WO2012114709A1 - Dispositif d'imagerie photo-acoustique, son procédé de fonctionnement et unité de sonde utilisée - Google Patents

Dispositif d'imagerie photo-acoustique, son procédé de fonctionnement et unité de sonde utilisée Download PDF

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Publication number
WO2012114709A1
WO2012114709A1 PCT/JP2012/001100 JP2012001100W WO2012114709A1 WO 2012114709 A1 WO2012114709 A1 WO 2012114709A1 JP 2012001100 W JP2012001100 W JP 2012001100W WO 2012114709 A1 WO2012114709 A1 WO 2012114709A1
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Prior art keywords
light
face
optical fibers
bundle fiber
photoacoustic
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English (en)
Japanese (ja)
Inventor
覚 入澤
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Fujifilm Corp
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Fujifilm Corp
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4206—Optical features
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/0093—Detecting, measuring or recording by applying one single type of energy and measuring its conversion into another type of energy
    • A61B5/0095—Detecting, measuring or recording by applying one single type of energy and measuring its conversion into another type of energy by applying light and detecting acoustic waves, i.e. photoacoustic measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/04—Analysing solids
    • G01N29/06—Visualisation of the interior, e.g. acoustic microscopy
    • G01N29/0654—Imaging
    • G01N29/0672—Imaging by acoustic tomography
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
    • G02B6/2808—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using a mixing element which evenly distributes an input signal over a number of outputs

Definitions

  • the present invention relates to a photoacoustic imaging device that generates a photoacoustic image by detecting a photoacoustic wave generated in a subject by irradiating the subject with light, and a probe unit used therefor and an operation of the photoacoustic imaging device It is about the method.
  • an ultrasonic image is generated by detecting ultrasonic waves reflected in the subject by irradiating the subject with ultrasonic waves.
  • Ultrasonic imaging for obtaining a morphological tomographic image is known.
  • development of an apparatus that displays not only a morphological tomographic image but also a functional tomographic image has been advanced in recent years.
  • One of such devices is a device using a photoacoustic analysis method.
  • This photoacoustic analysis method irradiates a subject with light having a predetermined wavelength (for example, visible light, near infrared light, or mid infrared light), and a specific substance in the subject absorbs the energy of this light.
  • a photoacoustic wave which is the resulting elastic wave, is detected and the concentration of the specific substance is quantitatively measured.
  • the specific substance in the subject is, for example, glucose or hemoglobin contained in blood.
  • Such a technique for detecting a photoacoustic wave and generating a photoacoustic image based on the detection signal is called photoacoustic imaging (PAI) or photoacoustic tomography (PAT).
  • the pulsed laser beam can be branched and guided by a plurality of optical fibers.
  • a probe unit in which an optical system and an ultrasonic detection probe are combined together is used. Accordingly, the cord portion of the probe unit is required to be flexible from the viewpoint of user handling performance.
  • Patent Document 1 discloses a method of guiding pulsed laser light to the tip of a probe unit using a bundle fiber in which a large number of thin silica optical fibers having a core and cladding structure (core / cladding structure) are bundled. Has been. However, a specific method for making the pulse laser beam incident on each of the optical fibers in the bundle fiber is not disclosed.
  • the present invention has been made in view of the above problems, and in photoacoustic imaging performed by guiding laser light using a plurality of optical fibers, each of the plurality of branched lights and each of the plurality of optical fibers are provided.
  • An object of the present invention is to provide a photoacoustic imaging apparatus that facilitates alignment and solves the problem of durability of optical fibers, a probe unit used therefor, and a method of operating the photoacoustic imaging apparatus. .
  • a photoacoustic imaging device includes: A light irradiator for irradiating measurement light into the subject, an electroacoustic converter for detecting a photoacoustic wave generated in the subject by irradiation of the measurement light and converting the photoacoustic wave into an electric signal, and an electric signal
  • a photoacoustic imaging device provided with an image generation part which generates a photoacoustic image based on, A homogenizer that uniformizes the intensity distribution of a single laser beam incident from the upstream side of the optical system, and a microlens array that branches the laser beam having a uniform intensity distribution into a plurality of branched light beams according to a predetermined branching pattern.
  • the bundle fiber causes each of the plurality of branched lights to enter each of the cores of the plurality of optical fibers from the one end face of the bundle fiber, and the plurality of branch lights incident on the core are incident on the other end face of the bundle fiber. It is arranged to guide light to the connected light irradiation part,
  • the light irradiating unit irradiates a plurality of branched lights as measurement light.
  • the “branch pattern” means a bright spot pattern formed on a focal plane perpendicular to the optical axis of the microlens array by the laser beam (branched light) branched by the microlens array.
  • One end face of a plurality of optical fibers is “arranged corresponding to the branch pattern” means that the end faces are arranged in the same plane so that the arrangement pattern of the end faces substantially matches the branch pattern. It means to arrange.
  • the “array pattern” of the end faces means an array pattern of representative points (for example, the centers of the end faces) related to one end face of a plurality of optical fibers.
  • the two patterns “substantially match” means that even if these patterns are different, each of the plurality of branched lights can enter each of the cores of the plurality of optical fibers. This means that they are treated as matching.
  • the photoacoustic imaging apparatus further includes a position adjusting unit that adjusts the positional relationship between the one end face of the bundle fiber and the light branching unit.
  • the light branching section preferably has a holographic diffusion plate between the homogenizer and the microlens array.
  • the branch pattern has a hexagonal structure
  • the one end face of the plurality of optical fibers is preferably arranged in a close-packed structure.
  • the one end face of the bundle fiber has a reflection mask on the end face so that the core on the end face is exposed.
  • the light branching part is for branching the laser light into 16 or more
  • the bundle fiber preferably includes at least 16 optical fibers.
  • the homogenizer is preferably composed of a holographic diffusion plate, a condensing plano-convex lens, and a light pipe.
  • the homogenizer is preferably composed of a flat top laser beam shaver.
  • the light irradiation part is the other end face of the plurality of optical fibers, It is preferable that the other end surfaces of the plurality of optical fibers are arranged in a line at intervals.
  • the light irradiation part is a light guide plate having a tapered shape
  • the other end surface of the bundle fiber is connected to the end surface on the short side of the light guide plate in a detachable state.
  • the probe unit according to the present invention is: Light that irradiates the subject with measurement light, detects photoacoustic waves generated in the subject due to measurement light irradiation, converts the photoacoustic waves into electrical signals, and generates a photoacoustic image based on the electrical signals
  • a light irradiator for irradiating measurement light into the subject An electroacoustic conversion unit that detects a photoacoustic wave generated in the subject by irradiation of measurement light and converts the photoacoustic wave into an electrical signal
  • a homogenizer that uniformizes the intensity distribution of a single laser beam incident from the upstream side of the optical system, and a microlens array that branches the laser beam having a uniform intensity distribution into a plurality of branched light beams according to a predetermined branching pattern.
  • each of the plurality of branched lights is incident on each of the cores of the plurality of optical fibers from the one end face of the bundle fiber, and the plurality of branched lights incident on the core are incident on the other end face of the bundle fiber. It is arranged to guide light to the connected light irradiation part,
  • the light irradiation unit irradiates a plurality of branched lights as measurement light.
  • the probe unit further includes a position adjusting unit that adjusts the positional relationship between the one end face of the bundle fiber and the light branching unit.
  • the light branching section preferably has a holographic diffusion plate between the homogenizer and the microlens array.
  • the branch pattern has a hexagonal structure
  • the one end face of the plurality of optical fibers is preferably arranged in a close-packed structure.
  • the one end face of the bundle fiber has a reflection mask on the end face so that the core on the end face is exposed.
  • the light branching part is for branching the laser light into 16 or more
  • the bundle fiber preferably includes at least 16 optical fibers.
  • the homogenizer is preferably composed of a holographic diffuser plate, a condensing plano-convex lens, and a light pipe.
  • the homogenizer is preferably composed of a flat top laser beam shaver.
  • the operation method of the photoacoustic imaging device is as follows.
  • Light that irradiates the subject with measurement light detects photoacoustic waves generated in the subject due to measurement light irradiation, converts the photoacoustic waves into electrical signals, and generates a photoacoustic image based on the electrical signals
  • the intensity distribution of one laser beam incident on the homogenizer from the upstream side of the optical system is homogenized by the homogenizer,
  • the laser light having a uniform intensity distribution is branched as a plurality of branched lights according to a predetermined branching pattern defined by the microlens array,
  • Each of the plurality of branched lights is incident on each of a plurality of optical fiber cores from the one end
  • a photoacoustic imaging apparatus and a probe unit include a homogenizer that uniformizes the intensity distribution of a single laser beam incident from the upstream side of the optical system, and a laser beam having a uniform intensity distribution with a predetermined branch pattern.
  • a bundle fiber including a plurality of optical fibers having a core / cladding structure, and a plurality of optical fibers on one end face of the bundle fiber.
  • a bundle fiber having one end face of the bundle fiber arranged corresponding to the branching pattern, and the bundle fiber allows each of the plurality of branch lights to enter each of the cores of the plurality of optical fibers from the one end face of the bundle fiber.
  • a plurality of branched lights incident on the core are placed on the other end face of the bundle fiber.
  • the connected light irradiation unit in which are arranged to guide characterized in that the connected light irradiation unit in which are arranged to guide. Therefore, by using the bundle fiber in which one end face of the plurality of optical fibers is arranged corresponding to the branching pattern, the alignment of each of the plurality of branched lights and each of the plurality of optical fibers can be performed collectively. it can.
  • by homogenizing the intensity distribution of the laser beam it is possible to prevent the energy distribution of the laser beam from branching while being strong at the center of the beam.
  • the operation method of the photoacoustic imaging apparatus is a laser beam in which the intensity distribution of one laser beam incident on the homogenizer from the upstream side of the optical system is made uniform by the homogenizer, and the intensity distribution is made uniform.
  • a bundle fiber that includes a plurality of optical fibers having a core / cladding structure according to a predetermined branch pattern defined by the microlens array, and includes a plurality of optical fibers having a core / cladding structure.
  • each of the plurality of branched lights is operated to enter each of the cores of the plurality of optical fibers from the one end face of the bundle fiber. Yes. Therefore, by using the bundle fiber in which one end face of the plurality of optical fibers is arranged corresponding to the branching pattern, the alignment of each of the plurality of branched lights and each of the plurality of optical fibers can be performed collectively. it can. On the other hand, by making the intensity distribution of the laser light uniform with a homogenizer, it is possible to prevent the energy density of the laser light from branching while being strong at the center of the beam.
  • FIG. 1 is a schematic diagram illustrating the overall configuration of the photoacoustic imaging apparatus 10 according to the present embodiment.
  • FIG. 2 is a block diagram illustrating a configuration of the image generation unit 2 of FIG.
  • FIG. 3 is a schematic sectional view showing the configuration of an embodiment of the optical branching section 12 and the bundle fiber 14 of the present invention.
  • the photoacoustic imaging apparatus 10 generates a measurement light L including a specific wavelength component and irradiates the subject 7 with the measurement light L, and the measurement light L is irradiated to the subject 7.
  • An image generation unit 2 that detects photoacoustic waves U generated in the subject 7 to generate photoacoustic image data of an arbitrary cross section, an electroacoustic conversion unit 3 that converts an acoustic signal and an electrical signal,
  • a display unit 6 for displaying the photoacoustic image data, an operation unit 5 for an operator to input patient information and imaging conditions of the apparatus, and a system control unit 4 for comprehensively controlling these units. .
  • the probe unit 70 of the present embodiment includes the electroacoustic conversion unit 3, the light branching unit 12, the bundle fiber 14, and the light irradiation unit 15.
  • the method of operating the photoacoustic imaging apparatus of the present invention irradiates the subject 7 with the measurement light L, detects the photoacoustic wave U generated in the subject 7 by the irradiation of the measurement light L, and detects the photoacoustic wave.
  • the intensity distribution of one laser light Lo incident on the homogenizer 41 from the upstream side of the optical system is calculated.
  • a plurality of optical fibers 13 having a core / cladding structure are obtained by branching the laser light Lo, which is made uniform by the homogenizer 41 and has a uniform intensity distribution, into a plurality of branched lights Ld according to a predetermined branching pattern defined by the microlens array 40. And one end face 13e of the plurality of optical fibers 13 on one end face 14e of the bundle fiber 14 is branched.
  • the bundle fibers 14 are arranged corresponding to the loops, and each of the plurality of branched lights Ld is made incident on each of the cores 13a of the plurality of optical fibers 13 from the one end face 14e of the bundle fiber 14, and enters the core 13a.
  • the photoacoustic imaging device 10 that guides the plurality of incident branched lights Ld to the light irradiation unit 15 and irradiates the plurality of branched lights Ld guided to the light irradiation unit 15 as the measurement light L is operated. .
  • the optical transmission unit 1 includes a light source unit 11 including a plurality of light sources having different wavelengths, a light branching unit 12 that branches the laser light Lo output from the light source unit 11 as a plurality of branched lights Ld, and a plurality of branched lights Ld.
  • a bundle fiber 14 that guides light to the light irradiation unit 15 and a light irradiation unit 15 that irradiates the body surface of the subject 7 with the measurement light L are provided.
  • the light source unit 11 includes, for example, one or more light sources that generate light having a predetermined wavelength.
  • a light emitting element such as a semiconductor laser (LD), a solid-state laser, or a gas laser that generates a specific wavelength component or monochromatic light including the component can be used.
  • the light source unit 11 preferably outputs pulsed light having a pulse width of 1 to 100 nsec as laser light.
  • the wavelength of the laser light is appropriately determined according to the light absorption characteristics of the substance in the subject to be measured.
  • hemoglobin in a living body has different optical absorption characteristics depending on its state (oxygenated hemoglobin, reduced hemoglobin, methemoglobin, carbon dioxide hemoglobin, etc.), it generally absorbs light of 600 nm to 1000 nm. Therefore, for example, when the measurement target is hemoglobin in a living body (that is, when imaging a blood vessel), it is generally preferable to set the thickness to about 600 to 1000 nm. Further, from the viewpoint of reaching the deep part of the subject 7, the wavelength of the laser light is preferably 700 to 1000 nm.
  • the output of the laser beam is 10 ⁇ J / cm 2 to several tens of mJ / cm 2 from the viewpoints of propagation loss of laser beam and photoacoustic wave, efficiency of photoacoustic conversion, detection sensitivity of the current detector, and the like. Is preferred. Further, the repetition of the pulsed light output is preferably 10 Hz or more from the viewpoint of image construction speed. Further, the laser light may be a pulse train in which a plurality of the above-mentioned pulse lights are arranged.
  • an Nd: YAG laser (emission wavelength: about 1000 nm) which is a kind of solid-state laser, or a He—Ne gas laser (emission light) which is a kind of gas laser.
  • a laser beam having a pulse width of about 10 nsec is formed using a wavelength of 633 nm.
  • a material such as InGaAlP (emission wavelength: 550 to 650 nm), GaAlAs (emission wavelength: 650 to 900 nm), InGaAs or InGaAsP (emission wavelength: 900 to 2300 nm) is used. Can be used.
  • a light-emitting element using InGaN that emits light with a wavelength of 550 nm or less is becoming available.
  • an OPO (Optical Parametrical Oscillators) laser using a nonlinear optical crystal capable of changing the wavelength can be used.
  • the light branching unit 12 branches the laser light Lo output from the light source unit 11 using the homogenizer 41 and the microlens array 40.
  • the number of branches is not particularly limited, but it is preferable to branch to 16 or more from the viewpoint of effectively dispersing the energy of the laser light Lo.
  • the light branching unit 12 includes a homogenizer 41 and a microlens array 40.
  • the microlens array 40 includes a plurality of microlenses arranged in a lattice pattern, and a predetermined branch pattern is defined by the number and arrangement of the microlenses.
  • the branch pattern is not particularly limited, but is preferably a square structure or a hexagonal structure, and more preferably a hexagonal structure.
  • the homogenizer 41 is an optical element for making the intensity distribution of the laser light Lo incident from the upstream side of the optical system uniform and guiding the laser light with the uniform intensity distribution to the microlens array 40. Further, the homogenizer 41 may be configured to expand the beam diameter of the laser light Lo having a uniform intensity distribution. In the present embodiment, the homogenizer 41 expands the laser light Lo output from the light source unit 11 in accordance with the width of the microlens array 40 (FIG. 3).
  • the homogenizer 41 may be composed of a single optical element or a combination of a plurality of optical elements.
  • the holographic diffusion plate 49 is preferably a low-angle diffusion plate of about 0.2 degrees to about 2.0 degrees.
  • the homogenizer 41 can also be constituted by a flat top laser beam shaver 52 in which an aspheric lens for correcting the beam intensity distribution, for example, is incorporated.
  • the specific configuration of the homogenizer 41 is an example in which the beam diameter of the laser light Lo is 3.0 mm.
  • the bundle fiber 14 guides the laser beam Lo branched by the light branching unit 12 to the light irradiation unit 15.
  • the bundle fiber 14 includes a plurality of optical fibers 13 having a core 13a and a clad 13b.
  • the optical fiber 13 is not particularly limited, but is preferably a quartz fiber.
  • the plurality of optical fibers 13 are arranged corresponding to a predetermined branch pattern defined by the microlens array 40 from the viewpoint of efficiently guiding the plurality of branch lights Ld.
  • the arrangement pattern of the end faces 13e of the plurality of optical fibers 13 on the incident end face 14e of the bundle fiber 14 can be appropriately selected according to the shape of the microlens array 40, and the arrangement of the plurality of optical fibers 13 in the bundle fiber 14 is easy.
  • FIG. 5A shows a case where the arrangement of the end faces 13e of the 64 optical fibers 13 has a square structure
  • FIG. 5B shows a case where the arrangement of the end faces 13e of the 61 optical fibers 13 has a close-packed structure.
  • the arrangement of the end faces 13e of the plurality of optical fibers 13 on the incident end face 14e of the bundle fiber 14 is particularly preferably a close-packed structure.
  • the plurality of optical fibers 13 in the bundle fiber 14 may be divided and arranged for each line using a V-groove substrate.
  • the V-groove substrate is selected so that the plurality of optical fibers 13 are arranged corresponding to the branch pattern of the microlens array 40, or the micro-groove is matched to the arrangement of the plurality of optical fibers 13 by the V-groove substrate.
  • a lens array 40 is designed.
  • the one end face 14e of the bundle fiber 14 preferably has a reflective mask M on the end face 14e so that the core 13a on the end face 14e is exposed as shown in FIG.
  • the bundle fiber 14 is usually manufactured by fixing a gap between the plurality of optical fibers 13 with an adhesive.
  • the adhesive has lower durability against laser light than optical fiber materials such as quartz. Therefore, the reflection mask M as described above can prevent the laser light from being irradiated to the region excluding the region of the core 13a where the plurality of branched lights Ld are incident.
  • Such a reflective mask M is formed by, for example, depositing a dielectric multilayer film on a thin glass plate that has been drilled in accordance with the arrangement pattern of the cores 13a, and then the glass 13 so that the cores 13a and the holes are matched with each other. It is possible to form the plate by sticking it to the one end face 14e of the bundle fiber 14.
  • the light irradiation unit 15 includes a plurality of emission end faces 13e of the plurality of optical fibers 13.
  • the plurality of emission end faces 13e of the plurality of optical fibers 13 constituting the light irradiation unit 15 are arranged along the periphery of the electroacoustic conversion unit 3, for example.
  • the plurality of emission end faces 13 e of the plurality of optical fibers 13 form a plane, a convex surface, or a concave surface together with the plurality of conversion elements 54 constituting the electroacoustic conversion unit 3. In this embodiment, it is a plane.
  • the some conversion element 54 which comprises the electroacoustic conversion part 3 is a transparent material, you may arrange
  • the electroacoustic conversion unit 3 is composed of, for example, a plurality of minute conversion elements 54 arranged in a one-dimensional or two-dimensional manner.
  • the conversion element 54 is a piezoelectric element made of a polymer film such as piezoelectric ceramics or polyvinylidene fluoride (PVDF).
  • the electroacoustic conversion unit 3 receives the photoacoustic wave U generated in the subject 7 by the light irradiation from the light irradiation unit 15.
  • the conversion element 54 has a function of converting the photoacoustic wave U into an electric signal at the time of reception.
  • the electroacoustic conversion unit 3 is configured to be small and light, and is connected to a receiving unit 22 described later by a multi-channel cable.
  • the electroacoustic conversion unit 3 is selected according to the diagnostic region from among sector scanning, linear scanning, convex scanning, and the like.
  • the electroacoustic conversion unit 3 may include an acoustic matching layer in order to efficiently transmit the photoacoustic wave U.
  • the acoustic impedance of the piezoelectric element material and the living body are greatly different. Therefore, when the piezoelectric element material and the living body are in direct contact with each other, reflection at the interface becomes large and the photoacoustic wave cannot be efficiently transmitted. For this reason, a photoacoustic wave can be efficiently transmitted by inserting the acoustic matching layer comprised with the substance which has an intermediate acoustic impedance between piezoelectric element material and a biological body. Examples of the material constituting the acoustic matching layer include epoxy resin and quartz glass.
  • the image generation unit 2 of the photoacoustic imaging apparatus 10 selectively drives the plurality of conversion elements 54 constituting the electroacoustic conversion unit 3 and gives a predetermined delay time to the electric signal from the electroacoustic conversion unit 3 to adjust the electric signal.
  • a receiving unit 22 that generates a received signal by performing phase addition, a scanning control unit 24 that controls the selection drive of the conversion element 54 and the delay time of the receiving unit 22, and various types of received signals obtained from the receiving unit 22
  • a signal processing unit 25 for performing the above processing.
  • the receiving unit 22 includes an electronic switch 53, a preamplifier 55, a reception delay circuit 56, and an adder 57.
  • the electronic switch 53 selects a predetermined number of adjacent conversion elements 54 when receiving photoacoustic waves in photoacoustic scanning. For example, when the electroacoustic conversion unit 3 includes 192 conversion elements CH1 to CH192 of an array type, such an array conversion element is converted into an area 0 (area of conversion elements from CH1 to CH64 by an electronic switch 53). ), Area 1 (region of the conversion element from CH65 to CH128) and area 2 (region of the conversion element from CH129 to CH192) are handled by being divided.
  • the preamplifier 55 amplifies a minute electric signal received by the conversion element 54 selected as described above, and ensures sufficient S / N.
  • the reception delay circuit 56 forms a converged reception beam by matching the phase of the photoacoustic wave U from a predetermined direction with the electrical signal of the photoacoustic wave U obtained from the conversion element 54 selected by the electronic switch 53. Give a delay time to do.
  • the adder 57 adds together the electric signals of a plurality of channels delayed by the reception delay circuit 56, and combines them into one reception signal. By this addition, phasing addition of acoustic signals from a predetermined depth is performed, and a reception convergence point is set.
  • the scanning control unit 24 includes a beam focusing control circuit 67 and a conversion element selection control circuit 68.
  • the conversion element selection control circuit 68 supplies position information of a predetermined number of conversion elements 54 at the time of reception selected by the electronic switch 53 to the electronic switch 53.
  • the beam focusing control circuit 67 supplies delay time information for forming reception convergence points formed by a predetermined number of conversion elements 54 to the reception delay circuit 56.
  • the signal processing unit 25 includes a filter 66, a signal processor 59, an A / D converter 60, and an image data memory 62.
  • the electrical signal output from the adder 57 of the receiving unit 22 removes unnecessary noise in the filter 66 of the signal processing unit 25, and thereafter, the signal processor 59 performs logarithmic conversion of the amplitude of the received signal to make the weak signal relative. Stress.
  • the received signal from the subject 7 has an amplitude with a wide dynamic range of 80 dB or more, and a weak signal is emphasized in order to display it on a normal monitor having a dynamic range of about 23 dB. Amplitude compression is required.
  • the filter 66 has a band pass characteristic, and has a mode for extracting a fundamental wave in a received signal and a mode for extracting a harmonic component.
  • the signal processor 59 performs envelope detection on the logarithmically converted received signal.
  • the A / D converter 60 A / D converts the output signal of the signal processor 59 to form photoacoustic image data for one line.
  • the photoacoustic image data for one line is stored in the image data memory 62.
  • the image data memory 62 is a storage circuit that sequentially stores the photoacoustic image data for one line generated as described above.
  • the system control unit 4 reads out data for one line of a certain section stored in the image data memory 62 and necessary for generating a one-frame photoacoustic image.
  • the system control unit 4 combines the data for one line while spatially interpolating to generate photoacoustic image data for one frame of the cross section. Then, the system control unit 4 stores the photoacoustic image data for one frame in the image data memory 62.
  • the display unit 6 includes a display image memory 63, a photoacoustic image data converter 64, and a monitor 65.
  • the display image memory 63 is a buffer memory that reads photoacoustic image data for one frame to be displayed on the monitor 65 from the image data memory 62 and temporarily stores it.
  • the photoacoustic image data converter 64 performs D / A conversion and television format conversion on the photoacoustic image data for one frame stored in the display image memory 63, and the output is displayed on the monitor 65.
  • the operation unit 5 includes a keyboard, a trackball, a mouse, and the like on the operation panel, and is used by an apparatus operator to input necessary information such as patient information, apparatus imaging conditions, and a display section.
  • the system control unit 4 includes a CPU (not shown) and a storage circuit (not shown), and controls each unit such as the optical transmission unit 1, the image generation unit 2, and the display unit 6 according to a command signal from the operation unit 5 and the entire system. Supervised. In particular, the input command signal of the operator sent via the operation unit 5 is stored in the internal CPU.
  • the photoacoustic imaging device 10 and the probe unit 70 of the present invention particularly include a homogenizer 41 that uniformizes the intensity distribution of one laser beam Lo incident from the upstream side of the optical system, and an intensity distribution.
  • Each of the plurality of branched lights Ld is connected to each of the cores 13a of the plurality of optical fibers 13.
  • the plurality of branched lights Ld incident on the one end surface 14e of the dollar fiber 14 and incident on the core 13a are guided to the light irradiation unit 15 connected on the other end surface 14e of the bundle fiber 14. It is characterized by that. That is, according to the present invention, the branch pattern of the microlens array 40 and the arrangement pattern of the end faces 13e of the plurality of optical fibers 13 on the incident end face 14e of the bundle fiber 14 correspond to each of the plurality of branch lights Ld and the plurality of lights. It is possible to perform alignment with each of the fibers 13 at once.
  • the intensity distribution of the laser light Lo is made uniform by the homogenizer 41, thereby preventing the energy distribution of the laser light Lo from branching while being strong at the beam center. This eliminates the need to separately align each of the plurality of branched lights Ld and each of the plurality of optical fibers 13, and further solves the problem of durability of the optical fiber.
  • the photoacoustic imaging apparatus 10 and the probe unit 70 of the present invention include a position adjusting unit 14 a that adjusts the positional relationship between the one end surface 14 e of the bundle fiber 14 and the light branching unit 12.
  • a position adjustment unit may be provided to control the microlens array 40.
  • the position adjusting unit 14a can be configured to measure the measurement light L emitted from the probe unit 70 and automatically adjust the positional relationship so that the measured light quantity becomes the maximum value. This makes it easier to align each of the plurality of branched lights Ld and each of the plurality of optical fibers 13.
  • the photoacoustic imaging device 10 and the probe unit 70 of the present invention are configured such that the optical branching unit 12 has a holographic diffusion plate 42 between the homogenizer 41 and the microlens array 40 as shown in FIG. can do.
  • the holographic diffusion plate 42 arranged in this manner changes the direction in which the condensing spot diameter of the plurality of branched lights Ld increases, and the plurality of branched lights when entering the core 13a on the incident end face 14e of the bundle fiber 14.
  • the beam diameter of Ld is optimized. Therefore, the plurality of branched lights Ld can be guided so as not to exceed the damage threshold energy density of the optical fiber 13.
  • the light irradiation unit 15 is the other end surface 13e of the plurality of optical fibers 13, and the other end surface 13e is spaced. It can be configured to be arranged in a line with the With this configuration, it is not necessary to provide an optical system with a complicated structure at the probe unit tip 71, and a uniform line-shaped light source can be obtained. In addition, a more uniform line light source can be obtained by adjusting the distance in consideration of the intensity of the branched light Ld emitted from each of the plurality of optical fibers 13. For example, it is preferable that the interval is adjusted to be wide when the intensity of the branched light Ld is strong, and to be narrowed when the intensity is weak.
  • the photoacoustic imaging device 10 and the probe unit 70 of the present invention are a light guide plate 72 in which the light irradiation unit 15 has a tapered shape, and the other end face 14 e of the bundle fiber 14.
  • it can be configured to be connected to the end face on the short side of the light guide plate 72 in a detachable state.
  • the other end surface 14 e of the bundle fiber 14 and the end surface on the short side of the light guide plate 72 are connected to each other in the connector portion 73.

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  • Physics & Mathematics (AREA)
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  • Life Sciences & Earth Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Acoustics & Sound (AREA)
  • Pathology (AREA)
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  • Biochemistry (AREA)
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  • Animal Behavior & Ethology (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Optical Couplings Of Light Guides (AREA)

Abstract

Le dispositif d'imagerie photo-acoustique permet un alignement facilité entre de multiples faisceaux divisés et de multiples fibres optiques servant à acheminer un laser. Pour ce faire, le dispositif d'imagerie photo-acoustique (10) comprend : une unité de division optique (12) comportant à la fois un homogénéisateur (41) qui égalise la répartition d'intensité d'un laser (Lo) et un réseau de microlentilles (40) qui divise le laser (Lo), dont la répartition d'intensité est égalisée, en multiples faisceaux divisés (Ld) selon un profil de division prédéterminé; et un faisceau de fibres (14) comprenant plusieurs fibres optiques (13), les surfaces (13e) à une extrémité des fibres optiques (13) à la surface (14e) d'une extrémité du faisceau de fibres (14) étant disposées de façon à correspondre au profil de division et le faisceau de fibres (14) est disposé de façon à ce que chaque faisceau divisé (Ld) soit incident sur le cœur (13a) de chaque fibre optique.
PCT/JP2012/001100 2011-02-22 2012-02-20 Dispositif d'imagerie photo-acoustique, son procédé de fonctionnement et unité de sonde utilisée Ceased WO2012114709A1 (fr)

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JP2011035447A JP2012173136A (ja) 2011-02-22 2011-02-22 光音響撮像装置、それに用いられるプローブユニットおよび光音響撮像装置の作動方法

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WO2015015893A1 (fr) * 2013-08-02 2015-02-05 富士フイルム株式会社 Sonde de détection d'onde acoustique et dispositif de mesure photo-acoustique

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JP2014230631A (ja) * 2013-05-29 2014-12-11 富士フイルム株式会社 光音響計測用プローブ並びにそれを備えたプローブユニットおよび光音響計測装置
JP2017080132A (ja) * 2015-10-29 2017-05-18 セイコーエプソン株式会社 超音波デバイス、超音波プローブ、電子機器、および超音波画像装置
CN111157457A (zh) * 2020-01-14 2020-05-15 广东工业大学 一种超快光声成像无损检测系统及方法

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JP2005021380A (ja) * 2003-07-02 2005-01-27 Toshiba Corp 生体情報映像装置
JP2006084932A (ja) * 2004-09-17 2006-03-30 Nippon Steel Corp 高出力レーザ光の光ファイバ伝送装置
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