JP2018086291A - Subject information acquisition device, display method, program, and processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem involved in a conventional device in a method for data presentation to a user and user-friendliness.SOLUTION: A subject information acquisition device includes a plurality of conversion elements for receiving an acoustic wave generated in a subject when light from a light source is irradiated and converting it to a plurality of reception signals, and a processing part for acquiring a characteristic distribution indicating a distribution of characteristic information corresponding to each of a plurality of positions in the subject using the plurality of reception signals. The processing part outputs image information for causing a distribution image created by using the characteristic distribution, and data indicating a time variation of the characteristic information in a predetermined region of the distribution image to be displayed in the same screen of a display part.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an object information acquisition apparatus, a display method, a program, and a processing apparatus. In particular, the present invention relates to a technique for acquiring characteristic information by receiving an acoustic wave generated by light.

  As one of optical imaging techniques for illuminating a subject from a light source and imaging characteristic information in the subject obtained based on incident light, there is photoacoustic imaging. In photoacoustic imaging, a subject is irradiated with pulsed light generated from a light source, and acoustic waves (typically ultrasound) generated from a site that absorbs the energy of pulsed light that has propagated and diffused within the subject are received. . And the characteristic information in a subject is imaged using the received signal.

  In other words, photoacoustic imaging uses the difference in the absorption rate of light energy between a site to be examined such as a tumor and other sites to distribute the distribution of characteristic information about the light absorption at each position in the subject (characteristics). Distribution). The obtained characteristic distribution includes an initial sound pressure distribution, a light absorption coefficient distribution, a substance concentration distribution, and the like.

  In Non-Patent Document 1, blood vessels are imaged by acquiring a total hemoglobin concentration distribution in a subject using a photoacoustic microscope. The photoacoustic microscope of Non-Patent Document 1 focuses light sequentially on a point-by-point basis (for each position) of a subject surface, and sequentially acquires acoustic waves generated from the point-by-point point. And the characteristic information based on the acoustic wave from each position is arranged one by one. In this non-patent document 1, oxygen metabolism data such as a time-dependent change of oxygen saturation in blood obtained using a photoacoustic microscope is shown, and such oxygen metabolism is useful as a diagnostic index. Is recognized.

Label-free oxygen-metabolic photomicroscopy in vivo, Journal of Biomedical Optics 16 (7) 076003 (2011)

  In the diagnosis of a tumor or the like, as described in Non-Patent Document 1, time variation of characteristic information may be useful as a diagnostic index. However, in the case of the photoacoustic microscope described in Non-Patent Document 1, it is not mentioned how to show the time variation of the characteristic information to the operator (user). In the case of such an apparatus used for diagnosis, it is important to improve the method of presenting data to the user and usability.

  The photoacoustic microscope of Non-Patent Document 1 is a method in which light is sequentially scanned while focusing light on each point of the subject surface, and characteristic information obtained is arranged point by point. As a method different from such a method, there is a method in which light is irradiated to a plurality of positions at once and an image is reconstructed using a plurality of received signals based on acoustic waves generated from the plurality of positions. The method of the photoacoustic microscope of Non-Patent Document 1 has an advantage of higher resolution than the method of performing image reconstruction described above, but takes time. In particular, when examining a relatively wide range of subjects such as breasts, it takes a long time and there is a problem in usability.

  Accordingly, an object of the present invention is to provide a subject information acquisition apparatus, a display method, a program, and a processing apparatus that are easy to use and can provide a presentation useful for diagnosis.

A subject information acquisition apparatus according to the present invention includes a light source that generates light, and a plurality of conversions that receive acoustic waves generated in the subject by being irradiated with light from the light source and convert the acoustic waves into a plurality of reception signals. A subject information acquisition apparatus comprising: an element; and a processing unit that acquires a distribution of characteristic information corresponding to a plurality of positions in the subject using the plurality of reception signals, respectively.
The processing unit displays a distribution image created using the characteristic distribution and data indicating temporal variation of characteristic information in a predetermined region of the distribution image on the same screen of the display unit. The image information is output.

The display method of the present invention is a display method for displaying an image on a display unit using a characteristic distribution acquired by an object information acquisition apparatus by receiving an acoustic wave generated in an object irradiated with light. There,
The acquired characteristic distribution is a distribution of characteristic information respectively corresponding to a plurality of positions in the subject acquired using a plurality of reception signals obtained by receiving the acoustic wave,
A step of displaying a distribution image created using the characteristic distribution and data indicating temporal variation of characteristic information in a predetermined region of the distribution image on the same screen of the display unit. Features.

  According to the present invention, it is possible to provide a user-friendly presentation useful for diagnosis.

It is a schematic diagram of the subject information acquiring apparatus according to the first embodiment. It is a timing chart which shows the reception timing of the acoustic wave which concerns on 1st Embodiment. It is a schematic diagram of the processing apparatus which concerns on 1st Embodiment. It is a flowchart which shows the flow of the display method of 1st Embodiment. It is a schematic diagram which shows an example of the screen displayed on a display part by 1st Embodiment. It is a schematic diagram which shows an example of the screen displayed on a display part by 1st Embodiment. It is a schematic diagram which shows an example of the screen displayed on a display part by 2nd Embodiment.

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

  In the following description, an acoustic wave includes an acoustic wave called a photoacoustic wave, an optical ultrasonic wave, a sound wave, and an ultrasonic wave, and an acoustic wave generated by light irradiation is particularly called a “photoacoustic wave”. The subject information acquisition apparatus of the following embodiment receives photoacoustic waves generated at a plurality of positions (parts) in a subject by irradiating at least light (electromagnetic waves including visible light and infrared rays) to the subject. Then, a characteristic distribution indicating the distribution of characteristic information corresponding to each of a plurality of positions in the subject is acquired.

  Characteristic information acquired by photoacoustic waves indicates characteristic information related to light absorption. The initial sound pressure of photoacoustic waves generated by light irradiation, or the optical energy absorption density derived from the initial sound pressure, the absorption coefficient And characteristic information reflecting the concentration of substances constituting the tissue. The substance concentration is, for example, oxygen saturation, total hemoglobin concentration, oxyhemoglobin or deoxyhemoglobin concentration.

  Of the acoustic waves, the acoustic wave transmitted from the probe is called “ultrasonic wave”, and the transmitted ultrasonic wave reflected in the subject is particularly called “reflected wave”. As described above, the object information acquisition apparatus according to the following embodiment can acquire a distribution related to the acoustic characteristics in the object by receiving not only the photoacoustic wave but also the reflected wave by the ultrasonic echo. Good. The distribution relating to the acoustic characteristics includes a distribution reflecting the difference in acoustic impedance of the tissue inside the subject. However, in the present invention, it is not essential to acquire a distribution related to transmission / reception of ultrasonic waves and acoustic characteristics.

  Furthermore, the subject information acquisition apparatus of the following embodiment is mainly intended for diagnosis of human or animal malignant tumors, vascular diseases, etc., follow-up of chemical treatment, and the like. Therefore, the subject is assumed to be a living body, specifically, a diagnosis target such as a breast, neck or abdomen of a human or animal.

  Further, the light absorber inside the subject indicates a tissue having a relatively high absorption coefficient inside the subject. For example, if a part of the human body is a subject, there are oxyhemoglobin or deoxyhemoglobin, blood vessels containing many of them, tumors containing many new blood vessels, and plaques on the carotid artery wall. Furthermore, molecular probes that specifically bind to malignant tumors using gold particles or graphite, capsules that transmit drugs, and the like are also light absorbers.

<First Embodiment>
The first embodiment will be described below with reference to the drawings. Hereinafter, the configuration of the subject information processing apparatus will be described first, and then the display method will be described.

(overall structure)
First, the overall configuration of the subject information acquiring apparatus according to the present embodiment will be described with reference to FIG. FIG. 1A is a schematic diagram of a subject information acquisition apparatus according to this embodiment, and FIG. 1B is a schematic diagram of a probe 130. The subject information acquisition apparatus of the present embodiment includes at least a light source 110, a probe 130 including a plurality of conversion elements 131, and a processing apparatus 140 as a processing unit. Further, the probe 130 of the present embodiment is configured to be able to perform both reception of photoacoustic waves and transmission and reception of ultrasonic waves. And the processing apparatus 140 can acquire both the characteristic distribution based on a photoacoustic wave, and the distribution regarding the acoustic characteristic based on the reflected wave by an ultrasonic echo.

  In FIG. 1A, light generated by the light source 110 is drawn into the probe 130 via an optical member such as a bundle fiber, and the subject 100 is irradiated with light from the emission end 120 in the probe 130. The light illuminated on the subject 100 diffuses inside the subject and is absorbed by the light absorber 101 inside the subject, thereby generating a photoacoustic wave. The plurality of conversion elements 131 included in the probe 130 receive photoacoustic waves generated from the subject 100 and convert them into electrical signals (reception signals), respectively. A plurality of received signals output from the probe 130 are sent to the processing device 140.

  The apparatus according to the present embodiment does not focus light at one position (one point) on the surface of the subject as in the photoacoustic microscope, but has a configuration in which light for one irradiation reaches a plurality of positions in the subject. is there. The probe 130 includes a plurality of conversion elements 131. Therefore, photoacoustic waves generated from a plurality of positions in the subject can be received by at least one light irradiation. That is, it is possible to acquire a characteristic information group (corresponding to a characteristic distribution indicating a distribution of characteristic information for each position) in a predetermined region composed of a plurality of positions (a plurality of points).

  In addition, the plurality of conversion elements 131 transmit ultrasonic waves to the subject 100 while shifting the timing of reception of the above-described photoacoustic waves. The transmitted ultrasonic waves are reflected in the subject, and the plurality of conversion elements 131 receive the returned reflected waves and convert them into analog electric signals (reception signals), respectively. A plurality of reception signals output from the plurality of conversion elements 131 are sent to the processing device 140.

  Here, timing control of light emission from the light source 110, reception of photoacoustic waves, transmission of ultrasonic waves, and reception of reflected waves will be described.

(Timing of light emission and transmission / reception)
FIG. 2 is a timing chart showing each timing. In FIG. 2, the light emission trigger indicates the light irradiation timing, and a detection signal from an optical sensor such as a photodiode that detects light from the light source 110 or a light emission instruction signal from the processing device 140 is used as a light emission trigger. Can be used as Since the light propagation speed is sufficiently higher than the acoustic wave propagation speed, the light emission timing by the light source and the timing at which the subject is irradiated with light can be treated as the same time.

  In FIG. 2A, the processing device 140 causes the transmission / reception unit 6 to receive a photoacoustic wave after light emission from the light source. It is preferable that the time from light emission to the start of photoacoustic wave reception is as short as possible. Next, after receiving the photoacoustic wave, the processing device 140 sends a transmission signal for transmitting ultrasonic waves from the conversion element 131 to the conversion element 131. Note that the ultrasonic transmission / reception in FIG. 2 (a) is performed only once between the light emission and the light emission, but is not limited to this, and is performed more than once between the light emission and the light emission as shown in FIG. 2 (b). Sound waves may be transmitted and received. In FIG. 2B, ultrasonic transmission / reception is performed three times, but the number of times is also arbitrary.

  Further, after receiving light emission and photoacoustic wave a predetermined number of times without performing transmission / reception of ultrasonic waves between light emission and light emission, after receiving the last light emission and photoacoustic wave (predetermined number of times), the ultrasonic wave Transmission and reception may be performed. Alternatively, after transmitting and receiving ultrasonic waves a predetermined number of times, light emission and photoacoustic waves may be received after the last (predetermined number of times) transmission and reception of ultrasonic waves.

  Next, each component of the subject information acquisition apparatus of this embodiment will be described in detail.

(Light source 110)
The light source 110 is preferably a pulse light source capable of generating pulsed light on the order of nanoseconds to microseconds. Specifically, a pulse width of about 10 nanoseconds is used to efficiently generate photoacoustic waves. The wavelength is preferably about 500 nm to 1200 nm. As a specific light source, a pulsed laser such as an Nd: YAG laser or an Alexandrite laser is preferable. Further, a Ti: sa laser or an OPO laser using Nd: YAG laser light as excitation light may be used. In addition, a solid laser, a gas laser, a dye laser, a semiconductor laser, or the like can be used. For light transmission from the light source 110 to the probe 130, an optical member such as a bundle fiber, a mirror, or a prism may be used.

(Probe 130)
As shown in FIG. 1B, the probe 130 includes a converter including a plurality of conversion elements 131 and an emission end 120 as an irradiation unit. The probe 130 is preferably covered with a housing 132. The emission end 120 is composed of a fiber, a lens, a diffusion plate, and the like, and irradiates the subject with light having a desired shape. The plurality of conversion elements 131 receive photoacoustic waves and convert them into reception signals (first reception signals), respectively.

  In addition, the conversion element 131 of this embodiment can also transmit an ultrasonic wave to the subject based on a transmission signal from the processing device 140. The transmitted ultrasonic wave is reflected based on the difference in acoustic impedance in the subject. The plurality of conversion elements 131 receive the reflected waves returned from the subject and convert them into reception signals (second reception signals), respectively.

  The conversion element 131 receives an acoustic wave and converts it into an electrical signal, such as a conversion element such as a piezoelectric element using a piezoelectric phenomenon, a conversion element using a resonance of light, a conversion element using a change in capacitance such as a CMUT. Any device that can be converted may be used. In this embodiment, the conversion element that receives the photoacoustic wave and the conversion element that transmits the ultrasonic wave and receives the reflected wave are performed by the common conversion element 131. However, as the probe of the present invention, a transducer having a plurality of transducer elements that receive photoacoustic waves and a transducer having a plurality of transducer elements that transmit and receive ultrasonic waves may be configured separately. Good. In addition, the probe 130 according to the present embodiment may be of a type that mechanically moves the probe 130 as well as a type that the user holds and operates.

  The plurality of conversion elements 131 can be arranged in a plane called a 1D array, 1.5D array, 1.75D array, or 2D array. Further, they may be arranged in an arc shape.

  Further, the plurality of conversion elements 131 may be arranged on a bowl-shaped support. Specifically, as described in International Publication No. 2010/030817, the receiving surfaces of the plurality of conversion elements 131 are arranged on the bowl-shaped inner surface of the support so as to be arranged in a three-dimensional spiral shape. It may be configured. Such an arrangement is preferable because photoacoustic waves can be received at a wide angle. Further, such an arrangement is an arrangement in which the directivity axes (axis along the direction having the highest reception sensitivity) of at least some of the conversion elements 131 are gathered in a specific region.

  And by such arrangement | positioning, the acoustic wave generated from the specific area | region can be received with higher sensitivity. By using the reception signal obtained from the conversion element 131 arranged in this way, a connection image of blood vessels and the like can be well connected and a distribution image with high resolution can be obtained.

  It is preferable to provide an acoustic medium (for example, water is acceptable) having an acoustic impedance close to the subject such as a liquid or a gel between the receiving surface of the plurality of conversion elements 131 arranged inside the bowl and the subject.

(Processing device 140)
The processing device 140 is obtained by receiving a received signal (received signal obtained by receiving a photoacoustic wave) or a received signal (received reflected wave) caused by an ultrasonic wave, which is output from the probe 130. Received signal) amplification, digital conversion processing, filter processing, and the like are performed. Then, photoacoustic image data and ultrasonic image data can be created using each received signal that has undergone signal processing. Hereinafter, a detailed configuration of the processing apparatus 140 will be described with reference to FIG.

  FIG. 3A is a schematic diagram showing the configuration of the processing apparatus 140 according to this embodiment. 3A, the processing device 140 includes a connection switching unit 701, a transmission control unit 702, a signal receiving unit 703, an information processing unit 704, and a control CPU 705 serving as a control unit that switch the connection state between the probe 130 and the processing device 140. .

  The control CPU 705 supplies data and control signals necessary for controlling each block. Specifically, the control CPU 705 controls a light emission instruction signal that instructs the light source 110 to emit light and a transmission signal that the transmission control unit 702 sends to the conversion element 131. Further, the control CPU 705 sends a signal for switching connection destinations of the plurality of conversion elements 131 to the connection switching unit 701, and supplies the signal reception unit 703 with control signals and parameters necessary for signal reception control. Further, the control CPU 705 causes the information processing unit 704 to determine whether the digital signal transferred from the signal receiving unit 703 to the information processing unit 704 is derived from the photoacoustic or ultrasonic wave. Supply parameters and control signals.

  The transmission control unit 702 outputs a transmission signal according to the control of the control CPU 705. The signal receiving unit 703 converts a plurality of reception signals output from the plurality of conversion elements 131 into digital signals. The signal receiving unit 703 includes an A / D conversion unit, a data memory, a multiplexer, and the like. The received signal derived from the photoacoustic wave and the received signal derived from the ultrasonic wave may be processed by using a common A / D converter or data memory prepared for each channel, and for the received signal derived from the photoacoustic wave. Separate A / D converters and data memories may be prepared for the received signals derived from the ultrasonic waves. The digital signal generated in the signal receiving unit 703 is transferred to the information processing unit 704.

  The connection switching unit 701 switches connection destinations of the plurality of conversion elements 131. The connection switching unit 701 connects the plurality of conversion elements 131 to the transmission control unit 702 or to the signal reception unit 703.

  The information processing unit 704 creates photoacoustic image data and ultrasound image data from the photoacoustic wave-derived digital signal and the ultrasound-derived digital signal transferred from the signal receiving unit 703, respectively. The information processing unit 704 can perform appropriate signal processing and image processing depending on whether the received signal is a signal caused by a photoacoustic wave or a signal caused by a reflected wave. Typically, when generating ultrasonic image data, a delay time corresponding to the arrival time of the reflected wave is given to the reception signal from each element to adjust the phase, and then the phasing addition (Delay) is added. & Sum). When generating photoacoustic image data, image reconstruction using an algorithm different from phasing addition may be performed. For example, as an image reconstruction method for generating a photoacoustic image, there is a back projection method in a time domain or a Fourier domain, which is usually used in tomography technology. By setting it as such a structure, photoacoustic image data and ultrasonic image data can be acquired based on a received signal. The image created by the information processing unit 704 may be a 2D image or a 3D image.

  The information processing unit 704 can acquire, as photoacoustic image data, a characteristic distribution indicating the distribution of characteristic information corresponding to a plurality of positions in the subject by at least one light irradiation. Characteristic information corresponding to each of a plurality of positions is a value corresponding to a plurality of pixels or voxels in the created image, and each pixel value or voxel value corresponds to an initial sound pressure value, an absorption coefficient value, a substance Concentration values are reflected.

  When a plurality of light irradiations are repeated as shown in FIG. 2C, a combined distribution obtained by combining (compounding) a plurality of characteristic distributions obtained by the plurality of light irradiations can also be generated as photoacoustic image data. Note that composition refers to overlay processing between images, such as arithmetic average processing, geometric average processing, harmonic average processing, etc., for a plurality of images or a plurality of images corrected for displacement between the images. Refers to what is done.

  The information processing unit 704 applies various correction processes such as brightness adjustment, distortion correction, and extraction of a region of interest to the generated photoacoustic image data to generate a distribution image for display. Furthermore, it is possible to superimpose the photoacoustic image data and the ultrasonic image data to create and display a superimposed image as shown in FIG. 5 as a distribution image. The obtained ultrasound image data includes a distribution relating to acoustic characteristics in the subject.

  Further, a plurality of characteristic distributions obtained in time series by a plurality of light irradiations may be switched (updated) and displayed in time series at regular time intervals. The constant time interval may be, for example, the same cycle as the light emission (0.1 sec interval in the case of 10 Hz light emission), or may be an interval of 1 sec so as to be visible. In addition to the characteristic distribution, the above-described composite distribution may be updated each time a composite distribution is obtained.

  Furthermore, the information processing unit 704 according to the present embodiment can also create data indicating the time variation of the characteristic information in a predetermined region in the created distribution image. The time variation of the characteristic information may be a time variation of the characteristic information at a predetermined position, or may be a time variation of a statistic of characteristic information (that is, a plurality of characteristic information) respectively corresponding to a plurality of positions in a predetermined region. The statistic refers to a statistical analysis result such as an average value, median value, mode value, maximum value, standard deviation, and mean square error. That is, the statistic of the plurality of characteristic information in the designated area indicates an average of a plurality of pixel values and voxel values in the designated area. The data indicating the time variation of the characteristic information created by the information processing unit 704 may be any data as long as the change with time is known as in the line graph shown in FIG.

  The information processing unit 704 according to the present embodiment creates image information for displaying a distribution image created using the characteristic distribution and data indicating temporal variation on the same screen, and outputs the image information to the display device 160. be able to. A flow of the display method and an example of the display screen will be described later with reference to FIGS. 4 and 5. First, a specific configuration of the information processing unit 704 will be described below.

(Specific Configuration of Information Processing Unit 704)
FIG. 3B is a diagram showing a configuration of the information processing unit 704 and its surroundings according to the present embodiment. The information processing unit 704 typically includes a GPU (Graphics Processing Unit), a workstation equipped with a CPU, and the like.

  The storage unit 722 stores the digital signal transferred from the signal receiving unit 703 and setting information regarding the measurement operation. The digital signal derived from photoacoustic or ultrasonic waves transferred from the signal receiving unit 703 is first stored in the storage unit 722.

  The CPU 724 receives instructions regarding various operations from the user via the operation unit 723, generates necessary control information, and controls each function via the system bus 725. In addition, the CPU 724 can perform integration processing on the digital signal derived from the photoacoustic wave stored in the storage unit 722. The integration process is a process of integrating a plurality of received signals (including an integrated average) by repeatedly performing light irradiation and photoacoustic wave reception at the same position (scanning position) with respect to the subject. . This integration process reduces system noise and improves the S / N ratio of the received signal. In addition, when an object to which the photoacoustic wave generation source moves with time, such as a contrast agent, is an inspection target, it is possible to grasp the movement path for the accumulated time. Similar processing can be performed by the control CPU 705, the GPU 721, or the like.

  The CPU 724 writes the digital signal after the integration process again in the storage unit 722. This is used for generation of photoacoustic image data by the GPU 721. In addition, the CPU 724 can receive information on a designated area designated by the user, and can calculate a statistic of characteristic information corresponding to each of a plurality of positions in the designated area.

  The FPGA 726 performs phasing addition using the ultrasonic-derived digital signal written in the storage unit 722 to create ultrasonic image data. The FPGA 726 is configured by an FPGA (Field Programmable Gate Array) chip.

  The GPU 721 creates photoacoustic image data using a digital signal that is integrated by the CPU 724 and written in the storage unit 722. Further, the GPU 721 can create a distribution image by applying various correction processes such as brightness adjustment, distortion correction, and clipping of a region of interest to the created photoacoustic image data and ultrasonic image data. . Further, the GPU 721 generates a superimposed image obtained by superimposing the photoacoustic image data and the ultrasonic image data as a distribution image, and displays image information for displaying data indicating the temporal variation of characteristic information and the distribution image side by side. Can be generated. Similar processing can be performed by the CPU 724 or the like. In this embodiment, the photoacoustic image data is created by the GPU 721 and the ultrasonic image data is created by the FPGA 726. However, the photoacoustic image data and the ultrasonic image data are created by a common GPU, FPGA, CPU, or the like. It is also possible to do.

(Operation unit 723)
The operation unit 723 is an input device for the user to specify parameters related to the characteristic information acquisition operation and perform various inputs. The operation unit 723 also performs input of parallel display, which will be described later, and setting of a ROI (region of interest) as a designated region. Note that when a 3D image is displayed as a distribution image, the ROI can also be specified in 3D. The size and coordinate system of the ROI can be arbitrarily changed, and the range of the ROI can be specified while being confirmed by the user by being superimposed on the distribution image. The operation unit 723 is generally configured with a mouse, a keyboard, a touch panel, and the like. Note that the operation unit 723 may be prepared separately and connected to the subject information acquisition apparatus without being configured to be included in the subject information processing apparatus.

(Display device 160)
The display device 160 serving as a display unit includes an LCD (Liquid Crystal Display), a CRT (Cathode Ray Tube), an organic EL display, and the like. Note that the display device 160 may be prepared separately and connected to the subject information acquisition device, without having the configuration of the subject information processing device.

  Next, examples of the display method and the display screen according to the present embodiment will be described.

(Display method and display screen)
The display flow of this embodiment will be described with reference to FIGS. FIG. 4 is a flowchart showing the display flow of this embodiment, and FIG. 5 is a schematic diagram showing an example of the display screen of this embodiment.

  The display flow of this embodiment will be described starting from the state in which the composite distribution as the photoacoustic image data and the ultrasonic image data are created. Specifically, when the subject is irradiated with light a plurality of times (for example, a predetermined number of times of about 30 times), the processing device 140 receives a plurality of reception signals output from a plurality of conversion elements for each emission timing. It is received a predetermined number of times (for example, at each light emission timing of 10 Hz). Then, the processing device 140 creates a characteristic distribution for a predetermined number of times, performs arithmetic averaging, and creates a composite distribution.

  In S101 of FIG. 4, the processing device 140 superimposes the composite distribution and the ultrasonic image, and causes the display device 160 to display the superimposed image as a distribution image. The upper diagram of FIG. 5 shows the display screen at that time. Since the distribution image 202 in FIG. 5 is a superimposed image, a difference in acoustic impedance inside the subject is indicated by the ultrasonic image, and morphological information such as a cancer boundary is indicated. The photoacoustic wave image shows functional information such as the concentration of a specific substance such as hemoglobin. When displaying the superimposed image, the ultrasonic image is displayed in gray scale, the photoacoustic image is displayed in color scale, and the transparency is set so that each image can be easily viewed. By such superposition display, it is possible to display a region 210 that is considered to be a cancer affected area or the like that has a large difference in acoustic impedance, or a region 200 that seems to be a blood vessel that is a region where light absorption is large.

  Next, when the user clicks the ROI setting icon 230 on the screen using the mouse as the operation unit 723 while the distribution image 202 is displayed, a rectangular ROI 220 is displayed on the distribution image. When the rectangular ROI 220 is moved and fixed by the mouse operation, in S102, the processing device 140 receives ROI setting information as information on the designated area from the user.

  When the user clicks the parallel display icon 201, the processing device 140 receives an input of the parallel display mode in S103.

  When receiving the parallel display mode input, the processing device 140 calculates an average value of the plurality of characteristic information in the ROI as a statistic of the plurality of characteristic information in the ROI in S104. That is, an average value of a plurality of pixel values and voxel values in the ROI is calculated. At this time, the average value is calculated for each of the plurality of characteristic distributions used when creating the composite distribution.

  Next, in S <b> 105, the processing apparatus 140 indicates the time variation for each light irradiation of the calculated average value of the plurality of characteristic information as data 240 indicating the time variation of the calculated statistic, next to the distribution image 202. Data 240 are displayed side by side (see the lower diagram of FIG. 5). In this specification, “parallel display” is not limited to the case where they are arranged side by side in the screen as shown in FIG. 5, but they may be arranged vertically or irregularly. It only has to be displayed.

  In the present embodiment, not only parallel display but also the distribution image 202 and the data 240 indicating the time variation may overlap.

  That is, it is preferable that the treatment apparatus 140 performs control so that the distribution image 202 and the data 240 indicating time variation are displayed together at a certain timing. The state in which both are displayed is not only the case where the distribution image 202 and the data 240 indicating time variation are displayed simultaneously (the display start timing is the same). Even if the distribution image 2020 and the data 204 indicating the time variation are started to be displayed at different timings, it is only necessary to have a state in which both are displayed at a certain timing.

  As described above, the processing device 140 outputs image information for displaying the distribution image 202 and the data 240 indicating the time variation on the same screen to the display device 160. As a result, it is easy to compare the distribution image and the data related to the time variation, and the user can easily grasp the position of the time variation, so that the usability is improved.

  Further, in the lower diagram of FIG. 5, the displayed data 240 indicating the time variation indicates the time variation of the average value of the characteristic information for each light irradiation (that is, the time variation of the same period as the light irradiation period). For example, if the light emission frequency is 10 Hz, the change in the characteristic information in increments of 0.1 sec is displayed. Thereby, for example, the time transition of the average intensity in the ROI of the characteristic information due to the difference in contraction caused by the pulsation of the blood vessel can be confirmed. As a result, it is possible to check the local blood shortage situation, determine the propagation of the drug through the blood vessel to the cancer affected area, and improve the diagnostic accuracy. However, the period indicating the time variation may be not only the time variation for each light irradiation but also the time variation for each predetermined number of light irradiations. Moreover, you may make it display the time fluctuation of a predetermined period (preferably 1 second or less period) irrespective of light irradiation.

  In the present embodiment, the steps of S102 and S103 may be reversed. Further, the parallel display icon 201 may be omitted, and when the ROI setting is received in S102, the steps of S103 and S104 may be automatically performed. When setting the ROI, a closed curve may be created on the screen by clicking and dragging with the mouse, and the ROI having a free shape may be set. If an ROI having a free shape can be set, noise called artifacts and an area to be intentionally excluded can be avoided, so that only an area necessary for diagnosis can be extracted and usability is improved.

  In the example of FIG. 5, the time variation of the characteristic information in the ROI designated by the user is displayed. However, not only the ROI designated by the user but also the processing device 140 extracts based on the distribution image. You may display the time fluctuation of the characteristic information in an area | region. Specifically, it is conceivable that the processing device 140 automatically extracts an area where the characteristic information value in the distribution image is larger than a predetermined value as the ROI.

  In addition, as a distribution image, not only a superimposed image of a composite distribution (a composite image of a characteristic distribution that is a photoacoustic image) and a distribution related to acoustic characteristics (an ultrasonic image), but also a distribution image of only a characteristic distribution or a composite distribution good.

  Furthermore, the distribution image obtained in time series may be displayed after being switched (updated) in time series at regular time intervals. The fixed time interval is a predetermined time interval such as a cycle in which the distribution image is acquired, and may be the same cycle as the light emission (0.1 sec interval in the case of light emission at 10 Hz), or 1 sec interval so as to be visible. But you can. Furthermore, as the distribution image display, a composite distribution display and a time-series image switching display may be selectable.

  In addition, when the distribution image is updated and displayed at regular time intervals, it is preferable that the data indicating the time variation of the characteristic information is also updated and displayed. Furthermore, it is preferable that the color and size of the plot points corresponding to the distribution images displayed in parallel are changed in accordance with the update of the distribution image. Further, when all of the acquired distribution image and data indicating the time variation are updated and displayed, the display may be re-displayed or returned to the first acquisition display.

  Further, different characteristic information may be indicated for the distribution image and the data indicating the time variation. That is, the distribution image may indicate the distribution of the absorption coefficient (first characteristic information), and the data indicating the time fluctuation of the oxygen saturation (second characteristic information) may be displayed as the data indicating the time fluctuation.

  In the above example, in response to the input of the parallel display mode from the user, the data 240 indicating the time variation of the characteristic information is displayed side by side (that is, only the distribution image 202 is displayed when there is no input of the parallel display mode). . However, when the distribution image is displayed, data indicating the time variation of the characteristic information of the predetermined area may be automatically displayed (by default). Further, the processing device 140 may selectively execute the parallel display mode and the single display mode. In other words, when the user inputs the single display mode, the distribution image and the data indicating the time variation of the characteristic information are not displayed side by side, and either the distribution image or the data indicating the time variation of the characteristic information is displayed. Only one of them may be displayed.

  Furthermore, in this embodiment, even when measurement of light irradiation, reception of acoustic waves, etc. continues and the distribution image is updated, once the ROI is set, it is set along with the update of the distribution image. It is preferable that the time variation of the characteristic information in the ROI is also updated. Specifically, by repeating S104 and S105, the calculation of characteristic information in the designated ROI and the plot of the value of the characteristic information are repeated. As a result, data 240 in which the value of the characteristic information is updated is displayed.

  Hereinafter, application examples in the present embodiment will be described.

(Application 1)
In this application example, when the processing device 140 obtains a statistic of a plurality of characteristic information in the ROI, only a part of the characteristic information in the ROI is used without using all the characteristic information in the ROI. Specifically, a threshold value is provided for the value (signal intensity) of the characteristic information, and an average value or the like is calculated using only the characteristic information that satisfies the threshold value. Typically, characteristic information whose value (signal intensity) is larger than a predetermined threshold value may be used except for characteristic information corresponding to a noise level. When the noise level of 80 dB is used as a threshold value, characteristic information with a signal intensity of 80 dB or less is removed, and averaging is performed using characteristic information with a signal intensity greater than 80 dB.

  Further, not only the lower limit threshold value but also the upper limit threshold value (for example, 150 dB) may be provided, and the characteristic information having the signal strength less than 150 dB may be averaged except for the characteristic information in which the signal strength suddenly increases. Furthermore, both lower and upper threshold values may be provided.

  As described above, in the case of not only the average but also other statistics, when obtaining the statistics, by providing at least one of the lower threshold and the upper threshold, the noise or the sudden fluctuation value is obtained. Characteristic information can be excluded. Therefore, it is possible to extract the time variation of the characteristic information of the more effective region portion, and it is easier to confirm the time variation of the characteristic information.

(Application example 2)
The application example is characterized in that the processing device 140 sets a plurality of ROIs in response to an input from the user. FIG. 6 is a schematic diagram of a display screen in this application example. First, when the user confirms the ROI setting icon 330 with the mouse cursor displayed on the screen, a rectangular ROI 320 is displayed on the distribution image 302. When the user moves and confirms this ROI 320 to a desired position, the processing device 140 receives the setting of the ROI 320 and displays data 340 indicating the time variation of the statistical amount of the characteristic information in the ROI 320.

  Furthermore, when the ROI setting icon 330 is clicked again by the user, another rectangular ROI 321 is displayed on the distribution image 302. When the user moves and confirms this ROI 321 to a desired position, the processing device 140 displays data 341 indicating the time variation of the statistical amount of the characteristic information in this ROI 321.

  In this way, if it is possible to set a plurality of ROIs, it is possible to simultaneously observe changes in the characteristic information of the ROIs at a plurality of locations in the same distribution image. Therefore, it is possible to easily recognize the difference in magnitude and amplitude of the characteristic information signal between different areas, so that it is possible to confirm differences in, for example, blood and drug transmission status, and further improve the diagnostic accuracy. There is.

<Second Embodiment>
In the present embodiment, the processing content of the processing device 140 is different from that of the first embodiment. The subject information acquisition apparatus of the present embodiment uses an apparatus having the same configuration as the apparatus shown in FIGS. The outline of the display method is basically the same as the flow described with reference to FIG. 4, and therefore, the following description will be focused on portions different from the first embodiment with reference to FIG. 7.

  The present embodiment is characterized in that the composite distribution is created again based on the data indicating the time variation of the characteristic information. FIG. 7 is a schematic diagram for explaining data 401 indicating temporal variation of characteristic information displayed in the present embodiment.

  The data indicating the time variation of the characteristic information shown in FIG. 7 is data created using the method described in the first embodiment. Specifically, as described in the flow of FIG. 4, the processing device 140 combines a plurality of characteristic distributions obtained by a plurality of light irradiations and displays a combined distribution. When the ROI is set in the composite distribution, the processing device 140 calculates the statistic of the characteristic information in the ROI for each characteristic distribution used in the composite distribution, and displays it as the time variation of the characteristic information. . That is, since the data of FIG. 7 includes characteristic information corresponding to characteristic distributions obtained by a plurality of times of light irradiation, the data is shown as time variation of the characteristic information for each light irradiation.

  Here, in the data 401 indicating the time variation of the characteristic information, a singular point 410 having a specifically large value and a singular point 411 having a specifically small value can be confirmed. Such singular point 410 and singular point 411 may be affected by a relative positional deviation between the probe and the subject at the time of measurement. However, since the displayed combined distribution is combined using the characteristic distribution of the time corresponding to the singular point 410 and the singular point 411, the reliability may be lowered.

  Therefore, in the present embodiment, when the user designates the singular point 410 or the singular point 411 using the mouse, the processing device 140 causes the characteristic distribution of time corresponding to the designated singular point 410 or singular point 411. The composite distribution can be created again. Therefore, according to the present embodiment, a distribution image with higher reliability can be presented.

<Third Embodiment>
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and the computer of the system or apparatus (or CPU, MPU, etc.) reads the program. To be executed.

  Each embodiment has been described above, but the present invention is not limited to these embodiments, and includes various modifications and application examples without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 110 Light source 120 Output end 130 Probe 131 Conversion element 140 Processing apparatus 160 Display apparatus

Processing apparatus of the present invention, have a processing unit that acquires a plurality of said object property information generated on the basis of the acoustic wave generated by light irradiation to a subject, wherein the processing unit, the plurality of times For each of the light irradiations, the characteristic information corresponding to each of a plurality of two-dimensional or three-dimensional positions in the subject is acquired based on the reception signal of the acoustic wave. 3D and distribution image related to the characteristic information respectively corresponding to a plurality of positions, and data indicating the time variation of the characteristic information in each of a plurality of different regions of interest within said distribution image to be displayed on the display unit.

Display method of the present invention is a display method of displaying a plurality of images relating to the subject characteristic information generated based on the acoustic wave generated by light irradiation to a subject, the plurality of times For each of the light irradiations, a step of acquiring characteristic information corresponding to a plurality of two-dimensional or three-dimensional positions in the subject based on the received acoustic wave signal , and two-dimensional in the subject Alternatively, a distribution image related to the characteristic information corresponding to each of a plurality of three-dimensional positions and data indicating temporal variation of the characteristic information in each of a plurality of different regions of interest in the distribution image are displayed on the display unit. with the method comprising the steps of, a.

Claims (23)

A light source that generates light;
A plurality of conversion elements that receive acoustic waves generated in the subject by being irradiated with light from the light source and convert the acoustic waves into a plurality of reception signals;
A processing unit for acquiring characteristic distributions indicating distributions of characteristic information respectively corresponding to a plurality of positions in the subject using the plurality of received signals;
A subject information acquisition apparatus comprising:
The processor is
Outputs image information for displaying a distribution image created using the characteristic distribution and data indicating temporal variation of characteristic information in a predetermined region of the distribution image on the same screen of the display unit. An object information acquisition apparatus characterized by: The processor is
Calculating a statistic of characteristic information of a plurality of positions in the predetermined region;
The object information acquiring apparatus according to claim 1, wherein data indicating time variation of the statistic is displayed as data indicating time variation of the characteristic information. The processing unit is configured to selectively execute at least a parallel display mode and a single display mode,
When receiving the input of the parallel display mode by the user, the distribution image and the data indicating the time variation of the characteristic information are displayed in the same screen,
When there is no input of the parallel display mode or when the user receives the input of the single display mode, the distribution image and the data indicating the time variation of the characteristic information are not displayed on the same screen. The object information acquiring apparatus according to claim 1, wherein the object information acquiring apparatus is an object information acquiring apparatus.   The processing unit receives information on a designated area designated by a user in the distribution image, and displays data indicating temporal variation of characteristic information in the designated area in the distribution image. The subject information acquisition apparatus according to any one of claims 1 to 3. The processing unit receives the plurality of reception signals output from the plurality of conversion elements for the predetermined number of times each time the light is irradiated when the subject is irradiated with the light a predetermined number of times. Generate characteristic distribution for the number of times,
5. The object information acquisition apparatus according to claim 1, wherein a combined distribution obtained by combining the predetermined number of characteristic distributions is displayed as the distribution image.   The processing unit receives a plurality of reception signals output from the plurality of conversion elements each time the light is irradiated when the subject is irradiated with the light a plurality of times. 6. The object information acquiring apparatus according to claim 1, wherein data indicating temporal variation of the characteristic information is displayed. The processor is
As the characteristic information, first characteristic information and second characteristic information different from the first characteristic information are acquired,
A distribution image created using a characteristic distribution indicating a distribution of the first characteristic information corresponding to each of a plurality of positions in the subject, and the second characteristic information in a predetermined region of the distribution image. The object information acquiring apparatus according to any one of claims 1 to 6, wherein data indicating time variation is displayed on the same screen.   The processing unit includes, as the characteristic information, information reflecting at least one of a sound pressure of an acoustic wave generated by absorbing the light, an absorption coefficient of the light, an oxygen saturation, and a substance concentration. The object information acquiring apparatus according to claim 1, wherein the object information acquiring apparatus is acquired. A plurality of conversion elements for receiving and converting acoustic waves generated by light irradiation into a plurality of first reception signals;
A plurality of conversion elements for transmitting acoustic waves, receiving reflected waves reflected in the subject and converting them into a plurality of second received signals, and
The processor is
Creating the characteristic distribution or a combined distribution in which the characteristic distributions are combined using the plurality of first received signals;
Creating a distribution relating to acoustic characteristics using the plurality of second received signals;
The subject information according to claim 1, wherein the superimposed image is displayed as the distribution image by superimposing the characteristic distribution or the composite distribution and the distribution relating to the acoustic characteristic. Acquisition device.   The plurality of conversion elements for receiving the acoustic wave generated by the light irradiation and the plurality of conversion elements for transmitting the acoustic wave and receiving the reflected wave are common. The subject information acquisition apparatus according to claim 9. A light source that generates light;
A plurality of conversion elements that receive acoustic waves generated in the subject by being irradiated with light from the light source and convert the acoustic waves into a plurality of reception signals;
A processing unit for acquiring characteristic distributions indicating distributions of characteristic information respectively corresponding to a plurality of positions in the subject using the plurality of received signals;
A subject information acquisition apparatus comprising:
The processor is
Controlling the distribution image created using the characteristic distribution and the data indicating the temporal variation of the characteristic information in a predetermined area of the distribution image to be displayed at a certain timing. A subject information acquisition apparatus characterized by the above. A display method for displaying an image on a display unit using a characteristic distribution acquired by an object information acquisition apparatus by receiving an acoustic wave generated in an object irradiated with light,
The acquired characteristic distribution is a distribution of characteristic information respectively corresponding to a plurality of positions in the subject acquired using a plurality of reception signals obtained by receiving the acoustic wave,
A step of displaying a distribution image created using the characteristic distribution and data indicating temporal variation of characteristic information in a predetermined region of the distribution image on the same screen of the display unit. Characteristic display method. In the displaying step,
13. The display method according to claim 12, wherein data indicating temporal variation of statistical information of characteristic information at a plurality of positions in the predetermined region is displayed as data indicating temporal variation of the characteristic information. At least the parallel display mode and the single display mode can be selectively executed,
When receiving the input of the parallel display mode by the user, the distribution image and data indicating temporal variation of the characteristic information are displayed in the same screen,
When there is no input of the parallel display mode or when the user receives the input of the single display mode, the distribution image and the data indicating the time variation of the characteristic information are not displayed on the same screen. The display method according to claim 12 or 13, characterized in that: A step of receiving information on a designated area designated by the user;
The display method according to any one of claims 12 to 14, wherein, in the displaying step, data indicating temporal variation of characteristic information in the designated area in the distribution image is displayed. In the displaying step,
13. When the subject is irradiated with light a predetermined number of times, a combined distribution obtained by combining the characteristic distributions for the predetermined number of times obtained each time the light is irradiated is displayed as the distribution image. 16. The display method according to any one of items 15 to 15. In the displaying step,
17. The data indicating the time variation of the characteristic information for each irradiation of the light is displayed as the data indicating the time variation when the subject is irradiated with light a predetermined number of times. The display method according to any one of the above items. The acquired characteristic information includes first characteristic information and second characteristic information different from the first characteristic information;
In the displaying step,
A distribution image created using a characteristic distribution indicating the distribution of the first characteristic information corresponding to each of a plurality of positions in the subject, and the second characteristic in a predetermined region of the distribution image 18. The display method according to claim 12, wherein data indicating temporal variation of information is displayed in the same screen. Receiving an information on the distribution of the acoustic characteristics in the subject acquired by the subject information acquiring device by transmitting an acoustic wave and receiving a reflected wave reflected in the subject;
In the displaying step,
19. The superimposed image in which the characteristic distribution or a combined distribution obtained by combining the characteristic distributions and a distribution related to the acoustic characteristics is superimposed is displayed as the distribution image. Display method described in. A display method for displaying an image on a display unit using a characteristic distribution acquired by an object information acquisition apparatus by receiving an acoustic wave generated in an object irradiated with light,
The acquired characteristic distribution is a distribution of characteristic information respectively corresponding to a plurality of positions in the subject acquired using a plurality of reception signals obtained by receiving the acoustic wave,
Controlling the distribution image created using the characteristic distribution and the data indicating the temporal variation of the characteristic information in a predetermined area of the distribution image to be displayed at a certain timing. A display method characterized by.   The program for making a computer perform each step of the display method of any one of Claims 12 thru | or 20. A processing device for outputting image information to a display unit,
A distribution of characteristic information corresponding to each of a plurality of positions in the subject is shown using a plurality of reception signals output from a plurality of conversion elements that have received acoustic waves generated in the subject irradiated with light. Get characteristic distribution,
Outputs image information for displaying a distribution image created using the characteristic distribution and data indicating temporal variation of characteristic information in a predetermined region of the distribution image on the same screen of the display unit. The processing apparatus characterized by performing. A processing device for outputting image information to a display unit,
A distribution of characteristic information corresponding to each of a plurality of positions in the subject is shown using a plurality of reception signals output from a plurality of conversion elements that have received acoustic waves generated in the subject irradiated with light. Get characteristic distribution,
Controlling the distribution image created using the characteristic distribution and the data indicating the temporal variation of the characteristic information in a predetermined area of the distribution image to be displayed at a certain timing. A processing apparatus characterized by the above.

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