JP2006094907A - Electronic endoscope system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve color reproducibility of a photographed image in an electronic endoscope system enabling PDT (Photodynamic Therapy). <P>SOLUTION: Laser beams for PDT emitted from a PDT device 60 are guided to the distal end 10A of an insertion portion of an electronic scope 10 by fiber optics 61. Leakage light from the fiber optics 61 is detected by a photodiode 62. Detecting signals outputted by the photodiode 62 responding to the detection of the leakage light are inputted in a timing controller 32. The timing controller 32 controls the rotations of a rotary plate 38 and emission of excitation light from an excitation light source 43 based on the input of the detecting signals to implement the irradiation of a living body with white light from a lamp 33, the irradiation of the living body with the excitation light from the excitation light source 43, and the irradiation with the laser beams for PDT alternately. The timing controller 32 drives an electronic shutter of a CCD (charge coupled device) 15 for cutting saturated electric charges during the irradiation with the laser beams for PDT. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic endoscope system that detects and treats a lesion site by irradiating a living body to which a tumor-affinity fluorescent substance is administered with a laser beam.

  Conventionally, photodynamic diagnosis (hereinafter referred to as PDD (Photodynamic Diagnosis)) in which a tumor-affinity fluorescent substance is administered to a living body to detect a tumor such as cancer, or photodynamic therapy (hereinafter referred to as PDT (Photodynamic) for treating a tumor). Therapy)). When a tumor-affinity fluorescent substance is administered to a living body and a predetermined time elapses, the fluorescent substance remains in the lesion site. PDD is a diagnostic method that uses this property to detect a lesion site by irradiating a living body that has passed a predetermined time after administration of a tumor affinity fluorescent substance with laser light and measuring the fluorescence emitted from the fluorescent substance. . PDT is a treatment method that utilizes the property that singlet oxygen generated when the above-described fluorescent substance absorbs light energy destroys a diseased tissue by its oxidizing action.

In recent years, PDD and PDT have been applied to endoscopes and applied to early detection and treatment of lesion sites. The laser light for PDT is extremely powerful. Therefore, in an electronic endoscope system having a PDT function, a cut filter that cuts the wavelength of the laser light for PDT in the reflected light from the living body is an objective so that the charge is not saturated in the photoelectric conversion of the solid-state imaging device. Arranged in the optical system.
Japanese Utility Model Publication No. 6-63009

  However, such a cut filter cuts not only the wavelength of the laser light for PDT but also the wavelength of the nearby band. As a result, there is a problem that the color reproducibility when displaying the image information acquired by the solid-state imaging device on the TV monitor is deteriorated.

  An object of the present invention is to solve the above problems and to improve color reproducibility when reproducing an image of a living body in an electronic endoscope system capable of performing PDD and PDT.

  An electronic endoscope system according to the present invention includes a normal light source that emits normal light in the visible band, a first oscillation unit that outputs diagnostic laser light for photodynamic diagnosis, and photodynamic therapy. A second oscillating means for outputting therapeutic laser light for irradiation, an irradiation light control means for controlling the irradiation timing of the normal light, the diagnostic laser light, and the therapeutic laser light to the living body, and at the time of normal light irradiation, Display control means for displaying on a monitor a normal light image of a living body acquired by a solid-state image sensor and a fluorescent image of a living body acquired by a solid-state image sensor when irradiated with a diagnostic laser beam, and irradiation with a therapeutic laser beam And a solid-state image sensor control means for cutting a saturation charge of the solid-state image sensor.

  The irradiation light control means controls the irradiation timing by controlling the relative relationship between the normal light irradiation period, the output period of the first oscillation means, and the output period of the second oscillation means. May be.

  For example, the irradiation light control means may control the timing of the irradiation of the normal light and the irradiation of the diagnostic laser light based on the cycle of the output of the therapeutic laser light unique to the second oscillation means. In that case, preferably, an optical fiber for transmitting the therapeutic laser beam output from the second oscillating means to the distal end of the insertion portion of the electronic scope and a therapeutic laser beam leaking from the optical fiber during the transmission of the therapeutic laser beam are provided. Leakage light detection means for detecting leakage light from the optical fiber to be detected, and the irradiation light control means controls the timing based on the detection result of the leakage light detection means.

  Preferably, the rotating plate is disposed so as to be interposed in the optical path of the normal light emitted from the normal light source and formed with an opening, and the irradiation light control means controls the rotation of the rotating plate, Control the timing of normal light irradiation and diagnostic laser light irradiation.

  Preferably, the display control unit includes a first storage unit that stores image information of the normal light image and a second storage unit that stores image information of the fluorescent image, and the processing specification of the video signal in the monitor The image information of the normal light image and the image information of the fluorescent image are read out from the first and second storage means at the compliant timing and output to the monitor.

  In addition, the electronic endoscope system according to the present invention includes irradiation of normal light in the visible band, irradiation of diagnostic laser light for photodynamic diagnosis, and irradiation of therapeutic laser light for photodynamic therapy. Are alternately executed at a predetermined cycle, the saturation charge of the solid-state image sensor due to the irradiation of the therapeutic laser light is cut, and the normal light image acquired by the solid-state image sensor and the diagnostic laser light when the normal light is irradiated When irradiating, a fluorescent image acquired by a solid-state imaging device is displayed in parallel on a monitor.

  As described above, according to the present invention, the solid-state image sensor control means cuts the saturation charge of the solid-state image sensor at the time of irradiation with the therapeutic laser beam, so there is no need to use a conventional cut filter. Therefore, the wavelength in the vicinity of the laser light wavelength that has been cut by the conventional cut filter is not cut, and the reflected light and autofluorescence of the living body are guided to the solid-state imaging device, and image processing is performed. As a result, the color reproducibility of the normal light image and the fluorescent image displayed on the monitor is improved.

  In addition, by cutting the saturation charge of the solid-state imaging device at the time of treatment laser light irradiation, autofluorescence images are acquired following treatment laser light irradiation and reproduced on a monitor. Does not cause halation. Therefore, the progress of treatment can be grasped sequentially, and the removal of the diseased tissue without excess or deficiency can be performed more efficiently.

  FIG. 1 is a block diagram of an electronic endoscope system to which an embodiment according to the present invention is applied. A light guide 11 made of a large number of optical fibers is inserted through the electronic scope 10. The light guide 11 extends to the insertion portion distal end 10 </ b> A of the electronic scope 10. A light distribution lens 12 is disposed in front of the emission end 11A of the light guide 11 at the insertion portion distal end 10A.

  The system controller 31 of the image processor 30 is, for example, a microprocessor that controls the entire electronic endoscope system. The timing controller 32 outputs a control signal for synchronizing driving to each driver described later.

  A lamp 33 that emits white light is provided in the image processor 30. For example, a xenon lamp or the like is used as the lamp 33. When the scope button 20 provided in the operation unit (not shown) of the electronic scope 10 is operated, a control signal is output from the system controller 31 to the lamp power supply 34, and the power from the lamp power supply 34 to the lamp 33 is output. Supply is started and the lamp 33 is driven to light. White light emitted from the lamp 33 is guided to the dichroic mirror 41 through the diaphragm 35 and the rotating plate 38. The white light passes through the dichroic mirror 41 and is condensed by the condenser lens 42 onto the incident end 11B of the light guide 11.

  In addition to the lamp 33, an excitation light source 43 is provided in the image processor 30. For example, a semiconductor laser that emits PDD excitation light having a wavelength of 408 nm (nanometer) is used as the excitation light source 43. When the scope button 20 is operated, a control signal for instructing the start of the rise of the excitation light source 43 is output from the system controller 31 to the excitation light source driver 45, and the excitation light source 43 is started up. The excitation light source 43 starts and stops emitting the PDD excitation light by the excitation light source driver 45 based on the control signal output from the timing controller 32. That is, the timing controller 32 controls the timing of emission of the PDD excitation light. The PDD excitation light emitted from the excitation light source 43 is guided to the dichroic mirror 41 through the lens 44. The PDD excitation light is reflected by the dichroic mirror 41 and condensed by the condenser lens 42 onto the incident end 11B of the light guide 11.

  FIG. 2 is a front view of the rotating plate 38. The rotating plate 38 has a circular shape, and a sector-shaped opening 38A is formed along the circumferential direction. The opening 38 </ b> A occupies a substantially ¼ area of the rotating plate 38. An output shaft of a motor 39 (see FIG. 1) is fixedly fitted to the center 38E of the rotating plate 38. When the opening 38A is positioned in the optical path of the white light from the lamp 33 according to the rotation of the motor 39, the white light is guided to the dichroic mirror 41, and the regions 38B, 38C, and 38D other than the opening 38A When positioned in the optical path, white light is blocked.

  Referring to FIG. 1 again, white light or PDD excitation light incident on the incident end 11B is guided to the insertion portion distal end 10A by the light guide 11 and is emitted from the emission end 11A. The emitted light is emitted to the front of the insertion portion distal end 10A through the light distribution lens 12, and the object to be observed is irradiated by this. Reflected light from the object to be observed or autofluorescence passes through the objective lens 13 provided at the distal end 10A of the insertion portion of the electronic scope 10 and an excitation light cut filter 14 that blocks the excitation light for PDD and passes white light and autofluorescence. Through the CCD 15. Thereby, an optical image and an autofluorescence image of the observation object are formed on the light receiving surface of the CCD 15.

  The drive of the CCD 15 is controlled by a CCD drive signal output from the CCD driver 16. The CCD 15 photoelectrically converts the optical image of the object to be observed and the autofluorescence image, and outputs an analog image signal. The analog image signal is subjected to A / D conversion and other predetermined image processing by a pre-stage signal processing circuit 46 of the image processor 30. An image signal obtained by irradiation with white light and subjected to image processing is stored in the first image memory 47 as image information of a white light image. An image signal obtained by irradiation with excitation light and subjected to image processing is stored in the second image memory 48 as image information of a fluorescent image.

  The image information stored in the first and second image memories 47 and 48 is read out based on the synchronization signal from the timing controller 32 and output to the subsequent signal processing circuit 49. In the post-stage signal processing circuit 49, the image information of the white light image and the image information of the fluorescent image are complemented in accordance with the TV vertical synchronization frequency of 60 Hz and output to the TV monitor 50. Thereby, the white light image and the fluorescence image are displayed in parallel on the TV monitor 50.

  The PDT device 60 is a laser device that emits a semiconductor laser for PDT. An optical fiber 61 is connected to the PDT device 60. The optical fiber 61 is inserted into the treatment instrument insertion path of the electronic scope 10, and the free end thereof is exposed from the forceps opening of the insertion portion distal end 10A. The PDT device 60 emits laser light having a wavelength of about 640 nm at a predetermined period. The emitted laser light is guided to the insertion portion distal end 10A through the optical fiber 61 and is irradiated on the living body.

  The photodiode 62 detects laser light leaking from the optical fiber 61. A detection signal output from the photodiode 62 when the laser beam is detected is input to the timing controller 32. The timing controller 32 synchronizes the rotation of the rotating plate 38, the on / off of the excitation light source 43, and the driving of the CCD 15 in accordance with the detection signal input period of the photodiode 62.

  FIG. 3 is a timing chart of PDT laser light irradiation, white light irradiation, PDD excitation light irradiation, and rotation of the rotating plate 38 controlled by the timing controller 32. Irradiation with the laser light for PDT is executed at a predetermined cycle determined by the specification of the PDT device 60. In this embodiment, as shown in FIG. 3, laser light is emitted from the PDT device 60 at timings t10 to t11, t12 to t13, t14 to t15, t16 to t17, t18 to t19, and t20 to t21. Irradiated. As described above, the photodiode 62 detects leakage light from the optical fiber 61 at these timings and outputs a detection signal to the timing controller 32.

  The timing controller 32 detects the detection signal from the photodiode 62 so that the rotation of the rotary plate 38 and the emission of the PDD excitation light from the excitation light source 43 are performed in synchronization with the emission of the laser light from the PDT device 60. A control signal is output to the motor drive circuit 40 and the laser drive circuit 45 based on the input timing.

  The timing controller 32 outputs a control signal to the motor drive circuit 40 so that the rotating plate 38 makes one rotation from t11 to t15. During the period from t11 to t12 when the detection signal of the photodiode 62 is not input, the opening 38A (see FIG. 2) is interposed in the optical path of the white light from the lamp 33, and the detection signal of the photodiode 62 is input. During time t13 to t14, the region 38B is interposed in the white light optical path, and the detection signal of the photodiode 62 is input again. During the period from t14 to t15, the rotation of the rotary plate 38 is controlled by the timing controller 32 so that the region 38D is interposed in the white light optical path.

  Further, the control signal is sent to the laser drive circuit 45 while the laser light is not emitted from the PDT device 60, the detection signal of the photodiode 62 is not inputted, and the observation object is not irradiated with white light, that is, between t13 and t14. Is output, and the object to be observed is irradiated with the excitation light for PDD.

  During the period from t11 to t12, the opening 38A is interposed in the optical path of white light, so that the white light is irradiated to the object to be observed without being shielded by the rotating plate 38. Accordingly, a white light image is acquired by the CCD 15 during these periods. Further, during the period from t13 to t14, the PDD excitation light is irradiated to the observation object in a state where the white light from the lamp 33 is shielded by the region 38C. Therefore, a fluorescence image is acquired by the CCD 15 during these periods.

  After t15, the PDT laser light irradiation, the white light irradiation, and the PDD excitation light irradiation are controlled at the same timing. That is, according to the electronic endoscope system of the present embodiment, treatment of a lesion site by the PDT device 60, observation of a living body by a white light image, and observation of a lesion site by a fluorescence image are alternately performed.

  Furthermore, in the first embodiment, the CCD 15 is driven by an electronic shutter during the period (t10 to t11, t12 to t13, t14 to t15, t16 to t17, t18 to t19, t20 to t21) during which the PDT laser beam is irradiated. The That is, the shutter speed (charge accumulation time) of the CCD 15 in each of these periods is adjusted. As shown in FIG. 4, a pulse signal (charge sweeping pulse) for cutting the accumulated charges is applied to the CCD 15 in accordance with the readout period (s30 to s40) of the charges accumulated in the CCD 15. s31). The timing of applying the charge sweeping pulse is controlled by the timing controller 32. By driving the electronic shutter, the charges accumulated in the CCD 15 from s30 to s31 are eliminated, and the charges accumulated from s31 to s40 are read out at s40.

  As described above, since the PDT laser light is generally extremely high in intensity, the charge accumulated in the CCD 15 is saturated during irradiation of the PDT laser light, and the image reproduced on the TV monitor 50 may cause halation. However, by appropriately controlling the shutter speed of the electronic shutter during the PDT laser light irradiation, the saturation charge of the CCD 15 is cut and halation is prevented. Therefore, the living body can be observed by the TV monitor 50 even during the treatment of PDT.

  According to the first embodiment, since the treatment of PDT and the diagnosis of PDD proceed alternately, the state of the affected part immediately after PDT can be visually recognized on the TV monitor 50. Therefore, removal of the affected part by PDT can be executed without excess or deficiency. Observation with white light irradiation can also be performed in parallel. Therefore, treatment and diagnosis can be performed more smoothly.

  Moreover, the halation at the time of the PDT laser beam irradiation is prevented without using a laser beam cut filter. Therefore, a decrease in color reproducibility is avoided in displaying a white light image acquired during white light irradiation. That is, according to the present embodiment, it is possible to prevent halation during irradiation of the PDT laser light without reducing the color reproducibility of the white light image.

  FIG. 5 is a block diagram of an electronic endoscope system to which the second embodiment according to the present invention is applied. Constituent elements similar to those in FIG. In the second embodiment, the timing controller 32 controls the laser light output period of the PDT device 63. That is, the irradiation of the other irradiation light is not controlled based on the specification of the laser light output of the PDT device 63, but the white light generated by the rotation of the rotating plate 38, the output of the laser light for PDT, the output of the excitation light for PDD All timings of irradiation are controlled by the timing controller 32. The timings of irradiation with the PDT laser light, white light irradiation and image acquisition, PDD excitation light irradiation and image acquisition are the same as those shown in the timing chart of FIG.

  According to the second embodiment, since the PDT device 63 is controlled by the timing controller 32, it is not necessary to provide the photodiode 62. Therefore, the system configuration is simplified.

1 is a block diagram of an electronic endoscope system to which a first embodiment according to the present invention is applied. It is a front view of a rotating plate. It is a timing chart of laser light irradiation for PDT, white light irradiation, excitation light irradiation for PDD, and rotation of a rotating plate. It is a timing chart which shows the principle of the electronic shutter of CCD. It is a block diagram of an electronic endoscope system to which a second embodiment according to the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic scope 30 Image processor 31 System controller 32 Timing controller 33 Lamp 38 Rotating plate 43 Excitation light source 50 TV monitor 60 PDT apparatus 61 Optical fiber 62 Photodiode

Claims (7)

A normal light source that emits normal light in the visible band;
First oscillation means for outputting diagnostic laser light for photodynamic diagnosis;
Second oscillation means for outputting a therapeutic laser beam for photodynamic therapy;
Irradiation light control means for controlling the irradiation timing of the normal light, the diagnostic laser light, and the treatment laser light to the living body;
The normal light image of the living body acquired by the solid-state image sensor during irradiation with the normal light and the fluorescent image of the living body acquired by the solid-state image sensor during irradiation of the diagnostic laser light are displayed on a monitor. Display control means;
An electronic endoscope system, comprising: a solid-state image sensor control unit that cuts a saturation charge of the solid-state image sensor when the therapeutic laser beam is irradiated.   The irradiation light control unit controls the relative relationship between the period of the normal light irradiation, the period of the output of the first oscillation unit, and the period of the output of the second oscillation unit. The electronic endoscope system according to claim 1, wherein the timing of irradiation is controlled.   The irradiation light control means controls the timing of the irradiation of the normal light and the irradiation of the diagnostic laser light based on the output period of the treatment laser light unique to the second oscillation means. The electronic endoscope system according to claim 2, wherein the system is an electronic endoscope system. An optical fiber for transmitting the therapeutic laser beam output from the second oscillating means to the distal end of the insertion portion of the electronic scope;
Leakage light detection means for detecting the treatment laser light leaking from the optical fiber during transmission of the treatment laser light,
The electronic endoscope system according to claim 3, wherein the irradiation light control unit controls the timing based on a detection result of the leakage light detection unit. A rotating plate disposed to be interposed in the optical path of the normal light emitted from the normal light source and having an opening formed therein;
The said irradiation light control means controls the timing of irradiation of the said normal light and the irradiation of the said diagnostic laser beam by controlling rotation of the said rotating plate, The said any one of Claim 2 thru | or 4 characterized by the above-mentioned. The electronic endoscope system described. The display control means includes
First storage means for storing image information of the normal light image; and second storage means for storing image information of the fluorescent image;
The image information of the normal light image and the image information of the fluorescent image are read out from the first and second storage means at a timing compliant with the video signal processing specifications in the monitor, and output to the monitor. The electronic endoscope system according to claim 1. Irradiation of normal light in the visible band, irradiation of diagnostic laser light for photodynamic diagnosis, and irradiation of therapeutic laser light for photodynamic treatment are alternately performed at a predetermined cycle,
The saturation charge of the solid-state imaging device due to the irradiation of the therapeutic laser light is cut,
A normal light image acquired by the solid-state image sensor when irradiated with the normal light and a fluorescent image acquired by the solid-state image sensor when irradiated with the diagnostic laser light are displayed in parallel on a monitor. Electronic endoscope system.

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