JP2016047210A - Photoacoustic probe and photoacoustic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operability by reducing consumption power and downsizing an outer shape, and to create an accurate photoacoustic image by detecting an accurate photoacoustic wave.SOLUTION: An photoacoustic probe 10 comprises: a light source part 13; and an acoustic wave detection part 14 that detects an acoustic wave in an analyte Bd. The light source part 13 has a plurality of long-shaped light source bodies 130, 132 in which light emitters 130 are arrayed, and a light source holding part 15 that holds the light source bodies 130, 132 at an interval with respect to the analyte Bd in an overlapping manner when viewed from the analyte Bd. The light source holding part 15 is provided with a light guide part 153 that guides light emitted from each of the light source bodies 130, 132 so as to avoid the light source body 130 that is closer to the analyte Bd than the light source body 132.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a photoacoustic imaging apparatus, and more particularly to a photoacoustic imaging apparatus including a photoacoustic probe that detects an acoustic wave generated in a subject by light irradiation.

  Conventionally, ultrasonic imaging using transmission / reception of ultrasonic waves is known as a technique for acquiring a tomographic image of a subject (for example, a living body) without invasiveness. Furthermore, conventionally, photoacoustic imaging using photoacoustic waves (ultrasonic waves) generated inside a living body by irradiating the subject with light has been developed.

  For example, in the photoacoustic imaging apparatus (photoacoustic imaging) described in Patent Literature 1, a light source that irradiates light to a measurement region, and an ultrasonic wave that transmits ultrasonic waves to the measurement region and receives elastic waves from the measurement region. It has a photoacoustic probe including a probe. In the photoacoustic probe, the light source and the ultrasonic probe are integrally fixed so as to be adjacent to each other, and light is emitted in a direction in which ultrasonic waves from the ultrasonic probe travel. Thus, the light source is arranged. A laser light source that emits laser light is used as the light source.

  Since the laser light has a large light energy, the laser beam can reach the deep part of the living body that is the subject, and a tomographic image of the deep part of the living body can be acquired. However, since the laser beam has high directivity, in the case of a configuration in which a plurality of the laser light sources are arranged, the irradiated light becomes uneven. The laser light source is large and the photoacoustic probe is large. Furthermore, since the laser light source generates a large amount of heat, a structure for heat dissipation is also required, and the structure tends to be complicated.

  Therefore, research has been conducted on the use of light emitting elements such as LEDs as light sources instead of the laser light sources. Since the light energy of the light emitted from the light emitting element is smaller than that of the laser light source, when the light emitting element is used as a light source, a structure capable of irradiating light with high light energy by using a plurality of the light emitting elements It is said.

JP 2008-49063 A

  When a plurality of light emitting elements are arranged in a plane, the number of light emitting elements that can be arranged is limited by an installation area (for example, an area of a mounting substrate). When the depth of the living body to be observed is deep, a large number of light emitting elements are required to obtain light energy necessary for light to reach the living body depth. Therefore, the area of the portion where the light emitting elements are arranged is increased, the photoacoustic probe is increased, and the operability is also deteriorated. Further, when the area of the portion where the light emitting elements are arranged is increased to some extent, the light of the light emitting elements installed at the ends does not reach the vicinity immediately below the photoacoustic probe, the light energy does not increase, and energy is wasted. End up.

  Therefore, the present invention improves operability by reducing power consumption and reducing the outer shape, and can accurately detect photoacoustic waves by collecting light and irradiating light with high light energy. An object is to provide a photoacoustic probe.

  It is another object of the present invention to provide a photoacoustic imaging apparatus that can create an accurate photoacoustic image.

  In order to achieve the above object, the present invention provides a light source unit that irradiates a subject with light, and a light source unit that is disposed adjacent to the light source unit and light from the light source unit is absorbed inside the subject. An acoustic wave detection unit for detecting the generated acoustic wave, and the light source unit includes a plurality of elongated light source bodies in which light emitting elements are arranged, and the plurality of light source bodies are connected to the subject. And a light source holding part that holds the light source holding part so as to overlap with each other when viewed from the contact part that comes into contact with the light source holding part. The light source holding part is closer to the contact part than the light source body. A light guide unit is provided that transmits the side of the light source body and guides it to the contact unit.

  According to this structure, the number of light emitting elements with respect to the area seen from the said contact part side of a light source part can be increased by arrange | positioning a light source body up and down. Thus, high-accuracy photoacoustic imaging can be performed using a light-emitting element such as an LED that consumes less power than a laser that has been used as a light source and can be easily downsized.

  In addition, by using the light guide unit, it is possible to guide the light from the light source body to the part close to the acoustic wave detection unit, and irradiate the part close to the surface of the subject with sufficient light. It is possible.

  In the above configuration, the contact portion receives light from the light source body closest to the subject and irradiates the subject, and the second region receives light from the light guide portion and irradiates the subject. And may have a region.

  In the above-described configuration, the light guide section includes a branch section that branches incident light, and the light guide section includes a short direction of a light source body in which the branched light is disposed near the subject. You may have a light guide formed so that it may pass outside rather than both ends.

  The said structure WHEREIN: The vertex of the said branch part may be formed so that it may become far from the said acoustic wave detection part rather than the center of the transversal direction of the light source body which injects light into the said light guide part.

  The said structure WHEREIN: What forms the inclination angle with respect to the optical axis of the light source body which makes light inject into the said light guide part of the said light guide path smaller than 45 degree | times can be mentioned.

  The said structure WHEREIN: The said light guide part may oppose and arrange | position the reflective surface which reflects the light which permeate | transmits an inside.

  The said structure WHEREIN: The said reflective surface may perform the process which raises the reflectance to the inside of the light which permeate | transmits an inside.

  The said structure WHEREIN: The distance of the said reflective surface arrange | positioned facing may be formed so that it may spread, so that the said subject is approached.

  In the above configuration, at least one of the plurality of light source bodies may be held with the optical axis of the light emitting element tilted toward the acoustic wave detection unit.

  The said structure WHEREIN: You may provide the said several light source part arrange | positioned so that the said acoustic wave detection part may be pinched | interposed.

  In the above configuration, the light emitting element may include any of a light emitting diode element, a semiconductor laser element, and an organic light emitting diode element.

  Examples of the apparatus provided with the photoacoustic probe described above include a photoacoustic imaging apparatus that images an internal state of the subject based on information from the photoacoustic probe.

  According to the present invention, light that can detect accurate photoacoustic waves by reducing power consumption and improving operability by reducing the outer shape, condensing light, and irradiating light with high light energy. An acoustic probe can be provided.

  Further, according to the present invention, it is possible to provide a photoacoustic imaging apparatus capable of creating an accurate photoacoustic image.

1 is a schematic external view of an example of a photoacoustic imaging apparatus according to the present invention. It is a block diagram of the photoacoustic imaging device shown in FIG. It is a schematic perspective view of the photoacoustic probe concerning this invention. It is a disassembled perspective view of the light source part with which the photoacoustic probe concerning this invention is equipped. It is the schematic of the light source board provided with the LED element. It is a perspective view of the light source holding part with which a light source part is equipped. It is sectional drawing cut | disconnected by the surface orthogonal to the longitudinal direction of the light source holding | maintenance part shown in FIG. It is sectional drawing of the light source holding | maintenance part used for the other example of the photoacoustic probe concerning this invention. It is sectional drawing of the light source holding | maintenance part used for the further another example of the photoacoustic probe concerning this invention. It is sectional drawing of the light source holding | maintenance part used for the further another example of the photoacoustic probe concerning this invention. It is sectional drawing of the light source holding | maintenance part used for the further another example of the photoacoustic probe concerning this invention.

  A photoacoustic imaging apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic external view of an example of a photoacoustic imaging apparatus according to the present invention, and FIG. 2 is a block diagram of the photoacoustic imaging apparatus shown in FIG.

  The photoacoustic imaging apparatus A according to the present invention irradiates light having a wavelength with a small attenuation inside the subject Bd (for example, about 650 nm to about 1100 nm in the case of a living body), and the internal tissue emits light energy. A tomographic image is obtained by detecting an elastic wave (ultrasonic wave) due to absorption and thermal expansion.

  As shown in FIGS. 1 and 2, the photoacoustic imaging apparatus A includes a photoacoustic probe 10 that irradiates a subject Bd that is a living body and detects a photoacoustic wave generated in the subject Bd. An image generation unit 20 that generates a photoacoustic image based on a photoacoustic wave detection signal is provided. In addition, the photoacoustic probe 10 transmits ultrasonic waves to the subject Bd and also detects ultrasonic waves that are reflected waves, and the image generation unit 20 generates an ultrasonic image based on the ultrasonic detection signal. Also generate. Furthermore, the photoacoustic imaging apparatus A also includes an image display unit 30 that displays an image based on the image signal generated by the image generation unit 20.

  The photoacoustic probe 10 includes a drive power supply unit 11, a light source unit 13 that emits light (infrared light: wavelength of about 850 nm) when power is supplied from the drive power supply unit 11, and a light emitting element provided in the light source unit 13. LED driving circuit 12 for controlling the above.

  Here, details of the photoacoustic probe 10 will be described with reference to a new drawing. FIG. 3 is a schematic perspective view of the photoacoustic probe. In the following description, as shown in FIG. 3, the arrangement direction of the acoustoelectric transducers 141 of the acoustic wave detection unit 14 is the X direction, the direction orthogonal to the arrangement direction is the Y direction, and the vertical direction on the paper is the Z direction.

  As shown in FIG. 3, the photoacoustic probe 10 includes an acoustic wave detection unit 14 and a light source unit 13 that is disposed in proximity to the acoustic wave detection unit 14. The photoacoustic probe 10 makes the lower side in the Z direction in FIG. 3 contact the subject Bd, and irradiates the subject Bd with light from the light source unit 13 or irradiates the subject with ultrasonic waves from the acoustic wave detection unit 14. An acoustic wave from the inside of the specimen Bd is detected.

  The acoustic wave detection unit 14 has a configuration in which acoustoelectric conversion elements 141 that transmit or detect ultrasonic waves are arranged in the X direction. The acoustic wave detection unit 14 has the same configuration as that of an ultrasonic probe used in a conventional ultrasonic tomographic diagnosis apparatus, and thus detailed description thereof is omitted.

  As shown in FIG. 3, the photoacoustic probe 10 includes two light source units 13. The two light source units 13 are long members extending in the arrangement direction (that is, the X direction) of the acoustoelectric conversion elements 141. Further, the two light source units 13 are arranged so as to sandwich the acoustic wave detection unit 14 from both sides in the Y direction. The light source unit 13 irradiates the subject Bd with planar light whose in-plane luminance is equalized. Thereby, uniform or substantially uniform light can be irradiated to the lower part of the acoustic wave detection part 14 in the Z-axis direction.

  The light emitted from the light source unit 13 enters the subject Bd while being scattered, and is absorbed by the light absorber (biological tissue) in the subject Bd. When the light absorber absorbs light, a photoacoustic wave (ultrasonic wave) that is an elastic wave is generated by adiabatic expansion. The generated photoacoustic wave propagates in the subject Bd and is converted into a voltage signal by the acoustoelectric conversion element 141. The acoustoelectric conversion element 141 of the acoustic detection unit 14 may generate an ultrasonic wave, send the ultrasonic wave into the subject Bd, receive the ultrasonic wave reflected in the subject Bd, and generate a voltage signal. Is possible. That is, the photoacoustic imaging apparatus A of the present embodiment can also perform ultrasonic imaging in addition to photoacoustic imaging.

  The acoustic wave (ultrasonic wave) used in the photoacoustic imaging apparatus A is greatly attenuated when propagating through the air layer. Therefore, the photoacoustic imaging apparatus A may use an acoustic matching fluid (gel) that matches the acoustic impedance between the acoustic wave detection unit 14 and the subject Bd. By applying this gel, the acoustic wave detection characteristics can be improved, and the LED element 131 of the light source unit 13 can be cooled.

  Next, the image generation unit 20 will be described. As shown in FIG. 2, the image generation unit 20 includes a reception circuit 21, an A / D converter 22, a reception memory 23, a data processing unit 24, a photoacoustic image reconstruction unit 25, a detection / logarithmic converter 26, and a photoacoustic image construction. 27, an ultrasonic image reconstruction unit 28, a detection / logarithmic converter 29, an ultrasonic image construction unit 210, an image composition unit 211, a control unit 212, and a transmission control circuit 213.

  The receiving circuit 21 selects some of the acoustoelectric transducers 141 from the plurality of acoustoelectric transducers 141 and performs a process of amplifying a voltage signal (detection signal) for the selected acoustoelectric transducers 141.

  In the case of photoacoustic imaging, for example, the plurality of acoustoelectric transducers 141 are divided into two areas adjacent in the X direction, and one area is selected for the first light irradiation, and the second light irradiation is performed. The remaining one area is selected at the time. In the case of ultrasonic imaging, for example, an ultrasonic wave is generated while switching a group of a plurality of adjacent acoustoelectric transducers 141 among a plurality of acoustoelectric transducers 141 (so-called linear electronic scan), and a receiving circuit. 21 also selects the group while switching.

  The A / D converter 22 converts the amplified detection signal from the reception circuit 21 into a digital signal. The reception memory 23 stores the digital signal from the A / D converter 22. The data processing unit 24 has a function of distributing the signal stored in the reception memory 23 to the photoacoustic image reconstruction unit 25 or the ultrasonic image reconstruction unit 28.

  The photoacoustic image reconstruction unit 25 performs phase matching addition processing based on the photoacoustic wave detection signal to reconstruct the photoacoustic wave data. The detection / logarithmic converter 26 performs logarithmic compression processing and envelope detection processing on the reconstructed photoacoustic wave data. Then, the photoacoustic image construction unit 27 converts the data processed by the detection / logarithmic converter 26 into luminance value data for each pixel.

  On the other hand, the ultrasonic image reconstruction unit 28 performs phase matching addition processing based on the ultrasonic detection signal to reconstruct the ultrasonic data. The detection / logarithmic converter 29 performs logarithmic compression processing and envelope detection processing on the reconstructed ultrasonic data. Then, the ultrasonic image construction unit 210 converts the data processed by the detection / logarithmic converter 29 into luminance value data for each pixel.

  The image synthesizing unit 211 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 30 displays an image based on the combined image data generated by the image combining unit 211.

  Note that the image composition unit 211 may output either photoacoustic image data or ultrasonic image data to the image display unit 30 as it is.

  In addition, the control unit 212 transmits a wavelength control signal to the LED drive circuit 12, and the LED drive circuit 12 that has received the wavelength control signal transmits the light trigger signal from the control unit 212 to the light source drive circuit 102. The drive circuit 12 transmits a drive signal to the LED element 131.

  Further, the transmission control circuit 213 transmits a drive signal to the acoustoelectric conversion element 141 in accordance with an instruction from the control unit 212 to generate an ultrasonic wave. Note that the control unit 212 also controls the receiving circuit 21 and the like.

(First embodiment)
Next, details of the light source unit 13 which is a main part of the photoacoustic probe 10 according to the present invention will be described with reference to the drawings. FIG. 4 is an exploded perspective view of a light source unit provided in the photoacoustic probe according to the present invention, and FIG. 5 is a schematic view of a light source substrate provided with LED elements. 6 is a perspective view of a light source holding unit provided in the light source unit, and FIG. 7 is a cross-sectional view taken along a plane orthogonal to the longitudinal direction of the light source holding unit shown in FIG. Although FIG. 7 is a cross-sectional view, hatching indicating the cross-section is omitted.

  The photoacoustic probe 10 includes two light source units 13, which have substantially the same configuration, and therefore, one of them will be illustrated and described as a representative.

  As shown in FIG. 4, the light source unit 13 includes a first light source substrate 130 (light source body), a second light source substrate 132 (light source body), a light source holding unit 15, a light source cover top 161, and a light source cover side 162. . As shown in FIG. 4, the light source holding unit 15 is configured to hold the first light source substrate 130 and the second light source substrate 132, and the second light source substrate 132 is further away from the subject than the first light source substrate 130. Is configured to be held. In addition, the second light source substrate 132 and the first substrate 130 are fixed by attaching the light source cover top 161 and the light source cover side 162 to the light source holding part 15. In the light source cover top 161, a wiring 4 for supplying a control signal and driving power from the LED driving circuit 12 to the LED elements 131 mounted on the first light source substrate 130 and the second light source substrate 132 penetrates.

  The first light source substrate 130 and the second light source substrate 132 have substantially the same configuration, and are wiring substrates having a wiring pattern formed on the surface. As shown in FIG. 5, LED elements 131, which are light emitting elements, are mounted on the surface of the light source substrate 130 (132) in a two-dimensional array so as to be equally spaced in the vertical and horizontal directions. The LED elements 131 may be arranged in a staggered manner. The light source substrate 130 (132) is connected to the LED drive circuit 12, receives a drive signal from the LED drive circuit 12, and the LED element 131 emits pulsed light based on the drive signal. In the light source unit 13, the LED elements 131 are mounted in a two-dimensional array on the light source substrate 130 (132) to emit planar light with a constant luminous flux. The LED element 131 is an element that irradiates light having a wavelength (here, about 850 nm) that easily penetrates into the living body.

  As shown in FIG. 6, the light source holding unit 15 includes a contact unit 150, a first substrate fixing unit 151, a second substrate fixing unit 152, and a light guide unit 153. The light source holding unit 15 is a holding member that holds the first light source substrate 130 and the second light source substrate 132 on which the LED elements 131 are mounted, and guides the light emitted from the LED elements 131 to the contact unit 150. The object Bd is irradiated from the contact part 150. Therefore, the light guide unit 153 and the contact unit 150 are configured to transmit light efficiently, and at least the light guide unit 153 and the contact unit 150 are each formed of a light-transmitting material. Note that examples of the light-transmitting material include acrylic and polycarbonate, but are not limited thereto. In the present embodiment, it is assumed that the entire light source holding part 15 is formed of a translucent material.

  As shown in FIGS. 6 and 7, the contact unit 150 has a flat plate shape, and contacts the subject Bd when the photoacoustic probe 10 detects tomographic image information of the subject Bd. Then, light necessary for detection of tomographic image information is emitted from the bottom surface 1500 of the contact portion 150. The contact portion 150 has a flat plate shape that is rectangular in plan view, and a first region 1501 extending along the axis at the center portion in the short-side direction and a first region 1501 disposed on both sides in the short-side direction of the first region 1501. 2 regions 1502.

  A first light source fixing part 151 for arranging the first light source substrate 130 is formed in a first area 1501 of the contact part 150, and a light guide part 153 is continuously provided in the second area 1502. The first light source fixing portion 151 is provided with a light incident surface 1511 on which light emitted from the LED element 131 mounted on the first light source substrate 130 enters.

  As shown in FIG. 7, the light from the LED element 131 of the first light source substrate 130 enters from the light incident surface 1511, passes through the first region 1501 of the contact portion 150, and is irradiated to the subject Bd from the bottom surface 1500. The

  The light guide unit 153 protrudes from both the second regions 1502 of the contact unit 150 so as to surround the first light source fixing unit 151, and has a configuration in which the light guiding unit 153 is coupled above the first light source fixing unit 151. That is, the light source holding part 15 has a shape having a through hole extending in the longitudinal direction, and the first light source substrate 130 is arranged in the through hole.

  And the 2nd light source fixing | fixed part 152 is continuously provided in the upper part of the part which the light guide part 153 couple | bonds. The second light source fixing part 152 is a box having an open upper surface for arranging the second light source substrate 132. The bottom surface of the second light source fixing unit 152 is a light incident surface 1521 on which light from the LED elements 131 of the second light source substrate 132 enters the light guide unit 153. The second light source fixing part 152 is formed so that the second light source substrate 132 disposed overlaps the first light source substrate 130 disposed in the first light source fixing part 151 in the Z direction. That is, as shown in FIG. 7, the center axis C <b> 1 in the short direction of the light source holding part 15 passes through the centers of the first light source fixing part 151 and the second light source fixing part 152. Further, as shown in FIG. 7, the light incident from the light incident surface 1521 travels toward the light guide unit 153.

  The light guide unit 153 guides the light from the LED element 131 mounted on the second light source substrate 132 disposed in the second light source fixing unit 152 to the contact unit 150. The light guide unit 153 includes a branch unit 1530 that is disposed below the light incident surface 1521 of the second light source fixing unit 152 and divides the light incident from the light incident surface 1521 in the short direction of the light source holding unit 15. Yes. The light guide unit 153 includes a first light guide 1531 on the side close to the acoustic wave detection unit 14 from the branch unit 1530 and a second light guide 1532 on the opposite side. The first light guide 1531 and the second light guide 1532 are formed to be inclined at an angle a with respect to the central axis C <b> 1 in the short direction of the light source holding unit 15.

  Of the light incident from the light incident surface 1521, light closer to the acoustic wave detection unit 14 than the branching unit 1530 enters the first light guide 1531, and far light enters the second light guide 1532. The first light guide path 1531 and the second light guide path 1532 have a structure in which a reflective surface 154 and a reflective surface 155 serving as a boundary with the outside are arranged to face each other. Light is repeatedly reflected between the reflection surface 154 and the reflection surface 155 in the first light guide path 1531 and the second light guide path 1532 and proceeds to the contact portion 150. Since the internal light is efficiently reflected by the reflective surfaces 154 and 155, the reflective surfaces of the reflective surfaces 154 and 155 are formed of a highly reflective material (metal) such as aluminum or gold. Thereby, the light inside the light guide unit 153 can be prevented from leaking to the outside from the reflective surface 154 and the reflective surface 155, and the attenuation of light from the LED elements 131 of the second light source substrate 132 can be suppressed.

  As shown in FIG. 7, the light from the LED element 131 of the first light source substrate 130 enters the first region 1501 of the contact portion 150 directly through the light incident surface 1521. Although the light from the LED element 131 is diffused light, it also has a certain degree of directivity, so that it is difficult to irradiate much light on the side of the LED element 131. Therefore, as in the present invention, the light from the LED element 131 of the second light source substrate 132 is guided to the side of the light from the LED element 131 of the first light source substrate 130 by using the light guide unit 153. Even if the LED element is used, it is possible to solve the shortage of light quantity on the side. As a result, it is possible to irradiate the region along the axis of the acoustic wave detector 14 inside the subject Bd with a sufficient amount of light.

  In the light guide unit 153, the light is guided to the contact unit 150 by repeating reflection on the reflection surfaces 154 and 155. Although the reflection surfaces 154 and 155 improve the reflection efficiency with the reflection film, the light flux attenuates each time it is reflected. Therefore, it is preferable that the number of reflections is small. In addition, it is preferable that the reflection surfaces 154 and 155 reflect light so that the light always travels toward the contact portion 150. In order to satisfy such conditions, the inclination angle a of the first light guide 1531 and the second light guide 1532 is set to 45 ° or less. By doing in this way, it can suppress that the light reflected by the reflective surfaces 154 and 155 (especially inner reflective surface 155) returns to the 2nd light source holding | maintenance part 152 side. In addition, since the first light guide path 1531 and the second light guide path 1532 can be formed linearly by reducing the angle, the number of reflections also decreases.

  Further, in the case of the configuration in which the light source substrates are arranged vertically as in the present invention, the amount of light can be increased without increasing the planar area of the light source unit 15. Thereby, it is possible to improve the accuracy of tomographic image information detected by the photoacoustic probe 10. On the other hand, the planar area of the light source unit 15 can be reduced by arranging the light source substrates vertically. Thereby, the photoacoustic probe 10 can be reduced in size, the photoacoustic probe 10 can be used also in a narrow part, and operability can be improved.

Further, by using the light guide unit 153, light can be guided also to a portion close to the acoustic wave detection unit 14, and therefore, sufficient light can be irradiated to a portion close to the surface of the subject Bd. Is possible.

(Second Embodiment)
Another example of the photoacoustic probe according to the present invention will be described with reference to the drawings. FIG. 8 is a cross-sectional view of a light source holding unit used in another example of the photoacoustic probe according to the present invention. As shown in FIG. 8, the light source holding part 15b has the same configuration as the light source holding part 15 except that the shapes of the first light guide path 1533 and the second light guide path 1534 of the light guide part 153b are different. Therefore, the detailed description of the light source holding unit 15b that is substantially the same as the light source holding unit 15 is omitted. In addition, detailed description of portions other than the light source holding portion 15b of the light-in-yang probe is omitted.

  As shown in FIG. 8, in the first light guide 1533, the reflecting surface 154 and the reflecting surface 155 are arranged so that the width W2 on the contact portion 150 side is wider than the width W1 on the branch portion 1530 side. . By arranging in this way, the incident angle at which the light reflected by the reflecting surface 154 or the reflecting surface 155 enters the other reflecting surface is increased. Thereby, it is possible to suppress the reflection of light so as to return to the branching portion 1530 side. The second light guide 1534 has the same configuration as the first light guide 1533. However, the present invention is not limited to this, and one of the first light guide path 1533 or the second light guide path 1534 may have the above-described configuration, and the other may have the same configuration as the light guide path of the first embodiment.

(Third embodiment)
Still another example of the photoacoustic probe according to the present invention will be described with reference to the drawings. FIG. 9 is a cross-sectional view of a light source holding unit used in still another example of the photoacoustic probe according to the present invention. As illustrated in FIG. 9, the light source holding unit 15 c has the same configuration as the light source holding unit 15 except that the shapes of the first light guide path 1535 and the second light guide path 1536 of the 153 c are different. Therefore, in the light source holding part 15c, the detailed description about the substantially same part as the light source holding part 15 is abbreviate | omitted. In addition, detailed description of portions other than the light source holding portion 15c of the light-in-yang probe is omitted.

  In the photoacoustic probe 10, it is preferable to irradiate strong light to the part located in the axial direction lower part of the acoustic wave detection part 14 inside a subject. That is, the amount of light emitted from the light source unit is preferably increased in a portion close to the acoustic wave detection unit 14.

  Therefore, in the light source holding unit 15c according to the present embodiment, the reflecting surfaces 1551 and 1552 are formed so that the branching unit 1530 is farther from the acoustic wave detecting unit 14 than the central axis C1. By forming in this way, most of the light from the LED element 131 of the second light source substrate 132 enters the first light guide 1535. Thereby, since a lot of light is guided to the acoustic wave detection unit 14 side of the contact surface 150, the amount of light irradiated on the lower part in the axial direction of the acoustic wave detection unit 14 is increased, and the accuracy of tomographic image information that can be acquired is increased. Can be increased. In addition, since the amount of light emitted in the direction away from the acoustic wave detection unit 14 is reduced, the intensity of the elastic wave from a position deviated from the lower side in the axial direction of the acoustic wave detection unit 14 is weakened. Is possible.

(Fourth embodiment)
Still another example of the photoacoustic probe according to the present invention will be described with reference to the drawings. FIG. 10 is a cross-sectional view of a light source holding unit used in still another example of the photoacoustic probe according to the present invention. As shown in FIG. 10, the light source holding part 15d has the same configuration as the light source holding part 15c except that the shapes of the first light guide path 1537 and the second light guide path 1538 of 153d are different. Therefore, in the light source holding part 15d, the detailed description about the substantially same part as the light source holding part 15c is abbreviate | omitted. In addition, detailed description of portions other than the light source holding portion 15d of the light-in-yang probe is omitted.

  The light source holding unit 15d illustrated in FIG. 10 shifts the branching unit 1530 in the direction away from the acoustic wave detection unit 14 in the same manner as the light source holding unit 15c. In the light source holding unit 15 d, the first light source fixing unit 151 is shifted in a direction away from the acoustic wave detection unit 14. That is, the angle of the inner reflective surface 156 of the first light guide 1537 and the second light guide 1538 with respect to the outer reflective surface 154 is the same. By arranging in this way, it is possible to suppress the end portion on the contact portion 150 side of the first light guide 1537 from being narrowed and to prevent light from returning to the branch portion 1530 side.

  Further, the light source holding portion 15 d is formed so that the reflection surface 1561 formed on the side portion of the first light source fixing portion 151 spreads toward the contact portion 150. By forming in this way, it can suppress that light returns to the branch part 1530 side.

(Fifth embodiment)
Still another example of the photoacoustic probe according to the present invention will be described with reference to the drawings. FIG. 11 is a cross-sectional view of a light source holding unit used in still another example of the photoacoustic probe according to the present invention. As shown in FIG. 11, the light source holding part 15e has the same configuration as the light source holding part 15d except that the shape of the first light source fixing part 151e is different. Therefore, in the light source holding part 15e, detailed description of substantially the same part as the light source holding part 15d is omitted. In addition, a detailed description of portions other than the light source holding portion 15e of the light-in-yang probe is omitted.

  In the light source holding unit 15d of the fourth embodiment, the first light source substrate 130 is arranged at a position away from the acoustic wave detection unit 14. In such a configuration, depending on the amount of deviation, a large amount of light from the LED element 131 of the first light source substrate 130 may be irradiated to a position away from the acoustic wave detection unit 14. In order to irradiate a large amount of light from the LED element 131 of the first light source substrate 130 on the acoustic wave detection unit 14 side, the first light source fixing unit 151e is configured such that the optical axis of the LED element 131 is the acoustic wave detection unit 14. An incident surface 1512 for inclining and fixing the first light source substrate 130 toward the side is provided.

  Thereby, most of the light from the LED element 131 of the second light source substrate 132 is guided to the acoustic wave detection unit 14 side, and the light from the LED element 131 of the first light source substrate 130 is directed to the acoustic wave detection unit 14 side. Irradiate. Thereby, since a lot of light is guided to the acoustic wave detection unit 14 side of the contact surface 150, the amount of light irradiated on the lower part in the axial direction of the acoustic wave detection unit 14 is increased, and the accuracy of tomographic image information that can be acquired is increased. Can be increased. In addition, since the amount of light emitted in the direction away from the acoustic wave detection unit 14 is reduced, the intensity of the elastic wave from a position deviated from the lower side in the axial direction of the acoustic wave detection unit 14 is weakened. Is possible.

  In the present embodiment, the first light source substrate is inclined, but the present invention is not limited to this. For example, the configuration may be such that the second light source substrate is tilted, or both the first light source substrate and the second light source substrate may be tilted.

  In each of the above embodiments, the light source unit using two light source substrates (light source bodies) has been described. However, the present invention is not limited to this, and three or more light source substrates are stacked one above the other. It is good also as a simple light source part.

  In each said embodiment, although the LED element is utilized as a light emitting element, it is not limited to this. A small element such as a light-emitting diode element, a semiconductor laser element, or an organic light-emitting diode element that can be easily controlled in light emission can be widely used. In addition, although a plurality of LED elements are mounted side by side on the light emitting substrate, the present invention is not limited to this, and may be directly arranged on a part of the constituent members of the light emitting unit.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this content. The embodiments of the present invention can be variously modified without departing from the spirit of the invention. Further, the above embodiments can be implemented in combination as appropriate.

A Photoacoustic imaging apparatus 10 Photoacoustic probe 11 Drive power supply unit 12 LED drive circuit 13 Light source unit 130 Light source substrate 131 LED element (light emitting element)
14 acoustic wave detection units 15, 15b to 15e light source holding unit 151 first light source fixing unit 152 second light source fixing unit 153 light guide unit 154 reflection surface 155 reflection surface 161 light source cover top 162 light source cover side 20 image generation unit 21 reception circuit 22 A / D converter 23 Reception memory 24 Data processing unit 25 Photoacoustic image reconstruction unit 26 Detection / logarithmic converter 27 Photoacoustic image construction unit 28 Ultrasonic image reconstruction unit 29 Detection / logarithmic converter 210 Ultrasonic image construction unit 211 Image Composition unit 212 Control unit 213 Transmission control circuit 30 Image display unit 4 Wiring

Claims (14)

A light source unit that emits light to the subject;
An acoustic wave detection unit that is disposed adjacent to the light source unit and detects an acoustic wave generated when light from the light source unit is absorbed inside the subject;
The light source unit is
A plurality of elongated light source bodies in which light emitting elements are arranged;
A contact portion that contacts the subject and emits light to the subject;
A light source holding part that holds the plurality of light source bodies at an interval so as to overlap each other when viewed from the contact part;
The light source holder includes a light guide that transmits light emitted from each light source through the side of the light source closer to the contact than the light source and guides the light to the contact. . A first region in which the contact portion receives light of a light source body closest to the subject and irradiates the subject;
The photoacoustic probe according to claim 1, further comprising: a second region that receives light from the light guide unit and irradiates the subject. The light guide section has a branch section that branches incident light;
2. The light guide section has a light guide path formed so that the branched light passes outside both ends in a short direction of a light source body arranged near the subject. Or the photoacoustic probe of Claim 2.   The photoacoustic probe according to claim 3, wherein the apex of the branching portion is formed so as to be farther from the acoustic wave detection unit than a center in a short direction of a light source body that makes light incident on the light guide unit. Child.   The photoacoustic probe according to claim 3 or 4, wherein an inclination angle with respect to an optical axis of a light source body that causes light to enter the light guide portion of the light guide path is smaller than 45 degrees.   The photoacoustic probe according to any one of claims 1 to 5, wherein the light guide section has a reflecting surface that reflects light that passes through the light guide section.   The photoacoustic probe according to claim 6, wherein the reflecting surface is subjected to a process for increasing a reflectance of light passing through the inside.   The photoacoustic probe according to claim 6 or 7, wherein a distance between the opposing reflecting surfaces is formed so as to be closer to the subject.   The photoacoustic probe according to any one of claims 1 to 8, wherein at least one of the plurality of light source bodies is held with an optical axis of the light emitting element inclined toward the acoustic wave detection unit. Child.   The photoacoustic probe according to any one of claims 1 to 9, further comprising a plurality of the light source units arranged so as to sandwich the acoustic wave detection unit.   The photoacoustic probe according to any one of claims 1 to 10, wherein the light emitting element includes a light emitting diode element.   The photoacoustic probe according to any one of claims 1 to 10, wherein the light emitting element includes a semiconductor laser element.   The photoacoustic probe according to any one of claims 1 to 10, wherein the light emitting element includes an organic light emitting diode element. A photoacoustic probe according to claim 1, comprising:
A photoacoustic imaging apparatus that images an internal state of the subject based on information from the photoacoustic probe.

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