increases. Can do.

  In addition, the conventional ultrasonic modulation optical tomographic image acquisition means can acquire a tomographic image from the surface of the test part to a depth of several millimeters on the order of several tens of μm, but the upper limit of the resolution of the image is several. There is a problem that the resolution is insufficient for observing cells and the like, and the depth that can be imaged is insufficient for observing the inside of a living body, and the spread in the medical field is delayed. By combining the optical tomographic image acquisition unit and the ultrasonic tomographic image acquisition unit, it is possible to effectively utilize the characteristics of the ultrasonic modulation optical tomographic image unit.

  Furthermore, since the ultrasonic modulation optical tomographic image acquisition means requires both a light irradiation part and an ultrasonic irradiation part, the configuration is complicated, and an image analysis means is also required, thereby reducing the manufacturing cost. Difficulties were also one of the factors that hindered popularization. However, in the tomographic image acquisition apparatus according to the present invention, the manufacturing cost is greatly increased by diverting the light irradiation unit, the ultrasonic irradiation unit, and the analysis unit used in the optical tomographic image acquisition unit and the ultrasonic tomographic image acquisition unit. The tomographic image acquisition apparatus provided with the ultrasonic modulation optical tomographic image acquisition means can be realized without doing so.

  A first light emitting end for emitting the first light to the test part; a first ultrasonic emission end for emitting the first ultrasonic wave to the test part; and A second light emitting end that emits the second light and at least one emitting end of the second ultrasonic emitting end that emits the second ultrasonic wave to the test portion are in the endoscope. If it is incorporated, the apparatus can be miniaturized. In addition, an ultrasonic oscillator mounted on an existing ultrasonic endoscope can be used as the first ultrasonic emission end and the second ultrasonic emission end. In this case, the low cost of the apparatus Is possible.

  A first light emitting end for emitting the first light to the test part; a first ultrasonic emission end for emitting the first ultrasonic wave to the test part; and A second light emitting end for emitting the second light and a second ultrasonic emitting end for emitting the second ultrasonic wave to the test part are integrally fixed and accommodated in the probe. If this is the case, the probe can be inserted into a forceps port of an endoscope, and the function of the tomographic image acquisition apparatus can be imparted to a conventional endoscope.

  If the first light exit end also serves as the second light exit end, the apparatus is downsized, and the optical tomographic image acquisition position and the ultrasonic modulation optical tomographic image acquisition position coincide with each other. Positioning at the time of synthesizing a tomographic image and an ultrasonically modulated optical tomographic image becomes easy.

  If the light source of the first light also serves as the light source of the second light, the configuration of the apparatus is simplified, and the size and cost can be reduced.

  If the first ultrasonic wave emission end also serves as the second ultrasonic wave emission end, the apparatus is downsized. Further, if the first ultrasonic oscillator also serves as the second ultrasonic oscillator, the configuration of the apparatus can be simplified, and the size and cost can be reduced.

  As in the present invention, a low-depth tomographic image that is a tomographic image of a low-depth region of the test part is selected from the optical tomographic image, and a medium-depth region of the test part is selected from the ultrasonic-modulated optical tomographic image. A medium depth tomographic image that is a tomographic image is selected, a high depth tomographic image that is a tomographic image of a high depth region of the test portion is selected from the ultrasonic tomographic image, and the low depth tomographic image and the medium depth tomographic image are selected. And the high-depth tomographic image, and a synthetic tomographic image generation unit that generates a synthetic tomographic image of the test part, for example, a low-depth region from the surface of the test part to about 2 mm is light A high-resolution tomographic image having a resolution of several μm acquired by the tomographic image acquisition unit is displayed, and a mid-depth region from about 2 mm to about 5 mm to 10 mm is a tomographic image having a resolution of several tens of μm acquired by the ultrasonic modulation optical tomographic image unit. Display with 5mm ~ A high-depth region from about 10 mm to 30 mm can display a synthetic tomographic image composed of a tomographic image having a resolution of several hundreds of μm acquired by the ultrasonic modulation tomographic image means. The depth of penetration can be easily visually confirmed. Here, the “resolution” is a resolution in the depth direction or a horizontal resolution that is a direction perpendicular to the depth direction. In each tomographic image, it is preferable that the resolution in the depth direction and the resolution in the horizontal direction are substantially the same.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an embodiment of a tomographic image acquisition apparatus according to the present invention.

  As shown in FIG. 1, the tomographic image acquisition apparatus according to the present embodiment is connected to the probe 10 that can be inserted into the forceps opening of the endoscope, the optical unit 30 connected to the probe, and the probe 10 and the optical unit 30. The signal processing unit 50 and a monitor 70 connected to the signal processing unit 50 are provided. The tomographic image acquisition apparatus includes an optical tomographic image acquisition function for acquiring an optical tomographic image, an ultrasonic modulation optical tomographic image acquisition function for acquiring an ultrasonically modulated optical tomographic image, and an ultrasonic wave for acquiring an ultrasonic tomographic image. It has a tomographic image acquisition function, and displays each tomographic image and a synthesized tomographic image synthesized from each tomographic image on a monitor.

  First, a configuration related to the ultrasonic image acquisition function will be described. The probe 10 is covered with a flexible sheath 11 and a rotating sheath 12 that can rotate with respect to the sheath 11. The rotating sheath 12 is provided with an ultrasonic transducer 13 that irradiates an ultrasonic wave to a test part (not shown) and receives a reflected wave (echo) reflected by the test part. The signal processing unit 50 transmits an ultrasonic signal that is an electric signal to the ultrasonic transducer 13 and receives a reflected wave signal that is an electric signal transmitted from the ultrasonic transducer 13. An ultrasonic signal processing unit 51 that generates tomographic information and a control unit 52 connected to the ultrasonic signal processing unit 51 are provided. The ultrasonic transducer 13 and the ultrasonic signal processing unit 51 are connected by a cable 14, a terminal 27, and a cable 53. The terminal 27 is provided around the distal end portion of the outer tube 16 of the optical fiber 15 to be described later in the probe 10.

  The cable 14 contacts the terminal 27, and the cable 53 is connected to the terminal 27. As a result, even when the rotary sheath 12 rotates, the cable 14, the terminal 27, and the cable 53 are always connected, so that the ultrasonic signal and the reflected wave signal are conducted without interruption.

  The ultrasonic signal processing unit 51 generates ultrasonic tomographic information based on the waveform of the received reflected wave signal and outputs it to the control unit 52. The control unit 52 generates an ultrasonic tomographic image based on the transmitted ultrasonic tomographic information. The control unit 52 is connected to each part, controls the operation timing of each part, and generates each tomographic image based on each tomographic information transmitted. Details of the operation of the controller 52 will be described later.

  Next, a configuration related to each optical tomographic image acquisition function will be described. First, the configuration of the probe 10 will be described. A fiber 15 is disposed at the center of the probe 10, and a flexible outer cylinder 16 is provided around the fiber 15. The outer cylinder 16 is covered with a flexible sheath 11. The distal end portion of the outer cylinder 16 is covered with the rotating sheath 12 and is pivotally supported by a plurality of bearings 21. The proximal end portion of the rotating sheath 12 is connected to the centerless motor 22. The centerless motor 22 has a function of a rotary encoder, and a signal indicating the rotation angle detected by the rotation angle detection unit of the centerless motor 22 is sent to the control unit 52 through the signal line 23.

  At the tip of the fiber 15, the light guided by the fiber 15 is condensed on the test part, and the reflected light reflected by the test part or ultrasonic modulation light described later is condensed on the core part of the fiber 15. A rod lens 17 and a mirror 18 that reflects each light in a right angle direction are provided. The mirror 18 is fixed to the rotary sheath 12 and is rotated by the rotation of the rotary sheath 12. An optical window 26 through which light reflected by the mirror 18 exits is provided at the distal end of the rotating sheath 12. Further, a condenser lens 19 is provided on the proximal end side of the fiber 15.

  Further, a linear drive device 24 is provided at the proximal end portion of the sheath 11. The linear drive device 24 moves the probe 10 parallel to the longitudinal direction of the probe 10 with respect to a forceps port of an endoscope (not shown). The linear drive device 24 has a function of a linear encoder, and a signal indicating the movement distance detected by the movement distance detection unit of the linear encoder is sent to the control unit 52 through the signal line 25.

  In addition, the ultrasonic transducer 13 described above is attached in the vicinity of the optical window 26 at the distal end portion of the rotary sheath 12 so that the ultrasonic wave is irradiated in the same direction as the light emission direction reflected by the mirror 18. . The position where the ultrasonic transducer 13 is disposed is not limited to the above position, and may be a position where the light irradiation region and the ultrasonic irradiation region substantially overlap and do not hinder light irradiation. Any position may be used.

  The optical unit 30 includes a light source unit 31 that emits low-coherence light L having a wavelength of 1300 nm, a fiber coupling optical system 32 that divides and combines the low-coherence light emitted from the light source unit 31 into reference light Lr and measurement light Ls. The optical path delay unit 33 arranged on the optical path of the reference light Lr and changing the optical path length of the reference light Lr, and the interference light Lc between the measurement light Ls ′ reflected at a predetermined depth of the test part and the reference light Lr And a light detection unit 34 for detecting the light intensity of the light. The light detection unit 34 also detects the light intensity of ultrasonic modulation light described later.

  The light source unit 31 includes a light source 36 that is made of SLD or the like and emits low-coherence light having a wavelength of 1300 nm, and a condenser lens 37 that condenses the low-coherence light emitted from the light source 36.

  The fiber coupling optical system 32 divides the low-coherence light emitted from the light source 36 into the measurement light Ls and the reference light Lr, and the measurement light that is reflected light from a predetermined depth of the test portion of the measurement light Ls. A fiber coupler 39 that combines Ls ′ and the reference light Lr to obtain the interference light Lc, a piezo element 40 that causes a slight frequency shift in the reference light Lr, and the light source unit 31 and the optical path delay unit via the fiber coupler 39. 33, and a fiber 42 that guides light between the light detection unit 34 and the sheath 12 through a fiber coupler 39.

  The optical path delay unit 33 converts the reference light Lr emitted from the fiber 41 into parallel light, and makes the reflected reference light Lr incident on the fiber 41, and by moving in the horizontal direction in FIG. A reference light mirror 45 that changes the optical path length of the reference light Lr and a drive unit 46 that moves the reference light mirror 45 in the horizontal direction are provided.

  The light detection unit 34 includes a light detector 47 that detects the light intensity of the interference light Lc and the ultrasonic modulation light, and a condensing lens 49 disposed in front of the light detector 47.

  The optical detector 47 is connected to the optical tomographic information generating unit 54, the ultrasonic modulated optical tomographic information generating unit 55, and the control unit 52, and the control result of the optical tomographic information generating unit 54 or the ultrasonic modulation is controlled by the control unit 52. Output to the optical tomographic information generation unit 55.

  The optical tomographic information generation unit 54 of the signal processing unit 50 generates optical tomographic information based on the light intensity of the interference light Lc detected by the photodetector 47, and outputs it to the control unit 52. The ultrasonic modulated optical tomographic information generating unit 55 generates ultrasonic modulated optical tomographic information based on the light intensity of the ultrasonic modulated light detected by the photodetector 47 and outputs the ultrasonic modulated optical tomographic information to the control unit 52.

  Next, acquisition of each tomographic image and generation and display operation of each tomographic image and composite tomographic image in the tomographic image acquisition apparatus according to the present embodiment configured as described above will be described.

  When observing the inside of the patient's body cavity, the probe 10 is inserted into the forceps opening of the endoscope, the endoscope is inserted into the body cavity of the patient, and based on the image displayed on the monitor of the endoscope, Visually guide the distal end of the insertion portion of the endoscope to a desired site.

  First, an operation when acquiring and displaying an ultrasonic tomographic image will be described. An ultrasonic signal is oscillated by the ultrasonic signal processing unit 51 under the control of the control unit 52. This ultrasonic signal is conducted to the ultrasonic transducer 13 via the cable 53, the terminal 27 and the cable 14.

  The ultrasonic signal is converted into an ultrasonic wave by the ultrasonic transducer 13, and the ultrasonic wave is irradiated to the test portion. The reflected wave reflected by the test portion is converted into an electric signal by the ultrasonic transducer 13 and transmitted to the ultrasonic signal processing unit 51 as a reflected wave signal. The ultrasonic signal processing unit 51 generates ultrasonic tomographic information based on the waveform of the received reflected wave signal and transmits it to the control unit 52.

  Further, the rotating sheath 12 is rotated by the centerless motor 22 to move the irradiation direction of the ultrasonic wave, and radial scanning is performed with the longitudinal direction of the fiber 15 as an axis. A signal indicating the rotation angle detected by the rotation angle detection unit of the centerless motor 22 is sent to the control unit 52 through the signal line 23.

  The control unit 52 generates a radial ultrasonic tomographic image based on the rotation angle of the centerless motor 22 and the ultrasonic tomographic information transmitted from the ultrasonic signal processing unit 51 and outputs it to the monitor 70. On the monitor 70, an ultrasonic tomographic image as shown in FIG.

  In addition, by performing linear scanning of the probe 10 by the linear driving device 24, a linear ultrasonic tomographic image can be acquired and displayed.

  Next, an operation when acquiring and displaying an optical tomographic image will be described. In this embodiment, an OCT apparatus is mounted as an optical tomographic image acquisition unit. Under the control of the control unit 52, low-coherence light for optical tomographic image acquisition is emitted from the light source unit 31. The low coherence light emitted from the light source 36 is condensed by the condenser lens 37 and introduced into the fiber 41.

  The low-coherence light transmitted through the fiber 41 is split by the fiber coupler 39 into reference light Lr that travels in the fiber 41 toward the optical path delay unit 33 and measurement light Ls that travels in the fiber 42 toward the sheath 12. Is done. The reference light Lr is modulated by the piezo element 40 provided on the optical path, and a slight frequency difference Δf is generated between the reference light Lr and the measurement light Ls.

  The measurement light Ls guided to the fiber 42 is incident on the fiber 15 through the lens 19, propagates in the fiber 15, is emitted from the tip of the fiber 15, and passes through the rod lens 17 and the mirror 18 to the test portion. Incident. Of the measurement light Ls incident on the test part, the measurement light Ls ′ reflected at a predetermined depth of the test part is fed back to the fiber 42 via the mirror 18, the rod lens 17, the fiber 15, and the lens 19. . The measurement light Ls ′ fed back to the fiber 42 is combined with a reference light Lr fed back to the fiber 41 described later in the fiber coupler 39.

  On the other hand, the reference light Lr after being modulated by the piezo element 40 passes through the fiber 41, enters the reference light mirror 45 through the condenser lens 44 of the optical path delay unit 33, and is reflected by the reference light mirror 45. The light passes through the condenser lens 44 again and is returned to the fiber 41. The reference light Lr fed back to the fiber 41 is combined with the above-described measurement light Ls ′ by the fiber coupler 39.

  The measurement light Ls ′ and the reference light Lr combined by the fiber coupler 39 overlap on the same axis again, and the measurement light Ls ′ and the reference light Lr interfere with each other to become interference light Lc, which is emitted from the fiber 41 and passes through the lens 49. Then, the light enters the photodetector 47.

  Since the reference light Lr and the measurement light Ls ′ are low coherence light with a short coherence distance, the measurement light Ls (Ls ′) is split into the fiber coupler 39 after the low coherence light is divided into the measurement light Ls and the reference light Lr. When the optical path length until reaching the optical path length is equal to the optical path length until the reference light Lr reaches the fiber coupler 39, both lights interfere with each other, and the beat repeats strength with the frequency difference (Δf) of the both interfering lights. A signal is generated.

  The light detector 47 detects the light intensity of the beat signal from the interference light Lc, performs heterodyne detection, detects the intensity of the measurement light Ls ′ reflected from a predetermined depth of the test section, and generates an optical tomographic information generation section. To 54.

  The optical tomographic information generation unit 54 generates optical tomographic information based on the intensity of the measurement light Ls ′ and outputs it to the control unit 52. Thereafter, the reference light mirror 45 is moved in the optical axis direction (horizontal direction in the figure) by the drive unit 46, and the optical path length until the reference light Lr reaches the fiber coupler 39 changes. For this reason, since the optical path length of the measurement light Ls (Ls ′) that interferes with the reference light Lr also changes, the depth at which the tomographic information of the test part is acquired also changes. In this way, the optical tomographic information is repeatedly acquired while changing the depth little by little. At each irradiation point, optical tomographic information is acquired from the surface of the test part to a depth of about 2 mm. The drive unit 46 of the optical path delay unit 33 is connected to the control unit 52, and information on the optical path length is sequentially output to the control unit.

  When the acquisition of the optical tomographic information at one point is completed, the irradiation direction of the measurement light Ls is moved by slightly rotating the rotating sheath 12 by the centerless motor 24, and the optical tomographic information at the irradiation point is acquired again. In this manner, radial scanning is performed with the longitudinal direction of the fiber 15 as an axis, and an optical tomographic image in a state where the test portion is cut into circles is acquired.

  The control unit 52 generates a radial optical tomographic image based on the optical path length, the rotation angle of the centerless motor 22, and the optical tomographic information output from the optical tomographic information generating unit 54, and outputs it to the monitor 70. On the monitor 70, an optical tomographic image having a depth of about 2 mm from the surface of the test portion as shown in FIG. The lateral resolution varies depending on the wavelength and the coherence length of the low-coherence light emitted from the light source 36, but can be increased to several μm if necessary. Further, the depth direction resolution varies depending on the moving speed of the mirror 45 of the optical path delay unit 33, the response speed of the photodetector 47, and the like, but can be increased to several μm if necessary.

  Furthermore, an operation when acquiring and displaying an ultrasonically modulated optical tomographic image will be described. Under the control of the control unit 52, an ultrasonic signal is oscillated from the ultrasonic signal processing unit 51, and the ultrasonic wave is irradiated from the ultrasonic transducer 13 to the test part.

  At the same time, low-coherence light is emitted from the light source unit 31. The light emitted from the light source 36 propagates in the fiber 41 and propagates in the direction of the probe 10 through the fiber 42 via the fiber coupler 39. The light that has propagated through the fiber 42 enters the fiber 15 through the lens 19, propagates through the fiber 15, is emitted from the tip of the fiber 15, and is irradiated onto the test portion through the rod lens 17 and the mirror 18.

  At this time, ultrasonic waves are applied to the portion to be examined. For this reason, the elastic wave forms a refractive index distribution with respect to the light in the test portion. That is, a tissue density state is formed in the test portion. In such a case, when light travels through the region to be examined, the density of the tissue acts on the light, and the light is modulated. By analyzing the modulated light (reflected light), it is possible to acquire tomographic information of the test portion irradiated with the light. The ultrasonic modulated light reflected by the test portion subjected to the action of ultrasonic waves is returned to the fiber 42 via the mirror 18, the rod lens 17, the fiber 15, and the lens 19, and emitted from the other end of the fiber 42. The light is collected by the lens 49 and enters the photodetector 47. The photodetector 47 detects the intensity of the ultrasonic modulation light.

  Under the control of the control unit 52, the output of the photodetector 47 is output to the ultrasonic modulation optical tomographic information generation unit 55. The ultrasonic signal is output from the ultrasonic signal processing unit 51 to the ultrasonic modulation optical tomographic information generation unit 55. The ultrasonic modulation optical tomographic information generation unit 55 generates ultrasonic modulation optical tomographic information based on the ultrasonic signal and the intensity of the reflected light detected by the photodetector 47. In addition, since the oscillation timing of the ultrasonic signal is known, it is possible to acquire ultrasonically modulated tomographic information up to a depth of about 5 mm to 10 mm from the surface of the test part by detecting the reflected light only once. . Further, the resolution in the depth direction and the lateral direction varies depending on the oscillation frequency of the ultrasonic wave, the degree of light condensing, etc., but can be increased to several tens of μm if necessary.

  When acquisition of ultrasonically modulated optical tomographic information at one point is completed, the centerless motor 24 slightly rotates the rotating sheath 12 to move the light irradiation direction, and again acquires ultrasonically modulated optical tomographic information at that irradiated point. To do. In this manner, radial scanning with the longitudinal direction of the fiber 15 as an axis is performed, and ultrasonically modulated optical tomographic information in a state where the test portion is cut into circles is acquired.

  The control unit 52 generates a radial optical tomographic image based on the rotation angle of the centerless motor 22 and the ultrasonic modulated optical tomographic information output from the ultrasonic modulated optical tomographic information generating unit 55 and outputs the radial optical tomographic image to the monitor 70. On the monitor 70, an ultrasonically modulated optical tomographic image as shown in FIG.

  Furthermore, an operation when acquiring and displaying a combined tomographic image (radial) obtained by combining an optical tomographic image, an ultrasonically modulated optical tomographic image, and an ultrasonic tomographic image will be described.

  First, an optical tomographic image, an ultrasonically modulated optical tomographic image, and an ultrasonic tomographic image of the part to be examined are acquired. As described above, a radial tomographic image may be acquired individually, but first, optical tomographic image information, ultrasonically modulated optical tomographic image information, and ultrasonic tomographic image information are acquired for a predetermined point of the test portion. Thereafter, the sheath 12 may be slightly rotated to acquire each tomographic image information at the next point, and three types of tomographic images may be acquired by one rotation of the sheath 12. Note that the ultrasonic tomographic image information and the ultrasonic modulated optical tomographic image information may be acquired simultaneously.

  After each tomographic image is temporarily stored in a storage unit (not shown), the control unit 52 serving as a synthetic tomographic image generation unit generates a tomographic image in a low-depth region (from the surface to a depth of about 2 mm) of the test unit. A low depth tomographic image that is an image is selected, and a medium depth tomographic image that is a tomographic image of a medium depth region (from a depth of about 2 mm to a depth of about 5 mm to about 10 mm) from the ultrasonically modulated optical tomographic image is selected. And selecting a high-depth tomographic image that is a tomographic image of a high-depth region (from a depth of about 5 mm to 10 mm to 30 mm) from the ultrasonic tomographic image; The depth tomographic image is synthesized and a synthesized tomographic image is generated and output to the monitor 70. A synthetic tomographic image as shown in FIG. 3 is displayed on the monitor 70.

  In this synthetic tomographic image, a low-depth region from the surface of the test part to about 2 mm is displayed as a high-resolution tomographic image acquired by the optical tomographic image acquisition means and having a resolution in the depth direction and the horizontal direction of several μm. The intermediate depth region from about 5 mm to about 10 mm is displayed as a tomographic image having a resolution of several tens of μm in the depth direction and the horizontal direction acquired by the ultrasonic modulated optical tomographic image means, and a high depth from about 5 mm to about 10 mm to 30 mm. The region can display a synthetic tomographic image consisting of a tomographic image having a resolution of several hundreds of μm in the depth direction and the horizontal direction acquired by the ultrasonic modulation tomographic image means. The achievement level can be easily visually confirmed.

  As is clear from the above description, in the tomographic image acquisition apparatus according to the present invention, in addition to the optical tomographic image acquisition unit and the ultrasonic tomographic image acquisition unit, the ultrasonic tomographic optical tomographic image acquisition unit is provided. The tomographic image of the low depth region can be acquired with high resolution by the optical tomographic image acquisition means, and the tomographic image of the high depth region of the test part can be acquired with low resolution by the ultrasonic tomographic image acquisition means. Since the tomographic image in the middle depth region can be acquired by the ultrasonic modulation optical tomographic image acquisition means with a higher resolution than the ultrasonic tomographic image, the depth becomes deep when displaying the composite tomographic image obtained by combining these tomographic images. Accordingly, since the resolution is gradually reduced, it is possible to display a composite tomographic image that is easier to see than in the past.

  In addition, the conventional ultrasonic modulation optical tomographic image acquisition means can acquire a tomographic image from the surface of the test part to a depth of several millimeters on the order of several tens of μm, but the upper limit of the resolution of the image is several. There is a problem that the resolution is insufficient for observing cells and the like, and the depth that can be imaged is insufficient for observing the inside of a living body, and the spread in the medical field is delayed. By combining the optical tomographic image acquisition unit and the ultrasonic tomographic image acquisition unit, it is possible to effectively utilize the characteristics of the ultrasonic modulation optical tomographic image unit.

  Furthermore, since the ultrasonic modulation optical tomographic image acquisition means requires both a light irradiation part and an ultrasonic irradiation part, the configuration is complicated, and an image analysis means is also required, thereby reducing the manufacturing cost. Difficulties were also one of the factors that hindered popularization. However, in the tomographic image acquisition apparatus according to the present embodiment, the light source 36, the ultrasonic transducer 13 and the control unit 52 used in the optical tomographic image acquisition unit and the ultrasonic tomographic image acquisition unit are diverted, so that the manufacturing cost is increased significantly. The tomographic image acquisition apparatus provided with the ultrasonic modulation optical tomographic image acquisition means can be realized without doing so.

  In addition, since the fiber 15 and the ultrasonic transducer 13 are integrally fixed and accommodated in the probe 10, the probe 10 can be inserted through the forceps port of the endoscope, and the function of the tomographic image acquisition apparatus can be achieved. It can be applied to a conventional endoscope.

  In addition, since the optical system for acquiring the optical tomographic image also serves as the optical system for acquiring the ultrasonic modulated optical tomographic image, the apparatus is downsized, and the acquisition position of the optical tomographic image and the acquisition of the ultrasonic modulated optical tomographic image are acquired. The positions coincide with each other, and alignment when the optical tomographic image and the ultrasonic modulated optical tomographic image are synthesized is facilitated.

  In addition, since the ultrasonic transducer 13 that generates an ultrasonic wave to acquire an ultrasonic tomographic image also serves as an ultrasonic transducer that generates an ultrasonic wave to acquire an ultrasonically modulated optical tomographic image, the configuration of the apparatus is simplified. This makes it possible to reduce the size and price.

  In the above embodiment, a radial composite tomographic image is generated, but each tomographic image may be acquired by linear scanning, and a linear composite tomographic image may be acquired and displayed. Alternatively, a three-dimensional tomographic image may be obtained by combining radial scanning and linear scanning to generate a three-dimensional synthetic tomographic image.

  Further, in the present embodiment, an irradiation unit and a light receiving (reception) unit for acquiring each tomographic image are incorporated into the probe. As a modification of the present embodiment, each tomographic image is included in the endoscope insertion unit main body. It is also possible to incorporate a part or all of the irradiation unit and the light receiving (reception) unit for acquiring the light. By incorporating at least a part of the tomographic image acquisition apparatus into the endoscope insertion section main body, the apparatus can be reduced in size. In addition, an ultrasonic oscillator mounted on an existing ultrasonic endoscope can be used as an ultrasonic oscillator for acquiring an ultrasonically modulated optical tomographic image. Is possible.

  As another modification of the present embodiment, an optical tomographic image acquisition function for acquiring an optical tomographic image and an ultrasonic modulation optical tomographic image acquisition function for acquiring an ultrasonically modulated optical tomographic image are provided. And a device that displays a combined tomographic image combined with an ultrasonically modulated optical tomographic image on a monitor. Furthermore, as another modified example, an ultrasonic modulated optical tomographic image acquiring function for acquiring an ultrasonic modulated optical tomographic image and an ultrasonic tomographic image acquiring function for acquiring an ultrasonic tomographic image are provided. An apparatus that displays on a monitor a combined tomographic image synthesized from an ultrasonic tomographic image can also be mentioned.

Schematic configuration diagram of an embodiment of a tomographic image acquisition apparatus according to the present invention Illustration of optical tomographic image, ultrasonic modulated optical tomographic image, ultrasonic tomographic image Illustration of composite tomographic image

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Probe 12 Rotating sheath 13 Ultrasonic transducer 15 Fiber 16 Outer cylinder 17 Rod lens 18 Mirror 21 Bearing 22 Centerless motor 24 Linear drive device 30 Optical unit 31 Light source part 32 Fiber coupling optical system 33 Optical path delay part 34 Optical detection part 50 Signal processing Unit 51 Ultrasonic signal processing unit 52 Control unit 54 Optical tomographic information generation unit 55 Ultrasonic modulation optical tomographic information generation unit 70 Monitor

Claims (9)

  1. An optical tomographic image acquisition means for irradiating the test part with a first light and acquiring an optical tomographic image of the test part based on the reflected light of the first light reflected by the test part; A tomography comprising: an ultrasonic tomographic image acquisition unit that irradiates a test unit with a first ultrasonic wave and acquires an ultrasonic tomographic image of the test unit based on a reflected wave of the ultrasonic wave reflected by the test unit In the image acquisition device,
    Ultrasound-modulated reflected light of the second light that is irradiated on the test part simultaneously with the second light and the second ultrasonic wave and reflected by the test part subjected to the action of the second ultrasonic wave A tomographic image acquisition apparatus comprising ultrasonic modulated optical tomographic image acquisition means for acquiring an ultrasonic modulated optical tomographic image of the test portion based on
  2. A first light emitting end for emitting the first light to the test part; a first ultrasonic emission end for emitting the first ultrasonic wave to the test part; and At least one of the second light emitting end that emits the second light and the second ultrasonic emitting end that emits the second ultrasonic wave to the test portion is in the endoscope. The tomographic image acquisition apparatus according to claim 1, wherein the tomographic image acquisition apparatus is incorporated in the apparatus.
  3. A first light emitting end for emitting the first light to the test part; a first ultrasonic emission end for emitting the first ultrasonic wave to the test part; and A second light emitting end for emitting the second light and a second ultrasonic emitting end for emitting the second ultrasonic wave to the test part are integrally fixed and accommodated in the probe. The tomographic image acquisition apparatus according to claim 1.
  4. The tomographic image acquisition apparatus according to claim 3, wherein the probe is inserted into a forceps opening of an endoscope.
  5. 5. The tomographic image acquisition apparatus according to claim 2, wherein the first light emission end also serves as the second light emission end. 6.
  6. The tomographic image acquisition apparatus according to claim 1, wherein the light source of the first light also serves as the light source of the second light.
  7. The tomographic image acquisition apparatus according to claim 2, wherein the first ultrasonic wave emission end also serves as the second ultrasonic wave emission end.
  8. The tomographic image acquisition apparatus according to claim 1, wherein the first ultrasonic oscillator also serves as the second ultrasonic oscillator.
  9. From the optical tomographic image, a low depth tomographic image that is a tomographic image of a low depth region of the test part is selected, and a medium depth that is a tomographic image of the medium depth region of the test part from the ultrasonically modulated optical tomographic image A tomographic image is selected, a high-depth tomographic image that is a tomographic image of a high-depth region of the examination part is selected from the ultrasonic tomographic image, and the low-depth tomographic image, the medium-depth tomographic image, and the high-depth tomographic image are selected. The tomographic image acquisition apparatus according to claim 1, further comprising a combined tomographic image generation unit configured to generate a combined tomographic image of the test portion.
JP2005018346A 2005-01-26 2005-01-26 Tomographic image acquisition device Withdrawn JP2006204430A (en)

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Cited By (12)

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JP2007216001A (en) * 2006-01-20 2007-08-30 Olympus Medical Systems Corp Object information analyzing apparatus, endoscope system and object information analyzing method
JP2008142454A (en) * 2006-12-13 2008-06-26 Fujifilm Corp Medical diagnostic probe and medical diagnostic system
JP2008168038A (en) * 2007-01-15 2008-07-24 Olympus Medical Systems Corp Method and apparatus for analyzing characteristic information of object, and endoscope apparatus
JP2008170363A (en) * 2007-01-15 2008-07-24 Olympus Medical Systems Corp Specimen data analyzer, endoscopic apparatus and specimen data analysis method
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JP2010508973A (en) * 2006-11-08 2010-03-25 ライトラブ イメージング, インコーポレイテッド Photo-acoustic imaging device and method
JP2014514092A (en) * 2011-04-13 2014-06-19 セント ジュード メディカル インコーポレイテッド Optical coherence tomography catheter for intraluminal elastographic property mapping using micropulpation
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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007216001A (en) * 2006-01-20 2007-08-30 Olympus Medical Systems Corp Object information analyzing apparatus, endoscope system and object information analyzing method
JP2010508973A (en) * 2006-11-08 2010-03-25 ライトラブ イメージング, インコーポレイテッド Photo-acoustic imaging device and method
JP2008142454A (en) * 2006-12-13 2008-06-26 Fujifilm Corp Medical diagnostic probe and medical diagnostic system
JP2008168038A (en) * 2007-01-15 2008-07-24 Olympus Medical Systems Corp Method and apparatus for analyzing characteristic information of object, and endoscope apparatus
JP2008170363A (en) * 2007-01-15 2008-07-24 Olympus Medical Systems Corp Specimen data analyzer, endoscopic apparatus and specimen data analysis method
JP2009066110A (en) * 2007-09-12 2009-04-02 Canon Inc Measurement apparatus
JP2009195617A (en) * 2008-02-25 2009-09-03 Olympus Medical Systems Corp Biological observation apparatus and biological tomographic image generation method
JP2014514092A (en) * 2011-04-13 2014-06-19 セント ジュード メディカル インコーポレイテッド Optical coherence tomography catheter for intraluminal elastographic property mapping using micropulpation
WO2014162365A1 (en) 2013-04-05 2014-10-09 テルモ株式会社 Image diagnostic device, method for controlling same, program, and computer-readable storage medium
US10478156B2 (en) 2013-09-27 2019-11-19 Terumo Kabushiki Kaisha Imaging apparatus for diagnosis, method of controlling the same, program, and computer readable storage medium
EP3378406A1 (en) 2017-03-21 2018-09-26 Terumo Kabushiki Kaisha Imaging apparatus for diagnosis, and operation method and program thereof
EP3378407A1 (en) 2017-03-22 2018-09-26 Terumo Kabushiki Kaisha Imaging apparatus for diagnosis

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