JP2008043383A - Fluorescence observation endoscope instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescence observation endoscope instrument which can display a fluorescence image based on excitation light having a plurality of wavelengths in one examination. <P>SOLUTION: A laser unit 40 incorporates a plurality of semiconductor lasers 50-1, 50-2, and 50-3 having different oscillation wavelengths. A system control circuit 42 makes the laser unit 40 sequentially repeatedly emit laser light of different wavelengths from the semiconductor lasers 50. The emitted laser light irradiates a portion to be examined as excitation light through a light guide 16 and a light distribution lens 11. Fluorescence emitted from biotissue excited by the laser light is imaged on a color imaging element 13 by an object lens 12. Then, the excitation light emitted from the semiconductor lasers 50-1, 50-2 and 50-3 is cut off by an excitation light cutting off filter 14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fluorescence observation endoscope apparatus that captures an image of fluorescence emitted from a living tissue of a test part by irradiating the test part with excitation light for fluorescence excitation through an endoscope.

  It is known that when a biological tissue is irradiated with light of a certain wavelength band as excitation light, fluorescence is emitted from a specific substance contained in the biological tissue (this fluorescence is called “autofluorescence”).

  For example, examples of substances that cause autofluorescence include nicotinamide adenine dinucleotide (hereinafter referred to as “NADH”), collagen, and the like.

  NADH is abundant in the living tissue of the epithelium in the colon. Further, NADH is known to tend to decrease at locations where there are lesions (for example, tumor, cancer) in living tissue. That is, when the subject is irradiated with excitation light, auto-fluorescence by NADH at a site where a lesion is occurring in the living tissue is weakened.

  Collagen is contained in a large amount of living tissue in the submucosa such as skin and connective tissue. It is also known that the mucous membrane tends to be thick at the site where the lesion is generated in the living tissue. When the mucous membrane becomes thick in this way, it becomes difficult for the excitation light to reach the submucosal layer. Therefore, when the subject is irradiated with the excitation light, autofluorescence due to collagen at the site where the lesion is generated in the living tissue is also weakened.

Based on such knowledge, there has been proposed a fluorescence observation endoscope apparatus that images autofluorescence of a living body through an endoscope and displays an image based on autofluorescence. For example, Patent Documents 1 and 2 disclose a fluorescence observation endoscope apparatus having a configuration in which a subject is irradiated with excitation light having a single wavelength during fluorescence observation. According to such a fluorescence observation endoscope apparatus, a lesion is generated in a portion displayed darker than a portion composed only of normal biological tissue by observing an image of the biological tissue when the excitation light is irradiated. Can be diagnosed.
Japanese Patent Application Laid-Open No. 07-155291 Japanese Patent No. 3560671

  By the way, the wavelength of the excitation light for exciting NADH and the wavelength of the excitation light for exciting collagen are different. Specifically, the wavelength of light used to excite NADH is about 350 nm, and the wavelength used to excite collagen is about 450 nm (see FIG. 7). Therefore, in the fluorescence observation endoscope apparatus that emits excitation light having a single wavelength, autofluorescence based on a plurality of substances cannot be observed simultaneously. In this case, the following problems occur.

  For example, when a fluorescence observation endoscope apparatus capable of irradiating excitation light of approximately 350 nm is used, when a site that does not originally contain NADH regardless of the presence or absence of a lesion is observed, NADH is caused from that site. Fluorescence will not be emitted. On the other hand, when a fluorescence observation endoscope apparatus capable of irradiating excitation light of approximately 450 nm is used, when a site originally containing no collagen is observed regardless of the presence or absence of a lesion, collagen is caused from that site. Fluorescence will not be emitted. In these cases, even if the living tissue has a lesion, the fluorescence intensity of the lesion does not change from that of a normal living tissue. Therefore, in the conventional fluorescence observation endoscope apparatus, there is a possibility that the operator may miss a place where a lesion exists in the living tissue.

  Of course, if a diagnosis using a fluorescence observation endoscope apparatus capable of emitting 350 nm excitation light and a diagnosis using a fluorescence observation endoscope capable of emitting 450 nm excitation light are performed in order, the lesion area can be determined from both fluorescence images. Therefore, the risk of missing a lesion is reduced unless both NADH and collagen are small.

  However, in this case, every time observation with excitation light of a different wavelength is performed, an operation of inserting the insertion portion of the fluorescence observation endoscope into the body cavity of the subject (operation of inserting the insertion portion from the mouth of the subject) is necessary. become. Since this work gives great pain to the subject, repeated examinations using different fluorescence observation endoscope devices impose an excessive burden on the subject.

  Accordingly, an object of the present invention is to provide a fluorescence observation endoscope apparatus capable of displaying a fluorescence image based on excitation light having a plurality of wavelengths in one examination.

  The fluorescence observation endoscope apparatus according to the present invention devised to solve the above problems irradiates a living tissue of a test part in a body cavity with excitation light, and the living tissue excited by the excitation light A fluorescence observation endoscope apparatus that captures an image due to emitted fluorescence, and images an image of an endoscope having an objective optical system at a tip thereof and the portion to be examined formed by the objective optical system. An imaging device that outputs a signal; an excitation light source device that emits excitation light of a plurality of wavelengths; an illuminating unit that irradiates the test portion with excitation light emitted from the excitation light source device; and the objective optical system; Filter means arranged between the imaging device and blocking excitation light of each wavelength emitted from the excitation light source device, and output from the imaging device while excitation light is emitted from the excitation light source device The video signal is acquired and the acquired video Characterized by comprising a display means for performing display based on the signal.

  According to the fluorescence observation endoscope apparatus of the present invention configured as described above, the excitation light emitted from the excitation light source apparatus is irradiated onto the living tissue of the test part by the illumination unit. Then, fluorescence corresponding to the wavelength of the irradiated excitation light is emitted from the living tissue, and this fluorescence enters the objective optical system. At the same time, the excitation light reflected on the surface of the living tissue also enters the objective optical system. Then, the light incident on the objective optical system passes through the filter means and enters the imaging device. At this time, the excitation light reflected on the surface of the living tissue is completely blocked by the filter means regardless of the excitation light of any wavelength. Therefore, according to the present invention, an image composed of fluorescence from a plurality of fluorescent materials excited by excitation light having a plurality of wavelengths can be captured by the imaging device.

  Therefore, according to the present invention, if display based on the video signal output from the imaging device is performed by the display means, a fluorescent image based on excitation light having a plurality of wavelengths can be displayed in one examination.

  The excitation light source device may emit excitation light sequentially for each wavelength, or may simultaneously emit excitation light having a plurality of wavelengths. When a plurality of wavelengths of excitation light are simultaneously irradiated onto a living tissue, each fluorescent substance emits fluorescence simultaneously according to the wavelength of each excitation light, but the fluorescence intensity of each fluorescent substance contained in the living tissue is Since all of them tend to be weaker in the lesioned portion than the surroundings, even if fluorescence is emitted from a plurality of fluorescent materials simultaneously by excitation light having a plurality of wavelengths, the lesioned portion is displayed darkly.

  In addition, the excitation light source device includes at least a first light emitting element that emits excitation light having a first wavelength that excites a tumor affinity substance and a second wavelength that excites a fluorescent substance originally contained in a living tissue. A second light-emitting element that selectively emits light, and the display unit is configured to emit excitation light having the first wavelength from the excitation first light-emitting element. A portion that is displayed brighter than the surroundings is extracted from the acquired video signal, and is further darker than the surroundings from the acquired video signal during a period in which excitation light of the second wavelength is emitted from the second light emitting element. A portion to be displayed may be extracted, and a portion in which both extracted portions coincide with each other may be displayed in a specific color.

  Each excitation light emitted from the excitation light source device may have a wavelength of 450 nm or less, and the filter means may be configured to block light having a wavelength of 450 nm or less.

  As described above, according to the present invention, it is possible to provide a fluorescence observation endoscope apparatus that can display fluorescence images based on excitation light having a plurality of wavelengths in one examination.

  Next, modes for carrying out the present invention will be described based on the attached drawings.

  FIG. 1 is an external view of a fluorescence observation endoscope apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the fluorescence observation endoscope apparatus includes a fluorescence observation endoscope 10, a light source processor device 20, and a monitor 60.

  FIG. 3 is an external view of the fluorescence observation endoscope 10. As shown in FIGS. 1 and 3, a fluorescence observation endoscope 10 is a normal electronic endoscope with a modification for fluorescence observation, and is formed into an elongated body cavity for insertion into a body cavity. An inner insertion portion 10a, an operation portion 10b having an angle knob for bending the distal end portion of the body cavity insertion portion 10a, a light guide flexible tube 10c for connecting the operation portion 10b and the light source processor device 20, And the connector 10d provided in the base end of this light guide flexible tube 10c is provided.

  FIG. 2 is a schematic diagram of the fluorescence observation endoscope apparatus according to the present embodiment. As shown in FIG. 2, an illumination window and a photographing window in which a light distribution lens 11 and an objective lens 12 (corresponding to an objective optical system) are fitted are formed on the distal end surface of the body cavity insertion portion 10a. In the body cavity insertion portion 10 a, an image sensor 13 (corresponding to an image pickup apparatus) that captures an image of a subject formed by the objective lens 12 along the optical axis of the objective lens 12, and the image sensor An amplifier 15 for amplifying the video signal output from 13 is incorporated. The image pickup device 13 is a color solid-state image pickup device (color CCD) in which a mosaic filter is covered on the image pickup surface.

  Further, between the objective lens 12 and the image pickup device 13, an excitation light cut filter 14 (blocking light in a predetermined wavelength band (light in the wavelength band of each excitation light described later) from the light beam emitted from the objective lens 12). (Corresponding to the filter means) is inserted.

  A signal cable 18 for transmitting a video signal output from the image sensor 13 is provided in the end surface of the connector 10d through the body cavity insertion portion 10a, the operation portion 10b, and the light guide flexible tube 10c. It is connected to the electrical connector 17.

  In parallel with the signal cable 18, a light guide fiber bundle 16 (hereinafter simply referred to as “light guide”) 16 made of quartz fiber is pulled into the body cavity insertion portion 10 a, the operation portion 10 b, and the light guide flexible tube 10 c. Has been passed. The distal end of the light guide 16 faces the light distribution lens 11 in the distal end portion of the body cavity insertion portion 10a, and the proximal end thereof is inserted into a metal pipe 19 protruding from the end face of the connector 10d and fixed. (The light guide 16 and the light distribution lens 11 correspond to illumination means).

  As shown in FIG. 2, a rod lens 16 a is disposed in contact with the light guide 16 on the proximal end side in the pipe 19. The rod lens 16a can uniformize the light distribution of the light emitted from the distal end surface by internally reflecting the light incident on the proximal end surface a plurality of times. Therefore, even if the light distribution of the light incident on the base end face of the rod lens 16a is biased, when the light is emitted from the front end face, it is emitted from the entire front end face with a uniform light distribution. Therefore, the light that passes through the rod lens 16a and enters the base end surface of the light guide 16 always has a uniform light distribution.

  The light source processor device 20 selectively introduces illumination light (white light) and laser light into the end face of the rod lens 16 a of the fluorescence observation endoscope 10 and also uses the image sensor 13 through the electrical connector 17 of the fluorescence observation endoscope 10. This is a device that generates a video signal by performing image processing on the video signal received from the video signal and outputs it to the monitor 60.

  The front panel of the housing of the light source processor device 20 is provided with a socket 20a that is a cylinder into which the pipe 19 of the fluorescence observation endoscope 10 is inserted from the outer surface side. The through hole formed in the socket 20a communicates with the internal space of the light source processor device 20. In the inner space of the light source processor device 20, the central axis of the socket 20a (that is, the light guide 16 in the pipe 19 inserted into the socket 20a, the central axis of the rod lens 16a) is sequentially extended. A condenser lens 28, a beam splitter 29, a rotary shutter 32, and a lamp 33 are disposed.

  The condensing lens 28 is a lens that condenses parallel light incident along the optical axis from the beam splitter 29 side on the base end surface of the rod lens 16a in the pipe 19 inserted into the socket 20a.

  The lamp 33 is supplied with a power supply current from a lamp power source 38 to emit white light (not shown), and a lens or reflector (not shown) for converting white light emitted from the light bulb as divergent light into parallel light. ). As a result, the lamp 33 emits white light as parallel light along the optical axis of the condenser lens 28 through the beam splitter 29 toward the condenser lens 28.

  The beam splitter 29 is disposed with an inclination of 45 degrees with respect to the optical axis of the condenser lens 28. The beam splitter 29 transmits white light from the lamp 33 and reflects light from a direction perpendicular to the optical axis of the condenser lens 28 along the optical axis of the condenser lens 28 to reflect the collected light. This is a half mirror that is incident on the optical lens 28.

  The rotary shutter 32 interposed between the lamp 33 and the beam splitter 29 is a disc having a single fan-shaped (1/4 annular ring) opening with a central angle of 90 degrees, The center of the arc of the opening coincides with the center of the outer circumference of the rotary shutter 32 (not shown). The center of the rotary shutter 32 is fixed to the tip of the drive shaft of the motor 34. When driven by the motor 34, the rotary shutter 32 rotates about the drive shaft. The rotary shutter 32 is arranged such that when it rotates, the opening and portions other than the opening alternately cross the optical path of white light. For this reason, when the opening of the rotary shutter 32 is arranged on the optical path of white light, white light passes, and when the part other than the opening of the rotary shutter 32 is arranged on the optical path of white light, White light is blocked.

  On the other hand, a collimator lens 39 and a laser unit 40 are arranged in order on the optical axis of the condenser lens 28 bent 90 degrees by the beam splitter 29. The laser unit 40 is a device that emits laser light of any one of three wavelengths as divergent light, and the collimator lens 39 converts the laser light emitted from the laser unit 40 as divergent light into parallel light. It is a lens.

  FIG. 4 is a diagram showing a detailed configuration of the laser unit 40 (corresponding to an excitation light source device). As shown in FIG. 4, the laser unit 40 includes a control system 410, eight semiconductor lasers 50 (corresponding to light emitting elements), and a relay fiber bundle 51. The eight semiconductor lasers 50 include first semiconductor lasers 50-1, 50-1, and 50-1 that emit light having a wavelength of 350 nm, and a second semiconductor laser 50 that emits light having a wavelength of 400 nm. -2 and 50-2, and third semiconductor lasers 50-3, 50-3, and 50-3 that emit light having a wavelength of 450 nm. FIG. 9A shows the wavelength band of the excitation light emitted from the first semiconductor laser 50-1, and FIG. 9B shows the excitation light emitted from the second semiconductor laser 50-2. FIG. 9C shows the wavelength band of the excitation light emitted from the third semiconductor laser 50-3.

  The distal end of the relay fiber bundle 51 is disposed at the object side focal point of the collimator lens 39. Further, the base end of each optical fiber constituting the relay fiber bundle 51 is connected to the light emitting point of each semiconductor laser 50. Therefore, the pumping light emitted from each semiconductor laser 50 and relayed and aggregated by each optical fiber constituting the relay fiber bundle 51 is emitted as diverging light from the tip of the relay fiber bundle 51.

  The control system 410 is connected to each semiconductor laser 50 and supplies a drive current to each semiconductor laser 50 at a timing instructed by the system control circuit 42.

  The optical path of the excitation light between the collimator lens 39 and the beam splitter 29 and them is covered by a shield case 44 made of a bottomed cylindrical opaque member in which only a portion that interferes with the optical path of white light is cut out. ing. Therefore, the excitation light is prevented from deviating from the original optical path and becoming stray light.

  FIG. 5 is a graph showing the transmission wavelength band of the excitation light cut filter 14. FIG. 6 shows the transmission wavelength band of the excitation light cut filter 14 and the wavelength bands of the laser light (350 nm, 400 nm, 450 nm) emitted from each semiconductor laser 50. It is a graph which compares and shows. As shown in FIGS. 5 and 6, the excitation light cut filter 14 transmits light in the visible wavelength band (wavelength band of approximately 470 nm or more) and completely cuts the light in the wavelength band of each excitation light. Designed to be For this reason, all the excitation light emitted from the laser unit 40 and reflected by the subject is cut by the excitation light cut filter 14, and thus is not imaged by the imaging element 13. On the other hand, the fluorescence emitted from the living tissue illuminated by the excitation light becomes light having a wavelength longer than that of the excitation light (approximately 470 nm or more), and therefore is incident on the image sensor 13 without being cut by the excitation light cut filter 14. .

  Further, on the front panel of the housing of the light source processor device 20, an electrical socket 21 made up of a number of electrodes each conducting with each terminal of the electrical connector 17 when the pipe 19 is inserted into the socket 20a, and an external operation. And an operation panel 23 having a plurality of switches. Each switch on the operation panel 23 is connected to the system control circuit 42. Each switch includes a switch associated with the normal observation mode, the first fluorescence observation mode, and the second fluorescence observation mode, and an operation signal generated by the operation on each switch is sent to the system control circuit 42, respectively. Entered.

  The system control circuit 42 is connected to the motor 34, the lamp power supply 38, and the control system 410 of the laser unit 40, and outputs signals for controlling them. The system control circuit 42 performs control corresponding to any one of the normal observation mode, the first fluorescence observation mode, and the second fluorescence observation mode according to each switch operated on the operation panel 23. Further, regardless of which mode is selected, the system control circuit 42 controls the lamp power supply 38 to start supplying power to the lamp 33 at the start of each mode.

  The video signal processing circuit 43 is a circuit for displaying a moving image corresponding to each observation mode on the monitor 60 by performing predetermined processing on the image signal (the video signal processing circuit 43 and the monitor 60 display the video signal). Equivalent to the means). The processing that the video signal processing circuit 43 performs on the image signal includes A / D conversion, high-frequency component removal, amplification, blanking, clamping, white balance, gamma correction, analog-digital conversion, and color separation. The video signal processing circuit 43 is connected to the system control circuit 42 and the terminal of the electrical socket 21, and the image signal output from the image sensor 13 is sent to the video signal processing circuit 43 through the amplifier 15 and the electrical socket 21. Entered. The video signal processing circuit 43 is provided with a first memory and a second memory (not shown) for temporarily storing image signals.

  Hereinafter, the contents of processing by the system control circuit 42 and the video signal processing circuit 43 in each observation mode will be described.

  When the normal observation mode is selected, the system control circuit 42 controls the motor 34 to place the opening of the rotary shutter 32 on the optical path of white light and controls the control system 410 to control all the semiconductors. The power supply to the laser 50 is stopped. As a result, only white light emitted from the lamp 33 is always incident on the rod lens 16 a and emitted from the tip of the fluorescence observation endoscope 10. Then, the imaging device 13 captures an image of the subject formed by the objective lens 12 with white light and outputs a video signal of a normal image. Further, the video signal processing circuit 43 displays a moving image of a normal color image on the monitor 60 based on the video signal of the normal image output from the image sensor 13.

  Next, processing by the system control circuit 42 and the video signal processing circuit 43 in the first fluorescence observation mode will be described using the timing chart of FIG.

  When the first fluorescence observation mode is selected, the system control circuit 42 controls the motor 34 and the control system 410 to rotate the rotary shutter 32 so as to rotate once during one frame period.

  In the first fluorescence observation mode, as shown in FIG. 10, four fields are handled as one frame. The system control circuit 42 controls the motor 34 to allow the white light to pass during the first field period of each frame and to block the white light during the other three field periods. Rotate. In addition, the system control circuit 42 controls the control system 410 so that while the rotary shutter 32 blocks white light, 350 nm excitation light, 400 nm excitation light, and 450 nm sequentially in accordance with each field period. The excitation light is emitted.

  Therefore, in this case, white light, 350 nm excitation light, 400 nm excitation light, and 450 nm excitation light are sequentially emitted from the light distribution lens 11. The imaging device 13 sequentially outputs an image signal based on the image of the subject by white light, the fluorescence image by excitation light of 350 nm, the fluorescence image by excitation light of 400 nm, and the fluorescence image by excitation light of 450 nm.

  Then, the video signal processing circuit 43 writes all the video signals output from the image sensor 13 to either the first memory or the second memory for each frame.

  At the same time, the video signal processing circuit 43 receives each video signal written to the other memory in the immediately preceding frame from the other memory (the first memory or the second memory that is not used for the video signal writing process). And a screen based on each video signal is displayed at a predetermined position on the monitor 60 (see FIG. 8). As shown in FIG. 10, the video signal processing circuit 43 switches between a memory for writing each video signal and a memory for reading each video signal every time a frame is switched.

  FIG. 8 shows a screen of the monitor 60 in the first fluorescence observation mode. As shown in FIG. 8, in the first fluorescence observation mode, WL, FL_A, FL_B, and FL_C are set as display areas obtained by dividing the single screen of the monitor 60 into four parts vertically and horizontally. Then, the video signal processing circuit 43 displays an image based on the video signal generated when the white light is irradiated on the display area WL, and based on the video signal generated when the 350 nm excitation light is irradiated. An image is displayed on the display area FL_A, an image based on the video signal generated when 400 nm excitation light is irradiated is displayed on the display area FL_B, and a video signal generated when 450 nm excitation light is irradiated Is displayed in the display area FL_C.

  Accordingly, when the first fluorescence observation mode is selected, the monitor 60 displays an image of the subject with white light, a fluorescence image with 350 nm excitation light, a fluorescence image with 400 nm excitation light, and a fluorescence with 450 nm excitation light. A moving image based on an image is displayed at the same time.

  Next, the second fluorescence observation mode in the present embodiment will be described based on the timing chart of FIG.

  When the second fluorescence observation mode is selected, the system control circuit 42 controls the motor 34 to place a portion other than the opening of the rotary shutter 32 on the optical path of white light.

  As shown in FIG. 13, in the second fluorescence observation mode, two fields are handled as one frame. The system control circuit 42 emits only 400 nm excitation light during the first field period of each frame and emits only 450 nm excitation light during the second half field period of each frame. To control.

  Therefore, in this case, 400 nm excitation light and 450 nm excitation light are alternately emitted from the light distribution lens 11. The imaging device 13 alternately outputs a video signal based on a fluorescence image by 400 nm excitation light and a fluorescence image by 450 nm excitation light.

  The video signal processing circuit 43 writes the video signal output from the image sensor 13 (fluorescent image video signal by 400 nm excitation light) into the second memory during the period corresponding to the first field of each frame. Then, the video signal written in the first memory in the immediately preceding field (fluorescent image video signal by 450 nm excitation light) is read out.

  Further, the video signal processing circuit 43 reads the video signal stored in the second memory written in the field. Then, based on both read video signals, the fluorescent image of the subject with 400 nm excitation light is displayed brighter than the surroundings, and the fluorescent image of the subject with 450 nm excitation light is displayed darker than the surroundings. Then, a calculation process for generating image data for displaying the extracted portion in a specific color is performed, and an image based on the image data is displayed on the monitor 60 (see FIG. 12C).

  Hereinafter, effects of the fluorescence endoscope apparatus according to the present embodiment will be described.

  FIG. 7 is a table showing a fluorescence excitation wavelength and a fluorescence emission wavelength of a substance (fluorescent substance that emits fluorescence) used for fluorescence observation of a living tissue. As shown in FIG. 7, NADH is contained in a large amount in the colon epithelium and the like, and is excited by excitation light of about 350 nm and emits fluorescence of about 450 nm. Elastin is abundantly contained in the submucosal layer such as the skin, and is excited by excitation light of about 400 nm and 450 nm and emits fluorescence of about 500 nm. Collagen is abundantly contained in the submucosal layer such as the aortic outer skin and is excited by excitation light of about 450 nm and emits fluorescence of about 500 nm.

  FIG. 14 shows a graph showing the intensity distribution of the fluorescence wavelength of NADH. As shown in FIG. 14, NADH emits fluorescence in a wide wavelength band centered around about 450 nm. Therefore, the wavelength band cut by the excitation light cut filter 14 partially overlaps the NADH fluorescence wavelength band. Nevertheless, as shown in FIG. 15, all NADH fluorescence having a wavelength band of about 470 nm or more passes through the excitation light cut filter 14. The excitation light cut filter 14 transmits all the fluorescence of collagen (excitation light wavelength: 450 nm) and fluorescence of elastin (excitation light wavelengths: 400 nm, 450 nm).

  Therefore, when the first fluorescence observation mode is selected when observing the body cavity of the subject, a moving image of the normal image (WC region), a moving image of the NADH fluorescence image by 350 nm excitation light (FL_A region), and 400 nm excitation light A moving image of a fluorescent image of elastin (FL_B region) and a moving image of a fluorescent image of collagen and elastin (FL_C region) by 450 nm excitation light can be observed simultaneously.

  In this case, when performing an examination of a site that contains a large amount of NADH (for example, in the colon, etc.), the surgeon looks at the fluorescence image displayed in the FL_A region of the monitor 60 and compares it with the surroundings. Thus, it can be diagnosed that a lesion has occurred in a darkened place. Also, when examining a site that contains a large amount of elastin (for example, the aortic rind), the fluorescence image displayed in the FL_B region of the monitor 60 becomes darker than the surroundings in the fluorescence image. It can be diagnosed that a lesion is occurring at a certain location. Further, when examining a part (for example, skin) that contains a large amount of collagen, the fluorescence image displayed in the FL_C region of the monitor 60 is darker than the surroundings in the fluorescence image. It can be diagnosed that a lesion has occurred at a location.

  Thus, according to the first fluorescence observation mode of the present embodiment, a moving image of the fluorescence image based on the wavelength of each excitation light by one examination (operation for inserting the endoscope insertion unit 10 into the body cavity of the subject). Are displayed on the monitor 60 at the same time, so that it is possible to prevent oversight of the lesioned part of the living tissue.

  Next, the observation of living tissue in the second fluorescence observation mode according to the present embodiment will be described. Note that the second fluorescence observation mode in the present embodiment is selected when performing a photodynamic diagnosis (hereinafter referred to as “PDD”) described below.

  PDD is a diagnostic method for observing a fluorescent image by irradiating a living tissue of a subject with excitation light having a wavelength capable of exciting the drug after administering a drug containing a tumor affinity substance to the subject (for example, intravenous injection). It is.

  First, the tumor affinity substance, which is a drug used for PDD, will be described. Examples of the tumor affinity substance include porphyrin and the like (talaporfin sodium, porfimer sodium and the like). In addition, the tumor affinity substance has a property that it tends to stay at a site where a tumor (lesion) is generated in a living tissue such as cancer. Therefore, after a while after administration of the tumor affinity substance to the subject, the tumor affinity substance accumulates at the location where the tumor is present when the living tissue has a tumor.

  Moreover, the graph which shows the absorption spectrum of talaporfin sodium which is a tumor affinity substance is shown by FIG. As shown in FIG. 11, talaporfin sodium has a peak of absorption wavelength (excitation wavelength) at about 400 nm. Talaporfin sodium emits fluorescence of approximately 630 nm when excited.

  Therefore, after administering talaporfin sodium to a subject and irradiating the subject's living tissue with excitation light of 400 nm, a portion having a lesion in the living tissue emits fluorescence more strongly than the surroundings (FIG. 12 ( A)). Based on such a principle, a general PDD examination is performed.

  Hereinafter, diagnosis by PDD using the second fluorescence observation mode in the present embodiment will be described.

  First, the surgeon administers talaporfin sodium to the subject. Then, the surgeon inserts the endoscope insertion portion 10a into the body cavity of the subject, and starts observation in the second fluorescence observation mode.

  In this case, as described above, the excitation light of 400 nm and the excitation light of 450 nm are alternately irradiated on the living tissue, and a fluorescence image when each excitation light is irradiated is captured by the image sensor 13. In addition, when 400 nm excitation light is irradiated to a biological tissue, fluorescence of talaporfin sodium in a lesioned part of the biological tissue is strongly emitted. Further, when 450 nm excitation light is irradiated onto the living tissue, the fluorescence of collagen and elastin in the lesioned part of the living tissue becomes weaker than the surroundings (see FIG. 12B).

  In the second fluorescence observation mode, the fluorescence image by 400 nm excitation light (fluorescence image of talaporfin sodium) is displayed brighter than the surroundings, and the fluorescence image by 450 nm excitation light (by collagen and elastin). In the fluorescent image, a portion that is darker than the surroundings is extracted, and the extracted portion is displayed on the monitor 60 in a state of being converted into a specific color (see FIG. 12C).

  As described above, when a PDD examination using the second fluorescence observation mode is performed, only a portion that is determined to be a lesion portion in two fluorescence images obtained based on two different substances is monitored with a specific color. 60 is displayed. For this reason, when performing a diagnosis by PDD using the second fluorescence observation mode using the fluorescence observation endoscope apparatus of the present embodiment, the operator sees a portion displayed in a specific color on the monitor 60, so that the operator The part can be easily specified. In this case, since the lesioned part is displayed on the monitor 60 in a specific color, the surgeon can easily diagnose the boundary between the site where the lesion is occurring in the living tissue and the normal site. Can do.

  In the second embodiment, as compared with the first embodiment, the semiconductor laser 50 included in the laser unit 40 includes only two types of semiconductor laser 50-1 (350 nm) and semiconductor laser 50-2 (400 nm). And the point that the characteristic of the transmission wavelength band of the excitation light cut filter 14 ′ cuts only light having a wavelength of about 400 nm or less. Further, in this embodiment, in the second fluorescence observation mode, 350 nm excitation light is irradiated at the timing when 450 nm excitation light is irradiated in the first embodiment.

  FIG. 16 is an explanatory diagram showing the relationship between the excitation light emitted from the laser unit 40 and the transmission wavelength band of the excitation light cut filter 14 ′ in the second embodiment. As shown in FIGS. 16A and 16B, in the second embodiment, the laser unit 40 emits excitation light of 350 nm or excitation light of 400 nm. Further, as shown in FIG. 16C, both of these excitation lights are blocked by the excitation light cut filter 14 '. Further, as shown in FIG. 7, NADH and elastin are excited by 350 nm and 400 nm excitation light to emit fluorescence.

  Therefore, in the first fluorescence observation mode by the fluorescence observation endoscope apparatus in the present embodiment, a fluorescence image based on the fluorescence of NADH and elastin can be observed. In addition, since the fluorescence intensity due to NADH is weakened at a site where there is a lesion in the living tissue, this example has the same effect as the first example in the second fluorescence observation mode.

  In the third embodiment, as compared to the first embodiment, the semiconductor laser 50 included in the laser unit 40 includes only two types of semiconductor laser 50-2 (400 nm) and semiconductor laser 50-3 (450 nm). Is different.

  FIG. 17 is an explanatory diagram showing the relationship between the excitation light emitted from the laser unit 40 and the transmission wavelength band of the excitation light cut filter 14 in the third embodiment. As shown in FIGS. 17A and 17B, in the third embodiment, 400 nm excitation light or 450 nm excitation light is emitted from the laser unit 40. In addition, as shown in FIG. 17C, both of these excitation lights can be blocked by the excitation light cut filter 14. Moreover, as shown in FIG. 7, elastin and collagen are excited by 400 nm and 450 nm excitation light to emit fluorescence.

  Therefore, in the first fluorescence observation mode of the fluorescence observation endoscope apparatus in the present embodiment, a fluorescence image based on the fluorescence of elastin and collagen can be observed. Other effects are the same as those of the first embodiment.

  As described above, in any of the embodiments, it is possible to display on the monitor 60 simultaneously fluorescent images of excitation light having a plurality of wavelengths by simply inserting the body cavity insertion portion 10a once into the body cavity of the subject.

  In any of the embodiments, if the PDD observation is performed in the second fluorescence observation mode, the operator can easily diagnose the boundary between the lesioned part and the normal part of the living tissue.

1 is an external view showing the external appearance of the fluorescence observation endoscope apparatus according to the first embodiment. Schematic showing the internal configuration of the fluorescence observation endoscope apparatus External view showing the external appearance of the fluorescence observation endoscope Detailed view showing the structure of the laser unit The graph which shows the transmission wavelength band of the excitation light cut filter 14 in 1st Example The graph which shows the wavelength spectrum of each semiconductor laser 50 in 1st Example, and the transmission wavelength band of the excitation light cut filter 14 Table showing the excitation and emission wavelengths of substances used for fluorescence observation of biological tissues The figure which shows the example of a display of the monitor in 1st fluorescence observation mode The figure which shows the wavelength spectrum of each semiconductor laser 50-1, 50-2, 50-3. Timing chart in the first fluorescence observation mode Explanatory drawing showing the absorption wavelength spectrum of talaporfin sodium The figure which shows the example of a display of the monitor in 2nd fluorescence observation mode Timing chart in second fluorescence observation mode Graph showing the fluorescence wavelength spectrum of NADH Explanatory drawing which shows the fluorescence wavelength spectrum of NADH, and the transmission wavelength band by the excitation light cut filter 14 Explanatory drawing which shows the wavelength spectrum of each semiconductor laser 50 in the 2nd Example, and the transmission wavelength band of the excitation light cut filter 14 Explanatory drawing which shows the wavelength spectrum of each semiconductor laser 50 in the 3rd Example, and the transmission wavelength band of the excitation light cut filter 14

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fluorescence observation endoscope 12 Objective optical system 13 Image pick-up element 14 Excitation light cut filter 16 Light guide fiber bundle 16a Rod lens 20 Light source processor apparatus 28 Condensing lens 29 Beam splitter 32 Rotary shutter 33 Lamp 40 Laser unit 42 System control circuit 43 Video signal processing circuit 50 Semiconductor laser 60 Monitor

Claims (3)

A fluorescence observation endoscope apparatus that irradiates a living tissue of a test part in a body cavity with excitation light and captures an image of fluorescence emitted from the living tissue excited by the excitation light,
An endoscope with an objective optical system at its tip;
An imaging device that captures an image of the test portion formed by the objective optical system and outputs a video signal;
An excitation light source device that emits excitation light of a plurality of wavelengths;
Illumination means for irradiating the test portion with excitation light emitted from the excitation light source device;
A filter unit disposed between the objective optical system and the imaging device and blocking excitation light of each wavelength emitted from the excitation light source device;
A display means for acquiring a video signal output from the imaging device while excitation light is emitted from the excitation light source device, and performing display based on the acquired video signal. Endoscopic device. The excitation light source device includes at least a first light emitting element that emits excitation light having a first wavelength that excites a tumor affinity substance and excitation light having a second wavelength that excites a fluorescent substance that is originally included in a living tissue. A second light emitting element that selectively emits,
The display means extracts a portion displayed brighter than the surroundings from a video signal acquired during a period in which the excitation light having the first wavelength is emitted from the first light emitting element, and further, the second light emitting element. A portion that is displayed darker than the surroundings is extracted from the video signal acquired during the period in which the excitation light having the second wavelength is emitted from the light emitting element, and the portion where the two extracted portions coincide with each other is displayed in a specific color. The fluorescence observation endoscope apparatus according to claim 1. Each excitation light emitted from the excitation light source device has a wavelength of 450 nm or less,
2. The fluorescence observation endoscope apparatus according to claim 1, wherein the filter means blocks light having a wavelength of 450 nm or less.