JP2009022652A - Endoscope light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endoscope light source device that enables PDT (photodynamic therapy) while effectively putting a conventional endoscope light source device to practical use. <P>SOLUTION: The endoscope light source device 1 is equipped with: an imaging optical system 10 for photographing the image of the object, which is formed by the objective lens 11 arranged in the leading end of an endoscope insertion part, by an imaging element 12, an observation light irradiation optical system 20 which guides the illumination light emitted from a white light source 21 or the exciting light emitted from an exciting light source 22 to the leading end of the endoscope insertion part through a light guide 23 to irradiate the tissue in the body cavity through a light distribution lens 24; and a treatment light irradiation optical system 30 which guides the luminous flux from the outside PDT light source 32 connected through a connector 31 to the leading end of the endoscope insertion part through the treatment probe 33 drawn through the forceps formed to the endoscope insertion part to irradiate the tissue in the body cavity though an emission lens 34. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic endoscope system that electronically captures and displays an image of a target region such as inside a body cavity using an imaging device, and more particularly to a system capable of photodynamic therapy (hereinafter referred to as PDT).

  In an electronic endoscope system, an image of an object formed by an objective lens arranged at the tip of an endoscope insertion portion is picked up by an image pickup device, and a video signal output from the image pickup device is processed by an image processing device. Display on an external monitor screen. An operator observes an image displayed as a moving image or a still image on the monitor screen, and grasps the state of the part to be imaged.

  On the other hand, endoscopic PDT is widely used as a treatment method for early cancers such as early lung cancer, superficial esophageal cancer, and superficial early gastric cancer. This is because the photosensitivity substance photofrin is intravenously administered to the patient, and after a predetermined time, the tumor site is irradiated with a relatively high intensity laser having a long wavelength (for example, 680 nm), and the photosensitivity incorporated into the tumor. It is a technology that excites substances and necroses cancer cells.

  Conventionally, in order to perform PDT, it is necessary to prepare a light source device, an endoscope, and a laser probe dedicated to PDT separately from a normal observation electronic endoscope system. That is, since the intensity of the therapeutic laser beam is high, the image sensor becomes saturated and imaging becomes impossible if a normal observation electronic endoscope system is used in combination. In addition, when a long wavelength cut filter is provided as in a dedicated endoscope, color reproducibility during normal observation deteriorates.

  Patent Document 1 includes a white light source for color observation, a plurality of laser oscillators for photodynamic diagnosis (hereinafter referred to as PDD) and PDT, and emits them in a time-sharing manner to impair color reproducibility. There is disclosed an endoscope apparatus that can use color image capturing and PDT together without any problem.

Japanese Patent Laying-Open No. 2005-211272

  However, the endoscope apparatus disclosed in Patent Document 1 has a completely different design from the conventional electronic endoscope system for observation, and the conventional electronic endoscope system cannot be effectively used. In addition, white light and therapeutic laser light are irradiated to the tissue in the body cavity via the same optical fiber and light distribution lens, and the white light and laser light are alternatively or exclusively irradiated. The irradiation range of the therapeutic laser beam cannot be confirmed during the PDT.

  The present invention has been made in view of such problems of the prior art, and a first object is to provide a system capable of PDT while effectively utilizing a conventional electronic endoscope system ( It is a second object (problem) to provide a system capable of confirming the irradiation range of a therapeutic laser beam during PDT.

  An electronic endoscope system according to a first aspect of the present invention devised to solve the above first problem is an intracorporeal cavity formed by an objective lens disposed at the distal end of an endoscope insertion portion. An imaging optical system that captures an image of the tissue with an imaging device, an observation light source that emits a light beam for observation, and a light guide that passes the light beam emitted from the observation light source through the insertion portion of the endoscope The observation light irradiation optical system that guides the distal end of the endoscope insertion section to irradiate the tissue in the body cavity and the light beam from the external photodynamic therapy light source connected through the connector is drawn to the insertion section of the endoscope. A transmission optical system that is incident on the passed therapeutic probe, and a light quantity that is disposed in the transmission optical system and changes the intensity of the light beam incident from the light source for photodynamic therapy to change the amount of the light beam incident on the therapeutic probe. Light intensity changing means and photodynamic treatment A control means for periodically reducing the intensity of the light beam incident on the therapeutic probe by controlling the light quantity changing means, and outputting an image signal obtained from the image sensor to the display device within the reduced period; It is characterized by providing.

  The light amount changing means preferably includes a shutter that periodically blocks the light beam incident from the photodynamic therapy light source, or a light reduction filter that periodically dims the light beam incident from the photodynamic therapy light source. .

  An electronic endoscope system according to the second aspect of the present invention devised to solve the second problem is formed by an objective lens disposed at the distal end of the endoscope insertion portion. An imaging optical system that captures an image of a tissue in a body cavity with an imaging device, an observation light source that emits a light beam for observation, and a light guide that passes the light beam emitted from the observation light source through the insertion portion of the endoscope An observation light irradiation optical system that guides the distal end of the endoscope insertion portion to the tissue in the body cavity, and a treatment probe in which the light beam from the light source for photodynamic treatment is passed through the insertion portion of the endoscope A treatment light irradiating optical system that guides the distal end of the endoscope insertion portion to irradiate the tissue in the body cavity and a neutral density filter that attenuates the light beam incident from the light source for photodynamic therapy. Light intensity changing means for changing the light intensity of the irradiated light beam and photodynamic therapy The image signal obtained from the image sensor during the period when the neutral density filter is inserted into the optical path by controlling the light amount changing means and periodically inserting the neutral density filter into the optical path of the therapeutic light irradiation optical system. And a control means for outputting to the display device.

  In any of the first and second aspects, the observation light source includes at least one of an excitation light source that emits excitation light for fluorescence observation and a white light source that emits white light for color observation, Preferably both are included. Further, it is desirable that the therapeutic probe is passed through a forceps channel provided in the endoscope.

  According to the electronic endoscope system according to the first aspect of the present invention, the conventional light source device of the electronic endoscope system is provided with the connector, the transmission optical system, and the light amount changing means, and is provided in the forceps channel of the endoscope, for example. A system capable of observation and PDT can be provided by simply passing through the therapeutic probe and appropriately setting the light source control and imaging timing by the control means, and the existing system can be used effectively.

  In addition, according to the electronic endoscope system according to the second aspect of the present invention, an image is acquired by the imaging device in a state in which the light amount of the therapeutic light beam is reduced during the photodynamic treatment. The irradiation range of the therapeutic light beam can be confirmed in the image. Since red laser light is used for PDT, the irradiation range of the therapeutic light beam is displayed in red in the image both when shooting a color image and when shooting a fluorescent image by autofluorescence or PDD.

  Next, an embodiment for carrying out the present invention will be described based on the attached drawings. FIG. 1 is a block diagram illustrating a schematic configuration of the electronic endoscope system according to the embodiment. FIG. 1 shows the configuration of the distal end portion of an endoscope insertion portion that is elongated to be inserted into a body cavity, and the connection relationship of each circuit in the light source processor device connected to the insertion portion. .

  As shown in FIG. 1, the electronic endoscope system 1 is a charge storage type imaging device such as a CCD image sensor that captures an image of an object formed by an objective lens 11 disposed at the distal end of an endoscope insertion portion. The imaging optical system 10 that captures an image with the element 12 and the illumination light emitted from the white light source 21 or the excitation light emitted from the excitation light source 22 are guided to the distal end of the endoscope insertion section via the light guide 23 to distribute the light. The light beam from the observation light irradiation optical system 20 that irradiates the tissue in the body cavity via 24 and the external light source 32 for photodynamic therapy (PDT) connected via the connector 31 is formed in the endoscope insertion portion. And a therapeutic light irradiation optical system 30 that guides the distal end of the endoscope insertion portion through the treatment probe 33 passed through the forceps channel and irradiates the tissue in the body cavity through the emission lens 34.

  That is, in the electronic endoscope system 1 according to the embodiment, a PDT light source 32 is connected to a light source device of a conventional fluorescence endoscope system via a connector 31 and a therapeutic probe 33 is connected to an endoscope insertion portion. It is configured by providing a transmission optical system through which the therapeutic light beam from the PDT light source 32 is incident on the therapeutic probe 33.

  The excitation light source 22 is used as a light source that emits excitation light for generating autofluorescence of tissue in a body cavity, and performs photodynamic diagnosis (PDD) by exciting a photosensitive substance previously administered to a living body. It is also used as a light source for PDD. The excitation light source 22 is a laser light source that generates ultraviolet light having an oscillation wavelength of about 320 nm to 400 nm. On the other hand, as the PDT light source 32, for example, an excimer laser having an oscillation wavelength of 630 nm is used.

  An excitation light cut filter 13 for removing a wavelength component corresponding to the excitation light emitted from the excitation light source 22 is incorporated between the objective lens 11 and the image sensor 12. As shown in FIG. 2, the excitation light cut filter has a characteristic of blocking the excitation light and transmitting light having a wavelength longer than that of the excitation light, so that the excitation light is incident on the image sensor 12 during fluorescence imaging. Thus, only a fluorescent image can be taken.

  On the linear optical path connecting the white light source 21 and the light guide 23, a first asynchronous shutter 25, a first synchronous shutter (rotary shutter) 26, a half mirror 27, and a condenser lens 28 are sequentially arranged from the light source side. Yes. The excitation light source 22 is disposed so that light is incident on the half mirror 27 perpendicular to the optical path.

  The first asynchronous shutter 25 includes a light shielding plate of a size that covers the optical path of white light, and is driven by the first motor 41 to allow or prohibit the white light from proceeding to the light guide 23 side. The first asynchronous shutter 25 does not operate in synchronization with the switching of the frame or field of the image signal at the time of shooting, and carelessly emits white light that is always emitted while the main power is on, depending on the observation mode. It is prohibited to enter the light guide 23.

  The first rotary shutter 26 is a disc in which a fan-shaped opening 26a having a central angle of about 180 ° is formed as shown in a planar shape in FIG. 3, and is orthogonal to the optical axis of the condenser lens 28 and offset. In this state, it is fixed to the rotating shaft of the second motor 42. The size of the opening 26a in the radial direction is set to be larger than the diameter of the white light. By driving the second motor 42 and rotating the first rotary shutter 26, the frame or field of the image signal can be switched during shooting. Synchronously, white light is turned on / off. Part of the white light from the white light source 21 that has passed through the first rotary shutter 26 passes through the half mirror 27, is condensed by the condenser lens 28, and enters the light guide 23.

  The first rotary shutter 26 is attached to the slide base 29 together with the second motor 42. By driving the third motor 43, the first rotary shutter 26 is set to the set position in the optical path shown in FIG. It is possible to switch between a retreat position that is off the optical path downward.

  On the other hand, the excitation light source 22 is arranged so that the excitation light is incident on the half mirror 27 from a direction orthogonal to the optical path of white light, and a part of the excitation light emitted from the excitation light source 22 is reflected by the half mirror 27. Then, the light is condensed by the condenser lens 28 and enters the light guide 23.

  The half mirror 27 is slid by the fourth motor 44, and is switched between the intersection position of the excitation light and the white light as shown in FIG.

  The transmission optical system of the treatment light irradiating optical system 30 causes the light beam from the PDT light source 32 connected to the connector 31 via an optical fiber to enter the treatment probe 33 passed through the insertion portion of the endoscope. The second asynchronous shutter 35, the second rotary shutter 36, and the mirror 37 are provided in this order from the connector 31 side.

  The second asynchronous shutter 35 has the same configuration as the first asynchronous shutter 25 disposed in the optical path of white light, includes a light shielding plate of a size that covers the optical path of the therapeutic light beam, and is driven by the fifth motor 45. Allowing or prohibiting the therapeutic luminous flux to proceed to the therapeutic probe 33 side is permitted. The second asynchronous shutter 35 does not operate in synchronization with the switching of the frame or field of the image signal at the time of shooting, and the therapeutic light beam that is always emitted while the main power is on is not prepared depending on the observation mode. It is prohibited to enter the therapeutic probe 33.

  As shown in FIG. 4, the second rotary shutter 36 is a circle in which a fan-shaped opening 36a is formed at a central angle of about 180 ° and a fan-shaped neutral density filter 36b is formed at the remaining central angle of about 180 °. The plate is fixed to the rotation axis of the sixth motor 46 in a state orthogonal to and offset from the central axis of the therapeutic light beam. The transmittance of the neutral density filter 36b is, for example, about 1%. The sizes in the radial direction of the aperture 36a and the neutral density filter 36b are set larger than the diameter of the therapeutic light beam. By driving the sixth motor 46 and rotating the second rotary shutter 36, an image signal is obtained during imaging. The intensity of the therapeutic light is switched in synchronization with the switching of the frame and field. The intensity is 100% when the opening 36a is located in the optical path, and 1% when the neutral density filter 36b is located in the optical path. The therapeutic light beam from the PDT light source 32 that has passed through the second rotary shutter 36 is reflected by the mirror 37 and enters the therapeutic probe 33. The second rotary shutter 36 corresponds to light amount changing means for changing the light amount of the light beam incident on the therapeutic probe.

  Next, the configuration of the electrical system that processes the image signal captured by the imaging optical system 10 and controls the excitation light source 22 and the motors 41 to 46 will be described. The electric system of the electronic endoscope system 1 includes a first to sixth drivers 51 to 56 for driving first to sixth motors 41 to 46, respectively, centering on a system controller 50 that controls the whole, and image signals at the time of photographing. A timing controller 57 for outputting a synchronizing signal for switching between frames and fields, and a CCD driver 58 for outputting a driving signal for driving the image pickup device 12 in synchronization with the signal from the timing controller 57. The second and sixth drivers 52 and 56 for driving the second motor 42 and the sixth motor 43 for the rotary shutters 26 and 36 are controlled by a synchronization signal from the timing controller 57, and the drivers for the other motors are system controllers. 50.

  Further, as a processing system for image signals, a pre-stage signal processing circuit 59 for processing a video signal output from the image sensor 12 and an image processing circuit for performing arithmetic processing on the digital video signal processed and output by the pre-stage signal processing circuit 58 60, a post-stage signal processing circuit 70 for converting the video signal calculated by the image processing circuit 60 into a standardized video signal to be displayed on the monitor 71 and outputting it.

  As shown in FIG. 5, the image processing circuit 60 uses first and second image memories 61 and 62 that temporarily store the image data from the previous stage video signal processing circuit 58 for each field, and a synchronization signal from the timing controller 57. Based on this, a memory controller 63 that controls reading and writing of data to and from these image memories 61 and 62, and a scan converter 64 that forms an image to be displayed on the monitor 71 based on the data read from the image memories 61 and 62 are provided. Yes.

  Further, the operation unit connected to the endoscope insertion unit has a mode changeover switch 72 for switching the operation mode among the normal observation mode, the fluorescence observation mode, the fluorescence observation / PDT mode, and the normal observation / PDT mode. Is provided. This switch is operated by an operator (operator) during observation and treatment with an endoscope.

  During the photodynamic treatment, the system controller 50 and the image processing circuit 60 periodically reduce the intensity of the light beam incident on the therapeutic probe 33 by controlling the second rotary shutter 36, and within the reduced period. 2 has a function as a control means for outputting an image signal obtained from the image sensor 12 to the monitor 71.

  Next, the operation of the electronic endoscope system 1 configured as described above will be described. When the system is turned on, the system controller 50 is activated and the white light source 21 is turned on. The PDT light source 32 is powered on separately. Thereby, the laser beam for treatment is always incident from the light source 32 for PDT. The system controller 50 reads the setting of the mode switch 71 and controls each part in accordance with each observation mode. Hereinafter, operations will be described in the order of the normal observation mode, the fluorescence observation mode, the fluorescence observation / PDT mode, and the normal observation / PDT mode with reference to the timing chart of FIG.

  When the normal observation mode is selected, the system controller 50 controls the motor via each driver and sets each shutter and mirror to the state shown in Table 1 below.

  The excitation light source 22 remains off. Thereby, the illumination light emitted from the white light source 21 continuously reaches the endoscope distal end portion via the light guide 23 and illuminates the tissue in the body cavity via the light distribution lens 24. Reflected light from the tissue illuminated with white light is taken into the imaging optical system 10 to form a color image of the tissue. The timing of imaging by the imaging device 12 in the normal observation mode is shown in FIG. 6A, and the timing of transferring the captured signal is shown in A2. In conformity with the NTSC interlace system, images of 30 fields and 60 fields are captured per second, and data of the previous field is transferred during imaging of the next field. The image data is sequentially stored in the image memories 61 and 62 for each field, and is synthesized by the scan converter 64 when the data for one field is prepared and output as image data for one frame. As a result, in the normal imaging mode, the color image of the tissue in the body cavity is displayed on the monitor 71 as a moving image.

  When the fluorescence observation mode is selected, the system controller 50 controls the motor via each driver and sets each shutter and mirror to the state shown in Table 2 below.

  Based on the synchronization signal from the timing controller 57, the system controller 50 turns off the excitation light source 22 while white light passes through the first rotary shutter 26, and excites the light source while white light is blocked by the first rotary shutter 26. 22 is caused to emit light. Thereby, white light emitted from the white light source 21 and excitation light emitted from the excitation light source 22 are incident on the light guide 23 alternately.

  While the excitation light is irradiated, the fluorescence from the excited tissue enters the imaging optical system 10 together with the excitation light. However, since the excitation light is blocked by the excitation light cut filter 13, only the fluorescence is incident on the image sensor 12. And a fluorescent image signal is obtained. Note that the fluorescent image includes green autofluorescence due to excitation of the living tissue and red fluorescence generated from a photosensitive substance that has accumulated in the cancer cells due to PDD. When PDD is performed, a photosensitive substance (photophilin) is intravenously administered into the body before starting the test. Photophilin flows out of normal cells after a certain period of time, but stays in the tumor site. For this reason, when photophyrin is excited by irradiating short-wave excitation light, red fluorescence is generated, and the tumor part can be easily identified.

  On the other hand, the reflected light from the tissue reaches the image sensor 12 during the period when white light is irradiated. The imaging device 12 repeats the normal image (color image) imaging, the fluorescence image imaging, and the PDD for each field at the timing shown in FIG. 6B for each field. As a result, the normal image data and the fluorescence image data are stored in the image memories 61 and 62 for each field, but they are not subjected to interlacing processing unlike the normal image data, and display independent screens. As described above, a known interpolation process is performed on the image data for one field to generate one frame of screen data.

  As shown in FIG. 7, the monitor 71 displays a normal image (color image) and a fluorescent image side by side. In the fluorescence image of FIG. 7, the dark portion at the center shows red fluorescence due to photophilin, and the surroundings show green autofluorescence.

  When the fluorescence observation / PDT mode is selected, the system controller 50 controls the motor via each driver and sets each shutter and mirror to the state shown in Table 3 below.

  In response to the synchronization signal from the timing controller 57, the system controller 50 turns off the excitation light source 22 while the therapeutic light beam passes through the opening 36a of the second rotary shutter 36, and reduces the therapeutic light beam to the second rotary shutter 36. While the light is reduced by the optical filter 36b, the excitation light source 22 is caused to emit light. As a result, the therapeutic light beam emitted from the PDT light source 32 repeats the intensity for each field and enters the therapeutic probe 33, and the excitation light emitted from the excitation light source 22 is light during the period when the intensity of the therapeutic light beam is weak. Incident on the guide 23.

  The irradiation timing of each light beam and the imaging timing by the image sensor are as shown in FIG. 6C. The intensity of the therapeutic light beam is switched for each field, and imaging is performed during a period when the intensity is low. While the PDT treatment light beam is irradiated at a high output, the amount of reflected light incident on the imaging optical system 10 is extremely large and the output of the imaging element 12 is saturated. Therefore, during this period, the charge of the imaging element 12 is not accumulated. Throw it away. During this time, the light energy of the therapeutic light beam irradiated with the photophilin staying in the cancer cells of the living tissue is absorbed, and the cancer cells are necrotized.

  During the period in which the therapeutic light beam is irradiated at a low output and the excitation light is irradiated, the reflected light of the therapeutic light beam, the fluorescence from the excited tissue, and the excitation light are incident on the imaging optical system 10. However, since the excitation light is blocked by the excitation light cut filter 13, the therapeutic light beam and the fluorescence reach the image sensor 12, and a signal of the fluorescence image is obtained. Thereby, the fluorescence image data is stored in the image memory 61 every other field. Then, a known interpolation process is performed on the image data for one field to generate one frame of screen data.

  An image as shown in FIG. 8 is displayed on the monitor 71 at the start of PDT. The center is displayed with red fluorescence due to photophilin, the surrounding area is displayed in light red with a low-power therapeutic light beam, and a green fluorescence image due to autofluorescence is displayed around it. . As the treatment progresses and the cancer cells become necrotic, as shown in FIG. 9, the fluorescence of that portion becomes weaker and displayed in black.

  When the normal observation / PDT mode is selected, the system controller 50 controls the motor via each driver and sets each shutter and mirror to the state shown in Table 4 below.

  The system controller 50 rotates the first and second rotary shutters 26 and 36 in synchronization with the synchronization signal from the timing controller 57. As a result, while the therapeutic light beam passes through the opening 36 a of the second rotary shutter 36, the white light is blocked by the first rotary shutter 26, and the therapeutic light beam is attenuated by the neutral density filter 36 b of the second rotary shutter 36. During this time, the white light passes through the opening 26a of the first rotary shutter 26. As a result, the therapeutic light beam emitted from the PDT light source 32 repeats the intensity for each field and enters the therapeutic probe 33, and the white light emitted from the white light source 21 is light during the period when the intensity of the therapeutic light beam is weak. Incident on the guide 23.

  The irradiation timing of each luminous flux and the imaging timing by the imaging device are as shown in FIG. 6D. The intensity of the therapeutic luminous flux is switched for each field, and imaging is performed during a period when the intensity is weak. While the PDT treatment light beam is irradiated at a high output, the amount of reflected light incident on the imaging optical system 10 is extremely large and the output of the imaging element 12 is saturated. Therefore, during this period, the charge of the imaging element 12 is not accumulated. Throw it away. During this time, the light energy of the therapeutic light beam irradiated with the photophilin staying in the cancer cells of the living tissue is absorbed, and the cancer cells are necrotized.

  During the period when the therapeutic light beam is irradiated with low power and white light is irradiated, the reflected light of the therapeutic light beam and the white light reflected from the tissue are incident on the imaging optical system 10 and reach the image sensor 12. A normal image (color image) signal is obtained. As a result, normal image data is stored in the image memory 61 every other field. Then, a known interpolation process is performed on the image data for one field to generate one frame of screen data.

  An image as shown in FIG. 10 is displayed on the monitor 71. The circular irradiation range is displayed in light red at the center of the normal image of the tissue by the low-power therapeutic light beam.

  As described above, according to the above-described embodiment, the irradiation range of the PDT treatment light beam can be confirmed on the monitor during the PDT treatment. In addition, since the illumination and excitation light fluxes and the PDT light flux are transmitted through different paths, the illumination light and the excitation light can irradiate a wide range, and the treatment light flux can be concentrated in a narrow range. Only a diseased tissue can be treated without imposing a burden on the surrounding tissue while ensuring a wide visual field.

  Next, two examples of modification of the above embodiment will be described. In the first modification, the second rotary shutter 36 of the above-described embodiment has the same configuration as that of the first rotary shutter 26 shown in FIG. 3, that is, the part of the neutral density filter is made opaque. In the following description, the second rotary shutter of the first modification is denoted by reference numeral 36A.

  Operations in the fluorescence observation / PDT mode and the normal observation / PDT mode in the first modification will be described. Note that the settings of the shutter, filter, and the like in each mode are the same as the settings in the corresponding mode in the above-described embodiment, and thus description thereof is omitted.

  When the fluorescence observation / PDT mode is selected in the first modification, the system controller 50 uses the synchronization signal from the timing controller 57 while the therapeutic light beam passes through the opening of the second rotary shutter 36A. Turns off the excitation light source 22 and causes the excitation light source 22 to emit light while the therapeutic light beam is blocked by the second rotary shutter 36A. Thereby, the therapeutic light beam emitted from the PDT light source 32 is intermittently incident on the therapeutic probe 33 for each field, and the excitation light emitted from the excitation light source 22 is light during the period when the therapeutic light beam is blocked. Incident on the guide 23.

  The irradiation timing of each light beam and the imaging timing by the image sensor are as shown in FIG. 11E. The irradiation / stop of the therapeutic light beam is switched for each field, and imaging is performed during the stop period. While the PDT treatment light beam is irradiated at a high output, the charge of the image sensor 12 is discarded without being accumulated. During this time, the light energy of the therapeutic light beam irradiated with the photophilin staying in the cancer cells of the living tissue is absorbed, and the cancer cells are necrotized.

  During the period when the therapeutic light beam is stopped and the excitation light is irradiated, the fluorescence from the excited tissue and the excitation light are incident on the imaging optical system 10. However, since the excitation light is blocked by the excitation light cut filter 13, only the fluorescence reaches the image sensor 12, and a signal of the fluorescence image is obtained. Thereby, the fluorescence image data is stored in the image memory 61 every other field. Then, a known interpolation process is performed on the image data for one field to generate one frame of screen data.

  An image as shown in FIG. 12 is displayed on the monitor 71 at the start of PDT. In the center, red fluorescence due to photophilin is displayed, and in the surrounding area, a green fluorescence image due to autofluorescence is displayed. As the treatment progresses and the cancer cells become necrotic, the fluorescence of that portion becomes weaker and displayed in black.

  When the normal observation / PDT mode is selected in the first modification, the system controller 50 rotates the first and second rotary shutters 26 and 36 </ b> A in synchronization with the synchronization signal from the timing controller 57. . As a result, white light is blocked by the first rotary shutter 26 while the therapeutic light beam is transmitted through the opening of the second rotary shutter 36A, and white light is blocked while the therapeutic light beam is blocked by the second rotary shutter 36A. The light passes through the opening 26 a of the first rotary shutter 26. Thus, the therapeutic light beam emitted from the PDT light source 32 is intermittently incident on the therapeutic probe 33 for each field, and the white light emitted from the white light source 21 is light during the period when the therapeutic light beam is blocked. Incident on the guide 23.

  The irradiation timing of each light beam and the imaging timing by the image sensor are as shown in FIG. 11F. The irradiation / stop of the therapeutic light beam is switched for each field, and imaging is performed during the stop period. While the PDT treatment light beam is irradiated at a high output, the charge of the image sensor 12 is discarded without being accumulated. During this time, the light energy of the therapeutic light beam irradiated with the photophilin staying in the cancer cells of the living tissue is absorbed, and the cancer cells are necrotized.

  During the period when the therapeutic light beam is stopped and the white light is irradiated, the white light reflected from the tissue enters the imaging optical system 10 and reaches the imaging element 12, and a signal of a normal image (color image) is obtained. . As a result, normal image data is stored in the image memory 61 every other field. Then, a known interpolation process is performed on the image data for one field to generate one frame of screen data. A normal image as shown on the left side of FIG.

  In the second modified example, the first and second rotary shutters of the above-described embodiment are changed to the configuration shown in FIGS. Other configurations are the same. In the second modification, the reference numeral of the first rotary shutter is 26B, and the reference numeral of the second rotary shutter is 36B. The first rotary shutter 26B is formed with a fan-shaped opening 26Ba having a central angle of about 90 °, and the second rotary shutter 36B is formed with a fan-shaped opening 36Ba having a central angle of about 270 °.

  The second modification is characterized in that when performing PDT, the irradiation time of the therapeutic light beam is lengthened and the imaging time is shortened. The operation in the fluorescence observation / PDT mode and the normal observation / PDT mode in the second modification will be described. Note that the settings of the shutter, filter, and the like in each mode are the same as the settings in the corresponding mode in the above-described embodiment, and thus description thereof is omitted.

  When the fluorescence observation / PDT mode is selected in the second modification, the system controller 50 transmits the therapeutic light beam through the opening 36Ba of the second rotary shutter 36B by the synchronization signal from the timing controller 57. The excitation light source 22 is turned off during the interval, and the excitation light source 22 is caused to emit light while the therapeutic light beam is blocked by the second rotary shutter 36B. Thereby, the therapeutic light beam emitted from the PDT light source 32 is intermittently incident on the therapeutic probe 33 for each field, and the excitation light emitted from the excitation light source 22 is light during the period when the therapeutic light beam is blocked. Incident on the guide 23.

  The irradiation timing of each light beam and the imaging timing by the image sensor are as shown in FIG. 14G, and the irradiation / stop of the therapeutic light beam is switched, and imaging is performed during the stop period. When the therapeutic light beam is stopped, the charges accumulated in the image sensor 12 are discharged at the timing shown in FIG. 14G2. During this time, the light energy of the therapeutic light beam irradiated with the photophilin staying in the cancer cells of the living tissue is absorbed, and the cancer cells are necrotized.

  During the period when the therapeutic light beam is stopped and the excitation light is irradiated, the fluorescence from the excited tissue and the excitation light are incident on the imaging optical system 10. However, since the excitation light is blocked by the excitation light cut filter 13, only the fluorescence reaches the image sensor 12, and a signal of the fluorescence image is obtained. Thereby, the fluorescence image data is stored in the image memory 61 every other field. Then, one frame of screen data is generated from the captured image data. The monitor 71 displays an image equivalent to that in FIG. 12 at the start of PDT.

  When the normal observation / PDT mode is selected in the second modification, the system controller 50 rotates the first and second rotary shutters 26B and 36B in synchronization with the synchronization signal from the timing controller 57. . As a result, white light is blocked by the first rotary shutter 26B while the therapeutic light beam is transmitted through the opening 36Ba of the second rotary shutter 36B, and white light is blocked while the therapeutic light beam is blocked by the second rotary shutter 36Ba. Is transmitted through the opening 26Ba of the first rotary shutter 26B. As a result, the therapeutic light beam emitted from the PDT light source 32 is intermittently incident on the therapeutic probe 33, and the white light emitted from the white light source 21 enters the light guide 23 during the period when the therapeutic light beam is blocked. Incident.

  The irradiation timing of each light beam and the imaging timing by the image sensor are as shown in FIG. 14H, and the irradiation / stop of the therapeutic light beam is switched, and imaging is performed during the stop period. While the PDT treatment light beam is irradiated at a high output, the charge of the image sensor 12 is discarded without being accumulated. During this time, the light energy of the therapeutic light beam irradiated with the photophilin staying in the cancer cells of the living tissue is absorbed, and the cancer cells are necrotized.

  During the period when the therapeutic light beam is stopped and the white light is irradiated, the white light reflected from the tissue enters the imaging optical system 10 and reaches the imaging element 12, and a signal of a normal image (color image) is obtained. . As a result, normal image data is stored in the image memory 61. Then, one frame of screen data is generated from the captured image data. A normal image as shown on the left side of FIG.

  According to the second modification, since the irradiation time of the therapeutic light beam per unit time becomes long, the time required for the treatment can be shortened, and the burden on the patient can be reduced.

It is a block diagram which shows the internal structure of the electronic endoscope system by one Embodiment of this invention. It is a graph which shows the characteristic of the excitation light cut filter contained in the electronic endoscope system of FIG. It is a top view of the 1st rotary shutter contained in the electronic endoscope system of FIG. It is a top view of the 2nd rotary shutter contained in the electronic endoscope system of FIG. It is a block diagram which shows the detail of the image processing circuit of the electronic endoscope system of FIG. It is a chart which shows the timing of the imaging and irradiation in each mode of the electronic endoscope system of FIG. It is explanatory drawing which shows the example of a screen displayed on a monitor in the fluorescence observation mode of the electronic endoscope system of FIG. It is explanatory drawing which shows the example of a screen displayed on a monitor at the time of a treatment start in the fluorescence observation / PDT mode of the electronic endoscope system of FIG. It is explanatory drawing which shows the example of a screen displayed on a monitor at the time of the completion | finish of a treatment in the fluorescence observation / PDT mode of the electronic endoscope system of FIG. It is explanatory drawing which shows the example of a screen displayed on a monitor in the normal observation / PDT mode of the electronic endoscope system of FIG. It is a chart which shows the timing of the imaging and irradiation in each mode of the electronic endoscope system concerning the 1st modification of the present invention. It is explanatory drawing which shows the example of a screen displayed on a monitor at the time of a treatment start in the fluorescence observation / PDT mode of the electronic endoscope system concerning the 1st modification of this invention. It is a top view of the 1st and 2nd rotary shutter contained in the electronic endoscope system concerning the 2nd modification of the present invention. It is a chart which shows the timing of the imaging and irradiation in each mode of the electronic endoscope system concerning the 2nd modification of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic endoscope system 10 Imaging optical system 11 Objective lens 12 Imaging element 13 Excitation light cut filter 20 Observation light irradiation optical system 21 White light source 22 Excitation light source 23 Light guide 24 Light distribution lens 26 First rotary shutter 27 Half mirror 28 Focusing Lens 30 Therapeutic light irradiation optical system 31 Connector 32 PDT light source 33 Therapeutic probe 36 Second rotary shutter 50 System controller 57 Timing controller 59 Pre-stage video signal processing circuit 60 Image processing circuit 70 Post-stage video signal processing circuit 71 Monitor 72 Mode change switch

Claims (6)

An imaging optical system that captures an image of a tissue in a body cavity formed by an objective lens disposed at a distal end of an endoscope insertion portion with an imaging element;
An observation light source that emits a light beam for observation;
An observation light irradiation optical system for irradiating a tissue in a body cavity with a light beam emitted from the observation light source through a light guide led to the insertion portion of the endoscope and leading to a tip of the endoscope insertion portion;
A transmission optical system that causes a light beam from an external photodynamic therapeutic light source connected via a connector to be incident on a therapeutic probe passed through the insertion portion of the endoscope; and
A light amount changing means that is arranged in the transmission optical system and changes the light amount of the light beam incident on the therapeutic probe by changing the intensity of the light beam incident from the photodynamic therapy light source;
By controlling the light amount changing means during photodynamic treatment, the intensity of the light beam incident on the therapeutic optical fiber is periodically reduced, and an image signal obtained from the imaging element within the reduced period is displayed. An electronic endoscope system comprising: control means for outputting to the electronic endoscope.   The electronic endoscope system according to claim 1, wherein the light quantity changing unit includes a shutter that periodically blocks a light beam incident from the light source for photodynamic therapy.   The electronic endoscope system according to claim 1, wherein the light amount changing unit includes a neutral density filter that periodically attenuates a light beam incident from the light source for photodynamic therapy. An imaging optical system that captures an image of a tissue in a body cavity formed by an objective lens disposed at a distal end of an endoscope insertion portion with an imaging element;
An observation light source that emits a light beam for observation;
An observation light irradiation optical system for irradiating a tissue in a body cavity with a light beam emitted from the observation light source through a light guide led to the insertion portion of the endoscope and leading to a tip of the endoscope insertion portion;
A therapeutic light irradiating optical system for guiding a light beam from a light source for photodynamic therapy to a distal end of the endoscope insertion portion through a treatment probe drawn through the insertion portion of the endoscope and irradiating the tissue in the body cavity; ,
A light amount changing means for changing the light amount of the light beam applied to the tissue in the body cavity, comprising a neutral density filter for dimming the light beam incident from the light source for photodynamic therapy;
During photodynamic therapy, by controlling the light amount changing means, the neutral density filter is periodically taken in and out of the optical path of the therapeutic light irradiation optical system, and within the period when the neutral density filter is inserted in the optical path. An electronic endoscope system comprising: control means for outputting an image signal obtained from the image sensor to a display device.   5. The observation light source includes at least one of an excitation light source that emits excitation light for fluorescence observation and a white light source that emits white light for color observation. The electronic endoscope system described.   The electronic endoscope system according to claim 1, wherein the therapeutic probe is pulled through a forceps channel provided in the endoscope.