JP2016205931A - Diagnostic system of tumor site, and imaging method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diagnostic system capable of discriminating a tumor site accurately, and to provide an imaging method therefor.SOLUTION: A diagnostic system of a tumor site for irradiating porphyrins accumulated on the intraoral tumor site with excitation light, and detecting luminescence emitted from porphyrins after being excited, includes a light irradiation part for irradiating the intraoral tumor site with excitation light, a light receiver for receiving the luminescence, and an image processing part for generating image information corresponding to the light intensity of the luminescence detected by the light receiver.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a tumor site diagnostic apparatus and imaging method.

  Conventionally, histopathological diagnosis has been the mainstream for diagnosing a tumor site (especially cancer) in the oral cavity, but a small lesion may be missed, and the diagnostic accuracy is not sufficient.

  In recent years, application of a photodynamic technique using 5-aminolevulinic acid (hereinafter abbreviated as “5-ALA” as appropriate) is being promoted as a new diagnostic method that replaces histopathological diagnosis. 5-ALA is a kind of amino acid that is also present in the living body, and is water-soluble and can be administered orally or locally. When 5-ALA is administered from outside the body, it is rapidly metabolized to heme in normal cells, but protoporphyrin IX (PpIX), which is a metabolite, selectively accumulates in cancer cells due to the difference in the activity of metabolic enzymes. Here, while heme does not recognize fluorescence, PpIX is a fluorescent substance, and thus cancer can be diagnosed by detecting this light. This is the principle of the photodynamic technique (see Patent Document 1).

International Publication No. 2013/002350

  The above contents are still in the laboratory level research stage at present, and various problems are expected to occur when actually applied to human diagnosis.

  An object of the present invention is to provide a diagnostic apparatus capable of accurately identifying a tumor site and an imaging method therefor.

The present invention is an apparatus for diagnosing a tumor site that irradiates porphyrins accumulated in a tumor site in the oral cavity with excitation light and detects luminescence emitted by the porphyrins after excitation,
A light irradiation unit for irradiating the excitation light to the tumor site in the oral cavity;
A light receiving portion for receiving the luminescence;
And an image processing unit that generates image information corresponding to the light intensity of the luminescence detected by the light receiving unit.

  In the present specification, “porphyrins” refers to those having a substituent on the porphine ring. For example, PpIX and protoporphyrins such as photo-protoporphyrin (PPp) generated from PpIX exist. In this specification, “luminescence” is a concept including fluorescence and phosphorescence.

  Although a tumor may occur anywhere in the human body, the diagnostic device of the present invention is used for diagnosis of a tumor site, particularly in the oral cavity. Unlike other organs such as the brain and fire extinguisher system, the oral cavity exposes the irradiation target area simply by having the subject open the mouth without performing so-called resection surgery such as craniotomy or laparotomy to irradiate light. be able to. Moreover, since the irradiation object area | region is specified in the oral cavity, the output of the excitation light to irradiate can be reduced compared with another organ. For this reason, the light irradiation part for irradiating excitation light can be reduced in size.

  As a result, a compact device in which the light irradiation unit, the light receiving unit, and the image processing unit are integrated can be realized as a diagnostic device for a tumor site in the oral cavity.

  The light irradiation unit may include a light source element that emits the excitation light having a peak wavelength of 400 nm or more and 410 nm or less.

  FIG. 1A shows an absorption spectrum of PpIX, which is a kind of porphyrins. FIG. 1B shows the luminescence spectrum of PpIX. PpIX exhibits high absorbance with respect to excitation light having a predetermined wavelength. Specifically, as shown in FIG. 1A, PpIX exhibits high absorbance for light having a wavelength of 370 nm or more and 450 nm or less, and particularly shows extremely high absorbance for light having a wavelength of 385 nm or more and 425 nm or less. When PpIX is irradiated with light in the above wavelength range, as shown in FIG. 1B, luminescence having a peak near 635 nm and high intensity in a wavelength band of 620 nm or more and 650 nm or less is emitted from PpIX.

  By the way, when excitation light is irradiated into the oral cavity, the light receiving unit may receive a part of the excitation light reflected in the oral cavity in addition to the luminescence. Luminescence has a very low output in comparison with the excitation light due to its nature, and the PpIX luminescence wavelength band includes a region with relatively low visual sensitivity. For this reason, there are cases where it is difficult to identify whether or not the tumor site is due to a mixture of some of the reflected excitation light and luminescence.

  Therefore, by setting the wavelength of the excitation light to a wavelength with extremely low visibility and high absorbance due to porphyrins, misdiagnosis due to mixed reflection of excitation light without causing a decrease in luminescence output Can be prevented.

  On the other hand, as long as the oral cavity is a part of the human body, it is preferable that the side effects caused by the irradiation with the excitation light be as small as possible. When the human body is irradiated with light in the ultraviolet region, it may cause erythema and skin damage.

  Therefore, as described above, by setting the peak wavelength of the excitation light to 400 nm or more and 410 nm or less, it is possible to improve the diagnostic accuracy of the tumor site while suppressing side effects on the human body to a minimum.

  The light receiving unit may include a filter that blocks light in at least a part of a wavelength band having a wavelength of 500 nm or more and 600 nm or less.

  It is common for teeth to be present in the oral cavity. These teeth contain enamel and dentin, and are known to emit luminescence when irradiated with excitation light. FIG. 2 shows a spectrum of luminescence generated when the teeth are irradiated with excitation light having a wavelength of around 400 nm. According to this, a strong optical signal is recognized over the range of 440 nm to 600 nm.

  Therefore, by providing a filter that blocks at least part of light in the wavelength range of 500 nm to 600 nm, which has particularly high visibility, light received from the teeth is suppressed from being received by the light receiving unit, and luminescence from the porphyrin is suppressed. The accuracy of receiving the sense can be increased.

  As this filter, a long wavelength transmission filter (LWPF: Long Wavelength Pass Filter) that transmits light having a wavelength longer than the threshold value with a predetermined wavelength of 500 nm to 600 nm as a threshold value may be used. The optical filter may transmit light other than a predetermined wavelength band in the range of 500 nm to 600 nm.

  The light source element can be composed of an LED. Thereby, a diagnostic apparatus can be made further compact.

  The diagnostic apparatus may include a control unit that controls the light irradiation unit and the light receiving unit. At this time, the control unit repeatedly executes control to stop the irradiation of the excitation light after irradiating the light irradiation unit with the excitation light for a predetermined time, Control that causes the image processing unit to output information corresponding to the light intensity of the luminescence detected by the light receiving unit during a period in which the light irradiation unit has stopped irradiating the excitation light. It doesn't matter.

  Porphyrins fluoresce within a period during which excitation light is irradiated, but also emit phosphorescence for a predetermined time after stopping irradiation of excitation light. According to the above configuration, the diagnosis based on the luminescence (that is, the above phosphorescence) received by the light receiving unit within the period when the irradiation of the excitation light is stopped can be performed, so that the excitation light reflected in the oral cavity is received. Misdiagnosis caused by receiving light at the portion is further prevented.

Under the above configuration, the light irradiation unit includes a light source element that emits the excitation light,
The time from when the supply of energy to the light source element stops until the emission of the excitation light stops is shorter than the time that the luminescence lasts,
The light receiving unit may output information corresponding to the detected light intensity of the luminescence to the image processing unit.

The present invention is an imaging method using an imaging device including a light irradiation unit that emits excitation light and a light receiving unit that receives light in a predetermined wavelength band,
A step (a) of irradiating the excitation light to the target region in the oral cavity to which a chemical solution containing 5-aminolevulinic acid (5-ALA) is applied, by controlling the light irradiation unit;
(B) detecting the light emitted from the target region by controlling the light receiving unit;
And (c) generating image information corresponding to the light intensity detected by the light receiving unit.

In the above method, the step (d) of soaking the chemical into a predetermined water-absorbing member;
A step (e) of removing the water absorbing member after placing it on the target region for a predetermined time or more;
The step (a) may be performed after the step (e).

  According to this method, it is possible to image a tumor site in the oral cavity by a very simple method. As the step (d), for example, a method can be employed in which absorbent cotton in which 5-ALA is dissolved in a solvent such as physiological saline is placed in the oral cavity for a predetermined time.

  Furthermore, according to this method, since the subject does not need to inject or orally administer a drug solution containing 5-ALA, the tumor site can be imaged without causing side effects such as liver dysfunction.

  The step (c) may be a step of generating image information corresponding to the light intensity of luminescence emitted from porphyrins present in the target region.

  The peak wavelength of the excitation light can be 400 nm or more and 410 nm or less.

  According to the present invention, it is possible to accurately diagnose or image a tumor site in the oral cavity.

It is a figure which shows the absorption spectrum of PpIX. It is a figure which shows the luminescence spectrum of PpIX. It is a figure which shows an example of the luminescence spectrum of a tooth | gear. It is drawing which shows typically the structure of 1st embodiment of the diagnostic apparatus of a tumor site | part. It is a block diagram which shows typically the internal structure of the diagnostic apparatus of FIG. It is drawing which shows typically the structure of the optical unit with which the diagnostic apparatus of FIG. 3 is provided. It is a photograph which shows one method of apply | coating the chemical | medical solution containing 5-ALA to the object area | region in an oral cavity. It is an example of the timing chart which shows the control content in 2nd embodiment of the diagnostic apparatus of a tumor site | part.

[First embodiment]
A first embodiment of a tumor site diagnostic apparatus will be described. FIG. 3 is a drawing schematically showing the configuration of the diagnostic apparatus according to the present embodiment, in which (a) corresponds to a front view, (b) corresponds to a side view, and (c) corresponds to a rear view.

  3 includes a base unit 2, an optical unit 3, a first operation unit 5, a second operation unit 7, and a display unit 9. Although not shown in FIG. 1, the diagnostic apparatus 1 includes an image processing unit 11 and a control unit 13 inside the base unit 2 (see FIG. 4). The first operation unit 5 is a mechanism for operating the optical unit 3. For example, the operator can adjust the focus of the optical unit 3 by operating the first operation unit 5. The second operation unit 7 is a mechanism for operating the display unit 9. For example, when the operator operates the second operation unit 7, the display position on the display unit 9 is changed or the displayed image is displayed. The user can instruct enlargement / reduction or output to the storage unit or an external device. The first operation unit 5 and the second operation unit 7 are not necessarily provided in the diagnostic device 1.

  FIG. 4 is a block diagram schematically showing the internal configuration of the diagnostic apparatus 1. As shown in FIG. 4, the optical unit 3 includes a light irradiation unit 20 and a light receiving unit 30. In this embodiment, the light irradiation unit 20 includes a light source unit 21 including a plurality of light source elements 23 and a first filter unit 22 that selects light of a predetermined wavelength band. In the present embodiment, the light receiving unit 30 includes a detection unit 31 configured by, for example, a CCD camera, and a second filter unit 32 that selects light of a predetermined wavelength band. When detecting the light transmitted through the second filter unit 32, the detection unit 31 outputs a signal corresponding to the light intensity to the image processing unit 11. The image processing unit 11 creates image information based on the signal and outputs it to the display unit 9. Accordingly, an image based on the signal received by the light receiving unit 30 (detecting unit 31) is displayed on the display unit 9. The light irradiation unit 20 and the light receiving unit 30 may be controlled by the control unit 13.

  In FIG. 4, an area to be irradiated with light from the light irradiation unit 20 is denoted by reference numeral 40. Since this apparatus 1 is assumed to be used for diagnosis of a tumor site in the oral cavity, this region 40 corresponds to a target region in the oral cavity.

  FIG. 5 is a drawing schematically showing the configuration of the optical unit 3. 5A corresponds to the drawing viewed in the optical axis direction, and FIG. 5B corresponds to the drawing viewed in the direction orthogonal to the optical axis.

  In this embodiment, the light irradiation part 20 formed in the annular | circular shape is arrange | positioned so that the light-receiving part 30 may be surrounded. Here, as an example, the light irradiation unit 20 assumes a case where a plurality of light source elements 23 are discretely arranged in a circular shape. Hereinafter, the light source element 23 will be described as being configured by an LED that emits light in a wavelength band including 405 nm, but may be configured by a laser diode and emits light in another wavelength band. It may be a configuration. In addition, the light source unit 21 may include an optical system arranged corresponding to each light source element 23 together with the plurality of light source elements 23.

  FIG. 5 illustrates the case where the first filter unit 22 is configured by arranging a plurality of filters corresponding to each of the plurality of light source elements 23. For example, a single filter is illustrated. You may be comprised by. The first filter unit 22 has a function of selectively transmitting light in the vicinity of 405 nm out of light emitted from the light source element 23. Note that the vicinity of 405 nm may be within a range of 395 nm to 415 nm, may be within a range of 400 nm to 410 nm, and may be within a range of 404 nm to 406 nm. More specifically, it is sufficient if it has a function of selectively transmitting light in a wavelength band with high absorbance by porphyrins.

  The light irradiation unit 20 irradiates the target region 40 in the oral cavity containing porphyrins with excitation light having a wavelength in the vicinity of 405 nm selected via the first filter unit 22 (see also FIG. 4). Of the target region 40, a tumor site where porphyrins are present emits luminescence when excited by irradiation with the excitation light. On the other hand, a non-tumor site in which no porphyrins exist in the target region 40 is not excited even when irradiated with excitation light, and thus does not generate luminescence. Luminescence emitted from the target region 40 and some excitation light reflected in the oral cavity are received by the light receiving unit 30.

  In the present embodiment, the second filter unit 32 included in the light receiving unit 30 is configured to include a plurality of filters. That is, a filter 33 that cuts light with a wavelength of 490 nm or less, a filter 34 that selectively transmits light with a wavelength of 560 nm to 650 nm, and a filter 35 that cuts light with a wavelength of 600 nm or less.

  Here, it is sufficient that the filter 33 has a function of cutting at least a wavelength band in which the luminescence intensity of porphyrins is extremely low, and the filter 34 is a wavelength having a relatively high luminescence intensity of porphyrins. What is necessary is just to have the function to select a belt | band | zone. Moreover, the filter 35 should just have a function which cuts the wavelength band with high intensity | strength of the luminescence of a tooth | gear among the wavelength bands with comparatively high intensity | strength of porphyrin luminescence.

  The filter 33 is provided for the purpose of blocking some excitation light and natural light reflected by the target region 40. The filter 34 is provided for the purpose of selecting a wavelength band in which the intensity of the luminescence is relatively high in order to selectively receive the luminescence of the porphyrins. For this reason, the filter 34 can also function as the filter 33.

  As described above with reference to FIG. 2, it is known that when excitation light is irradiated on a tooth, luminescence having intensity in a predetermined wavelength band is emitted. For this reason, the filter 35 is provided for the purpose of blocking the luminescence of the teeth. However, by designing the filter 34 so as not to transmit the wavelength region cut by the filter 35, the filter 34 can also function as the filter 35.

  That is, the second filter unit 32 may be provided with, for example, only the filter 34 for the purpose of saving space and low cost. Conversely, the second filter unit 32 is arranged serially as described above for the purpose of improving the wavelength selection accuracy. A plurality of filters (33, 34, 35) may be provided. In the latter case, for example, another filter such as a filter for cutting infrared light may be further provided.

  Of the light emitted from the target region 40 in the oral cavity, only the light that has passed through the second filter unit 32 is received by the detection unit 31. The reflected light of the excitation light, the natural light, the luminescence of the teeth, etc. are blocked or significantly attenuated by the second filter unit 32. Therefore, in the detection unit 31, the light having a wavelength of 600 nm or more and 650 nm or less, more specifically, near the wavelength of 635 nm Light is received. Thereby, in the detection part 31, the luminescence of porphyrins can be selectively received.

  The detection unit 31 outputs the intensity of the received light to the image processing unit 11 together with position information within the target region 40, for example. For example, the image processing unit 11 creates image information in which information corresponding to the light intensity is superimposed on imaging information of the target region 40 and outputs the image information to the display unit 9. Thereby, on the display part 9, the image information on which the received luminescence was superimposed on the image in the oral cavity is displayed. The luminescence of porphyrins is light with a wavelength of 635 nm, which is red light. For this reason, a tumor site | part can be specified by confirming the location currently glowing red from the image projected on the display part 9. FIG.

When imaging the oral cavity using the diagnostic device 1, first, prior to imaging, a chemical solution containing 5-ALA may be applied to the target region 40 in the oral cavity. In this case, more specifically, a solution obtained by dissolving 5-ALA in a solvent such as physiological saline at a concentration of about 0.5% to about 10% is soaked in a water absorbent member such as absorbent cotton or sponge material. The water absorbing member is placed on the target region 40 in the oral cavity for a predetermined time (for example, about 20 to 30 minutes). Then, after removing the water absorbing member, the diagnostic device 1 emits excitation light from the light irradiation unit 20 to the target region 40 with a radiation intensity of, for example, 50 mW / cm ² or more and 150 mW / cm ² or less for 0.5 seconds or more. Irradiate for a period of 5 seconds or less. As a result, porphyrins can be accumulated if a tumor site is present in the target region 40 at a stage before irradiation with excitation light, and as described above, displayed on the display unit 9. By confirming the red light emission location on the image, the tumor site can be easily determined.

  FIG. 6 is a photograph showing a method of applying a chemical solution containing 5-ALA to the target region 40 in the oral cavity. In FIG. 6, reference numeral 41a indicates the upper front tooth, reference numeral 41b indicates the lower front tooth, reference numeral 42a indicates the upper jaw, and reference numeral 42b indicates the lower jaw. The subject is opened and the target area 40 is exposed. In order to maintain this open state, in the photograph of FIG. 6, after inserting the mouthpiece 45 into the oral cavity with the surface of the target region 40 exposed, the mouthpiece 45 is sandwiched between both the upper jaw 42a and the lower jaw 42b. It is fixed like so. In this state, absorbent cotton 44 impregnated with a solution containing 5-ALA is placed in a predetermined area including the target area 40. The absorbent cotton 44 is held in contact with the mouthpiece 45 in addition to the inner cheeks and jaws in the oral cavity.

  Even after the installation of the absorbent cotton 44 is completed, the mouthpiece 45 may be left installed in the oral cavity for the predetermined time necessary for the 5-ALA to be absorbed into the target region 40. Thereby, before 5-ALA permeates into the object area | region 40, it can suppress that the absorbent cotton 44 moves in an oral cavity.

[Second Embodiment]
A second embodiment of the diagnostic apparatus 1 will be described. In the following, only portions different from the first embodiment will be described.

  In the present embodiment, the control unit 13 controls the light irradiation unit 20 and the light receiving unit 30 based on a predetermined rule. Specifically, the control unit 13 repeatedly executes control to stop the irradiation of the excitation light after irradiating the light irradiation unit 20 with the excitation light for a predetermined time. In addition, the control unit 13 performs control to operate the light receiving unit 30 only during a time period when the excitation light is not emitted from the light irradiation unit 20.

  FIG. 7 is an example of a timing chart showing the contents of control performed by the control unit 13 in the present embodiment. In FIG. 7, (a) shows the intensity change of the excitation light emitted from the light source unit 21 provided in the light irradiation unit 20 under the configuration of the present embodiment. FIG. 7B shows a change in intensity of luminescence emitted from porphyrins. FIG. 7C shows an operating state of the detection unit 31 included in the light receiving unit 30 under the configuration of the present embodiment.

  As shown in FIG. 7, in the present embodiment, the detection unit 31 is configured to be able to detect light only during the time T <b> 2 when excitation light is not emitted from the light source unit 21 under the control of the control unit 13. It has become. Porphyrins emit fluorescence over time T1 during which excitation light is irradiated, but have the property of continuously emitting light (phosphorescence) even after irradiation of excitation light is stopped. The intensity of this phosphorescence decreases with time. In FIG.7 (b), this has shown that the intensity | strength of luminescence is reducing with progress of time at time T2.

  As a specific example of the control content of the control unit 13, after supplying current to the light source unit 21 over time T1, the control of stopping supply of current to the light source unit 21 over time T2 is repeated. Can do. Further, the control unit 13 supplies a current to the detection unit 31 for a time T2 during which no current is supplied to the light source unit 21 so that the detection unit 31 can detect the current. The supply can be stopped to make it undetectable.

  According to said structure, the excitation light is not irradiated from the light irradiation part 20 in the period when the detection part 31 can detect light. For this reason, the detection unit 31 does not detect a part of the excitation light reflected by the target region 40 in the oral cavity. Therefore, luminescence from the porphyrins (phosphorescence in this embodiment) can be accurately detected.

  Phosphorescence emitted from porphyrins is not instantaneously extinguished, but is emitted continuously for a certain period of time. The duration of this phosphorescence is longer than the time from when the control unit 13 performs control for stopping the supply of current to the light source unit 21 until the light source unit 21 actually stops emission of excitation light completely. . For this reason, the light receiving unit 30 can receive phosphorescence emitted from porphyrins even after the irradiation of excitation light is stopped. In the present embodiment, the control unit 13 controls the light irradiation unit 20 to resume irradiation with excitation light after the time required for the light receiving unit 30 to receive phosphorescence has elapsed. It does n’t matter what you do.

  In particular, in the case where the light source element 23 is configured by an LED, the time (rise time) from the start of the current supply to the start of the emission of the excitation light, and the excitation light emission after the current supply is stopped. Any time until the injection stops (fall time) can be realized in a short time. For this reason, by the control of this embodiment, the light-receiving part 30 receives a part of the excitation light, so that the effect of reducing the possibility of misdiagnosis of the tumor site is sufficiently exerted.

  FIG. 7 illustrates a case where the time T2 is set within a time period in which the intensity of phosphorescence emitted from porphyrins exceeds the minimum intensity (detection limit threshold value) Wth that can be detected by the detection unit 31. However, the control unit 13 may restart the control for irradiating the light irradiation unit 20 with the excitation light after the phosphorescence intensity has decreased to a level below Wth. Even in this case, since the detection unit 31 can detect at least the time when the intensity of phosphorescence shows the intensity equal to or greater than the detection limit threshold Wth, the tumor site is diagnosed based on the information of the light intensity received during this time. It is possible.

  In the present embodiment, the control unit 13 controls the light irradiation unit 20 and the light receiving unit 30 so that a part of the excitation light reflected by the target region 40 in the oral cavity is not received by the light receiving unit 30. From this point of view, the control unit 13 does not cause the light receiving unit 30 to output the information related to the light intensity received in the time zone in which the excitation light is irradiated from the light irradiation unit 20 to the image processing unit 11, You may perform control which makes the image process part 11 output the information regarding the light intensity received in the time slot | zone when the excitation light is not irradiated from the light irradiation part 20. FIG. That is, in this case, the light receiving unit 30 may be in a state where it can receive light even during a period in which excitation light is irradiated from the light irradiation unit 20.

[Another embodiment]
Hereinafter, another embodiment will be described.

  <1> In the above embodiment, the diagnostic device 1 includes the display unit 9, but the display unit 9 may be configured to be provided outside the diagnostic device. In this case, the image information generated by the image processing unit 11 can be displayed on a monitor outside the diagnostic apparatus 1.

  <2> In the above embodiment, the light irradiation unit 20 includes the first filter unit 22. However, when the excitation light emitted from the light source unit 21 is light having a narrow-band spectrum, the light irradiation unit 20 is not necessarily limited to the first filter unit 22. One filter unit 22 may not be provided.

  Moreover, in the said embodiment, although the light-receiving part 30 shall be provided with the 2nd filter part 32 containing a some filter (33,34,35), the light of the peak wavelength vicinity of the luminescence emitted from porphyrins is used. If mainly light can be received, the number of filters may be appropriately increased or decreased, and the second filter unit 32 itself may not be provided.

  <3> The configuration of the diagnostic apparatus 1 described with reference to FIG. 3 and the configuration of the optical unit 3 described with reference to FIG. 5 are merely examples, and the diagnostic apparatus 1 of the present invention is illustrated in these drawings. It is not limited to the structure made.

  <4> In the second embodiment, the time T1 when the excitation light is irradiated from the light irradiation unit 20 and the time T2 when the irradiation of the excitation light is stopped do not have to be set to the same time every time. Moreover, these time (T1, T2) is suitably set within the range of conditions that can achieve the above-mentioned purpose.

DESCRIPTION OF SYMBOLS 1: Diagnosis apparatus 2: Base part 3: Optical unit 5: 1st operation part 7: 2nd operation part 9: Display part 11: Image processing part 13: Control part 20: Light irradiation part 21: Light source part 22: 1st Filter part 23: Light source element 30: Light receiving part 31: Detection part 32: Second filter part 33, 34, 35: Filter 40: Target area 41a in the oral cavity 41a: Upper front tooth 41b: Lower front tooth 42a: Upper jaw 42b: Lower jaw 44: Absorbent cotton 45: mouthpiece

Claims (10)

A diagnostic apparatus for a tumor site that irradiates porphyrins accumulated in a tumor site in the oral cavity with excitation light and detects luminescence emitted by the porphyrins after excitation,
A light irradiation unit for irradiating the excitation light to the tumor site in the oral cavity;
A light receiving portion for receiving the luminescence;
An apparatus for diagnosing a tumor site, comprising: an image processing unit that generates image information corresponding to the light intensity of the luminescence detected by the light receiving unit.   The tumor site diagnosis apparatus according to claim 1, wherein the light irradiation unit includes a light source element that emits the excitation light having a peak wavelength of 400 nm or more and 410 nm or less.   3. The tumor site diagnosis apparatus according to claim 2, wherein the light receiving unit includes a filter that blocks light in at least a part of a wavelength band having a wavelength of 500 nm to 600 nm.   The said light source element is comprised with LED, The diagnostic apparatus of the tumor site | part of Claim 2 or 3 characterized by the above-mentioned. A control unit for controlling the light irradiation unit and the light receiving unit;
The controller is
After irradiating the light irradiation unit with the excitation light for a predetermined time, repeatedly executing the control to stop the irradiation of the excitation light,
Information corresponding to the light intensity of the luminescence detected by the light receiving unit is output to the image processing unit while the light irradiation unit stops irradiating the excitation light to the light receiving unit. The tumor site diagnosis apparatus according to any one of claims 1 to 4, wherein the control is performed. The porphyrins are materials having the property of emitting the luminescence over a predetermined time after irradiation of the excitation light is stopped when the excitation light is irradiated,
The light irradiation unit includes a light source element that emits the excitation light,
The time from when the supply of energy to the light source element stops until the emission of the excitation light stops is shorter than the time that the luminescence lasts,
6. The tumor site diagnosis apparatus according to claim 5, wherein the light receiving unit causes the image processing unit to output information corresponding to the detected light intensity of the luminescence. An imaging method using an imaging device including a light irradiation unit that emits excitation light and a light receiving unit that receives light in a predetermined wavelength band,
(A) irradiating the excitation light to the target region in the oral cavity to which a chemical solution containing 5-aminolevulinic acid is applied, by controlling the light irradiation unit;
(B) detecting the light emitted from the target region by controlling the light receiving unit;
And (c) generating image information corresponding to the light intensity detected by the light receiving unit. A step (d) of soaking the chemical into a predetermined water-absorbing member;
A step (e) of removing the water absorbing member after placing it on the target region for a predetermined time or more;
The imaging method according to claim 7, wherein the step (a) is executed after the step (e).   The imaging method according to claim 7 or 8, wherein the step (c) is a step of generating image information corresponding to light intensity of luminescence emitted from porphyrins existing in the target region. . The imaging method according to claim 7, wherein a peak wavelength of the excitation light is 400 nm or more and 410 nm or less.