JP2010012295A - Living body information imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a living body information imaging apparatus, having high contrast resolution and spatial resolution in maneuverability of the living body information imaging apparatus. <P>SOLUTION: This living body information imaging apparatus includes: an optical transmission section 1 which irradiates a subject 7 with light containing a specified wave length component; an electric sound converting section 23 which receives an acoustic wave generated in the subject 7 by the light applied by the optical transmission section 1 and converts the acoustic wave to an electric signal; an image data generating section 2 which generates a first image data based on the received signal obtained by the electric sound converting section 23; an electric sound converting section 23 which receives an ultrasonic wave reflection signal obtained by transmitting the ultrasonic wave to the subject 7 and converts the ultrasonic wave reflection signal to an electric signal; an image data generating section 2 which generates a second image data based on the received signal obtained by the electric sound converting section 23; and a display part 6 which synthesizes the first image data and the second image data and displays the same. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a biological information video apparatus that collects an acoustic signal generated based on the energy of light irradiated inside a subject and images biological information of the subject. More specifically, two auditory images, one generated from the energy of the light irradiated to the subject to be examined and the ultrasonic echo image generated from the ultrasound irradiated to the subject to be examined, are captured and superimposed. With regard to the method and apparatus, by superimposing two images, it is possible to know the distribution of the substance concentration with respect to the morphological features in the tissue of the subject.

  A biological information measurement method for measuring the concentration of a substance component contained in a body fluid such as blood or cell fluid of a subject or a biological tissue has been conventionally performed in health management or determination of a therapeutic effect. In the component analysis of the body fluid for the purpose of measuring the concentration of this substance component, it is necessary to first remove the body fluid from the body by blood collection. Therefore, this method causes a great deal of pain due to skin damage to the subject. At the same time, subjects and workers are exposed to the risk of biohazard contamination.

  In response to such conventional problems, numerous patents and newspaper articles describe non-invasive methods for obtaining information about analyte concentration in human subject tissue. One of these methods is “photoacoustic spectroscopy”. In photoacoustic spectroscopy, in this photoacoustic spectroscopy, when visible light, near-infrared light, or mid-infrared light having a predetermined wavelength is irradiated on the subject, it is contained in the blood in the subject. The specific substance such as glucose or hemoglobin that is absorbed as a result of absorbing the energy of the irradiation light is detected, and the concentration of the specific substance is quantitatively measured. In this regard, US Pat. No. 5,348,002, European Patent No. 9838904A1, and European Patent No. 0215776A1 disclose methods for noninvasive determination of substances in human tissue using photoacoustic measurements. Yes. The light may be visible light, infrared light, or intermediate infrared light.

  In addition to the glucose and hemoglobin described above, there are cholesterol, neutral fat, bilirubin, collagen, and the like as substances that are non-invasive biological information measurement targets. Diagnosis of skin cancer, breast cancer, etc. by photoacoustic spectroscopic analysis using the light wavelength that maximizes the absorption of the substance selected from these substances has become apparent in recent years. In addition, there is an increasing expectation for a diagnostic imaging method that applies this new spectroscopic analysis technique and visualizes the concentration distribution of the substance as a two-dimensional image.

  As a conventional non-invasive glucose measurement method, there is a method of measuring glucose concentration by irradiating near-infrared light of a different wavelength onto the skin surface of a subject and processing an acoustic wave obtained at this time ( For example, see Patent Document 1 and Patent Document 2.)

  Further, in the conventional photoacoustic spectroscopic analysis method, a method using a piezoelectric element such as a microphone or a zircon-lead titanate ceramic (PZT) for detecting an acoustic wave has been proposed (for example, Patent Document 3 and Patent Document 4). reference.).

In addition to hemoglobin and glucose, photoacoustic spectroscopy can also be used to determine other specimens in human tissue such as cholesterol, natural fat, bilrubin, collagen, and the like. The diagnosis of skin cancer and breast cancer based on the results of photoacoustic spectroscopy has recently proved effective in the medical field. The photoacoustic spectroscopy uses an appropriate substance selected from these substances and light having a wavelength that is most easily absorbed by the selected substance. Furthermore, there is an increasing expectation for the invention of a diagnostic method that provides a two-dimensional image representing the concentration distribution of these substances.

  Photoacoustic spectroscopy is used to measure the concentration of a substance in tissue, whereas ultrasound images are used to determine the presence of morphological features such as cysts and lumps in human organs. Have been widely used. By combining the distribution and morphological characteristics of substances in human tissue, the tissue can be characterized more precisely, malignant tumors can be diagnosed more accurately, and abnormal lesion areas can be more accurately defined and these Better diagnosis and improved health care are realized because it can lead to surgical removal of the area.

  Breast cancer is one of the leading causes of death in women. Breast cancer screening and early diagnosis have tremendous value in reducing mortality and reducing health care costs. Current methods include palpation of breast tissue to detect abnormal lump and regular mammograms to look for suspicious tissue deformations. If there is a suspicious part in the mammogram, an ultrasound image is taken and a surgical biopsy is performed. These series of steps take a considerable amount of time to reach a final conclusion.

  Non-invasive optical techniques allow the distribution of blood vessels within the tissue to be determined, and thus the location of potential tumors can be known by abnormal angiogenesis within the tissue region.

  Non-invasive optical techniques include time-resolved light transmission within the tissue. Another method is to measure the modulation and the change in phase angle associated with the propagation of photon density waves in the tissue. These were introduced in several newspaper articles (B. Chance “Near Infrared Images Using Continuous Phase-Modulated Pulsed Light for Quantification of Blood and Blood Oxidation” Advances in Optical Biopsy and Optical Mammography, R. Alfano ed. , Annals of the New York Academy of Sciences 1998; Volume 838, pp. 29-45, “Frequency Domain Optical Mammography; Edge Effect Modification, Medical Physics 1996” by S. Fantini et al., Volumes 23, 1-6. Page, MA Francescani et al. “Frequency Domain Technology Advances Optical Mammography; First Medical Results” Proceedings of the National Academy of Sciences USA, 1997; Vol. 94, pages 6468-6473 (1997). In these methods, the inaccuracy of the image conversion and the distortion of the image in the region near the edge of the body part such as the breast are problems.

  Conventional imaging methods, including ultrasound, CAT scanning, X-ray, MRI, show the body part, in this case the morphology of the chest, without showing the distribution of hemoglobin. Furthermore, MRI and CAT scanning are large and expensive instruments that cannot be easily deformed.

  The diagnosis method and apparatus using the distribution of substances in the morphological image and the morphological features can make better diagnosis.

  For a method of determining the specimen distribution in the breast tissue using photoacoustic imaging, see A. A. "Laser photoacoustic imaging of the chest: detection of angiogenesis due to cancer" SPIE Proceedings 1999; Volume 3597, pages 352-363, and Araevski et al. A. Olaevski et al., “Photoacoustic Imaging for Blood Visualization and Breast Cancer Diagnosis” SPIE Proceedings 2002; 4618, 81-94. Also, US Pat. No. 5,840,023 discloses “photoacoustic imaging for medical diagnostics”, and EP 01/10295 discloses “photoacoustic monitoring of blood oxidation” and US Patent No. 6,309,352B1 also describes “Real-time photoacoustic monitoring of changes in tissue characteristics”.

  Olaevsky et al. Uses only photoacoustic imaging and does not combine with ultrasound imaging. They do not teach the combination of photoacoustic and ultrasonic images detected using aligned ultrasonic transducers. According to this method, the blood vessel image may be distorted due to the influence of morphological characteristics on the bulk modulus of tissue.

  For other applications of optical methods for generating images of specimen distribution in tissue, see Q. Zhu et al., “Tomographic Images Combining Ultrasound and Optics” SPIE Proceedings 1999; Volume 3579, pages 364-370; Zhu et al., “Optical Imaging as an Accompaniment to Ultrasound in Distinguishing Benign Tissue Deformation from Malignant Tissue Deformation” SPIE Proceedings 1999; Volume 3579, pages 532-539. Zhu et al. Define morphological characteristics in tissue using ultrasound imaging and apply frequency domain imaging to determine angiogenesis, eg, the distribution of hemoglobin. Optical fibers and photomultiplier tubes are used as detectors for optical methods, and ultrasonic transducers are used to perform ultrasound imaging by aligning angiogenic and morphological images that are less optimal. . There is no teaching of a combination of photoacoustic and ultrasonic images detected using aligned ultrasonic transducers.

  On the other hand, in recent years, research on an imaging method in the case where this photoacoustic effect is applied to diagnosis of breast cancer has been advanced (for example, see Non-Patent Document 1). FIG. 14 shows a photoacoustic image data collection system 100 described in Non-Patent Document 1, in which a laser generator 101 that generates pulsed light and light that supplies this light pulse to a breast 102 of a subject. A fiber 103, a concave array type electroacoustic transducer 104 arranged to face the optical fiber 103, and a computer system 105 that performs optical pulse transmission control, acoustic wave collection, and image reconstruction. Has been. After the breast 2 is inserted between the optical fiber 103 and the arrayed electroacoustic transducer 104, the internal tissue of the breast 102 is irradiated with light (laser light) from the optical fiber 103, so that the blood component of the internal tissue Newly generated acoustic waves are received by the array type electroacoustic transducer 104.

  According to this method, for example, the concentration of hemoglobin in blood can be measured with higher sensitivity than other substance components by the photoacoustic effect by a predetermined light wavelength. Therefore, a photoacoustic image obtained for a tumor tissue such as breast cancer in which the blood flow volume is higher than that of a normal tissue is superior to an image obtained by a conventional ultrasonic diagnostic apparatus, X-ray apparatus, MRI apparatus, or the like. Have the potential to detect This is because angiogenesis, which is the number of blood vessels, and blood vessel flow rate are higher in the tumor tissue than in the normal tissue in order to correspond to the high metabolic activity in the tumor. As the tumor and surrounding blood vessels increase, angiogenesis becomes more frequent. The generation of new blood vessels in the tumor is known as angiogenesis.

  However, all of the methods proposed in Patent Documents 1 to 4 are intended to measure the concentration of a specific substance at a local site, and the imaging technique for the concentration distribution is not mentioned.

  Further, according to the method described in Non-Patent Document 1, there is a problem in operability because the optical fiber 103 and the arrayed electroacoustic transducer 104 are arranged to face each other with the breast 102 interposed therebetween. . In particular, when imaging is performed by receiving an acoustic wave from within a living body, it is necessary to eliminate air intervening between the arrayed electroacoustic transducer 104 and the living body as much as possible. The conversion element 104 is preferably integrated.

  Furthermore, imaging using this acoustic wave (hereinafter referred to as a photoacoustic imaging method) is performed only for a specific component such as hemoglobin, and a signal cannot be obtained from a region without this specific component. Therefore, for example, when the photoacoustic imaging method is applied to breast cancer examination as in Non-Patent Document 1, there is a problem that it is difficult to grasp the exact positional relationship of the tumor tissue with respect to the surrounding normal breast tissue.

  Therefore, combining morphological characteristics and imaging of substance concentration distribution into those characteristics, while eliminating image distortion and incorporating common body interface and common detector for imaging measurement and substance distribution measurement There is a need to develop methods and devices for diagnosing disease states. This method and apparatus should be able to apply the same pressure, the same air gap, and the same interface for imaging and material distribution measurements.

Japanese Examined Patent Publication No. 3-47099 Japanese Patent Publication No. 5-58735 JP-A-10-189 JP 11-235331 A

Alexander A, et.al: Laser optoacoustic imaging of breast cancer in vivo, Proc. SPIE, Vol. 4256: pp. 6-15, 2001.

  An object of the present invention is to provide a data collection system with excellent operability in imaging of biological information (photoacoustic imaging method) obtained by using the photoacoustic effect in a living body, and further to provide high contrast resolution and spatial resolution. An object of the present invention is to provide a biological information video apparatus capable of generating image data.

  An aspect of the present invention includes a light generation unit that generates light including a specific wavelength component, a light irradiation unit that irradiates a subject with light generated by the light generation unit, and light generated by the light generation unit. Waveguide means for guiding to the light irradiating unit, and a first electric for converting an acoustic wave generated in the subject by light irradiated by the light irradiating unit into an electric signal using a plurality of electroacoustic transducers arranged. Acoustic conversion means, first image data generation means for generating first image data based on a signal obtained by the first electroacoustic conversion means, and ultrasonic transmission means for transmitting ultrasonic waves into the subject A second electroacoustic transducer that converts a plurality of components reflected in the subject among the ultrasonic waves transmitted by the ultrasonic transducer to an electrical signal using an arrayed electroacoustic transducer; Obtained by the second electroacoustic conversion means Second image data generating means for generating second image data based on a signal to be transmitted; and display means for displaying the first image data and the second image data; The part and the plurality of electroacoustic transducers are arranged one-dimensionally.

  According to the present invention, in the visualization (photoacoustic imaging method) of biological information obtained using the photoacoustic effect in the living body, the data collection system having excellent operability is provided, and further, high contrast resolution and spatial resolution are provided. It is possible to provide a biological information video apparatus capable of generating image data having the same.

1 is a block diagram showing a schematic configuration of a biological information video apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram of an image data generation unit of the biological information video apparatus according to the first embodiment of the present invention. 1 is a configuration diagram of an applicator according to a first embodiment of the present invention. 1 is an external view of an applicator according to a first embodiment of the present invention. FIG. 3 is a diagram showing an irradiation method using an optical fiber in the first embodiment of the present invention. The figure which shows the reception method of the acoustic wave in the 1st Embodiment of this invention. The figure which shows the frequency spectrum of the received ultrasonic wave in the 2nd Embodiment of this invention. The figure which showed the irradiation position of the irradiation light in the 3rd Embodiment of this invention, and the reception position of an acoustic wave. The block diagram of the applicator in the 4th Embodiment of this invention. The block diagram of the electroacoustic conversion part in the 4th Embodiment of this invention. The block diagram of the applicator in the modification of the 4th Embodiment of this invention. The figure which shows the irradiation method using the slit in the 5th Embodiment of this invention. The time chart which shows the scanning method of the photoacoustic imaging method pulse echo method in embodiment of this invention. The figure which shows the collection system of the conventional photoacoustic image data. The external view of a part of electroacoustic transducer in the 6th Embodiment of this invention. The top view of a part of electroacoustic conversion part of FIG. The block diagram of the electroacoustic conversion part in the 7th Embodiment of this invention. The block diagram of the electroacoustic conversion part in the 8th Embodiment of this invention.

  One aspect of the present invention is a method for determining the distribution of analyte concentration in human tissue and overlaying this distribution on a morphological image of a body part to be examined to perform a more accurate diagnosis.

One aspect of the present invention is:
a) contacting a diagnostic probe further comprising an ultrasound imaging element and a photoacoustic irradiation and detection element to the breast tissue;
b) irradiating the breast tissue with a short light pulse having a wavelength in the absorption spectrum band of hemoglobin to generate a photoacoustic signal;
c) detecting the photoacoustic signal using an ultrasonic transducer to determine the distribution of new blood vessels in the breast tissue;
d) generating and detecting ultrasonic images of the morphology of the human breast tissue simultaneously or sequentially using an ultrasonic transducer aligned with the photoacoustic detection transducer used in the detection of the photoacoustic signal; Process,
e) superimposing the photoacoustic hemoglobin distribution image on the ultrasound morphological image to generate a composite image of the distribution of blood vessels in different morphological structures of the breast, wherein the morphological structure is the target tumor;
f) predicting the possibility of diagnosis based on the distribution of the new blood vessels on the tumor, and a method for diagnosing human breast cancer.

  The methods and apparatus of the present invention can be used to determine the concentration of chemotherapeutic substances in human normal and malignant tissues, thus providing a method for eliciting the potential effects of treatment. Such a class of therapeutic agents are those used for photodynamic therapy. Thus, in addition to helping a better and more accurate diagnosis, the methods and devices of the present invention can also be used to direct treatment.

  The wavelength of light is in the visible near-infrared spectrum, where the wavelength is longer than that which is not so much absorbed by tissue moisture and tissue dyes and can penetrate deeply into the tissue. A preferred spectral range is between 530 nm and 1300 nm.

  The photoacoustic detection element and the ultrasonic detection element used in the method and apparatus of the present invention are common. This maximizes the alignment between the two images and minimizes the change in the interface between the detector and the body between the two imaging methods.

  The ultrasonic vibrator is a piezoelectric element such as a piezoelectric ceramic or a polymer film such as polyvinylpyrrolidone fluoride. A preferred material is PZNT (lead / zirconium / niobium / titanium) single crystal.

Another aspect of the present invention is an apparatus for improving the diagnosis of diseases such as human breast cancer by determining the concentration of a substance such as hemoglobin in the morphological characteristics of a tissue such as a lump or tumor. This device
a) a light generating device for generating light having a specific wavelength component;
b) an irradiation device for irradiating the subject to be inspected with the light generated by the light generation device;
c) waveguide means for guiding the light generated by the light generation device to the irradiation device;
d) first electroacoustic conversion means for converting a sound wave generated in the subject by light irradiated by the irradiation device into an electrical signal by using an array of a plurality of electroacoustic conversion elements;
e) first image data generation means for generating first image data based on the signal obtained by the first electroacoustic conversion means;
f) ultrasonic transmission means for transmitting ultrasonic waves to the subject;
g) a second electroacoustic conversion means for converting an ultrasonic component transmitted by the ultrasonic transmission means and reflected in the body of the subject into an electric signal using an array of a plurality of electroacoustic conversion elements;
h) second image data generation means for generating second image data based on the signal obtained by the second electroacoustic conversion means;
i) A display means for displaying the first image data and the second image data is provided.

  In this generalized application as a subject information imaging device, several aspects of the device of the present invention are described in the following eight embodiments.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS.

  The biological information video apparatus described in the first embodiment enables imaging of hemoglobin distribution in a living body for the purpose of diagnosing breast cancer, and its features are arranged in an electroacoustic conversion unit. An electroacoustic conversion unit integrated with the light irradiation unit is formed by arranging the optical fiber output end of the light irradiation unit in the gap between the placed electroacoustic conversion elements. Then, the respective image data obtained by the photoacoustic imaging method using the electroacoustic conversion unit and the conventional pulse echo method are synthesized and displayed on the same part in the living body.

  Hereinafter, a sound wave generated by the photoacoustic imaging method is referred to as an acoustic wave, and a sound wave transmitted and received in a normal pulse echo method is referred to as an ultrasonic wave.

  The configuration of the biological information video apparatus in the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a schematic configuration of the entire biological information video apparatus according to the first embodiment, and FIG. 2 is a block diagram of an image data generation unit 2 of the biological information video apparatus.

  This biological information video apparatus includes an optical transmitter 1 that irradiates a subject 7 with light of a predetermined wavelength, photoacoustic image data based on acoustic waves obtained by irradiating the subject 7 with this light, and conventional ultrasonic waves. An image data generation unit 2 for generating image data, a display unit 6 for displaying the photoacoustic image data and ultrasonic 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 optical transmission unit 1 includes a light source unit 11 including a plurality of light sources having different wavelengths, an optical multiplexing unit 12 that synthesizes light of a plurality of wavelengths on the same optical axis, and a multipath that guides the light to the body surface of the subject 7. A waveguide unit 14 of a channel, an optical scanning unit 13 that performs scanning by switching channels used in the waveguide unit 14, and a light irradiation unit 15 that irradiates the subject 7 with light supplied by the waveguide unit 14; It has.

  The light source unit 11 includes a plurality of light sources that generate light of different wavelengths. As the light source, a light emitting element such as a semiconductor laser (LD), a light emitting diode (LED), a solid state laser, or a gas laser that generates a specific wavelength component or monochromatic light including the component is used. For example, when measuring the hemoglobin concentration of the subject 7, a Nd: YAG laser having a wavelength of about 1000 nm, which is a kind of solid-state laser, or a 633 nm He—Ne gas laser, which is a kind of gas laser, is used, and a pulse of about 10 nsec. A laser beam having a width is formed. Although 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.

When a small light emitting element such as an LD or LED is used, InGaAlP is used when the emission wavelength is about 550 to 650 nm, GaAlAs is used when the emission wavelength is about 650 to 900 nm, and InGaAs or InGaAsP is used when the emission wavelength is about 900 to 2300 nm. Elements using these materials can be used. Recently, a light-emitting element using InGaN that emits light at a wavelength of 550 nm or less is becoming available.

Furthermore, an OPO (Optical Parametrical Oscillators) laser using a nonlinear optical crystal whose wavelength is variable can be used.

  The optical multiplexing unit 12 is for superimposing light having different wavelengths generated from a plurality of light sources on the same optical axis, and each light is first converted into parallel rays by a collimating lens, and then a right angle prism or The optical axis is adjusted by the dichroic prism. With such a configuration, a relatively small multiplexing optical system can be obtained, but a commercially available multiple wavelength multiplexer / demultiplexer developed for optical communication may be used. Further, when a light source such as an OPO laser whose wavelength can be continuously changed is used for the light source unit 11, the optical multiplexing unit 12 is not necessarily required.

  The waveguide section 14 is for guiding the light output from the optical multiplexing section 12 to the subject 7 and uses an optical fiber or a thin film optical waveguide for efficient light propagation, but directly propagates in space. It is also possible. The waveguide unit 14 used in the first embodiment of the present invention is composed of a plurality of optical fibers 71 described later, and a predetermined optical fiber 71 is selected from the plurality of optical fibers 71. Supply light.

  The optical scanning unit 13 scans the subject 7 with light by supplying light while sequentially selecting a plurality of optical fibers 71 arranged in the waveguide unit 14.

  The light irradiation unit 15 is an output end of the waveguide unit 14 and is integrated with an electroacoustic conversion unit 23 described later. For example, the output end of the optical fiber 71 in the light irradiation unit 15 is disposed adjacent to the array type conversion element 54 that constitutes the electroacoustic conversion unit 23.

  On the other hand, the image data generation unit 2 of the biological information video apparatus selectively drives the electroacoustic conversion unit 23 that converts an acoustic signal and an electric signal, and receives the electroacoustic conversion unit 23 from the electroacoustic conversion unit 23. A transmission / reception unit 22 that selectively receives a signal, gives a predetermined delay time to the transmission / reception signal, and performs phasing addition; A signal processing unit 21 that outputs a rate pulse for setting a repetition period of transmission ultrasonic waves radiated inside the subject 7, and a signal process that performs various processes on the reception signal obtained from the transmission / reception unit 22. Part 25.

  The electroacoustic transducer 23 has M transducer elements 54 arrayed in a one-dimensional manner at its tip, and the tip is brought into contact with the body surface of the subject 7 to generate acoustic waves or ultrasonic waves. Send and receive. The conversion element 54 has a function of converting an electrical drive pulse into a transmission ultrasonic wave at the time of transmission, and converting an acoustic wave or a reception ultrasonic wave into an electric signal at the time of reception. The electroacoustic conversion unit 23 is generally called an ultrasonic probe and is configured to be small and light, and is connected to a transmission / reception unit 22 described later by a multi-channel cable. The electroacoustic conversion unit 23 is selected according to the diagnostic site from among sector scanning, linear scanning, convex scanning, etc. In this embodiment, the electroacoustic conversion unit 23 for linear scanning is used. Describe the case.

  As shown in FIG. 2, the transmission / reception unit 22 includes a transmission delay circuit 51, a pulser 52, an electronic switch 53, a preamplifier 55, a reception delay circuit 56, and an adder 57.

  The transmission delay circuit 51 is a delay circuit for setting the convergence distance of the transmission ultrasonic wave at the time of transmission, and is N ′ (M> N ′) of the M conversion elements 54 constituting the electroacoustic conversion unit 23. ) Is supplied to the rate pulse output from the rate signal generator 21 and supplied to the pulser 52.

  The pulser 52 is a drive circuit that generates a high-voltage pulse for driving the N ′ number of conversion elements 54. For example, an impulse having a peak value of several hundred volts is used as an output signal from the transmission delay circuit 51. Form.

  The electronic switch 53 selects the adjacent N ′ number of conversion elements 54 from the M number of conversion elements 54 constituting the electroacoustic conversion unit 23 at the time of transmission by the pulse echo method. Further, when receiving the photoacoustic imaging method, N adjacent conversion elements 54 are selected from the M conversion elements 54, and when receiving the pulse echo method, N ′ number of conversion elements 54 are selected. . The received signals obtained by the N and N ′ conversion elements 54 are supplied to the preamplifier 55.

  On the other hand, the preamplifier 55 amplifies a minute reception signal received by the N ′ number of conversion elements 54 selected by the electronic switch 53 to ensure sufficient S / N.

  The reception delay circuit 56 applies a predetermined response to an acoustic reception signal or an ultrasonic reception signal obtained from N or N ′ (M> N ′, M> N) conversion elements 54 selected by the electronic switch 53. A delay time for forming a converged reception beam is provided by matching the phases of the acoustic wave from the region or the reception ultrasonic wave.

  The adder 57 adds the N′-channel ultrasonic reception signal or the N-channel acoustic reception signal to a single reception signal. By adding the N ′ channel or the N channel, received signals from a predetermined depth are phased and added, and a reception convergence point is set.

  The rate signal generator 21 generates clock pulses for setting the transmission timing of ultrasonic pulses performed at a predetermined repetition frequency. This repetition frequency depends on the depth of field of the image, but is set to 4 KHz to 8 KHz in the present embodiment.

  The scanning control unit 24 includes a conversion element selection control circuit 68 and a beam focusing control circuit 67. The conversion element selection control circuit 68 includes N ′ conversion elements 54 at the time of transmission and N elements at the time of reception, which are selected by the electronic switch 53. Alternatively, the positional information of the N ′ conversion elements 54 is supplied to the electronic switch 53. On the other hand, the beam focusing control circuit 67 transmits the delay time information for forming the transmission convergence point and the reception convergence point formed by the N conversion elements 54 and the N ′ conversion elements 54 to the transmission delay circuit 51 and the reception delay. Supply to circuit 56.

  The signal processing unit 25 includes a filter 66, a logarithmic converter 58, an envelope detector 59, an A / D converter 60, an image data memory A61, and an image data memory B62. The output of the adder 57 of the transmission / reception unit 22 is obtained by removing unnecessary noise in the filter 66 of the signal processing unit 25 and then logarithmically converting the amplitude of the reception signal by the logarithmic converter 58 to relatively emphasize the weak signal. . In general, 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 to display it on a normal CRT 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. An envelope detector 59 performs envelope detection on the logarithmically converted received signal, and an A / D converter 60 A / D converts the output signal of the envelope detector 59 to form image data. .

  The image data includes image data (hereinafter referred to as photoacoustic image data) generated based on an acoustic reception signal obtained when light is incident on the subject 7 by the photoacoustic imaging method, and a normal pulse. As widely used in the echo method, it refers to image data (hereinafter referred to as ultrasonic image data) generated based on an ultrasonic reception signal obtained as a reflected wave when transmission ultrasonic waves are transmitted to the subject 7. . The image data memory A61 is a storage circuit that stores the former photoacoustic image data, and the image data memory B62 is a storage circuit that stores the latter ultrasonic image data.

  The display unit 6 includes a display image memory 63, a converter 64, and a CRT monitor 65. The display image memory 63 is a buffer memory for temporarily storing the image data to be displayed on the CRT monitor 65, and the photoacoustic image data stored in the image data memory A61 and the ultrasonic image stored in the image data memory B62. The data is synthesized in this display image memory 63. The converter 64 performs D / A conversion and television format conversion on the composite image data read from the display image memory 63, and the output is displayed on the CRT monitor 65.

  The operation unit 5 includes a keyboard, a trackball, a mouse and the like on the operation panel, and is used by the apparatus operator to input necessary information such as patient information and imaging conditions of the apparatus.

  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 data generation unit 2, and the display unit 6 according to a command signal from the operation unit 5 and controls the entire system. To supervise. In particular, the input command signal of the operator sent via the operation unit 5 is stored in the internal CPU.

  Next, an applicator 70 in which the light irradiation unit 15 and the electroacoustic conversion unit 23 are integrated will be described with reference to FIGS. 3 and 4. FIG. 3A shows a specific example of an arrangement method of the optical fiber 71 constituting the waveguide section 14 and the conversion element 54 constituting the electroacoustic conversion section 23, and has a length s, a thickness t, and a width a. M conversion elements 54-1 to 54-M having one-dimensional arrangement are arranged one-dimensionally at an arrangement interval d. On the other hand, the optical fibers 71 are arranged in the same direction as the arrangement direction of the conversion elements 54 in the arrangement gap of the conversion elements 54 and in the vicinity of the center in the length direction.

  FIG.3 (b) shows sectional drawing of the applicator 70 in the AA cross section of Fig.3 (a). That is, the applicator 70 that directly contacts the body surface of the subject 7 and performs irradiation of irradiation light and transmission ultrasonic waves and reception of acoustic waves and reception ultrasonic waves includes an optical fiber 71 for light irradiation and reception of acoustic signals. And a conversion element 54 for transmitting and receiving ultrasonic waves. Then, electrodes 73-1 and 73-2 for supplying drive signals and extracting received signals are mounted on the first surface (upper surface) and the second surface (lower surface) of the conversion element 54, respectively. The electrode 73-1 is fixed to the support base 72. The other electrode 73-2 is provided with an acoustic matching layer 74 for efficiently transmitting and receiving ultrasonic waves, and its surface is covered with a protective film 75. In FIG. 3A, the support base 72, the acoustic matching layer 74, and the protective film 75 are omitted.

  FIG. 4 is an external view of the applicator 70. The electroacoustic conversion unit 23 and the light irradiation unit 15 arranged on the left surface of the applicator 70 are in contact with the surface of the subject 7, and the irradiation and sound of the irradiation light are detected. Wave reception and ultrasonic transmission / reception are performed. On the other hand, the optical fiber 71 connected to the light irradiation unit 15 and the coaxial cable 77 connected to the electrode 73 of the conversion element 54 are gathered together by a coating 76, and the other end of the optical fiber 71 is connected to the optical scanning unit 13 and coaxial. The other end of the cable 77 is connected to the transmission / reception unit 22 of the image data collection unit 2.

  Next, a procedure for generating photoacoustic image data according to the first embodiment of the present invention will be described with reference to FIGS. However, FIG. 5 is a diagram showing a method of irradiating irradiation light in the applicator 70, and FIG. 6 is a diagram showing a method of receiving an acoustic wave in the same applicator 70. In this figure, the support base 72, the acoustic matching layer 74 and the protection are also shown. The film 75 is omitted.

  The operator sets necessary image capturing conditions in the photoacoustic imaging method and the pulse echo method in the operation unit 5. The image capturing conditions include various specifications of the applicator 70 in addition to the number of frames, the depth of field, the rate frequency, and the image display method. Further, the operator simultaneously sets various conditions relating to the light source such as the light wavelength used for photoacoustic imaging, and stores the set imaging conditions in a storage circuit (not shown) of the system control unit 4.

  When the setting of the various imaging conditions is completed, the operator installs the applicator 70 at a predetermined position on the subject 7 and then issues a photoacoustic image data collection start command in photoacoustic imaging from the operation unit 5. input.

  Upon receiving this photoacoustic image data collection start command, the system control unit 4 reads out the setting conditions relating to the light source from the internal storage circuit, and selects, for example, an Nd / YAG laser from the light source unit 11 according to the setting conditions. Monochromatic light having a wavelength is generated. The monochromatic light generated by the light source unit 11 is sent to the optical scanning unit 13 via the optical multiplexing unit 12, and the optical scanning unit 13 includes a plurality of optical fibers 71 (71-1) arranged as shown in FIG. ~ 71-M-1), for example, the optical fiber 71-3 is selected to supply the monochromatic light. The selected optical fiber 71-3 guides this light to the light irradiation unit 15 of the applicator 70, and irradiates the subject 7 from the tip thereof. In this case, the monochromatic light emitted from the optical fiber 71-3 is emitted in a direction substantially perpendicular to the subject contact surface of the applicator 70, as indicated by an arrow in FIG.

  The hemoglobin in the blood of the subject 7 absorbs the energy of the emitted monochromatic light and causes a temperature rise, and generates an acoustic wave due to a pressure change resulting from the temperature rise. The acoustic wave generated at this time is a pulse wave having a broadband spectrum component of 100 KHz to 2 MHz.

  In the photoacoustic effect, the wavelength of light to be irradiated is determined by the substance to be measured, and the amount of the component can be quantified from the magnitude of the acoustic wave obtained as a result of irradiation with this wavelength. That is, the amount of hemoglobin in the irradiated region can be quantitatively measured by irradiating the subject 7 with monochromatic light having a wavelength of 1000 nm by the Nd / YAG laser.

  Subsequent to the irradiation of light on the subject 7, acoustic waves are received. For example, for an acoustic wave generated in a blood vessel region at a distance L from the subject contact surface of the applicator 70 as shown in FIG. 6, the system control unit 4 scans information stored in advance in the storage circuit. Is supplied to the conversion element selection control circuit 68 of the scanning control unit 24, and the delay time information regarding the focal length setting at the time of reception is supplied to the beam convergence control circuit 67 of the same scanning control unit 24. To do.

  Based on the control signal of the conversion element selection control circuit 68, the electronic switch 53 includes N (N = 6) adjacent conversion elements 54 among the M conversion elements 54-1 to 54 -M of the applicator 70. -1 to 54-6 are selected. On the other hand, the reception delay circuit 56 gives a delay time for setting the reception focal length to L with respect to the reception signals obtained by these conversion elements 54 based on the control signal of the beam convergence control circuit 67. That is, the conversion element selection control circuit 68 turns on the electronic switches 53-1 to 53 -N (N = 6) based on the selection information of the conversion element 54 supplied from the system control unit 4, and performs light irradiation. The conversion elements 54-1 to 54-6 are selected as reception conversion elements 54 around the optical fiber 71-3 selected and used. The acoustic wave generated inside the subject 7 is converted into an electrical signal by the conversion elements 54-1 to 54-6, then supplied to the preamplifier 55 via the electronic switch 53, amplified to a predetermined amplitude, and received. Input to the delay circuit 56.

  In the reception delay circuit 56 composed of N channels, the nth reception delay circuit 56 gives a delay time τ (n) expressed by the following equation to the reception signal obtained by the conversion element 54-n.

^{τ (n) = d 2 (} N-1) 2 - (2n-N-1) 2 / 8CFo ... (1)
However, d is the arrangement interval of the conversion elements 54, C is the acoustic wave propagation velocity of the subject 7 (about 1500 m / sec), Fo is the reception focal length, and conversion elements 54-1 to 54 are set if Fo = L. After the delay time is given to the reception signal obtained by −6, addition is performed by the adder 57, so that the phases of the acoustic waves generated at the distance L can be made to coincide and be combined.

  According to the present embodiment, the time from when the object 7 is irradiated with light until the acoustic wave is received by the conversion element 54 is proportional to the distance L. Therefore, in the reception of acoustic waves, a so-called dynamic convergence method in which the value of the reception focal length Fo in the equation (1) is increased with time can be applied, and the acoustic waves generated by the irradiation of the optical fiber 71-3 have a depth of Regardless of (distance), since it is always received in a converged state, it is possible to generate photoacoustic image data having good sensitivity and spatial resolution from these received signals.

  The received signals of the conversion elements 54-1 to 54-6 synthesized by the adder 57 are subjected to amplitude compression and logarithmic conversion 58 and envelope detection 59 after noise components are removed by the filter 66 of the signal processing unit 25. Detection is performed, and the digital signal is further converted by the A / D converter 60 and stored in the image data memory A61 for photoacoustic image data.

If the first scan in the photoacoustic imaging is completed by the above procedure,
A second scan is performed using the optical fiber 71-4. According to the control signal of the system control unit 4, the optical scanning unit 13 selects the optical fiber 71-4 in the optical fiber 71 (71-1 to 71-M-1), and applies the monochromatic light of the light source unit 11 to the applicator. The object 7 is irradiated from the light irradiation unit 15 of 70.

  For a new acoustic wave generated inside the subject 7 by irradiation of light from the optical fiber 71-4, the conversion element selection control circuit 68 is based on the selection information of the conversion element 54 supplied from the system control unit 4. Then, the electronic switches 53-2 to 53-7 are turned on, and the conversion elements 54-2 to 54-7 are used as the receiving conversion elements 54 with the optical fiber 71-4 selected and used at the time of light irradiation as the center. select. At this time, the conversion elements 54-2 to 54-6 are connected to the preamplifiers 55-2 to 55-6 and the reception delay circuit 56-2 via the electronic switches 53-2 to 53-6, as in the first scanning. The conversion element 54-7 is connected to the preamplifier 55-1 and further to the reception delay circuit 56-1 via the electronic switch 53-7.

  In this case, the reception delay circuits 56-2 to 56-6 to which the reception signals of the conversion elements 54-2 to 54-6 are supplied are received by the reception delay circuits 56-2 to 56-6 and the reception signals of the conversion element 54-7 are supplied. Assuming that the delay circuit 56-1 is # 6, the delay time shown in the previous equation (1) is given to the received signal of the conversion element 54 supplied to the #n reception delay circuit 56, and the adder 57 adds and synthesizes it. Is done. In this case as well, the dynamic convergence method is applied as in the first scanning, and the acoustic wave generated inside the subject 7 can always be received in a converged state regardless of the depth. The received signals of the conversion elements 54-2 to 54-7 synthesized in the adder 57 are subjected to noise removal, amplitude compression, and envelope detection in the filter 66, logarithmic converter 58 and envelope detection 59, and the A / It is converted into a digital signal by the D converter 60 and stored in the image data memory A61.

  Similarly, the system controller 4 selects the optical fiber 71-5, the optical fiber 71-6,..., The optical fiber 71-M-3 in the optical scanning unit 13, and irradiates the subject 7 with light. The acoustic wave newly generated at this time is received by selecting the conversion elements 54-3 to 54-8, the conversion elements 54-4 to 54-9... The conversion elements 54 -M- 5 to 54 -M by the electronic switch 53. To do. Each 6-channel received signal is converted into image data memory A61 as photoacoustic image data via a preamplifier 55, a reception delay circuit 56, a filter 66, a logarithmic converter 58, an envelope detector 59, and an A / D converter 60. The image data for one sheet is collected.

  When the collection of photoacoustic image data by the photoacoustic imaging method is completed by the above procedure, the process proceeds to collection of ultrasonic image data by the pulse echo method that is displayed simultaneously with the photoacoustic image data. When the operator of the apparatus confirms that the collection of the photoacoustic image data has been completed, the operator of the apparatus inputs an ultrasonic image data collection start command by the pulse echo method from the operation unit 5.

  The beam convergence control circuit 67 of the scanning control unit 24 that has received the instruction signal for the first scan of the pulse echo method from the system control unit 4 transmits data related to the setting of the convergence point of the transmission ultrasonic wave and the reception ultrasonic wave to the transmission delay circuit 51. The delay time is sent to the reception delay circuit 56 to set the delay time. On the other hand, the conversion element selection control circuit 68 of the scanning control circuit unit 24 supplies the electronic switch 53 with data related to the conversion element 54 of the electroacoustic conversion unit 23 that is selected and used in the first scan, Set the channel to the ON state.

  At the same time as these settings are completed, a pulse for determining the transmission timing of the first ultrasonic pulse is sent from the rate signal generator 21 to the transmission delay circuit 51 configured by the N ′ channel, where the convergence distance of the transmission ultrasonic wave is determined. After the delay time τf to be determined is given, it is supplied to the pulser 52. Here, the delay time τf (n) in the n ′ (n ′ = 1 to N ′)-th delay circuit is set as follows.

τf (n ′) = d ² {(N′−1) ² − (2n′−N′−1) ² } / 8CF ₀ (2) where d is the arrangement interval of the conversion elements 54 and C is The acoustic wave propagation velocity of the subject 7, Fo is a transmission focusing point.

  The output of the rate signal generation unit 21 given the transmission delay time of the expression (2) is supplied to the pulser 52, and a drive pulse for driving the conversion element 54 to emit ultrasonic waves to the subject 7 is formed. The The output of the pulsar 52, that is, the drive signal of the conversion element 54, selectively drives N 'conversion elements 54-1 to 54-N' out of M conversion elements 54 arranged via the electronic switch 53. Transmission ultrasonic waves are emitted to the subject 7.

  A part of the ultrasonic wave radiated into the subject 7 is reflected by the boundary surface of the organ or the acoustic scatterer of the living tissue, and is received again by the conversion element 54 as a reception ultrasonic wave and converted into an electric signal. . The electronic switch 53 selects the ultrasonic reception signals obtained by the conversion elements 54-1 to 54-N ′, and the reception signals of these N ′ channels are sent to the reception delay circuit 56 via the preamplifier 55, respectively. After a delay time necessary for beam convergence of the received ultrasonic wave is given, it is supplied to the adder 57. The N′-channel ultrasonic reception signal is added and synthesized by the adder 57, and after noise removal, logarithmic compression, and envelope detection are further performed by the filter 66, the logarithmic converter 58, and the envelope detector 59. A / D converted and stored as image data in the first scan in the image data memory B62. Although it is preferable to apply the dynamic convergence method at the time of reception, the method is the same as that of the photoacoustic imaging method already described, and thus detailed description thereof is omitted.

  The second and subsequent scans are performed by repeating the same procedure as the first scan described above. That is, in the second scan, the conversion elements 54-2 to 54-N ′ + 1 are selected by the electronic switch 53, and in the third scan, the conversion elements 54-3 to 54-N ′ + 2 are selected. Ultrasonic waves are transmitted and received, and such an operation is repeated until the conversion elements 54-MN + 1 to 54-M are selectively driven. The transmission delay circuit 51 and the reception delay circuit 56 converge the transmission ultrasonic beam and the reception ultrasonic beam. The method for setting the delay time is almost the same as in the case of the photoacoustic imaging method. The detailed explanation is omitted.

  Through the procedure described above, one piece of image data obtained by the pulse echo method is stored in the image data memory B62 of the signal processing unit 25. When the collection of the photoacoustic image data and the ultrasonic image data is completed, the system control unit 4 reads the photoacoustic image data and the ultrasonic image data from the image data memory A61 and the image data memory B62, and displays the display image memory 63. Synthesize and save once. Further, the synthesized image data is supplied to the conversion circuit 64 to perform D / A conversion and TV format conversion, and then displayed on the CRT monitor 65.

  In this manner, the collection of the photoacoustic image data and the ultrasonic image data is repeatedly performed, and the respective image data obtained at this time are combined and displayed on the CRT monitor 65, whereby the operator can view the combined image in real time. It will be possible to observe.

  When the display image memory 63 combines the photoacoustic image data and the ultrasonic image data and displays them on the CRT monitor 65, the acoustic wave is generated by the photoacoustic image by superimposing and displaying the respective image data. It becomes easy to grasp the source. In this case, for example, a method of identifying and displaying both by a color, such as displaying a red photoacoustic image superimposed on a black and white ultrasonic image, is preferable.

  According to the first embodiment described above, since the photoacoustic image and the ultrasonic image can be collected using the same conversion element 54, it is possible to accurately superimpose and display each image. In particular, in the generation of the photoacoustic image, since the so-called phasing addition method is performed in which the phases of the acoustic reception signals obtained from many conversion elements 54 are added together, for example, the light irradiated to the subject 7 Even if the light is scattered or diffused, the source of the acoustic wave can be accurately captured.

  In the description of the first embodiment described above, the number of conversion elements used for collecting the acoustic reception signals of photoacoustic imaging is six for convenience of explanation, but is not limited to this. In addition, although the number of transmission conversion elements and the number of reception conversion elements used in the pulse echo method are both N ', transmission / reception may be performed with different numbers of conversion elements.

  In the description of this embodiment, the ultrasonic image data is collected after the photoacoustic image data is collected, but the collection order of these image data is not limited. Further, a plurality of photoacoustic image data and ultrasonic image data are collected, the former is temporarily stored in the image data memory A61, and the latter is temporarily stored in the image data memory B62. The desired data is stored in the image data memory A61 and the image data memory B62. These images may be selected and combined in the display image memory 63.

    On the other hand, when collecting photoacoustic image data, component amounts may be obtained using light of a plurality of wavelengths for one substance. For example, when measuring the amount of hemoglobin component, hemoglobin in the living body absorbs light from 600 nm to 1000 nm as described above, but the absorption of reduced hemoglobin is relatively large near 600 nm compared to oxyhemoglobin, and reduced near 1000 nm. Absorption of oxyhemoglobin is greater than that of hemoglobin. By utilizing such a difference in absorption characteristics, oxygenated hemoglobin and reduced hemoglobin in the living body can be separated and quantified, or the total amount of hemoglobin can be obtained. The 1000 nm Nd: YAG laser or the 633 nm He—Ne gas laser may be used, and the measurement results obtained by the respective wavelengths may be identified and displayed in different colors. In this case, the photoacoustic image may be superimposed on the ultrasonic image, but may be displayed side by side.

  In addition, for the same part of the subject 7, a substance other than hemoglobin, such as cholesterol and glucose, is measured in the same procedure using monochromatic light having an optimum wavelength, and the measurement result and the measurement result of hemoglobin are different. You may identify and display with a color. In this case as well, the photoacoustic image may be superimposed on the ultrasonic image, but can be displayed side by side, and the display method is not limited.

(Second Embodiment)
Next, as a second embodiment of the present invention, a case where ultrasonic image data is collected by a harmonic imaging method will be described with reference to FIG. Note that the photoacoustic image data collection method and the ultrasonic wave transmission method in the pulse echo method in the present embodiment are the same as those in the first embodiment, and thus the description thereof is omitted.

  The frequency spectrum of the acoustic wave in the photoacoustic imaging method is distributed in the range of 200 KHz to 2 MHz with 1 MHz as the center frequency. Therefore, the conversion element 54 of the electroacoustic conversion unit 23 has characteristics corresponding to this frequency component. However, this is lower than the center frequency (fo: 3.5 MHz, for example) of a normal pulse echo method.

  In the first embodiment, since photoacoustic image data and ultrasonic image data are collected using the same conversion element 54, the spatial resolution is degraded in the ultrasonic image obtained by applying the conventional pulse echo method. Will be invited.

  In order to improve such a problem, collection of ultrasonic image data to which the harmonic imaging method is applied will be described. The harmonic imaging method is an imaging method that effectively utilizes an ultrasonic nonlinear phenomenon that occurs in the tissue of the subject 7. For example, when an ultrasonic pulse having a center frequency of fo is emitted to the subject 7, For example, a double harmonic component (2fo) is newly generated by the non-linear phenomenon, and this harmonic component is received by the conversion element 54 together with the fundamental component (fo). The generation of this harmonic component depends on the tissue properties of the subject 7, the propagation distance to the reflection site, or the ultrasonic intensity at the reflection site.

  In the collection of the ultrasonic image data, a part of the transmission ultrasonic wave radiated to the subject 7 is reflected on the boundary surface or tissue of the organ of the subject 7 having different acoustic impedance. These ultrasonic waves newly generate ultrasonic pulses having a center frequency of 2 fo due to the non-linear characteristics of the tissue. Therefore, the received ultrasonic wave reflected in the tissue of the subject 7 and returning to the conversion element 54 is an ultrasonic pulse (fundamental wave component) having a center frequency fo and an ultrasonic pulse having a center frequency of 2 fo (harmonic). Component) is mixed.

  The frequency spectrum of the received ultrasonic wave at this time is shown in FIG. FIG. 7A shows a frequency spectrum of a transmission ultrasonic wave transmitted to the subject 7, which is distributed around fo. On the other hand, the frequency spectrum of the received ultrasonic wave from the subject 7 shown in FIG. 7B is composed of a fundamental wave component distributed around fo and a harmonic component distributed around 2fo, Generally, the harmonic component is about 20 dB smaller than the fundamental component. Incidentally, the cause of the generation of this harmonic is because the propagation speed of the ultrasonic pulse in the subject tissue depends on the sound pressure of the ultrasonic wave. Due to this property, waveform distortion occurs in the received signal, and the harmonic component is generated. It is known to occur.

  The ultrasonic waves received from the subject 7 are converted from ultrasonic waves into electrical signals (ultrasonic reception signals) by the conversion element 54, and the ultrasonic reception signals are transmitted to the filter 66 of the signal processing unit 25 via the transmission / reception unit 22. Sent. The filter 66 has a bandpass characteristic centered on 2fo as shown in FIG. 7C and a bandpass characteristic centered on fo (not shown). In the harmonic imaging method, the second harmonic component is extracted by the filter 66, and the output is stored in the image data memory B62 via the logarithmic converter 58, the envelope detector 59, and the A / D converter 60. Is done. On the other hand, in the photoacoustic imaging method, the fundamental wave component is extracted by the filter 66 as in the first embodiment, and the output thereof is passed through the logarithmic converter 58, the envelope detector 59, and the A / D converter 60. And stored in the image data memory B62.

  Next, the system control unit 4 reads out the ultrasound image data stored in the image data memory B62 and the photoacoustic image data stored in the image data memory A61, combines them in the display image memory 63, and then converts them. The information is displayed on the CRT monitor 65 via 64.

  According to the second embodiment, the ultrasonic image data is generated with twice the frequency component as compared with the first embodiment. Therefore, even when photoacoustic image data and ultrasonic image data are collected using the same conversion element 54, it is possible to superimpose and display a photoacoustic image on an ultrasonic image with excellent resolution. Since it is possible to simultaneously collect and display the image data, it is possible to provide an apparatus with excellent operability.

  In the above description of the present embodiment, the harmonic imaging method using the second harmonic component has been described. However, the present invention is not limited to this, and the third and higher harmonic components are used. Sound image data may be generated.

(Third embodiment)
Next, as a third embodiment of the present invention, a simplified reception method in photoacoustic imaging will be described with reference to FIG. The ultrasonic image data collection method and the photoacoustic imaging method of light irradiation in this embodiment are the same as those in the first embodiment, and a description thereof will be omitted.

  FIG. 8 is a diagram showing the irradiation position of the irradiation light and the reception position of the acoustic wave in the third embodiment. For example, as shown in this figure, the light is applied to the subject 7 using the optical fiber 71-1. When irradiated, the irradiated light travels straight while maintaining a narrow width, and therefore has strong directivity. Therefore, it is possible to generate a photoacoustic image without performing a phasing addition process when receiving an acoustic wave.

  In the first scanning of the photoacoustic imaging, hemoglobin in the blood of the subject 7 is absorbed by the irradiation light from the optical fiber 71-1, and generates an acoustic wave by absorbing the energy of the irradiated light. Upon reception of this acoustic wave, the system control unit 4 supplies the selection information of the conversion element 54 in the scanning information stored in advance in the storage circuit to the conversion element selection control circuit 68 of the scanning control unit 24.

  The conversion element selection control circuit 68 turns on the electronic switches 53-1 to 53-2 based on the selection information of the conversion element 54 supplied from the system control unit 4, and selects and uses the light at the time of light irradiation. The conversion elements 54-1 to 54-2 located on both sides of the fiber 71-1 are selected as reception conversion elements. The acoustic wave generated inside the subject 7 is converted into an electrical signal by the conversion elements 54-1 to 54-6, then supplied to the preamplifier 55 via the electronic switch 53, amplified to a predetermined amplitude, and received. Input to the delay circuit 56. The reception delay circuit 56 is provided for collecting simultaneously displayed ultrasonic image data, and is not used in this photoacoustic image data collection. That is, the signals obtained by the conversion elements 54-1 and 54-2 pass through the reception delay circuit 56 as they are and are synthesized by the adder 57.

  The acoustic reception signals of the conversion elements 54-1 to 54-2 synthesized by the adder 57 are subjected to amplitude compression by the logarithmic converter 58 and the envelope detection 59 after the noise component is removed by the filter 66 of the signal processing unit 25. And is further converted to a digital signal by the A / D converter 60 and stored in the image data memory A61 for photoacoustic image data.

  In the second scanning performed next, light irradiation is performed by the optical fiber 71-2, and acoustic waves are received using the conversion elements 54-2 to 54-3. The acoustic image data obtained at this time is also stored in the image data memory A61 as in the first scanning. The above operation is repeated until the image data is collected using the optical fiber 71-M-1 and the conversion elements 54-M-1 to 54-M, and the photoacoustic image data for one sheet obtained at this time is obtained. Is stored in the image data memory A61.

  Next, the photoacoustic image data stored in the image data memory A61 and the ultrasonic image data collected by the subsequent pulse echo method and stored in the image data memory B62 are synthesized in the display image memory 63. After that, the image is displayed on the CRT monitor 65 via the conversion circuit 64.

  According to the third embodiment, since the number of transducers used for reception can be greatly reduced, the optical fiber 71 at the end can be used effectively, and thus a wide image width (view width). Can be obtained.

  In the description of the third embodiment, the number of conversion elements used for receiving the acoustic wave is two, but the present invention is not limited to this.

(Fourth embodiment)
In the first to third embodiments already described, when a plurality of optical fibers 71 and conversion elements 54 are arranged in the same direction, the optical fibers 71 are arranged in the gaps of the conversion elements 54 as shown in FIG. . In this case, in each conversion element 54, the optical fiber 71 is inserted into the gap, so that an acoustic coupling occurs between the adjacent conversion elements 54, and the function as an independent element is deteriorated. That is, due to this acoustic coupling, there is a possibility that image quality degradation is caused in both the photoacoustic image and the ultrasonic image.

  In the fourth embodiment, when the optical fiber 71 and the conversion element 54 are integrated in the applicator 70, a method of arranging the optical fiber 71 without degrading the performance of the conversion element 54 will be described with reference to FIGS. Will be described.

  FIG. 9 shows the configuration of the applicator 70 used in the present embodiment. Similar to the applicator 70 used in the first to third embodiments, the applicator 70 is an electroacoustic including a light irradiation unit 15 that is an output end of the optical fiber 71 and a conversion element 54. Although the conversion unit 23 is integrated, the light irradiated from the light irradiation unit 15 is configured to be transmitted to the subject 7 through the electroacoustic conversion unit 23. That is, the electroacoustic transducer 23 is made of a material that can transmit light.

  Each material constituting such an electroacoustic transducer 23 will be described with reference to FIG. However, FIG. 10 shows a configuration of an applicator 70 used in the fourth embodiment. The conversion element 54 of the electroacoustic conversion unit 23 polishes a PZNT single crystal wafer, which is a transparent piezoelectric material, to a predetermined thickness t, and then cuts the single crystal plate into an array with a pitch d using a dicing saw. The gap of width b generated by cutting is filled with an optically transparent resin 80 and cured.

  Next, an independent electrode 73-1 is formed on the first surface of the one-dimensionally arranged single crystals, and an electrode 73-2 is formed on the second surface by sputtering.

Further, an acoustic matching layer 74 and a protective film 75 are laminated on the surface on which the electrode 73-2 is mounted. However, an optically transparent resin is also used for the acoustic matching layer 74 and the protective film 75. The electrode 73 is made of, for example, a transparent conductive material such as ITO (indium-tin-oxide) or In ₂ O ₃ (Sn) used for liquid crystal displays, plasma displays, and the like. As described above, a transparent conductive material is used for the electrode 73, an optically transparent resin is used for the acoustic matching layer 74, the protective film 75, and the resin 80 filled in the gap between the conversion elements 54, and the conversion element 54 is also transparent. A piezoelectric single crystal is used. The electroacoustic conversion unit 23 configured by fixing these materials to a support base 72 made of a transparent resin can be configured to be optically transparent, and the light irradiated from the light irradiation unit 15 is electroacoustic. It is possible to irradiate the subject 7 through the conversion unit 23.

  In the first to third embodiments, the arrangement interval of the optical fibers 71 is determined by the arrangement interval of the conversion elements 54. However, in the fourth embodiment, since there is no such restriction, As shown in FIG. 11, it becomes possible to arrange with high density. The arrangement interval of the optical fibers 71 determines the scanning interval in photoacoustic imaging. Therefore, according to the present embodiment, a photoacoustic image having a high scanning density can be obtained. In particular, when the spatial resolution of an image is determined by the directivity of irradiation light as in the third embodiment, the image quality can be improved by high-density scanning of light.

  According to the fourth embodiment described above, the light irradiation unit 15 can be disposed behind the electroacoustic conversion unit 23 by using the optically transparent electroacoustic conversion unit 23. Accordingly, since acoustic coupling in the conversion element 54 can be reduced, a good photoacoustic image and pulse echo image can be obtained.

  Furthermore, according to this method, since the optical fibers 71 can be arranged with high density, the spatial resolution of the photoacoustic image can be improved.

(Fifth embodiment)
In the first to fourth embodiments described above, the optical scanning unit 13 moves the irradiation position on the subject 7 by sequentially selecting a plurality of optical fibers 71 arranged. For example, many optical fibers 71 in the waveguide section 14 and the optical scanning section 13 for selecting these are required, complicating the apparatus.

  The present embodiment is carried out for the purpose of improving such problems in the formation of irradiation light, and the irradiation light in the photoacoustic imaging method has a substantially uniform characteristic over a wide range, and the photoacoustic image Is determined by the convergence of the acoustic wave in the conversion element 54. Note that the acoustic wave receiving method in the present embodiment is the same as in the first embodiment.

  The outline of the irradiation light forming method according to the fifth embodiment of the present invention will be described below with reference to FIG. FIG. 12A shows the positional relationship between the slit plate 78 newly used in this embodiment and the conversion element 54, and FIG. 12B shows a schematic configuration of the applicator 70 in this embodiment. In addition, the electroacoustic transducer 23 has an optically transparent configuration similar to that described in the fourth embodiment.

  In this embodiment, as shown in FIG. 12A, a slit plate 78 is arranged in parallel to the array surface of the conversion elements 54. A slit is formed in the center of the slit plate 78 in the arrangement direction of the conversion elements 54, and the light passing through the slit has a wide beam width with respect to the arrangement direction of the conversion elements 54. In the slice direction perpendicular to the arrangement direction, it has a narrow beam width.

  In addition to the slit plate 78, the applicator 70 in the present embodiment shown in FIG. 12B includes a lens 79 that forms diffused light output from the light irradiation unit 15 into a parallel beam with respect to the traveling direction. I have. The light supplied to the light irradiation unit 15 can be directly guided from the light source unit 11 or the optical multiplexing unit 12 by the waveguide unit 14, and the optical scanning unit 13 becomes unnecessary. The waveguide 14 in this case is not limited to the optical fiber 71, and may be one channel as long as sufficient power can be obtained.

  Next, the collection procedure of the photoacoustic image data in this Embodiment is demonstrated using FIG.2, FIG.6 and FIG.12.

  The operator sets necessary image capturing conditions in the photoacoustic imaging method and the pulse echo method in the operation unit 5. Further, the operator simultaneously sets various conditions regarding the light source such as the light wavelength used for measurement, and the system control unit 4 stores these photographing conditions in an internal storage circuit (not shown). When the setting of the various imaging conditions is completed, the operator installs the applicator 70 at a predetermined position of the subject 7 and then inputs a photoacoustic image data collection start command from the operation unit 5.

  Receiving the photoacoustic image data collection start command, the system control unit 4 reads the setting condition regarding the light source from the storage circuit, and selects, for example, an Nd / YAG laser in the light source unit 11 according to the setting condition and has a wavelength of 1000 nm Generate monochromatic light. The monochromatic light generated by the light source unit 11 is guided to the light irradiation unit 15 of the applicator 70 by, for example, the waveguide unit 14 configured by the optical fiber 71, and is diffused and irradiated from the distal end portion. This diffused light is converted into a parallel beam by the lens 79 and supplied to the slit of the slit plate 78. The beam width in the arrangement direction and the beam width in the slice direction of the light passing through the slits of the slit plate 78 are set by the opening widths in the respective directions of the slits.

  The light whose beam width in the slicing direction is narrowed by the slit is transmitted through the optically transparent electroacoustic transducer 23 and irradiated onto the light beam irradiation range of the subject 7 shown in FIG. The hemoglobin in the blood of the subject 7 absorbs this irradiation light and generates an acoustic wave.

  In FIG. 6, the electroacoustic conversion unit 23 in the applicator 70 with respect to the acoustic wave generated in the blood vessel region at a distance L from the subject contact surface of the applicator 70 includes M conversion elements 54-1 to 54-1. 54 -M is selected from 54 -M to 54 -N (N = 6), and the reception focal length is set to L with respect to the acoustic reception signals received by these conversion elements 54. That is, the system control unit 4 supplies the selection information of the conversion element 54 from the scanning information stored in advance in the storage circuit to the conversion element selection control circuit 68 of the scanning control unit 24, and the focus at the time of reception. The delay time information corresponding to the distance is supplied to the beam convergence control circuit 67 of the same scanning control unit 24.

  The conversion element selection control circuit 68 turns on the electronic switches 53-1 to 53 -N (N = 6) based on the selection information of the conversion element 54 supplied from the system control unit 4, and converts the conversion element 54-1. ~ 54-6 are selected as receiving conversion elements. The acoustic wave generated inside the subject 7 is converted into an electric signal by the conversion elements 54-1 to 54-6, then supplied to the preamplifier 55 via the electronic switch 53, amplified to a predetermined amplitude, and received. Input to the delay circuit 56.

  In the reception delay circuit 56 composed of N channels, the equation (1) shown in the description of the first embodiment for the acoustic reception signal of the conversion element 54-n supplied to the nth reception delay circuit 56 ) Delay time. If Fo = L, the adder 57 adds the delay time to the N (N = 6) channel acoustic reception signals obtained by the conversion elements 54-1 to 54-6. Thus, the phase of the acoustic wave generated at the position of the distance L on the perpendicular line (shown by a broken line) from the midpoint of the conversion elements 54-3 and 54-4 to the conversion element array surface can be synthesized. it can. Furthermore, the dynamic convergence method is applied also in this embodiment, and reception is always performed in a converged state regardless of the depth (distance).

  The acoustic reception signals of the conversion elements 54-1 to 54-6 synthesized by the adder 57 are amplitude-removed by the logarithmic converter 58 and the envelope detector 59 after the noise component is removed by the filter 66 of the signal processing unit 25. Compression and detection are performed, and further, the digital signal is converted by the A / D converter 60 and stored in the image data memory A61 for photoacoustic image data.

If the first scan in the photoacoustic imaging is completed by the above procedure,
Similar to the case of the first scanning, the lens 79 and the slit plate 78 are used to irradiate the light beam irradiation range of the subject 7 with a parallel beam. With respect to a new acoustic wave generated inside the subject 7 by this irradiation light, the conversion element selection control circuit 68 uses the electronic switch 53-based on the selection information of the conversion element 54 supplied from the system control unit 4. 2 to 53-7 are turned on, and the conversion elements 54-2 to 54-7 are selected as the conversion elements 54 for reception. At this time, the conversion elements 54-2 to 54-6 are connected to the preamplifiers 55-2 to 55-6 and the reception delay circuit 56-2 via the electronic switches 53-2 to 53-6, as in the first scanning. The conversion element 54-7 is connected to the preamplifier 55-1 and further to the reception delay circuit 56-1 via the electronic switch 53-7.

  In this case, the reception delay circuits 56-2 to 56-6 to which the reception signals of the conversion elements 54-2 to 54-6 are supplied are received by the reception delay circuits 56-2 to 56-6 and the reception signals of the conversion element 54-7 are supplied. Assuming that the delay circuit 56-1 is # 6, the delay time given by the equation (1) is given to the reception signal of the conversion element 54 supplied to the #n reception delay circuit 56, and the adder 57 adds and synthesizes the delay circuit The In this case as well, the dynamic convergence method is applied as in the first scanning, and the acoustic wave generated inside the subject 7 can always be received in a converged state regardless of the depth. After the above delay time is given to the N (N = 6) channel acoustic reception signals obtained by the conversion elements 54-1 to 54-6, the adder 57 adds the delay times, thereby converting the conversion element 54-. 4 and 54-5 can be synthesized by matching the phases of the acoustic waves generated on the perpendicular line (shown by a broken line) with respect to the conversion element array surface from the midpoint.

  The acoustic reception signals of the conversion elements 54-2 to 54-7 synthesized in the adder 57 are subjected to noise removal, amplitude compression, and envelope detection in the filter 66, logarithmic converter 58 and envelope detector 59, Further, it is converted into a digital signal by the A / D converter 60 and stored in the image data memory A61 as photoacoustic image data.

  Thereafter, the third and subsequent scans are similarly performed, and the system control unit 4 converts the acoustic signals obtained by the irradiation of the parallel light into the conversion elements 54-3 to 54-8 and the conversion elements 54-4 to 54 with the electronic switch 53. -9. Reception is performed using the conversion elements 54-M-5 to 54-M. Each 6-channel received signal is converted into image data memory A61 as photoacoustic image data via a preamplifier 55, a reception delay circuit 56, a filter 66, a logarithmic converter 58, an envelope detector 59, and an A / D converter 60. The generation of the acoustic image data for one sheet is finished.

Next, image data is collected by the pulse echo method. Since the image data collection procedure of the pulse echo method in the present embodiment is the same as that of the first embodiment, the description thereof is omitted. According to the embodiment, the number of optical fibers 71 in the waveguide section 14 can be greatly reduced, and the optical scanning section 13 is also unnecessary. Furthermore, since the irradiation light is continuously irradiated in the arrangement direction, the scanning density can be freely set by setting the delay time at the time of reception, and the restriction when the optical fiber 71 is used can be eliminated. it can.

  In the description of the fifth embodiment, the case where the reception convergence point is set on the vertical line with respect to the conversion element array plane indicated by the broken line has been described. However, by the delay time control of the reception signal obtained from the conversion element 54 The position of the convergence point can be set freely.

  Next, a modification of the scanning method in this embodiment will be described with reference to FIG. Although the collection of the image data in the above embodiment has been described as being alternately performed in units of frames, it may be performed alternately in units of scanning. For example, when scanning in the first direction by the photoacoustic imaging method is completed, scanning in the first direction by the pulse echo method may be performed, and then scanning in the second direction by the photoacoustic imaging method may be performed. Furthermore, in the above embodiment, the case where the collection of the photoacoustic image data and the collection of the pulse echo image data are performed separately has been described. The photoacoustic image data and the ultrasonic image data may be collected at the same time by aligning the timing of the light pulse generated from 11 and the rate pulse generated from the rate signal generating unit 21 of the acoustic image data generating unit 2.

  13A and 13B are diagrams for comparing the above scanning orders. FIG. 13A is a frame-unit scanning method described in the first embodiment, FIG. 13B is a scanning unit scanning method, and FIG. 13C shows the scanning order of the photoacoustic imaging method and the pulse echo method in the simultaneous scanning method. Both the photoacoustic image data and the ultrasonic image data are generated by scanning in the α direction (θ1 to θα). Yes.

  That is, in the scanning method in units of frames shown in FIG. 13A, scanning for collecting photoacoustic image data for one sheet is performed α times in the θ1 to θα directions, and then ultrasonic image data is collected. Are scanned α times. On the other hand, in the scanning method of the scanning unit shown in FIG. 13B, after performing scanning in the θ1 direction for collecting photoacoustic image data, scanning in the θ1 direction for collecting ultrasonic image data is performed. Further, a scan in the θ2 direction for collecting photoacoustic image data is performed. According to the scanning method in which the above operation is repeated, the shift in the collection timing between the data in a predetermined direction is greatly shortened. Therefore, even when a fast-moving organ or blood is a measurement target. The same time phase can be measured.

  FIG. 13 (b ′) is a modification of FIG. 13 (b). For example, when the amount of transmitted light is increased to improve reception sensitivity in photoacoustic imaging, unit time is used to ensure biological safety. Since it is necessary to reduce the number of hits per irradiation, it is desirable to reduce the number of scans of the photoacoustic imaging method per unit time from the number of scans of the pulse echo method as shown in FIG.

  On the other hand, the method of simultaneously performing the scanning of the photoacoustic imaging method and the scanning of the pulse echo method shown in FIG. 13C does not cause a shift in the acquisition timing between the image data. Accurate measurement is possible for fast measurement objects. In this simultaneous scanning method, when the frequency of the acoustic wave in the photoacoustic imaging method and the frequency of the ultrasonic image in the pulse echo method are the same, the above two image data are mixed and received. Although it is impossible to identify and display by color, the output of the A / D converter 60 of the signal processing unit 25 may be stored directly in the display image memory 63. Therefore, the image data memory A61 and the image data The memory B62 can be deleted, and further, the photoacoustic image data and the ultrasonic image data are not required to be combined.

  Further, by using a two-frequency probe as the conversion element 54 of the electroacoustic conversion unit 13, the images of the photoacoustic imaging method and the pulse echo method are identified and displayed even in the simultaneous scanning method. This two-frequency probe has two kinds of frequencies exceeding two by joining two conversion elements 54 having different thicknesses as described in Japanese Patent Application Laid-Open No. 61-100277 or Japanese Patent Application Laid-Open No. 62-39661. Sound waves can be received.

Therefore, for example, by setting the frequency of the acoustic wave of the photoacoustic imaging method to 1.5 MHz and the frequency of the ultrasonic wave of the pulse echo method to 3 MHz, even if these signals are simultaneously received by the conversion element 54, the signal Discrimination by the filter 66 of the processing unit 22 makes it possible to independently generate photoacoustic image data and ultrasonic image data, and further, it can be identified by color and displayed on the CRT monitor 65 of the display unit 6. (Sixth embodiment)
The sixth embodiment relates to the electroacoustic conversion unit of the above-described embodiment. FIGS. 15A and 15B are external views of an electroacoustic conversion unit according to the sixth embodiment of the present invention. FIG. 16 is a plan view of the electroacoustic transducer shown in FIG. FIG. 15 (a) shows an example in which a light-transmitting PZNT single crystal is used as a piezoelectric element of a conversion element, and FIG. 15 (b) shows PZT ceramics having no light transmission characteristic as a piezoelectric element of a conversion element. The example used is shown.

  As shown in FIG. 15 (a), a plurality of piezoelectric bodies 81 having optical transparency are arranged in a matrix (two-dimensional shape) with a constant interval. For example, a short optical fiber is disposed as the optical path 83 in each of the spaces surrounded by the four neighboring piezoelectric bodies 81. The optical path 83 may be disposed between two piezoelectric bodies 81 that are adjacent in the scanning direction. A gap between the piezoelectric body 81 and the optical path 83 is filled with a resin 82 having a light transmittance higher than that of the piezoelectric body 81 but lower than that of the optical fiber. The electroacoustic conversion unit is integrated by curing the filled resin 82.

  Here, assuming that the center frequency is 1 MHz, the piezoelectric body 81 has a rectangular parallelepiped shape with a width of 0.35 mm and a height of 0.58 mm. The piezoelectric bodies 81 are arranged with an interval of 0.18 mm. In that case, the optical path 83 has a diameter of, for example, 0.25 mm.

  As shown in FIG. 16, a single electrode pattern 87 having optical transparency is commonly formed on a plurality of piezoelectric bodies 81 arranged in a line in a direction orthogonal to the scanning direction. The plurality of piezoelectric bodies 81 connected in common to the single electrode pattern 87 substantially constitute a single piezoelectric vibrator.

  An optical fiber 71 is connected to the optical path 83 with an optical adhesive. The light guided through the optical fiber 71 is irradiated to the subject through the optical path 83. Note that the piezoelectric body 81 and the resin 82 are light transmissive, that is, the electroacoustic conversion unit is made of a material capable of transmitting light, so that the optical fiber 71 is connected to the optical path 83. Even if a structure for outputting light via the optical path 83 is not employed, any of the structures shown in FIGS. 9 to 12 described above can be employed.

(Seventh embodiment)
The seventh embodiment relates to the electroacoustic transducer of the above-described embodiment. 17 (a) and 17 (b) are external views of an electroacoustic transducer according to the seventh embodiment of the present invention. The electroacoustic transducer of the present embodiment employs a multi-fiber optical fiber tape 88 in which a plurality of optical fibers 93 are regularly arranged on the tape material at regular intervals. A plurality of piezoelectric bodies 90 of PZNT or PZT are arranged in a line. Electrodes are formed on the upper and lower surfaces of each piezoelectric body 90, thereby forming a piezoelectric vibrator.

  An acoustic matching layer 89 is individually attached to the front of each transducer, and a backing material 91 is commonly attached to the back. The electrodes of the plurality of vibrators arranged are pulled out in a direction orthogonal to the arrangement by a flexible printed circuit board (FPC) 92 for wiring. Two sets of transducer arrays 94 are bonded together with the multi-fiber optical fiber tape 88 interposed therebetween. The use of such a multi-core optical fiber tape 88 simplifies the manufacture of an electroacoustic transducer having optical transparency through an optical fiber.

(Eighth embodiment)
The eighth embodiment relates to the electroacoustic conversion unit of the above-described embodiment. 18 (a) and 18 (b) are external views of an electroacoustic transducer according to the eighth embodiment of the present invention. As shown in FIG. 18A, a pair of signal-side electrodes 98 are formed on a flexible printed circuit board (FPC) 97 having a thickness of, for example, 0.05 mm with a substantially central portion interposed therebetween. A ground side electrode 99 is formed with a substantially central portion interposed therebetween. An optical fiber 110 having a diameter of 0.2 mm, for example, is attached to the substantially central portion of the flexible printed circuit board 97. The signal side electrode 98 and the ground side electrode 99 on one side of the optical fiber 110 are electrically connected to the signal side electrode and the ground side electrode of the vibrator 96 using PZNT or PZT as a piezoelectric material by Au sputtering or the like. Connected to. Similarly, on the other side of the optical fiber 110, the signal side electrode 98 and the ground side electrode 99 of the FPC 97 are electrically connected to the signal side electrode and the ground side electrode of the vibrator 96 by Au sputtering or the like, respectively. Is done.

  As shown in FIG. 18B, the plurality of vibrator plates 111 configured in this manner are stacked in the scanning direction and bonded together by an adhesive.

  Also according to the present embodiment, as in the seventh embodiment, it is possible to simplify the manufacture of an electroacoustic transducer having optical transparency using an optical fiber.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to said embodiment, It can change and implement. For example, in the above embodiment, the conversion element 54 of the electroacoustic conversion unit 23 and the optical fiber 71 of the light irradiation unit 15 are arranged in a planar shape, but may be arranged in a convex shape or a concave shape.

  In addition, although an example in which the photoacoustic image and the ultrasonic image are superimposed and displayed on the display unit 6 has been described, when the superimposed display of the photoacoustic image prevents observation of the ultrasonic image, these two images are displayed side by side. Also good.

  Furthermore, the method of collecting the photoacoustic image data and the ultrasonic image data has been shown based on the operator's collection start command. For example, when the collection of the photoacoustic image data is completed, the ultrasonic image data is automatically collected. You may move on to the collection.

  On the other hand, in the present invention, it is not necessary to match the display range of the photoacoustic image and the display range of the ultrasonic image. A method in which the operation control unit performs selection based on an instruction signal input by the operator through the operation unit 5 is preferable.

  The present invention has a data collection system with excellent operability in imaging of biological information (photoacoustic imaging method) obtained using the photoacoustic effect in a living body, and further has an image having high contrast resolution and spatial resolution. It can be used in fields where data can be generated.

DESCRIPTION OF SYMBOLS 1 ... Optical transmission part 2 ... Image data generation part 4 ... System control part 5 ... Operation part 6 ... Display part 7 ... Subject 11 ... Light source part 12 ... Optical multiplexing part 13 ... Optical scanning part 14 ... Waveguide part 15 ... Light Irradiation unit 21 ... Rate signal generation unit 22 ... Transmission / reception unit 23 ... Electroacoustic conversion unit 24 ... Scanning control unit 25 ... Signal processing unit

Claims (34)

A light generating unit that generates light including a specific wavelength component;
A light irradiator that irradiates the subject with light generated by the light generator; and
Waveguide means for guiding the light generated by the light generation unit to the light irradiation unit;
First electroacoustic conversion means for converting an acoustic wave generated in the subject by light irradiated by the light irradiation unit into an electric signal using an electroacoustic conversion element arranged in a plurality;
First image data generation means for generating first image data based on a signal obtained by the first electroacoustic conversion means;
Ultrasonic transmission means for transmitting ultrasonic waves into the subject;
Second electroacoustic conversion means for converting a plurality of components reflected in the subject out of the ultrasonic waves transmitted by the ultrasonic transmission means into an electric signal using an electroacoustic conversion element arranged;
Second image data generation means for generating second image data based on a signal obtained by the second electroacoustic conversion means;
Display means for displaying the first image data and the second image data;
The biological information video apparatus, wherein the plurality of optical fiber openings and the plurality of electroacoustic transducers are arranged one-dimensionally. The biological information video apparatus according to claim 1, wherein the plurality of optical fiber openings and the plurality of electroacoustic transducers are disposed on substantially the same plane. The biological information video apparatus according to claim 1, wherein the plurality of optical fiber openings are arranged in a gap formed when the electroacoustic transducers are arranged. 2. The first electroacoustic conversion unit converts the acoustic wave into an electric signal by selecting and using a plurality of adjacent electroacoustic conversion elements among a plurality of electroacoustic conversion elements. Biological information video device. 9. The first image data generation unit performs phasing addition processing on a plurality of electric signals obtained by the electroacoustic transducer selected by the first electroacoustic transducer. The biological information video apparatus described. The biological information according to claim 1, further comprising an optical scanning unit, wherein the optical scanning unit selects a predetermined optical fiber from the plurality of optical fibers and supplies light to the light irradiation unit. Video equipment. The center positions of the plurality of electroacoustic transducers selected in the first electroacoustic transducer are substantially coincident with the opening positions in the light irradiation section of the optical fiber selected by the optical scanning unit. The biological information video apparatus according to claim 6. 2. The biological information video apparatus according to claim 1, wherein the electroacoustic transducer in the first and second electroacoustic transducers is composed of a piezoelectric single crystal containing lead titanate. The electroacoustic transducer is disposed between the light irradiator and a subject, and light output from the light irradiator passes through the electroacoustic transducer and irradiates the subject. The biological information video apparatus according to claim 8. The biological information video apparatus according to claim 9, wherein an arrangement density of the plurality of optical fiber openings in the light irradiation unit is higher than an arrangement density of the plurality of electroacoustic transducers. An optical lens is further provided between the light irradiating unit and the electroacoustic transducers arranged one-dimensionally, and the optical lens transmits light output from the light irradiating unit in the arrangement direction of the electroacoustic transducers. 10. The biological information video apparatus according to claim 9, wherein a predetermined width is set. A slit plate is further provided between the optical lens and the electroacoustic transducer, and the slit plate is a beam in a slice direction perpendicular to the arrangement direction of the electroacoustic transducer with respect to the light output from the optical lens. The biological information video apparatus according to claim 11, wherein a width is set. 2. The biological information video apparatus according to claim 1, wherein the second image data generation unit generates image data by extracting a harmonic component of a reception signal collected by the second electroacoustic conversion unit. . The irradiation of light from the irradiation unit for generating the first image data and the transmission of ultrasonic waves by the ultrasonic transmission unit for generating the second image data are alternately performed. The biological information video apparatus according to claim 1. The biological information video apparatus according to claim 14, wherein the irradiation of light from the irradiation unit and the transmission of ultrasonic waves by the ultrasonic transmission unit are alternately performed in each of a plurality of directions. After the irradiation unit sequentially irradiates light in a plurality of directions, the generation of the first image data for one sheet is completed, and then the ultrasonic transmission unit sequentially superimposes the plurality of directions. The biological information video apparatus according to claim 1, wherein the second image data for one sheet is generated by transmitting a sound wave. The irradiation of light of the irradiation unit for generating the first image data and the transmission of ultrasonic waves of the ultrasonic transmission means for generating the second image data are performed substantially simultaneously. The biological information video apparatus according to claim 1. The biological information video apparatus according to claim 1, wherein the display unit displays the first image data and the second image data on the same monitor. 19. The biological information video apparatus according to claim 18, wherein the display means superimposes and displays the first image data and the second image data. 20. The biological information video apparatus according to claim 19, wherein the display means displays the first image data and the second image data in different colors. 2. The biological information video apparatus according to claim 1, wherein generation of light in the light generation unit and generation of ultrasonic waves by the ultrasonic transmission means are performed substantially simultaneously. The first electroacoustic conversion means, the ultrasonic wave transmission means, and the second electroacoustic conversion means are commonly used as piezoelectric vibrators, and the plurality of piezoelectric vibrators are arranged in a matrix at regular intervals. The biological information video apparatus according to claim 1, wherein an optical path is formed in a gap between the piezoelectric vibrators. The first electroacoustic conversion means, the ultrasonic transmission means, and the second electroacoustic conversion means are shared as a piezoelectric vibrator, and the plurality of piezoelectric vibrators are arranged on both sides of a multi-core optical fiber tape. 2. The biological information video apparatus according to claim 1, wherein each of the biological information video apparatuses is arranged in a line. The first electroacoustic conversion means, the ultrasonic transmission means, and the second electroacoustic conversion means are shared as a piezoelectric vibrator, and the pair of piezoelectric vibrators are attached to a flexible printed circuit board together with an optical fiber. The biological information video apparatus according to claim 1, wherein a vibrator plate is configured, and the plurality of vibrator plates are stacked and bonded together with an adhesive. A light irradiating means for irradiating the subject with light; an ultrasonic transmitting means for transmitting ultrasonic waves to the subject; and an acoustic wave generated in the subject by the irradiated light or by the transmitted ultrasonic waves. An electroacoustic conversion unit that converts and outputs an electric signal, and an electric signal output by the electroacoustic conversion unit are input, and first image data is generated based on an acoustic wave caused by the irradiation light. Image data generation means; and second image data generation means for inputting the electric signal output by the electroacoustic conversion means and generating second image data based on the acoustic wave caused by the transmitted ultrasonic waves; A biological information video apparatus comprising display means for displaying the first image data and the second image data. 26. The biological information video apparatus according to claim 25, wherein the ultrasonic transmission means is used in part with the electroacoustic conversion means. 26. The biological information video apparatus according to claim 25, wherein the display means displays the first image data and the second image data on the same monitor. The object is irradiated with light and ultrasonic waves, acoustic waves generated in the object are received by the light and ultrasonic waves, and each is converted into an electric signal, and each image data is based on each electric signal. And displaying each of these image data. The object is irradiated with light, the acoustic wave generated in the object is received by this light, converted into an electrical signal, image data is generated based on the electrical signal, and the image data is displayed. A biometric information video device. a) contacting a diagnostic probe comprising an ultrasonic imaging device and a photoacoustic irradiation and detection device to the breast tissue;
b) irradiating the breast tissue with a short light pulse having a wavelength in the absorption spectrum band of hemoglobin to generate a photoacoustic signal;
c) detecting the photoacoustic signal using an ultrasonic transducer to determine the distribution of new blood vessels in the breast tissue;
d) generating and detecting an ultrasonic image of the morphology of the human breast tissue using an ultrasonic transducer superimposed on the photoacoustic detection transducer used in the detection of the photoacoustic signal;
e) superimposing the photoacoustic neovascularization image on the ultrasound morphological image to generate a composite image of the distribution of blood vessels in different morphological structures of the chest, the morphological structure comprising: A method for diagnosing human breast cancer, characterized by being a tumor of interest. 31. A method according to claim 30, characterized in that the wavelength of the light is in the spectral range between 530 nm and 1300 nm. The method according to claim 25, wherein the photoacoustic detection element and the ultrasonic detection element are common. a) a light generating device for generating light having a specific wavelength component;
b) an irradiation device for irradiating the subject to be inspected with the light generated by the light generation device;
c) waveguide means for guiding the light generated by the light generation device to the irradiation device;
d) a first electroacoustic conversion means for converting a sound wave generated in the subject by light irradiated by the irradiation device into an electric signal by using an array of a plurality of electroacoustic conversion elements; ,
e) first image data generation means for generating first image data based on the signal obtained by the first electroacoustic conversion means;
f) ultrasonic transmission means for transmitting ultrasonic waves to the subject;
g) a second electroacoustic conversion means for converting an ultrasonic component transmitted by the ultrasonic transmission means and reflected in the body of the subject into an electrical signal using an array of a plurality of electroacoustic conversion elements;
h) second image data generation means for generating second image data based on the signal obtained by the second electroacoustic conversion means;
i) Overlaying the distribution of the concentration of the specimen such as hemoglobin on the imaged morphological characteristics such as a tumor, comprising display means for displaying the first image data and the second image data. A device for diagnosing diseases such as human breast cancer. A light generation device for generating light having a specific wavelength component;
An irradiation device for irradiating a subject to be inspected with light generated by the light generation device;
Waveguide means for guiding the light generated by the light generation device to the irradiation device;
A first electroacoustic conversion means for converting a sound wave generated in the subject by the light irradiated by the irradiation device into an electrical signal by using an array of a plurality of electroacoustic conversion elements;
First image data generation means for generating first image data based on a signal obtained by the first electroacoustic conversion means;
Ultrasonic transmission means for transmitting ultrasonic waves to the subject;
A second electroacoustic conversion means for converting an ultrasonic component transmitted by the ultrasonic transmission means and reflected in the body of the subject into an electrical signal using an array of a plurality of electroacoustic conversion elements;
Second image data generation means for generating second image data based on the signal obtained by the second electroacoustic conversion means;
Subject information imaging for determining distribution of concentration of specimen on morphological characteristics of tissue imaged, comprising display means for displaying first image data and second image data apparatus.

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