JP2016073509A - Photoacoustic apparatus and photoacoustic wave measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoacoustic apparatus and photoacoustic wave measuring method capable of reducing positional deviation between a light irradiation part/a probe and an analyte measurement part caused by movement of the analyte under measurement and an operator, and suppressing deterioration in an image quality.SOLUTION: The photoacoustic apparatus includes: a light source 100 that generates light to be applied to an analyte; a transducer 101 that, upon being irradiated with the light, receives photoacoustic waves generated inside the analyte 105; a transmissive member disposed in contact with the analyte 105 and transmitting light 109 and the photoacoustic wave; and a signal processing part 111 for acquiring characteristic value information in the analyte through a reception signal output from the transducer 101. The transmissive member has an adherence property on a surface in contact with the analyte.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photoacoustic apparatus and a photoacoustic wave measuring method using the same.

  One of imaging techniques using light is a photoacoustic imaging technique. In photoacoustic imaging, first, pulsed light generated from a light source is irradiated onto a subject. The irradiation light propagates and diffuses in the subject, and the energy of the light is absorbed at a plurality of locations in the subject to generate an acoustic wave (hereinafter referred to as a photoacoustic wave). The photoacoustic wave is received by the transducer, and the received signal is analyzed in the processing device, whereby information relating to the optical characteristic value inside the subject is acquired as image data. Thereby, the optical characteristic value distribution in the subject is visualized.

  In recent years, in order to image a finer light absorber using photoacoustics, it is required to improve resolution. Then, development of a photoacoustic microscope has been promoted that images an absorber such as a microvessel near the surface of a subject with high resolution by focusing sound or condensing pulsed light. In Patent Document 1, the resolution is improved by condensing pulsed light with a lens and placing the subject at the focal position of the light.

  In addition, by irradiating with light having different wavelengths, it is possible to obtain a distribution related to the concentration of a substance present in the subject. In this case, the absorption coefficient of light in the subject can be obtained for each wavelength, and the distribution related to the concentration of the substance can be imaged using these values and the wavelength dependency of the light absorption specific to the substance to be obtained. In particular, the oxygen saturation of blood can be obtained based on the concentrations of oxyhemoglobin HbO and deoxyhemoglobin Hb.

Special table 2011-519281

  When photoacoustic imaging is used for a living body, movement of the living body such as pulsation and respiration causes image quality degradation. In addition, when a handheld photoacoustic apparatus is used, the image quality is similarly deteriorated by the hand shake of the surgeon and the movement of the subject.

  This image quality degradation is caused by the position of the light irradiation unit or probe of the apparatus and the measurement object being shifted during measurement due to these body movements. In Patent Document 1, the measurement unit and the subject are in contact with each other via a polyethylene film, and when a body movement occurs, the positional relationship between the light irradiation unit and the probe and the surface portion of the subject to be measured is determined. It will shift.

  In addition, when imaging a distribution related to the concentration of a substance by multi-wavelength measurement, the measurement position for each wavelength is shifted due to body movement, so that the accuracy of the calculated concentration distribution is deteriorated.

  The photoacoustic apparatus of the present invention includes a light source that generates light for irradiating a subject, a conversion element that receives a photoacoustic wave generated in the subject when the light is irradiated, and the subject A transparent member that is disposed in contact with the light and transmits the light and the photoacoustic wave, and a signal processing unit that acquires characteristic value information in the subject from a reception signal output from the conversion element, The permeable member has adhesiveness on a surface in contact with the subject.

  According to the present invention, it is possible to reduce the positional deviation between the light irradiation unit and the probe and the subject measurement unit, which is caused by the movement of the subject or the operator during measurement, and it is possible to suppress the deterioration of the image quality.

1 is a schematic diagram illustrating an overall configuration of a photoacoustic apparatus according to Embodiment 1. FIG. 3 is a schematic diagram showing a container according to Embodiment 1. FIG. FIG. 3 is a schematic diagram illustrating an overall configuration of a photoacoustic apparatus according to Embodiment 2. It is a schematic diagram which shows the whole structure of the photoacoustic apparatus which concerns on Embodiment 3. It is a schematic diagram which shows the whole structure of the photoacoustic apparatus which concerns on Embodiment 4. 3 is a flowchart illustrating an example of a measurement flow according to the first embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In principle, the same components are denoted by the same reference numerals, and description thereof is omitted.

  The photoacoustic apparatus, which is the object information acquisition apparatus of the present invention, uses the received signal obtained by receiving the photoacoustic wave, and information on characteristic values (characteristic value information) corresponding to each of a plurality of positions in the object. ) To get. In this specification, the “photoacoustic wave” is an acoustic wave generated by absorbing light, and is also called an optical ultrasonic wave. Also, it may be called “acoustic wave”, “ultrasonic wave”, “sonic wave”, or “elastic wave” generated by light absorption.

  The characteristic value information acquired in one embodiment of the present invention reflects the absorption rate of light energy. Specifically, there are characteristic values relating to the absorption coefficient, the concentration of substances constituting the tissue, and the like. Information on the concentration of a substance is, for example, oxygen saturation, total hemoglobin concentration, oxyhemoglobin or deoxyhemoglobin concentration. Further, it may be glucose concentration, collagen concentration, melanin concentration, fat or water volume fraction, and the like. Further, two-dimensional or three-dimensional characteristic value distribution data may be generated based on characteristic values at a plurality of positions. The distribution data can be generated as image data.

  In addition, the object information acquisition apparatus in the following embodiments is mainly intended for diagnosis of vascular diseases and malignant tumors of humans and animals, and follow-up of chemical treatment. Therefore, as a subject, a part of a living body, specifically, a subject to be examined such as a human or animal skin, a subcutaneous part, or a breast is assumed. In particular, it can be suitably used when a shallow region within a few millimeters from the skin surface is to be examined.

[Embodiment 1]
Hereinafter, the configuration and processing of the subject information acquisition apparatus according to the first embodiment will be described.

(Overall equipment configuration)
FIG. 1 is a schematic diagram showing the configuration of the photoacoustic apparatus of the present embodiment. The photoacoustic apparatus of the present embodiment includes a light source 100, a probe 102 including a conversion element 101 that receives a photoacoustic wave, and a container 104 filled with an acoustic matching medium 103. The surface of the container 104 on the subject side (hereinafter referred to as the bottom surface 106) is provided with an adhesive film member as a permeable member on the outside of the container, that is, the side in contact with the subject 105.

  Light from the light source 100 is guided to the light emitting unit 108 by the optical waveguide unit 107 and emitted from the light emitting unit 108. The light 109 emitted from the light emitting unit 108 passes through the bottom surface 106 and is irradiated to the subject 105, and reaches the light absorber 110 serving as a target site. The light absorber 110 typically includes a blood vessel in a living body, particularly a substance such as hemoglobin present in the blood vessel. The light absorber 110 absorbs the energy of light and generates a photoacoustic wave. The generated photoacoustic wave propagates through the subject, passes through the bottom surface 106, and reaches the conversion element 101. The conversion element 101 outputs a time-series reception signal by receiving a photoacoustic wave. The output reception signal is input to the signal processing unit 111. The signal processor 111 sequentially receives received signals generated by the irradiated light.

  When the photoacoustic apparatus is a photoacoustic microscope or the like, the transducer may include one conversion element 101. However, when the photoacoustic apparatus is a biological information acquisition apparatus that examines a subject such as a breast. It is preferable that a plurality of conversion elements 101 provided in the probe 102 are provided. In addition, a scanning mechanism 113 for performing measurement while scanning the measurement unit 112 such as the light emitting unit 108 and the probe 102 is provided. Moreover, the control part 114 for controlling each structural block in a photoacoustic apparatus is provided. The control unit 114 supplies necessary control signals and data to each component block. Specifically, a signal for instructing the light source 100 to emit light, a reception control signal for the conversion element 101, and a control signal for the scanning mechanism 113 are supplied. Also, signal amplification control of the signal processing unit 111, AD conversion timing control, reception signal storage control, generation of characteristic value information in the subject, and the like are performed. The characteristic value information in the subject generated in the signal processing unit 111 is displayed on the image display unit 115.

  Hereinafter, a specific configuration example of the present embodiment will be described.

(Container and film)
The scanning mechanism 113 scans the probe 102 and the light emitting unit 108, thereby performing photoacoustic wave measurement while scanning a measurement point on the subject 105. At this time, the surface of the conversion element 101 is immersed in the acoustic matching medium 103 in order to receive photoacoustic waves. In addition, the acoustic matching medium 103 uses a fluid medium in order to scan the probe 102. As such an acoustic matching medium 103, water, ultrasonic gel, castor oil, or the like can be used. Other materials may be used as long as they have fluidity and acoustic impedance close to that of the subject. A film member that transmits the generated photoacoustic wave and irradiation light 109 is used for the bottom surface 106 of the container 104 in which the acoustic matching medium 103 is stored. Furthermore, the subject 105 side of the film member has adhesiveness. Due to this adhesiveness, the surface portion of the subject 105 (for example, skin in the case of a living body) and the bottom surface of the container 104 are fixed, and the positional relationship between the measurement region near the surface of the subject and the container 104 is kept constant.

  Although not shown in FIG. 1, the positional relationship between the scanning position of the probe 102 and the container 104 is configured to correspond one-to-one. For example, a configuration in which the measurement unit 112 and the container 104 are fixed via the scanning mechanism 113 can be considered. By using such a configuration and an adhesive member, it is possible to prevent the positional relationship between the measurement region near the surface of the subject and the measurement position of the probe 102 from being shifted due to the movement of the subject 110 during measurement. can do.

  2A and 2B show the configuration of the container 104, where FIG. 2A is a front view seen from the upper side in FIG. 1, and FIG. 2B is a side view seen from the front side of the page. The end portion of the film member 124 is fixed between the packing 122 provided at the opening portion of the frame portion 121 of the container 104 and the fixing portion 123. Further, the end portion of the film member 124 may be directly attached to the opening portion of the frame portion 121 by an adhesive without using the packing 122 or the fixing portion 123.

  As the film member, a member having adhesiveness on one surface and transmitting the photoacoustic wave and the irradiation light 109 is used. The transmittance of the photoacoustic wave and the irradiation light 109 is 70% or more and less than 100%, and more preferably 80% or more and less than 100%. Further, the adhesiveness is preferably such that the container 104 is not displaced by the movement of the subject 110 and that the skin of the subject 110 is not damaged when the container 104 is removed. That is, the adhesive force of one surface of the film member is 0.1 to 10.0 (N / 10 mm) (according to JIS standard, a 10 mm wide sample is attached to a stainless steel adherend, 30 cm per minute, The force when peeled at an angle of 180 ° is preferred. Further, the film member is preferably waterproof. As such a film member, for example, a film using a polyurethane film as a base material and using an acrylic pressure-sensitive adhesive as an adhesive on one side can be considered. As the substrate, it is also possible to use a film such as polyethylene, polyvinylidene chloride, polyvinyl chloride, or polyolefin.

  A film is suitable as the transparent member of the bottom surface 106, but any member that has adhesiveness on one side and transmits the generated photoacoustic wave and irradiation light 109 may be used. For example, a polyurethane gel member may be used. It is also possible to use it. At this time, it is preferable to use a hydrophobic medium as the acoustic matching medium 103 so that the acoustic matching medium 103 does not leak out and leak. For example, castor oil can be used. Moreover, the adhesiveness of the polyurethane gel surface is controlled by the ratio of the hydroxyl groups of the polyurethane. On the other hand, when a hydrophobic gel is used, the acoustic matching medium 103 is preferably water or an ultrasonic gel.

(Scanning mechanism, scanning method)
1 shows a configuration in which the scanning mechanism 113 scans the probe 102 and the light emitting unit 108 and thereby performs measurement while scanning the measurement point on the subject 105. However, such a configuration is not necessarily required, and it is only necessary to perform measurement while scanning measurement points on the subject 105. With such a configuration, the irradiation light 109 from the light emitting unit 108 can irradiate the subject 105 in a wide range, and the scanning mechanism 113 can scan the measurement point by scanning only the probe 102. . Further, the probe 102 may be fixed using a probe capable of receiving a wide range of photoacoustic waves (for example, a single transducer or an array type transducer having a wide focus range). The irradiation light 109 from the light emitting unit 108 is condensed and applied to the subject 105, and the scanning mechanism 113 can scan the measurement point by scanning only the light emitting unit 108.

  As a scanning method in which the scanning mechanism 113 scans the probe 102 and the light emitting unit 108, it is possible to scan by changing the position of the probe 102 and the light emitting unit 108, or to scan by changing the angle. . Further, the scanning mechanism 113 can scan the measurement point on the subject 105 without directly scanning the probe 102 and the light emitting unit 108. For example, by using a mirror that reflects the photoacoustic wave and the irradiation light 109, the irradiation position of the irradiation light 109 and the detection position of the photoacoustic wave are scanned by moving the mirror. By taking such a configuration, it is possible to perform measurement while scanning the measurement point. In this case, as in the case of directly scanning the probe 102 and the light emitting unit 108, both the irradiation light 109 and the photoacoustic wave detection position can be scanned, or only one of them can be scanned. is there. When scanning, it is possible to scan by changing the angle of the mirror or by changing the position of the mirror. As such a mirror, a galvanometer mirror, a MEMS mirror, or the like can be used.

(light source)
The light source 100 is preferably a pulsed light source capable of generating pulsed light on the order of nanoseconds to microseconds. As a specific pulse width, a pulse width of about 1 to 100 nanoseconds is used. As the wavelength, a wavelength in the range of about 400 nm to 1600 nm is used. In particular, when imaging a blood vessel near the surface of a living body with high resolution, it is preferable to use a visible light region. It is also possible to use terahertz waves, microwaves, and radio waves. As a specific light source 100, a laser is preferable. As the laser, various lasers such as a solid laser, a gas laser, a dye laser, and a semiconductor laser can be used. In particular, a pulsed laser such as an Nd: YAG laser or an Alexandrite laser is preferable. Further, a Ti: sa laser or an OPO (Optical Parametric Oscillators) laser using Nd: YAG laser light as excitation light may be used. In addition, a light emitting diode or the like can be used instead of the laser.

  Moreover, when measuring using light of a plurality of wavelengths, a laser capable of converting the oscillating wavelength is more preferable. However, since it is only necessary to irradiate the subject 108 with a plurality of wavelengths, it is also possible to use a plurality of lasers that oscillate light of different wavelengths while performing oscillation switching or alternately irradiating them. When multiple lasers are used, they are collectively expressed as a light source.

(Optical waveguide part, light emitting part)
Light is transmitted from the light source 100 to the subject 105 by the optical waveguide unit 107 and the light emitting unit 108. The optical waveguide 105 is preferably an optical fiber. However, since light only needs to be transmitted from the light source 100 to the subject 105, the optical waveguide unit 105 and the light emitting unit 106 can be used in combination with optical elements such as lenses and mirrors. Furthermore, it is possible to irradiate the subject directly with light from the light source 100. In the photoacoustic microscope, it is preferable to focus and irradiate the beam light with a lens or the like in order to increase the resolution. On the other hand, when irradiating the irradiation light 109 over a wide range, it is preferable that the light emitting unit 106 irradiates with a lens or the like by expanding the diameter of the beam light.

(Probe)
The probe 102 includes one or more conversion elements 101. The conversion element 101 receives acoustic waves, such as a piezoelectric element using a piezoelectric phenomenon such as lead zirconate titanate (PZT), a conversion element using optical resonance, and a capacitive conversion element such as CMUT. Any conversion element may be used as long as it can be converted into an electric signal. When a plurality of conversion elements 115 are provided, the conversion elements 115 are preferably arranged so as to be arranged in a plane or curved surface called a 1D array, a 1.5D array, a 1.75D array, or a 2D array. In particular, in the case of a photoacoustic microscope, the probe 102 is preferably a focus type probe. When there is one conversion element 101, an acoustic lens is provided on the conversion element 101 to focus the acoustic wave. In addition, when there are a plurality of conversion elements 101, it is possible to focus acoustic waves using a single acoustic lens or array type acoustic lens. It is also possible to focus by doing so. In the probe 102, an amplifier that amplifies the analog signal output from the conversion element 101 may be provided.

(Signal processing part)
The signal processing unit 111 is divided into a signal collection unit and a signal analysis unit. As the signal collecting unit, a circuit generally called DAS (Data Acquisition System) can be used. Specifically, the signal collecting unit includes an amplifier that amplifies the received signal, an AD converter that digitizes the analog received signal, a memory that stores the received signal, and the like. The memory is typically composed of a storage medium such as a ROM, a RAM, and a hard disk. Note that the memory may be configured not only from one storage medium but also from a plurality of storage media.

  As the signal analysis unit, a processor such as a CPU or GPU (Graphics Processing Unit) or an arithmetic circuit such as an FPGA (Field Programmable Gate Array) chip can be used. In addition, it may be comprised not only from one processor and an arithmetic circuit but from several processors and arithmetic circuits. In addition, the signal analysis unit may include a memory that stores a received signal, generated distribution data, display image data, various measurement parameters, and the like. The memory is typically composed of one or more storage media such as a ROM, a RAM, and a hard disk.

(Imaging method)
The signal analysis unit acquires the characteristic value information in the subject for each position using the reception signal output from the signal collection unit. An example of the characteristic value information in the subject is the sound pressure distribution of the generated photoacoustic wave. In the case of a photoacoustic microscope, the signal analysis unit detects the obtained received signal with respect to time change, and then converts the time axis direction of the signal for each light pulse into the depth direction, and displays it on the space coordinates. Plot. By performing this for each scanning position, sound pressure distribution data is constructed. On the other hand, in the case of photoacoustic tomography, sound reconstruction data (distribution data) corresponding to a position on a two-dimensional or three-dimensional spatial coordinate is obtained by performing image reconstruction using a received signal obtained for each channel. ) As the image reconstruction method, a known reconstruction method such as Universal Back Projection (UBP) described in US Pat. No. 5,713,356 or Filtered Back Projection (FBP) can be used. Further, a phasing addition (Delay and Sum) process may be used.

  In addition, when measuring with multiple wavelengths, values related to the optical absorption characteristics in the subject are obtained for each wavelength, and the concentration of the substance is determined using these values and the wavelength dependence of the optical absorption characteristics specific to the substance to be obtained. Construct distribution data. For example, the concentrations of oxyhemoglobin HbO and deoxyhemoglobin Hb are calculated to construct blood oxygen saturation distribution data.

(Control part)
Similarly to the signal processing unit 111, the control unit 114 can be configured by combining one or a plurality of circuits such as a processor such as a CPU and a GPU and an FPGA chip. Moreover, you may provide the memory which memorize | stores various measurement parameters. The memory is typically composed of one or more storage media such as a ROM, a RAM, and a hard disk.

(Display section)
As the display unit 115, a display such as an LCD (Liquid Crystal Display), a CRT (Cathode Ray Tube), or an organic EL display can be used. Note that the display unit 115 may be separately prepared and connected to the photoacoustic apparatus without being configured to be included in the photoacoustic apparatus of the present embodiment.

(Handheld type)
Further, the present embodiment can be used as a handheld photoacoustic apparatus. In that case, for example, a member surrounded by a dotted line 116 is held by a single casing, whereby a handheld device can be configured. At this time, the surface where the housing 116 contacts the subject 105 becomes the bottom surface 106, and an adhesive film member or gel member is used.

(Measurement flow chart)
The measurement flow of this embodiment is shown in FIG. In step S501, the adhesive surface of the adhesive film member and the subject surface are bonded together, and the measurement region near the subject surface and the apparatus 116 are fixed. In step S502, the light source 100 starts light irradiation, and photoacoustic measurement is started. In step S503, the scanning mechanism 113 performs measurement while scanning the measurement point. In step S504, signal processing is performed using the time-series received signals output from the conversion element 101 to generate photoacoustic image data. In step S505, the image data created in step S504 is displayed on the image display unit 115. In step S506, the adhesive surface of the film member is peeled from the subject. However, the process of S506 may be performed at any timing as long as the measurement is completed in S503.

  By using the photoacoustic apparatus shown in such an embodiment, the positional deviation between the light irradiation unit and the probe and the subject measurement unit caused by the movement of the subject or the operator during measurement is reduced, It becomes possible to suppress degradation of image quality.

[Embodiment 2]
The configuration and processing of the subject information acquisition apparatus according to the second embodiment of the present invention will be described.

  The present embodiment relates to a photoacoustic microscope that acquires a high-resolution photoacoustic image using a focus-type probe. FIG. 3 is a schematic diagram showing the configuration of the photoacoustic microscope of the present embodiment. In addition, the same code | symbol is attached | subjected to the component similar to the apparatus shown in FIG. 1, and detailed description is abbreviate | omitted. Moreover, regarding the specific configuration example of each configuration in the present embodiment, the description of the same components as in the first embodiment will be omitted.

  The photoacoustic microscope of this embodiment includes a light source 100, a focus probe 202 including a conversion element 201 that receives a photoacoustic wave, and a container 204 filled with an acoustic matching medium 203. The container 204 is the same as that of the first embodiment, and the bottom surface 206 is a film member having adhesiveness on the outside of the container, that is, the side in contact with the subject 105. Light from the light source 100 is guided to the light emitting unit 208 by the optical waveguide unit 107. The light 209 emitted from the light emitting unit 208 is collected in the vicinity of the light absorber 110 as a target site within the subject by the optical member 217 and the optical member 218. At that time, the object 105 is irradiated through the bottom surface 206. An axicon mirror can be used as the optical member 217, and an optical mirror or the like can be used as the optical member 218.

  The light absorber 110 typically includes a blood vessel in a living body, in particular, a substance such as hemoglobin present in the blood vessel, a tumor, and the like. The light absorber 110 absorbs light energy and generates photoacoustic waves. The generated photoacoustic wave propagates through the subject, passes through the bottom surface 206, and reaches the conversion element 201. The conversion element 201 outputs a time-series reception signal by focusing and receiving the photoacoustic wave. The conversion element 201 preferably includes an acoustic lens that focuses the acoustic wave. The output reception signal is input to the signal processing unit 111. A reception signal generated by the irradiated pulsed light is sequentially input to the signal processing unit 111.

  In addition, a scanning mechanism 213 for performing measurement while scanning the measurement unit 212 such as the light emitting unit 208 and the probe 202 is provided. Moreover, the control part 114 for controlling each structural block in a photoacoustic apparatus is provided. The control unit 114 supplies necessary control signals and data to each component block. Specifically, a signal for instructing the light source 100 to emit light, a reception control signal for the conversion element 201, and a control signal for the scanning mechanism 213 are supplied. Also, signal amplification control of the signal processing unit 111, AD conversion timing control, reception signal storage control, generation of characteristic value information in the subject, and the like are performed. The characteristic value information in the subject generated in the signal processing unit 111 is displayed on the image display unit 115.

  As shown in FIG. 3, the scanning mechanism 213 shows a configuration in which the measurement unit 212 is scanned, thereby performing measurement while scanning the measurement point on the subject 105. However, such a configuration is not necessarily required, and it is only necessary to perform measurement while scanning measurement points on the subject 105.

  The signal processing unit 111 performs envelope detection on the obtained reception signal with respect to time change, and then converts the time axis direction of the signal for each optical pulse into the depth direction and plots it on spatial coordinates. By performing this for each scanning position, sound pressure distribution data is constructed. In addition, when measuring with multiple wavelengths, values related to the optical absorption characteristics in the subject are obtained for each wavelength, and the concentration of the substance is determined using these values and the wavelength dependence of the optical absorption characteristics specific to the substance to be obtained. Image the distribution. For example, the concentrations of oxyhemoglobin HbO and deoxyhemoglobin Hb are calculated to construct blood oxygen saturation distribution data.

  Further, the present embodiment can be used as a handheld photoacoustic apparatus. In that case, for example, a member surrounded by a dotted line 216 is held by a single casing, whereby a handheld device can be configured. At this time, the surface of the housing 216 in contact with the subject 105 is the bottom surface 206, and an adhesive film member or gel member is used. Other specific configuration examples and signal processing are as described above. By using the photoacoustic microscope shown in such an embodiment, the positional deviation between the light irradiation unit and the probe and the subject measurement unit caused by the movement of the subject and the operator during measurement is reduced, It becomes possible to suppress degradation of image quality.

[Embodiment 3]
The configuration and processing of the subject information acquisition apparatus in Embodiment 3 of the present invention will be described.

  The present embodiment relates to a photoacoustic microscope that obtains a high-resolution photoacoustic image by focusing irradiation light and irradiating a subject. FIG. 4 is a schematic diagram showing the configuration of the photoacoustic microscope of the present embodiment. In addition, the same code | symbol is attached | subjected to the component similar to the apparatus shown in FIG. 1, and detailed description is abbreviate | omitted. Further, regarding the specific configuration example of each configuration in the present embodiment, the description of the same components as those in the first and second embodiments is omitted.

  The photoacoustic microscope of this embodiment includes a light source 100, a probe 302 including a conversion element 301 that receives a photoacoustic wave, and a container 304 filled with an acoustic matching medium 303. The container 304 is the same as that of the first embodiment, and the bottom surface 306 is a film member having adhesiveness on the outside of the container, that is, the side in contact with the subject 105. Light from the light source 100 is guided to the light emitting unit 308 by the optical waveguide unit 107. The light 309 emitted from the light emitting unit 308 is condensed on a target site in the subject 105 by the optical lens 317. At that time, the object 105 is irradiated through the bottom surface 306. An objective lens is preferably used as the optical lens 317.

  The light absorber 110 typically includes a blood vessel in a living body, in particular, a substance such as hemoglobin present in the blood vessel, a tumor, and the like. The light absorber 110 absorbs light energy and generates photoacoustic waves. The generated photoacoustic wave propagates through the subject, passes through the bottom surface 306, and reaches the conversion element 301. The conversion element 301 outputs a time-series reception signal by receiving the photoacoustic signal. The conversion element 301 preferably includes an acoustic lens that focuses the acoustic wave. The output reception signal is input to the signal processing unit 111. A reception signal generated by the irradiated pulsed light is sequentially input to the signal processing unit 111.

  In addition, a scanning mechanism 313 for performing measurement while scanning the measurement unit 312 such as the light emitting unit 308 and the probe 302 is provided. Moreover, the control part 114 for controlling each structural block in a photoacoustic apparatus is provided. The control unit 114 supplies necessary control signals and data to each component block. Specifically, a signal for instructing the light source 100 to emit light, a reception control signal for the conversion element 301, and a control signal for the scanning mechanism 313 are supplied. Also, signal amplification control of the signal processing unit 111, AD conversion timing control, reception signal storage control, generation of characteristic value information in the subject, and the like are performed. The characteristic value information in the subject generated in the signal processing unit 111 is displayed on the image display unit 115.

  As shown in FIG. 4, the scanning mechanism 313 is configured to scan the probe 302 and the light emitting unit 308 and thereby perform measurement while scanning the measurement point on the subject 305. However, such a configuration is not necessarily required, and it is only necessary to perform measurement while scanning measurement points on the subject 105.

  As such a configuration, the probe 302 may be fixed using a probe capable of receiving a wide range of photoacoustic waves (for example, a single transducer or an array type transducer having a wide focus range). The irradiation light 309 from the light emitting unit 308 is condensed and applied to the subject 105, and the scanning mechanism 313 can scan the measurement point by scanning only the light emitting unit 308. As a scanning method in which the scanning mechanism 313 scans the irradiation light 309, scanning can be performed by changing the position of the light emitting unit 308, or by changing the angle. Further, the scanning mechanism 313 can scan the measurement point on the subject 105 without directly scanning the light emitting unit 308. For example, by using a mirror that reflects the irradiation light 309 and moving the mirror, the irradiation position of the irradiation light 309 is scanned. By taking such a configuration, it is possible to perform measurement while scanning the measurement point.

  Further, the present embodiment can be used as a handheld photoacoustic apparatus. In that case, for example, a member surrounded by a dotted line 316 is held by a single housing, whereby a handheld device can be configured. At this time, the surface of the housing 316 in contact with the subject 105 is the bottom surface 306, and an adhesive film member or gel member is used. Other specific configuration examples and signal processing are as described above. By using the photoacoustic microscope shown in such an embodiment, the positional deviation between the light irradiation unit and the probe and the subject measurement unit caused by the movement of the subject and the operator during measurement is reduced, It becomes possible to suppress degradation of image quality.

[Embodiment 4]
The configuration and processing of the subject information acquisition apparatus in Embodiment 4 of the present invention will be described.

  FIG. 5 is a schematic diagram showing the configuration of the photoacoustic apparatus of the present embodiment. In addition, the same code | symbol is attached | subjected to the component similar to the apparatus shown in FIG. 1, and detailed description is abbreviate | omitted. Further, regarding the specific configuration example of each configuration in the present embodiment, the description of the same configuration as in the first embodiment is omitted.

  The photoacoustic apparatus of this embodiment includes a probe 402 including a light source 100 and a conversion element 401 that receives a photoacoustic wave. Further, an adhesive gel member 406 is provided on the side in contact with the subject 105. Light from the light source 100 is guided to the light emitting unit 408 by the optical waveguide unit 107. The light 409 emitted from the light emitting unit 408 is collected on a target site in the subject 105. At that time, the subject 105 is irradiated through the gel member 406. The light absorber 110 absorbs light energy and generates photoacoustic waves. The generated photoacoustic wave propagates in the subject, passes through the gel member 406, and reaches the conversion element 401.

  The conversion element 401 outputs a time-series received signal by receiving the photoacoustic signal. The output reception signal is input to the signal processing unit 111. A reception signal generated by the irradiated pulsed light is sequentially input to the signal processing unit 111. A scanning mechanism 413 for measuring while scanning the light emitting unit 408 is provided. The positional relationship of the measurement unit including the scanning mechanism 413 is maintained by the housing 416. Moreover, the control part 114 for controlling each structural block in a photoacoustic apparatus is provided. The control unit 114 supplies necessary control signals and data to each component block. The characteristic value information in the subject generated in the signal processing unit 111 is displayed on the image display unit 115.

  The scanning mechanism 113 scans the light emitting unit 408 and thereby performs measurement while scanning the measurement point on the subject 105. At this time, in order to receive the photoacoustic wave, the conversion element 401 and the gel member 406 are in contact with each other. The subject 105 side of the gel member 406 has adhesiveness. Due to this adhesiveness, the surface portion of the subject 105 (for example, skin in the case of a living body) and the bottom surface of the housing 416 are fixed, and the positional relationship between the measurement region near the surface of the subject and the housing 416 is kept constant. By using such a configuration and an adhesive member, it is possible to prevent the positional relationship between the subject and the measurement position from shifting due to the movement of the subject 110 during measurement.

  As the gel member 406, a member having adhesiveness on one surface and transmitting the photoacoustic wave and the irradiation light 109 is used. The transmittance and adhesive strength of the photoacoustic wave and the irradiation light 109 are the same as those of the film member used in the first embodiment. For example, a polyurethane-based gel can be used. The adhesiveness of the polyurethane gel surface is controlled by the ratio of the hydroxyl groups of the polyurethane.

  The scanning mechanism 413 only needs to be able to perform measurement while scanning a measurement point on the subject 105. As such a configuration, the probe 302 may be fixed using a probe capable of receiving a wide range of photoacoustic waves (for example, a single transducer or an array type transducer having a wide focus range). The irradiation light 409 from the light emitting unit 408 is condensed and applied to the subject 105, and the scanning mechanism 413 can scan the measurement point by scanning only the light emitting unit 408.

  As a scanning method in which the scanning mechanism 413 scans the irradiation light 409, the scanning can be performed by changing the position of the light emitting unit 408 or by changing the angle. Furthermore, the scanning mechanism 413 can scan the measurement point on the subject 105 without directly scanning the light emitting unit 408. For example, the irradiation position of the irradiation light 409 is scanned by moving the mirror using a mirror that reflects the irradiation light 409. By taking such a configuration, it is possible to perform measurement while scanning the measurement point. It is also possible to scan the measurement point by changing the focus position of the photoacoustic wave by using an array type transducer and adjusting and receiving the delay time for each conversion element. In that case, the irradiation light 409 may be condensed and scanned, or the beam may be expanded to fix the irradiation position.

  Further, the present embodiment can be used as a handheld photoacoustic apparatus. In that case, for example, the surgeon holds the case surrounded by the dotted line 416 to perform the measurement. Other specific configuration examples and signal processing are as described above. By using the photoacoustic microscope shown in such an embodiment, the positional deviation between the light irradiation unit and the probe and the subject measurement unit caused by the movement of the subject and the operator during measurement is reduced, It becomes possible to suppress degradation of image quality.

Claims (13)

A light source that generates light for irradiating the subject;
A conversion element that receives a photoacoustic wave generated in the subject by being irradiated with the light; and
A transmissive member disposed in contact with the subject and transmitting the light and the photoacoustic wave;
A signal processing unit that acquires characteristic value information in the subject from a reception signal output from the conversion element,
The photoacoustic apparatus, wherein the transparent member has adhesiveness on a surface in contact with the subject.   The photoacoustic apparatus according to claim 1, wherein the surface in contact with the subject has an adhesive force of 0.1 to 10.0 (N / 10 mm).   The photoacoustic apparatus according to claim 1, wherein the conversion element is immersed in a fluid acoustic matching medium stored in a container.   The photoacoustic apparatus according to claim 3, wherein a surface of the container on the subject side is the transmissive member.   The photoacoustic apparatus according to claim 4, wherein the transparent member is a film member having adhesiveness on at least one side.   The photoacoustic apparatus according to claim 5, wherein the film member is waterproof.   The photoacoustic apparatus according to claim 6, wherein the film member uses a polyurethane film as a base material and an acrylic adhesive as an adhesive on one side.   The photoacoustic apparatus according to claim 1, wherein the conversion element is in contact with the transmissive member.   The photoacoustic apparatus according to claim 8, wherein the transmissive member is a gel member.   The photoacoustic apparatus according to claim 9, wherein the gel member is a polyurethane-based gel member.   The photoacoustic apparatus according to claim 1, further comprising an image display unit configured to display characteristic value information in the subject.   The photoacoustic apparatus according to any one of claims 1 to 11, wherein the transmissivity of light and photoacoustic waves of the transmissive member is 70% or more and less than 100%. A step of adhering the measurement unit and the surface of the subject with a permeable member having adhesiveness;
Irradiating the subject with light; and
Receiving a photoacoustic wave generated in the subject by being irradiated with the light by a conversion element;
Obtaining characteristic value information in the subject from a reception signal output from the conversion element;
The photoacoustic wave measuring method characterized by having.

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