JP2016049126A - Photo-acoustic wave detector, and photo-acoustic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a photo-acoustic wave with an intensity sufficient for generating a tomogram image at a depth part of an analyte with a relatively lower power light source.SOLUTION: A photo-acoustic imaging device includes a photo-acoustic wave detector, an internally detected image generation unit, and an image formation unit. The photo-acoustic wave detector includes an internal light source and an internal detection unit. The internal light source includes a light emission element which is inserted inside the analyte, and radiates the emission light thereof to a light absorber inside the analyte. The internal detection unit detects, at inside the analyte, a photo-acoustic wave generated in the light absorber, and generates an internally detected signal on the basis of the detection result of the photo-acoustic wave. The internally detected image generation unit generates an internally detected tomogram image of the analyte on the basis of the internally detected signal. The image formation unit forms a photo-acoustic image by using the internally detected tomogram image.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a photoacoustic wave detector and a photoacoustic imaging apparatus.

  In recent years, development of a photoacoustic imaging apparatus that inspects a specific object inside a living body in a nondestructive manner has been advanced. This photoacoustic imaging apparatus irradiates a subject such as a living body with laser light having a predetermined wavelength. Then, a photoacoustic wave, which is an elastic wave generated by a specific object (light absorber) inside the subject when the laser light is absorbed, is detected by a probe in contact with the surface of the subject. By generating a tomographic image based on the detection result, a photoacoustic image showing the light absorber inside the subject in the region directly under the probe is formed. In a typical photoacoustic imaging apparatus, a photoacoustic wave is detected on the surface of a subject.

  Here, the light incident on the inside of the subject diffuses according to the depth from the surface. Therefore, when light is irradiated from the surface of the subject, it is difficult for sufficient light to reach the light absorber in the deep part. In such a case, the light absorber absorbs only a very low amount of light, so that only a weak photoacoustic wave is generated. Furthermore, photoacoustic waves also diffuse according to the distance to the subject surface. Therefore, in a general photoacoustic imaging apparatus, even if the probe is applied to the surface of the subject, the detection intensity of the photoacoustic wave generated by the light absorber in the deep part of the subject is very small.

  For this reason, in recent years, a photoacoustic imaging apparatus including a convex type ultrasonic endoscope has been developed as disclosed in Patent Document 1, for example. In this photoacoustic imaging apparatus, an optical fiber, a balloon having a light scattering structure, and a transducer array are provided at the distal end of an ultrasonic endoscope. In addition, laser light generated outside the ultrasonic endoscope is guided to the tip of the ultrasonic endoscope inserted into the subject by an optical fiber. At the tip of the ultrasonic endoscope, laser light emitted from the optical fiber and scattered by the balloon is irradiated inside the subject. Then, the photoacoustic wave generated by the light absorber that has absorbed the laser light is detected by the transducer array at the tip of the ultrasonic endoscope, and a tomographic image of the deep part of the subject is acquired.

JP 2012-249739 A

  However, when laser light with high light output is used as in Patent Document 1, it is necessary to provide a laser light generating device in the photoacoustic imaging device, and a light guide member such as an optical fiber in the ultrasonic endoscope. And it is necessary to provide a scattering member. Therefore, the apparatus becomes large and complicated, and it is difficult to reduce the cost of the apparatus. On the other hand, if light is generated outside the ultrasonic endoscope using a light emitting element having a lower output than the laser light, the light distribution angle of the emitted light from the light emitting element is wider than that of the laser light. It is difficult to guide the light generated outside the endoscope to the ultrasonic endoscope.

  The present invention has been made in view of such a situation, and detects a photoacoustic wave having an intensity sufficient for generating a tomographic image of a deep part of a subject using a relatively low-output light source. An object of the present invention is to provide a photoacoustic wave detector and a photoacoustic imaging apparatus.

  In order to achieve the above object, a photoacoustic wave detector according to an aspect of the present invention has a light emitting element inserted into a subject, and the light emitted from the light emitting element is a light absorber in the subject. An internal light source that irradiates the light source, and an internal detection unit that detects a photoacoustic wave generated in the light absorber inside the subject and generates an internal detection signal based on the detection result of the photoacoustic wave 1).

  According to the first configuration, light irradiation is performed from the light emitting element inside the subject, and photoacoustic wave detection is also performed inside the subject. Therefore, even when the light absorber is in the deep part of the subject, light irradiation and photoacoustic wave detection can be performed at a position relatively close to the light absorber. Therefore, it is possible to detect a photoacoustic wave having an intensity sufficient for generating a tomographic image of a deep part of the subject using a light source having a relatively low output.

  In the photoacoustic wave detector having the first configuration, the internal detection unit is provided on a side surface of the insertion portion that is inserted into the subject, and the light-emitting element includes a curved surface or a plurality of planes, and the insertion portion. It is good also as a structure (2nd structure) mounted in the mounting surface which goes to the normal line direction of this side surface.

  According to the second configuration, it is possible to generate a tomographic image along the side surface of the insertion portion of the photoacoustic wave detector inserted into the subject.

  In the photoacoustic wave detector having the second configuration, the mounting surface is formed of a curved surface, and the internal detection unit is provided along the entire circumference of the side surface when viewed from the insertion direction of the insertion portion. In the plan view, a configuration (third configuration) may be employed in which light is emitted in a direction toward the normal direction of the side surface over the entire circumference of the side surface.

  According to the third configuration, a wide-range tomographic image along the entire circumference of the side surface of the insertion portion of the photoacoustic wave detector can be generated.

  In the photoacoustic wave detector having the second or third configuration, the configuration further includes a reflecting member that reflects the light emitted from the light emitting element in a direction toward the normal direction of the side surface of the insertion portion (fourth configuration). It is good.

  According to the fourth configuration, the light emitted in the direction toward the insertion direction is reflected by the reflection surface in the direction toward the normal direction of the side surface of the insertion portion. Therefore, it is possible to efficiently irradiate the subject with light.

  The photoacoustic wave detector having the first configuration further includes a reflecting member that reflects light emitted from the light emitting element in a direction toward the normal direction of the side surface, and the internal detection unit is inserted into the subject. The light emitting element is mounted on a mounting surface whose normal direction is the direction toward the insertion direction of the insertion portion, and the reflecting member has a reflecting surface facing the mounting surface (fifth). It is good also as a structure.

  According to the fifth configuration, the light emitted in the direction toward the insertion direction can be reflected by the reflection surface and reflected in the direction toward the normal direction of the outer surface of the internal detection unit. Therefore, it is possible to efficiently irradiate the subject with light. Furthermore, since it becomes easy to irradiate the region near the internal detection unit, it is possible to detect a photoacoustic wave having a sufficient intensity even when the light absorber is located near the internal detection unit.

  In the photoacoustic wave detector having any one of the second to fifth configurations, the insertion portion may be configured to be rotatable about the insertion direction of the insertion portion (sixth configuration).

  According to the sixth configuration, the light irradiation direction can be changed to any direction out of the directions perpendicular to the insertion direction. Therefore, it is possible to arbitrarily change the area shown in the tomographic image.

  In the photoacoustic wave detector having any one of the first to sixth configurations, the light emitting element may be a light emitting diode element (seventh configuration).

  Alternatively, in the photoacoustic wave detector having any one of the first to sixth configurations, the light emitting element may be a semiconductor laser element (eighth configuration).

  Alternatively, in the photoacoustic wave detector having any one of the first to sixth configurations, the light emitting element may be an organic light emitting diode element (9th configuration).

  According to any one of the seventh to ninth configurations, the light distribution angle of the light emitting element becomes relatively wide, so that it is possible to irradiate light uniformly with respect to the normal direction of the side surface of the insertion portion. In addition, the internal light source can be reduced in size. Furthermore, the subject can be irradiated with pulsed light having a high emission frequency with a simple configuration. Therefore, since more tomographic images can be formed per unit time, a clearer and higher-definition photoacoustic image can be acquired.

  In order to achieve the above object, a photoacoustic imaging apparatus according to an aspect of the present invention includes a photoacoustic wave detector having any one of the first to ninth configurations and a subject based on an internal detection signal. The internal detection image generation unit that generates the internal detection tomographic image and the image forming unit that forms the photoacoustic image using the internal detection tomographic image (tenth configuration).

  According to the 10th structure, irradiation of the light radiate | emitted from a light emitting element and the detection of a photoacoustic wave can be performed inside a subject. Further, an internal detection tomographic image based on an internal detection signal of a photoacoustic wave detected inside the subject is generated, and a photoacoustic image is formed using the internal detection tomographic image. Therefore, even if the light absorber is in the deep part of the subject, light irradiation and photoacoustic wave detection can be performed at a position relatively close to the light absorber, and a photoacoustic image of the light absorber can be formed. it can. Accordingly, it is possible to detect a photoacoustic wave having an intensity sufficient to generate a tomographic image of a deep part of the subject using a relatively low output light source, and form the photoacoustic image.

  The photoacoustic imaging apparatus of the tenth configuration further includes an external light source that irradiates light to the light absorber from outside the subject, and the timing at which the external light source irradiates light is synchronized with the internal light source. It is good also as a structure (11th structure).

  According to the eleventh configuration, an external light source on the surface of the subject can be used as an auxiliary light source. Therefore, the detection intensity of the photoacoustic wave can be further increased.

  In the photoacoustic imaging apparatus having the tenth or eleventh configuration, the photoacoustic wave generated by the light absorber in the subject is detected outside the subject, and external detection is performed based on the detection result of the photoacoustic wave. An external detection unit that generates a signal; and an external detection image generation unit that generates an external detection tomographic image of the subject based on the external detection signal. The image forming unit further uses the external detection tomographic image to perform photoacoustics. A configuration for forming an image (a twelfth configuration) may be employed.

  According to the twelfth configuration, a photoacoustic image is obtained using an internal detection tomographic image of a photoacoustic wave detected inside the subject and an externally detected tomographic image of a photoacoustic wave detected on the surface of the subject. Can be formed. In the internal detection tomogram, the detection intensity of the photoacoustic wave generated in the deep part of the subject is high, and in the external detection tomogram, the detection intensity of the photoacoustic wave generated in a region near the surface of the subject is high. Therefore, a clear photoacoustic image with a higher S / N ratio can be obtained in the photoacoustic wave detection depth direction.

  According to the present invention, a photoacoustic wave detector capable of detecting a photoacoustic wave having an intensity sufficient to generate a tomographic image of a deep part of a subject using a light source having a relatively low output, and photoacoustic An imaging device can be provided.

It is an external appearance perspective view which shows an example of a photoacoustic imaging device. It is a schematic diagram which shows an example which detects a photoacoustic wave inside a subject. It is a block diagram which shows the structural example of a photoacoustic imaging device. It is a structure figure showing an example of an insertion portion of an ultrasonic endoscope concerning a 1st embodiment. It is a structural diagram showing an example of an insertion portion of an ultrasonic endoscope according to a second embodiment. It is a structural diagram showing an example of an insertion portion of an ultrasonic endoscope according to a third embodiment. FIG. 10 is a structural diagram illustrating an example of an insertion portion of an ultrasonic endoscope according to a fourth embodiment. It is a structural diagram showing another example of the insertion portion of the ultrasonic endoscope according to the fourth embodiment. FIG. 10 is a structural diagram illustrating an example of an insertion portion of an ultrasonic endoscope according to a fifth embodiment. It is an external appearance perspective view which shows another example of a photoacoustic imaging device. It is a schematic diagram which shows another example which detects a photoacoustic wave in the inside and surface of a subject. It is a schematic diagram which shows another example which detects a photoacoustic wave in the inside and surface of a subject. It is a block diagram which shows the other structural example of a photoacoustic imaging device. It is an example of arrangement | positioning of the external light source provided in a 1st light irradiation part.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is an external perspective view showing an example of the photoacoustic imaging apparatus 100. FIG. 2 is a schematic diagram showing an example of detecting a photoacoustic wave inside the subject 150. FIG. 3 is a block diagram illustrating a configuration example of the photoacoustic imaging apparatus 100.

  As illustrated in FIG. 1, the photoacoustic imaging apparatus 100 includes a radial ultrasonic endoscope 20, an image generation unit 30, and an image display unit 40.

  The ultrasonic endoscope 20 is a photoacoustic detector that can be inserted into a body cavity 150a of a subject 150 such as a living body. The ultrasonic endoscope 20 has a function of irradiating light on the subject 150 and detecting photoacoustic waves generated by the light absorber P in the subject 150 in the body cavity 150a as shown in FIG. With this function, the ultrasonic endoscope 20 is inserted in the body cavity 150a in the Y direction, and the subject 150 on a plane (a plane including the X direction and the Z direction) intersecting the side peripheral surface of the insertion portion 20a at the distal end thereof. Tomographic image information is acquired. In addition, the ultrasonic endoscope 20 has a function of transmitting an ultrasonic wave to the subject 150 in the body cavity 150a and detecting an ultrasonic wave as a reflected wave thereof.

  As shown in FIG. 3, the ultrasonic endoscope 20 includes an internal light irradiation unit 21 and an internal acoustoelectric conversion unit 22. The internal light irradiation unit 21 includes a light source including an LED (Light Emitting Diode) element 212a (light emitting diode element; see, for example, FIG. 4 described later). The internal acoustoelectric conversion unit 22 is an internal detection unit that detects a photoacoustic wave generated in the light absorber P and an elastic wave such as an ultrasonic wave reflected in the subject 150, and detects a detection signal based on the detection result. The image is generated and output to the image generation unit 30. Hereinafter, this detection signal is referred to as an internal detection signal.

  In the ultrasonic endoscope 20, light is irradiated from the LED element 212a in the body cavity 150a inside the subject 150, and photoacoustic waves are also detected in the body cavity 150a. Therefore, even when the light absorber P is in the deep part of the subject 150, the ultrasonic endoscope 20 can irradiate light and detect photoacoustic waves at a position relatively close to the light absorber P. A photoacoustic image of the body P can also be formed. Accordingly, it is possible to detect a photoacoustic wave having an intensity sufficient to generate a tomographic image of a deep part of the subject 150 using a light source having a relatively low output, and form the photoacoustic image.

  A further configuration of the ultrasonic endoscope 20 will be described in detail later.

  Next, the image generation unit 30 processes the internal detection signal output from the ultrasonic endoscope 20 and performs imaging. For example, the image generation unit 30 generates a photoacoustic image using tomographic image information based on the internal detection signal based on the detection result of the photoacoustic wave, and uses the tomographic image information based on the internal detection signal based on the ultrasonic detection result. To generate an ultrasonic image.

  As shown in FIG. 3, the image generation unit 30 includes a reception circuit 301, an A / D converter 302, a reception memory 303, a data processing unit 304, a photoacoustic image reconstruction unit 305, a detection / logarithmic converter 306, and a photoacoustic image construction. Unit 307, ultrasonic image reconstruction unit 308, detection / logarithmic converter 309, ultrasonic image construction unit 310, image synthesis unit 311, control unit 312, transmission control circuit 313, operation unit 314, power supply unit 315, and endoscope A mirror light source driving unit 316 is provided.

  The receiving circuit 301 selects at least a part from a plurality of ultrasonic vibration elements 22A (described later) included in the internal acoustoelectric conversion unit 22, and amplifies a voltage signal (internal detection signal) for the selected ultrasonic vibration element 22A. To perform the process.

  The A / D converter 302 converts the amplified detection signal output from the receiving circuit 301 into a digital signal. The reception memory 303 stores the digital signal from the A / D converter 302. The data processing unit 304 has a function of distributing the signal stored in the reception memory 303 to the photoacoustic image reconstruction unit 305 or the ultrasonic image reconstruction unit 308.

  The photoacoustic image reconstruction unit 305 performs phase matching addition processing based on the photoacoustic wave detection signal to reconstruct photoacoustic wave data. The detection / logarithmic converter 306 performs logarithmic compression processing and envelope detection processing on the reconstructed photoacoustic wave data. Then, the photoacoustic image construction unit 307 converts the data processed by the detection / logarithmic converter 306 into luminance value data for each pixel. That is, photoacoustic image data (for example, gray scale) is generated as luminance value data for each pixel in the vertical and horizontal directions on the image.

  This photoacoustic image data is data indicating a photoacoustic image formed by performing an averaging process on tomographic images based on photoacoustic wave detection signals. Each pixel of the photoacoustic image represents the detection level of the photoacoustic wave after the averaging process, for example, in a gray scale of 256 gradations.

  The photoacoustic image reconstruction unit 305, the detection / logarithmic converter 306, the photoacoustic image construction unit 307, and the image synthesis unit 311 are examples of the internal detection image generation unit and the image formation unit of the present invention. Process.

  On the other hand, the ultrasound image reconstruction unit 308 performs phase matching addition processing based on the ultrasound detection signal to reconstruct the ultrasound data. The detection / logarithmic converter 309 performs logarithmic compression processing and envelope detection processing on the reconstructed ultrasonic data. Then, the ultrasonic image construction unit 310 converts the data processed by the detection / logarithmic converter 309 into luminance value data for each pixel. That is, ultrasonic image data (for example, gray scale) is generated as luminance value data for each pixel in the vertical and horizontal directions on the image.

  The image synthesizing unit 311 synthesizes the photoacoustic image data and the ultrasonic image data to generate synthesized image data. Here, for image synthesis, a photoacoustic image may be superimposed on an ultrasonic image, or a photoacoustic image and an ultrasonic image may be arranged in parallel. The image display unit 40 displays an image based on the combined image data generated by the image combining unit 311. Note that the image composition unit 311 may output either the photoacoustic image data or the ultrasonic image data to the image display unit 40 as it is.

  The control unit 312 controls each component of the photoacoustic imaging apparatus 100 using a program and control information stored in a non-transitory storage medium (memory) (not shown). For example, the control unit 312 transmits a light trigger signal or the like to the endoscope light source driving unit 316.

  The transmission control circuit 313 transmits a drive signal to the internal acoustoelectric conversion unit 22 in accordance with a control signal output from the control unit 312 to generate an ultrasonic wave.

  The operation unit 314 accepts a user operation input and outputs an input signal corresponding to the operation input to the control unit 312.

  The power supply unit 315 supplies power to each component of the photoacoustic imaging apparatus 100.

  The endoscope light source drive unit 316 is a drive circuit unit that drives the light source of the internal light irradiation unit 21 of the ultrasonic endoscope 20. For example, when receiving an optical trigger signal from the control unit 312, the endoscope light source driving unit 316 transmits a driving signal to the internal light irradiation unit 21. As will be described later, when the internal light irradiation unit 21 includes a plurality of types of light sources that emit pulsed light having different wavelengths, a wavelength control signal is output from the control unit 312. In this case, when receiving the wavelength control signal from the control unit 312, the endoscope light source driving unit 316 selects and drives the light source according to the wavelength control signal.

  Next, the image display unit 40 will be described. The image display unit 40 is a display device having a touch panel. As illustrated in FIG. 3, the image display unit 40 includes an LCD (Liquid Crystal Display) 401 and an input detection unit 402. The LCD 401 displays an image (for example, a photoacoustic image) based on the image signal generated by the image generation unit 30. The input detection unit 402 receives user operation input. When the display screen of the LCD 401 is touch-inputted by a user's finger or a touch pen, the input detection unit 402 outputs an input signal corresponding to the touch input to the control unit 312.

  Next, a detailed configuration of the ultrasonic endoscope 20 will be described. FIG. 4 is a structural diagram showing an example of the insertion portion 20a of the ultrasonic endoscope 20 according to the first embodiment. 4A is a cross section of the insertion portion 20a along the alternate long and short dash line AA, and BB is a cross section of the insertion portion 20a along the alternate long and short dash line BB.

  As shown in FIG. 4, an internal light irradiation unit 21 and an internal acoustoelectric conversion unit 22 are provided in the insertion portion 20 a inserted into the body cavity 150 a of the subject 150.

  The internal light irradiation unit 21 includes a substrate 211, an internal light source 212, and a sealing layer 213. The substrate 211 is, for example, a flexible substrate, has a cylindrical shape having an axis parallel to the insertion direction (Y direction) of the insertion portion 20a, and is provided at the distal end of the insertion portion 20a. Further, the substrate 211 is provided concentrically with the side peripheral surface of the insertion portion 20a in a plan view as viewed from the insertion direction, for example. In addition, the board | substrate 211 is not limited to the illustration of FIG. 4, A cylindrical shape or a column-shaped board | substrate (for example, a printed circuit board, a metal substrate) may be sufficient.

  The internal light source 212 includes a plurality of LED elements 212a inserted into the subject 150, and irradiates the inside of the subject 150 (particularly, the light absorber P) with light emitted from the LED elements 212a. The LED elements 212a are arranged on the main surface of the substrate 211 so as to emit light evenly in the normal direction of all the side peripheral surfaces of the insertion portion 20a along the insertion direction and the side peripheral surface. Therefore, the mounting surface of the LED element 212a is a concentric curved surface with the side peripheral surface of the insertion portion 20a when viewed from the Y direction. For example, in FIG. 4, 5 rows in the axial direction and 10 rows (that is, 50) of LED elements 212 a in the circumferential direction are arranged on the substrate 211.

  The LED element 212a is an LED light source that is driven to emit pulsed light. The PRF (Pulse Repetition Frequency) of the pulsed light is not particularly limited, but can be, for example, 1000 [times / sec]. By using the LED light source, the internal light source 212 can be miniaturized, and the subject can be irradiated with pulsed light having a high emission frequency with a simple configuration. Therefore, more tomographic image information can be acquired per unit time (for example, a period required for updating the display of the LCD 401 described later), so that the photoacoustic image can be made clearer and higher in definition.

  In addition, the LED element 212a may be comprised by the LED light source with the same light emission wavelength, and may be comprised by the multiple types of LED light source from which light emission wavelength differs. Moreover, what is necessary is just to select the wavelength with a high absorptivity with respect to a measuring object (light absorber P) regarding the setting of the light emission wavelength of the LED element 212a. For example, if the measurement target is oxygenated hemoglobin in blood, the emission wavelength can be selected to be 760 nm, which has a high absorption rate for oxygenated hemoglobin. Further, when the measurement target is reduced hemoglobin in blood, 850 nm having a high absorption rate for reduced hemoglobin can be selected. For example, when the subject 150 is irradiated with pulsed light having a wavelength of 760 nm, light is absorbed by oxyhemoglobin in blood contained in arterial blood vessels or tumors in the subject 150, and a photoacoustic wave is generated, which will be described later. In the photoacoustic image construction unit 307, a photoacoustic image including an arterial blood vessel and a tumor is generated.

  The sealing layer 213 seals the substrate 211 and the plurality of LED elements 212a. The material of the sealing layer 213 should just be a translucent material which permeate | transmits the emitted light of the some LED element 212a, and is not specifically limited. The sealing layer 213 may be formed using glass, for example, or may be a translucent resin material or a translucent composite resin material including a filler.

  The internal acoustoelectric conversion unit 22 is provided on the side circumferential surface of the insertion portion 20a inserted into the subject 150, at a stage subsequent to and in the vicinity of the internal light irradiation unit 21 with respect to the insertion direction. The internal acoustoelectric converter 22 includes an ultrasonic vibration element 22A, an acoustic lens (not shown), an acoustic matching layer (not shown), and a backing member (not shown).

  The ultrasonic vibration element 22A is a piezoelectric element that generates an ultrasonic wave by vibration when a voltage is applied and generates a voltage when vibration (ultrasonic wave) is applied. As shown in FIG. 4, a plurality of ultrasonic vibration elements 22 </ b> A are arranged along the entire circumference on the side circumferential surface of the insertion portion 20 a. Therefore, the ultrasonic endoscope 20 can acquire a wide range of tomographic image information along the entire circumference of the side circumferential surface of the insertion portion 20a.

  Note that an acoustic matching layer is provided on the entire outer surface of the ultrasonic vibration element 22A along the entire circumference of the side peripheral surface, and an acoustic lens is provided on the entire surface of the acoustic matching layer. Further, a backing member for suppressing the propagation of ultrasonic waves is provided on all inner surfaces of the ultrasonic vibration element 22A. The acoustic matching layer reduces the difference in acoustic impedance between the subject 150 and the ultrasonic vibration element 22A. For example, the acoustic matching layer has a function of efficiently transmitting ultrasonic waves generated from the ultrasonic vibration element 22 </ b> A into the subject 150. Further, the acoustic matching layer also has a function of efficiently transmitting ultrasonic waves (including photoacoustic waves) from within the subject 150 to the ultrasonic vibration element 22A. The acoustic lens has a function of focusing the ultrasonic wave output from the ultrasonic vibration element 22A.

Second Embodiment
Next, a second embodiment will be described. In the following, a configuration different from the first embodiment will be described. Moreover, the same code | symbol is attached | subjected to the structure part similar to 1st Embodiment, and the description may be abbreviate | omitted.

  FIG. 5 is a structural diagram illustrating an example of the insertion portion 20a of the ultrasonic endoscope 20 according to the second embodiment. In addition, AA of FIG. 5 is a cross section of the insertion part 20a which follows the dashed-dotted line AA.

  As shown in FIG. 5, the substrate 211 has an axis parallel to the insertion direction of the insertion portion 20a and has a cylindrical shape with a square cross section. Note that the shape of the substrate 211 may be a columnar shape, and the cross section may be a polygon other than a square (for example, a triangle, a hexagon, etc.).

  On each side surface of the substrate 211 facing the side peripheral surface of the insertion portion 20a, an LED element 212a is arranged so that light can be emitted in the normal direction of the side surface (mounting surface). For example, in FIG. 5, 5 rows by 3 columns (that is, 15) of LED elements 212 a are arranged on each side surface of the substrate 211. Note that LED elements 212a having the same emission wavelength may be disposed on all side surfaces of the substrate 211, or LED elements 212a having different emission wavelengths may be disposed on each side surface.

  Further, the internal light irradiation unit 21 includes a reflection unit 214 and four reflection plates 215 in addition to the substrate 211, the internal light source 212, and the sealing layer 213.

  The reflecting portion 214 is a reflecting member that has a reflecting surface 214a that reflects the emitted light of the LED element 212a on the surface facing the LED element 212a, and is provided at the front stage of the substrate 211 (forward with respect to the inserting direction) in the insertion portion 20a. ing.

  The reflecting plate 215 is a reflecting member having reflecting surfaces 215a that reflect the emitted light of the LED elements 212a on both main surfaces. Each reflecting plate 215 is extended on each side surface of the substrate 211 in a direction from an end side parallel to the insertion direction toward the side peripheral surface of the insertion portion 20a.

  The reflecting surfaces 214 a and 215 a of the reflecting portion 214 and the reflecting plate 215 reflect light emitted in the direction toward the insertion direction from the LED element 212 a and travel in the normal direction of the outer surface of the internal acoustoelectric conversion portion 22. Can be reflected in the direction. Therefore, the subject 150 can be irradiated with light efficiently. Furthermore, since it becomes easy to irradiate light to the region near the outer surface of the internal acoustoelectric conversion unit 22, even if the light absorber P is in a position close to the internal acoustoelectric conversion unit 22, it is sufficient from the light absorber P. It is possible to detect a photoacoustic wave having a high intensity.

  Note that the above-described configuration including the reflective surfaces 214a and 215a is applicable not only to the configuration of the present embodiment but also to the configurations of other embodiments (for example, FIG. 9 described later).

<Third Embodiment>
Next, a third embodiment will be described. In the following, a configuration different from the first and second embodiments will be described. Moreover, the same code | symbol is attached | subjected to the component similar to 1st and 2nd embodiment, and the description may be abbreviate | omitted.

  FIG. 6 is a structural diagram showing an example of the insertion portion 20a of the ultrasonic endoscope 20 according to the third embodiment. In addition, AA of FIG. 6 is a cross section of the insertion part 20a which follows the dashed-dotted line AA.

  As shown in FIG. 6, the internal light irradiation unit 21 includes a substrate 211, an internal light source 212, and a sealing layer 213. In the internal light irradiation unit 21, the substrate 211 is provided in parallel with the insertion direction of the insertion portion 20 a, and LED elements 212 a are disposed on both main surfaces of the substrate 211. For example, in FIG. 6, 5 rows by 4 columns (that is, 20) of LED elements 212 a are arranged on each main surface of the substrate 211. In addition, the internal light irradiation unit 21 includes a reflection member (for example, the reflection unit 214 of FIG. 5) having a reflection surface 214a that reflects the emitted light of the LED element 212a on the surface facing the LED element 212a in the insertion portion 20a. It may be provided in front of the substrate 211 in the insertion direction.

  Further, as shown in FIG. 6, the ultrasonic endoscope 20 is provided with an actuator 23. The actuator 23 is a rotational drive unit that can rotationally drive the insertion portion 20a around the insertion direction based on a control signal output from the control unit 312.

  In FIG. 6, the insertion portion 20a is rotatable about the insertion direction. Therefore, the irradiation direction of the pulsed light emitted from the LED element 212a can be changed to any direction out of the directions perpendicular to the insertion direction of the insertion portion 20a. Therefore, the measurement area shown in the tomographic image can be arbitrarily changed.

  Although LED elements 212a having the same emission wavelength may be arranged on both main surfaces of the substrate 211, it is preferable that LED elements 212a having different emission wavelengths are arranged for each main surface. In this way, the wavelength of the pulsed light applied to a desired measurement region can be changed by rotating the insertion portion 20a. Accordingly, the photoacoustic image can be formed by changing the wavelength of the pulsed light according to the type of the light absorber P.

<Fourth embodiment>
Next, a fourth embodiment will be described. Hereinafter, configurations different from those of the first to third embodiments will be described. Moreover, the same code | symbol is attached | subjected to the component similar to 1st-3rd embodiment, and the description may be abbreviate | omitted.

  FIG. 7 is a structural diagram illustrating an example of the insertion portion 20a of the ultrasonic endoscope 20 according to the fourth embodiment. In addition, AA of FIG. 7 is a cross section of the insertion part 20a which follows the dashed-dotted line AA.

  In the internal light irradiation unit 21, the substrate 211 is provided in front of the internal acoustoelectric conversion unit 22 so as to intersect the insertion direction of the insertion portion 20 a. The LED element 212a is disposed on the main surface in the insertion direction, and emits pulsed light in the direction in the insertion direction.

  Further, as shown in FIG. 7, the internal light irradiation part 21 is configured to further include a reflection part 214 in addition to the substrate 211, the internal light source 212, and the sealing layer 213. The reflecting portion 214 is a reflecting member having a reflecting surface 214a that reflects the emitted light of the LED element 212a on the surface facing the LED element 212a, and is provided in the insertion portion 20a in front of the substrate 211 in the insertion direction. The reflection surface 214a can reflect light emitted from the LED element 212a in the insertion direction and reflect the light in the direction normal to the outer surface of the internal acoustoelectric conversion unit 22. Therefore, the subject 150 can be irradiated with light efficiently. Furthermore, since it becomes easy to irradiate light to the region near the outer surface of the internal acoustoelectric conversion unit 22, even if the light absorber P is in a position close to the internal acoustoelectric conversion unit 22, it is sufficient from the light absorber P. It is possible to detect a photoacoustic wave having a high intensity.

(Modification of the fourth embodiment)
The arrangement of the LED elements 212a and the reflecting member 214 may be reversed with respect to the insertion direction. FIG. 8 is a structural diagram illustrating another example of the insertion portion of the ultrasonic endoscope according to the fourth embodiment. In addition, AA of FIG. 8 is a cross section of the insertion part 20a which follows the dashed-dotted line AA.

  In FIG. 8, the substrate 211 is provided at the distal end of the insertion portion 20a of the ultrasonic endoscope 20, and the reflection member 214 is provided behind the substrate 211 with respect to the insertion direction. In addition, the LED element 212 a is disposed on the main surface of the substrate 211 that faces the reflecting surface 214 a of the reflecting member 214. The reflection surface 214a can reflect light emitted from the LED element 212a in the direction toward the insertion direction and reflect the light in a direction toward the normal direction of the outer peripheral surface of the internal acoustoelectric conversion unit 22. Even with such a configuration, the same effect as that of the configuration of FIG. 7 can be obtained.

<Fifth Embodiment>
Next, a fifth embodiment will be described. Hereinafter, configurations different from those of the first to fourth embodiments will be described. Moreover, the same code | symbol is attached | subjected to the component similar to 1st-4th embodiment, and the description may be abbreviate | omitted.

  FIG. 9 is a structural diagram showing an example of the insertion portion 20a of the ultrasonic endoscope 20 according to the fifth embodiment. In addition, CC of FIG. 9 is a surface in alignment with the dashed-dotted line CC which looked at the insertion part 20a from the insertion direction (Y direction).

  As shown in FIG. 9, the substrate 211 has a frustum shape having an axis parallel to the insertion direction of the insertion portion 20a and having a square cross section. Each side surface of the frustum shape is inclined toward the internal acoustoelectric conversion unit 22 side. The shape of the substrate 211 may be a cone shape such as a cone or a pyramid, and the cross section perpendicular to the insertion direction is a circle or a polygon other than a square (for example, a triangle, Hexagonal shape).

  On each side surface of the substrate 211 facing the side peripheral surface of the insertion portion 20a, an LED element 212a is arranged so that light can be emitted in the normal direction of the side surface (mounting surface). For example, in FIG. 9, nine LED elements 212 a are arranged on each side surface of the substrate 211. Note that LED elements 212a having the same emission wavelength may be disposed on all side surfaces of the substrate 211, or LED elements 212a having different emission wavelengths may be disposed on each side surface.

  In FIG. 9, since the LED element 212 a is disposed on the side surface of the substrate 211 that is inclined toward the internal acoustoelectric conversion unit 22, the light emitted from the LED element 212 a is normal to the outer surface of the internal acoustoelectric conversion unit 22. The light can be irradiated toward the light absorber P in the direction. Furthermore, since it becomes easy to irradiate light to the region near the outer surface of the internal acoustoelectric conversion unit 22, even if the light absorber P is in a position close to the internal acoustoelectric conversion unit 22, it is sufficient from the light absorber P. It is possible to detect a photoacoustic wave having a high intensity.

<Sixth Embodiment>
Next, a sixth embodiment will be described. In the sixth embodiment, the photoacoustic imaging apparatus 100 further includes an ultrasonic probe 50 for acquiring tomographic image information on the surface of the subject 150. Further, photoacoustic imaging and ultrasonic imaging using both the ultrasonic endoscope 20 and the ultrasonic probe 50 are possible. Other than these are the same as in the first to fifth embodiments. Below, a different structure from 1st-5th embodiment is demonstrated. Moreover, the same code | symbol is attached | subjected to the component similar to 1st-5th embodiment, and the description may be abbreviate | omitted.

  FIG. 10 is an external perspective view showing another example of the photoacoustic imaging apparatus 100. FIG. 11A and FIG. 11B are schematic views showing another example of detecting a photoacoustic wave inside and on the surface of the subject 150. 11A is a schematic diagram viewed from the Z direction, and FIG. 11B is a schematic diagram viewed from the Y direction. FIG. 12 is a block diagram illustrating another configuration example of the photoacoustic imaging apparatus 100.

  As shown in FIG. 10, the photoacoustic imaging apparatus 100 further includes an ultrasonic probe 50 in addition to the radial ultrasonic endoscope 20, the image generation unit 30, and the image display unit 40. As shown in FIGS. 11A and 11B, the ultrasonic probe 50 has a function of irradiating light from the surface of the subject 150 and detecting photoacoustic waves generated by the light absorber P in the subject 150. The ultrasonic probe 50 also has a function of transmitting ultrasonic waves to the subject 150 and detecting ultrasonic waves that are reflected waves.

  As shown in FIG. 12, the ultrasonic probe 50 includes a drive power supply unit 501, a light source drive unit 502, first and second light irradiation units 503A and 503B each having external light sources 504A and 504B, and external acoustoelectric conversion. Part 505. In addition, the ultrasonic probe 50 includes a lens member that collects the light emitted from the external light sources 504A and 504B, and a light guide unit (for example, an acrylic resin) that guides the light collected by the lens member to the subject 150. (Made light guide plate, optical fiber) or the like.

  The drive power supply unit 501 supplies power to the light source drive unit 502. In FIG. 12, the drive power supply unit 501 is a power supply source of the ultrasonic probe 50, but is not limited to this example, and each component of the ultrasonic probe 50 is supplied with power from the power supply unit 315. May be.

  The light source driving unit 502 includes a light source driving circuit 502A and a light source driving circuit 502B. The light source driving circuit 502A controls driving of the external light source 504A, and the light source driving circuit 502B controls driving of the external light source 504B. When the ultrasonic probe 50 performs photoacoustic imaging together with the ultrasonic endoscope 20 to acquire a tomographic image of the same measurement region, the light source drive circuits 502A and 502B are configured to output pulsed light from the ultrasonic endoscope 20. In accordance with the irradiation timing, pulsed light is emitted from the external light sources 504A and 504B. That is, the light source driving circuits 502A and 502B set the external light sources 504A and 504B so that the emission timing of the pulsed light from the external light sources 504A and 504B and the irradiation timing of the pulsed light from the ultrasonic endoscope 20 are synchronized. Drive control.

  The first and second light irradiation units 504A and 504B are arranged so as to face each other in the Y direction with the external acoustoelectric conversion unit 505 interposed therebetween (see FIG. 11A). The first and second light irradiation units 504A and 504B are provided so as to be positioned in the vicinity of the subject 150 when the ultrasonic probe 50 is brought into contact with the subject 150.

  The external light sources 504A and 504B provided in the first and second light irradiation units 503A and 503B, respectively, include light emitting elements such as LED elements (not shown), for example. 150 is irradiated with pulsed light. FIG. 13 is an arrangement example of the external light sources 504A and 504B provided in the first light irradiation unit 503A. In the following, an arrangement example in the first light irradiation unit 503A will be described with reference to FIG. 13, but external light sources 504A and 504B provided in the second light irradiation unit 503B are also similar to the first light irradiation unit 503A. Be placed.

  The external light sources 504A and 504B are alternately arranged in the Y direction as shown in FIG. Each of the external light sources 504A and 504B includes three rows of LED elements in the Y direction and six rows (that is, 3 × 6 = 18) of LED elements in the Z direction. This LED element is an LED light source that is driven to emit pulsed light. The PRF (Pulse Repetition Frequency) of the pulsed light is not particularly limited, but can be, for example, 1000 [times / sec].

  As described above, if the external light sources 504A and 504B are respectively LED light sources, the external light sources 504A and 504B can be miniaturized, and the subject can be irradiated with pulsed light having a high emission frequency with a simple configuration. Accordingly, more tomographic image information can be acquired per unit time (for example, a period required for updating the display of the LCD 401 described later), so that a photoacoustic image described later can be made clearer and higher in definition.

  Further, the external light sources 504A and 504B have different emission wavelengths of the LED elements. That is, the external light sources 504A and 504B emit light having different wavelengths. Regarding the setting of the wavelength, a wavelength having a high absorptance with respect to the measurement target (light absorber P) may be selected.

  Next, the external acoustoelectric conversion unit 505 is an external detection unit that detects a photoacoustic wave generated in the light absorber P and an elastic wave such as an ultrasonic wave reflected in the subject 150, and is based on the detection result. A detection signal is generated and output to the image generation unit 30. Hereinafter, this detection signal is referred to as an external detection signal.

  The external acoustoelectric conversion unit 505 includes an ultrasonic vibration element 505A, an acoustic lens (not shown), an acoustic matching layer (not shown), and a backing member (not shown).

  The ultrasonic vibration element 505A is a piezoelectric element that generates an ultrasonic wave by vibration when a voltage is applied and generates a voltage when vibration (ultrasonic wave) is applied. The ultrasonic vibration element 505A generates an ultrasonic wave to propagate the ultrasonic wave into the subject 150, detects the ultrasonic wave reflected within the subject 150, and generates a voltage signal. That is, using the ultrasonic probe 50, ultrasonic imaging can be performed in addition to photoacoustic imaging.

  The ultrasonic vibration elements 505A are disposed between the first and second light irradiation units 503A and 503B (see FIG. 11A), and a plurality of ultrasonic vibration elements 505A are disposed in the Z direction (see FIG. 11B). Note that an acoustic matching layer and an acoustic lens are sequentially provided on the surface of the ultrasonic vibration element 505A on the subject 150 side (for example, the lower surface of the ultrasonic vibration element 505A in FIGS. 11A and 11B). Further, a backing member that suppresses the propagation of ultrasonic waves is provided on the surface opposite to the surface (for example, the upper surface of the ultrasonic vibration element 505A in FIGS. 11A and 11B).

  Next, processing of the image generation unit 30 for the ultrasonic probe 50 will be described. The receiving circuit 301 further performs a process of selecting at least a part from the ultrasonic vibration element 505A and amplifying a voltage signal (external detection signal) for the selected ultrasonic vibration element 505A.

  In the A / D converter 302, the amplified detection signal (internal detection signal, external detection signal) output from the receiving circuit 301 is converted into a digital signal.

  The photoacoustic image reconstruction unit 305, the detection / logarithmic converter 306, and the photoacoustic image construction unit 307 perform photoacoustic wave imaging processing to generate photoacoustic image data. This photoacoustic image data is data indicating a photoacoustic image formed by performing an averaging process on tomographic images based on photoacoustic wave detection signals. It should be noted that the photoacoustic image reconstruction unit 305, the detection / logarithmic converter 306, the photoacoustic image construction unit 307, and the image synthesis unit 311 are the internal detection image generation unit, external detection image generation unit, and image formation unit of the present invention. This is an example, and photoacoustic wave imaging processing is performed.

  For example, consider a case where photoacoustic imaging is performed using both the ultrasonic endoscope 20 and the ultrasonic probe 50. In this case, the photoacoustic obtained by averaging the internally detected tomographic image based on the internal detection signal output from the ultrasonic endoscope 20 and the externally detected tomographic image based on the external detection signal output from the ultrasonic probe 50. An image can be formed. In the externally detected tomographic image, the detection depth direction of the photoacoustic wave is opposite to that of the internally detected tomographic image. For example, in the internal detection tomogram, the detection depth direction is the -X direction, and in the external detection tomogram, the detection depth direction is the X direction. Therefore, it goes without saying that the addition averaging process when forming the photoacoustic image is performed after the process of matching the two measurement depth directions.

  If a photoacoustic image is formed in this way, for example, a photoacoustic image in which an internal detection tomographic image and an external detection tomographic image are superimposed can be obtained. That is, a photoacoustic image can be formed using an internal detection tomographic image of a photoacoustic wave detected inside the subject 150 and an externally detected tomographic image of a photoacoustic wave detected on the surface of the subject 150. it can. In the internal detection tomogram, the detection intensity of the photoacoustic wave generated in the deep part of the subject 150 is high, and in the external detection tomogram, the detection intensity of the photoacoustic wave generated in a region near the surface of the subject 150 is high. . Therefore, a clear photoacoustic image with a higher S / N ratio can be obtained in the photoacoustic wave detection depth direction.

  In the photoacoustic imaging described above, the photoacoustic image is formed by adding and averaging the internal detection tomographic image and the external detection tomographic image. However, in the photoacoustic imaging apparatus 100 of the present embodiment, the internal detection tomographic image. It is also possible to perform an averaging process on the externally detected tomogram separately. In this case, a photoacoustic image based on the internally detected tomographic image and a photoacoustic image based on the externally detected tomographic image can be formed individually.

  Moreover, in the photoacoustic imaging apparatus 100 of this embodiment, a photoacoustic image can also be formed based on one of an internal detection tomographic image and an external detection tomographic image. In this case, pulse light having the same emission timing is irradiated from both the ultrasonic endoscope 20 and the ultrasonic probe 50, and a photoacoustic wave is detected by one of the ultrasonic endoscope 20 and the ultrasonic probe 50. Also good. In this way, when forming a photoacoustic image based on the internal detection tomographic image, the external light sources 504A and 504B of the ultrasonic probe 50 on the surface of the subject 150 can be used as auxiliary light sources. When a photoacoustic image is formed based on an externally detected tomographic image, the internal light source 212 of the ultrasonic endoscope 20 in the body cavity 150a can be used as an auxiliary light source. Therefore, the detection intensity of the photoacoustic wave can be further increased. Therefore, a clearer photoacoustic image can be obtained.

  Whether to form a photoacoustic image based on the internal detected tomographic image and the externally detected tomographic image or to individually form the photoacoustic image on each tomographic image can be selected, for example, according to a user operation input.

  On the other hand, the ultrasound image reconstruction unit 308, the detection / logarithmic converter 309, and the ultrasound image construction unit 310 perform imaging processing of ultrasound reflected in the subject 150, and create ultrasound image data. The The ultrasonic image data is data indicating an ultrasonic image formed by performing an averaging process on tomographic images based on ultrasonic detection signals. When ultrasonic imaging is performed using both the ultrasonic endoscope 20 and the ultrasonic probe 50, an internal detection tomographic image based on an internal detection signal output from the ultrasonic endoscope 20 and an output from the ultrasonic probe 50 are used. It is possible to form an ultrasonic image obtained by adding and averaging the externally detected tomographic image based on the externally detected signal.

  The control unit 312 can control each component of the ultrasonic probe 50 using a program and control information stored in a non-transitory storage medium (memory) (not shown). For example, the control unit 312 transmits a wavelength control signal, an optical trigger signal, and the like to the light source driving unit 502. The transmission control circuit 313 transmits a drive signal to the external acoustoelectric conversion unit 505 according to the control signal output from the control unit 312 to generate an ultrasonic wave.

  As described above, in the photoacoustic imaging apparatus 100 of the present embodiment, photoacoustic imaging is performed using both the ultrasonic endoscope 20 and the ultrasonic probe 50, and tomographic image information of a common measurement region is superimposed. A photoacoustic image can be formed (see FIGS. 11A and 11B). The same applies to the formation of an ultrasonic image by ultrasonic imaging. Below, an example of the photoacoustic imaging process in the photoacoustic imaging device 100 of this embodiment is demonstrated.

  First, the measurement positions in the Y direction and the Z direction of the ultrasonic endoscope 20 and the ultrasonic probe 50 are adjusted. In this process, the ultrasonic endoscope 20 is inserted into the body cavity 150 a and the ultrasonic waves are output from the internal acoustoelectric conversion unit 22. Then, in a state where the ultrasonic probe 50 is in contact with the surface of the subject 150, the ultrasonic wave output from the ultrasonic endoscope 20 is transmitted while the ultrasonic probe 50 is moved in the Y direction and the Z direction. Detect at 50. If the position of the ultrasonic probe 50 in the Y direction and the Z direction is the same as that of the ultrasonic endoscope 20 and the ultrasonic probe 50 is located immediately above the ultrasonic endoscope 20 with respect to the −X direction, The detection intensity at the acoustic probe 50 is maximized. Accordingly, the positions in the Y direction and Z direction where the ultrasonic detection intensity is maximum are set as the measurement positions of the ultrasonic probe 50.

  Next, position adjustment of the internal detection tomographic image of the ultrasonic endoscope 20 and the external detection tomographic image of the ultrasonic probe 50 is performed. In this process, a plane in which the plurality of ultrasonic vibration elements 22A included in the internal acoustoelectric conversion unit 22 are arranged (see, for example, the section BB in FIG. 4) and a plurality of ultrasonic vibration elements included in the external acoustoelectric conversion unit 505 are included. The arrangement direction (Z direction) of 505A and the plane including the X direction are matched. First, the ultrasonic probe 50 detects the ultrasonic wave output from the ultrasonic endoscope 20 while rotating the ultrasonic probe 50 around the X direction. When the two planes coincide with each other, the intensity detected by the ultrasonic probe 50 is maximized. Therefore, the rotational position where the ultrasonic detection intensity is maximum is set as the measurement position of the ultrasonic probe 50.

  Next, photoacoustic imaging and photoacoustic image formation are performed. The subject 150 is irradiated with pulsed light having the same emission timing from the ultrasonic endoscope 20 and the ultrasonic probe 50, and an internal detection signal based on the photoacoustic wave detected by the ultrasonic endoscope 20, and the ultrasonic probe 50 And an external detection signal based on the photoacoustic wave detected in (1). Then, a photoacoustic image is formed based on the internal detection tomographic image generated from the internal detection signal and the external detection tomographic image generated from the external detection signal.

  In the above-described photoacoustic imaging process, the PRF of each pulsed light emitted from the ultrasonic endoscope 20 and the ultrasonic probe 50 may be the same or different. That is, the light emission timings of the two need only be synchronized. For example, the PRF of the pulsed light of the ultrasonic endoscope 20 is 1000 [times / sec], and the PRF of the pulsed light of the ultrasonic probe 50 is 500 [times]. / Sec].

  The embodiment of the present invention has been described above. Note that the above-described embodiment is an exemplification, and various modifications can be made to each component and combination of processes, and it will be understood by those skilled in the art that they are within the scope of the present invention.

  For example, in the above-described embodiment, the internal light source 212 and the external light sources 504A and 504B are LED light sources, but the present invention is not limited to this example. The internal light source 212 and the external light sources 504A and 504B only need to include a light source that can emit pulsed light. For example, the internal light source 212 and the external light sources 504A and 504B may be a light source including a semiconductor laser element (semiconductor laser element light source). A light source (organic light-emitting diode element) may be included. Alternatively, the internal light source 212 and the external light sources 504A and 504B may be light sources including at least one of a light emitting diode element, a semiconductor laser element, and an organic light emitting diode element. By so doing, the light distribution angle of the light emitting element becomes relatively wide, so that it is possible to uniformly irradiate light in the normal direction of the side surface of the insertion portion 20a. Further, the internal light source 212 can be reduced in size. Furthermore, the subject 150 can be irradiated with pulsed light having a high emission frequency with a simple configuration. Therefore, since more tomographic images can be formed per unit time, a clearer and higher-definition photoacoustic image can be acquired.

  Further, in the above-described embodiment, the LED element 212a is mounted on the side surface of a cube (column, cone, frustum, etc.) whose cross-sectional shape perpendicular to the axial direction is circular or square, a plate-shaped main surface, and the like. However, the mounting surface of the LED element 212a is not limited to these examples. The mounting surface of the LED element 212a may be a surface that is formed of a curved surface or a plurality of flat surfaces and that faces the normal direction of the side peripheral surface of the insertion portion 20a. In this way, a tomographic image along the side peripheral surface of the insertion portion 20a of the ultrasonic endoscope 20 inserted into the subject 150 can be generated.

  In the above-described embodiment, the endoscope light source driving unit 316 is provided in the image forming unit 30, but the present invention is not limited to this example. The endoscope light source driving unit 316 may be provided in the ultrasonic endoscope 20.

  Moreover, the structure provided with the actuator 23 demonstrated in 3rd Embodiment is applicable also to the structure of embodiment other than 3rd Embodiment. For example, when applied to the configurations of the second and fifth embodiments, the measurement portion reflected in the tomographic image is changed by changing the insertion portion 20a, or the wavelength of the pulsed light irradiated to the desired measurement region is changed. can do. Further, in embodiments other than the third embodiment, even when a plurality of types of LED light sources having different emission wavelengths are arranged in a biased manner, the emitted light of various LED light sources is irradiated by rotating the insertion portion 20a. You can change the area. For example, in FIG. 4, FIG. 6 and FIG. 7 (first and fourth embodiments), the LED light source disposed in the left half region of the AA cross section of the insertion portion 20a and the right half region. Let us consider a case where the wavelength of the emitted light is different from that of the LED light source. Even in such a case, the region irradiated with the emitted light of each LED light source can be changed by rotating the insertion portion 20a. By so doing, it is possible to change the wavelength of the pulsed light applied to the desired measurement region. Accordingly, the photoacoustic image can be formed by changing the wavelength of the pulsed light according to the type of the light absorber P.

DESCRIPTION OF SYMBOLS 100 Photoacoustic imaging apparatus 150 Subject 20 Ultrasound endoscope 20a Insertion part 21 Internal light irradiation part 211 Substrate 212 Internal light source 212a LED element 213 Sealing layer 22 Internal acoustoelectric conversion part 22A Ultrasonic vibration element 23 Actuator 30 Image Generation unit 301 Reception circuit 302 A / D converter 303 Reception memory 304 Data processing unit 305 Photoacoustic image reconstruction unit 306 Detection / logarithmic converter 307 Photoacoustic image construction unit 308 Ultrasound image reconstruction unit 309 Detection / logarithmic converter 310 Ultrasound Image construction unit 311 Image composition unit 312 Control unit 313 Transmission control circuit 314 Operation unit 315 Power supply unit 316 Endoscope light source drive unit 40 Image display unit 401 LCD
402 Input detection unit 50 Ultrasonic probe 501 Drive power supply unit 502 Light source drive unit 502A, 502B Light source drive circuit 503A First light irradiation unit 503B Second light irradiation unit 504A, 504B External light source 505 External acoustoelectric conversion unit 505A Ultrasonic vibration element P light absorber

Claims (12)

An internal light source having a light emitting element inserted into the subject, and irradiating light emitted from the light emitting element to the light absorber in the subject;
An internal detection unit that detects a photoacoustic wave generated in the light absorber inside the subject and generates an internal detection signal based on the detection result of the photoacoustic wave;
A photoacoustic wave detector. The internal detection unit is provided on a side surface of an insertion portion to be inserted into the subject,
2. The photoacoustic wave detector according to claim 1, wherein the light emitting element is mounted on a mounting surface that is formed of a curved surface or a plurality of flat surfaces and faces in a normal direction of the side surface of the insertion portion. The mounting surface comprises a curved surface;
The internal detection unit is provided along the entire circumference of the side surface of the insertion part in a plan view seen from the insertion direction of the insertion part,
The photoacoustic wave detector according to claim 2, wherein the light emitting element emits light in a direction toward a normal direction of the side surface over the entire circumference of the side surface in the plan view.   The photoacoustic wave detector of Claim 2 or Claim 3 further provided with the reflection member which reflects the said light radiate | emitted from the said light emitting element in the direction which goes to the normal line direction of the said side surface. A reflection member that reflects the light emitted from the light emitting element in a direction toward the normal direction of the side surface;
The internal detection unit is provided on a side surface of an insertion portion to be inserted into the subject,
The light emitting element is mounted on a mounting surface whose normal direction is a direction toward the insertion direction of the insertion portion,
The photoacoustic wave detector according to claim 1, wherein the reflecting member has a reflecting surface facing the mounting surface.   The photoacoustic wave detector according to any one of claims 2 to 5, wherein the insertion portion is rotatable about an insertion direction of the insertion portion.   The photoacoustic wave detector according to any one of claims 1 to 6, wherein the light emitting element is a light emitting diode element.   The photoacoustic wave detector according to claim 1, wherein the light emitting element is a semiconductor laser element.   The photoacoustic wave detector according to claim 1, wherein the light emitting element is an organic light emitting diode element. The photoacoustic wave detector according to any one of claims 1 to 9,
An internal detection image generation unit for generating an internal detection tomographic image of the subject based on the internal detection signal;
An image forming unit that forms a photoacoustic image using the internal detection tomographic image;
A photoacoustic imaging apparatus. An external light source that irradiates light to the light absorber from outside the subject;
The photoacoustic imaging apparatus according to claim 10, wherein a timing at which the external light source emits light is synchronized with the internal light source. An external detection unit for detecting a photoacoustic wave generated by a light absorber in the subject outside the subject and generating an external detection signal based on the detection result of the photoacoustic wave;
An external detection image generation unit that generates an external detection tomographic image of the subject based on the external detection signal;
Further comprising
The photoacoustic imaging apparatus according to claim 10 or 11, wherein the image forming unit forms the photoacoustic image by further using the externally detected tomographic image.

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