JP2023060587A - Optical ultrasonic diagnostic device - Google Patents

Abstract

To acquire accurate data on a light absorber positioned in a deep part.SOLUTION: An optical ultrasonic diagnostic device includes an irradiation unit, a control unit, a reception unit, and a generation unit. The irradiation unit irradiates a light absorber group including a first light absorber and a second light absorber positioned in a deeper part than the first light absorber with light. The control unit controls the irradiation unit so as to irradiate the light absorber group with first light to lower a light absorption rate of the first light absorber, and controls the irradiation unit so as to irradiate the light absorber group with second light in a state that the light absorption rate of the first light absorber is lowered. The reception unit receives a first optical ultrasonic wave generated in the light absorber group by the irradiation of the first light, and a second optical ultrasonic wave generated in the light absorber group by the irradiation of the second light. The generation unit generates third data by taking a difference between first data based on the first optical ultrasonic wave and second data based on the second optical ultrasonic wave.SELECTED DRAWING: Figure 1

Description

An embodiment of the present invention relates to a photoacoustic diagnostic apparatus.

Photoacoustic Imaging (PAI) is known as a technique for imaging a light absorber in a subject. Photoacoustic imaging utilizes the fact that photoacoustic waves (also called photoacoustic waves) are generated from light absorbers when a subject is irradiated with light, and the distribution of light absorbers is converted into image information. Technology.

For example, photoacoustic diagnostic devices (also called photoacoustic devices) are being developed as devices for performing photoacoustic imaging, and there are various photoacoustic diagnostic devices.

For example, when the light absorber A (e.g., melanin, etc.) is located in the surface layer and the light absorber B (e.g., blood vessel, etc.) is located deeper than the light absorber A, in the first irradiation, the light absorber A A light source with a wavelength that absorbs light is used, and a light source with a wavelength that light absorber A and light absorber B absorb in the second irradiation is used, and by taking the difference between the detection signals obtained respectively, light There is a photoultrasonic diagnostic apparatus that removes the information of the absorber A and enhances the image of the light absorber B. FIG.

However, in such a photoacoustic diagnostic apparatus, the light absorption rate of the light absorber A located in the surface layer greatly affects the light irradiation to the light absorber B located in the deep part. For this reason, it is difficult to obtain accurate data on the light absorber B positioned deep.

JP 2013-55988 A

A problem to be solved by the present invention is to obtain accurate data on a light absorber located in a deep part.

A photoacoustic diagnostic apparatus according to an embodiment includes an irradiation unit, a control unit, a reception unit, and a generation unit. The irradiating section irradiates a light absorber group including a first light absorber and a second light absorber positioned deeper than the first light absorber. The control unit controls the irradiation unit to irradiate the group of light absorbers with first light that reduces the light absorption rate of the first light absorbers, and controls the light of the first light absorbers. The irradiation unit is controlled so as to irradiate the light absorber group with the second light in a state where the absorptance is lowered. The receiving unit receives a first optical ultrasonic wave generated in the light absorber group by the irradiation of the first light and a second optical ultrasonic wave generated in the light absorber group by the irradiation of the second light. receive sound waves. The generation unit generates third data by obtaining a difference between first data based on the first optical ultrasound and second data based on the second optical ultrasound.

FIG. 1 is a diagram showing an example of the configuration of a photoultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a flowchart illustrating an example of the flow of processing executed by the photoultrasonic diagnostic apparatus according to the first embodiment; FIG. 3A is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the first embodiment; FIG. 3B is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the first embodiment; FIG. 4A is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the first embodiment; 4B is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the first embodiment; FIG. FIG. 5 is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the first embodiment; 6A is a diagram showing an example of an image based on second image data according to the first embodiment; FIG. 6B is a diagram illustrating an example of an image based on first image data according to the first embodiment; FIG. 6C is a diagram illustrating an example of an image based on third image data according to the first embodiment; FIG. FIG. 7A is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the second embodiment; FIG. 7B is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the second embodiment; FIG. 8A is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the second embodiment; FIG. 8B is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the second embodiment; FIG. 9 is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the second embodiment. FIG. 10A is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the third embodiment; FIG. 10B is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the third embodiment; FIG. 11A is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the third embodiment; FIG. 11B is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the third embodiment; FIG. 12 is a diagram for explaining an example of processing executed by the photoacoustic diagnostic apparatus according to the third embodiment;

A photoultrasonic diagnostic apparatus according to an embodiment will be described below with reference to the drawings. In addition, the following embodiments are not limited to the following description. Further, the embodiments can be combined with other embodiments and conventional techniques as long as there is no contradiction in the processing content.

(First embodiment)
FIG. 1 is a block diagram showing a configuration example of a photoultrasonic diagnostic apparatus 1 according to the first embodiment. A photoacoustic imaging apparatus 1 shown in FIG. 1 is an apparatus for imaging a light absorber in a subject by photoacoustic imaging (PAI). As shown in FIG. 1, the photoacoustic diagnostic apparatus 1 according to the first embodiment has an apparatus main body 100, a light irradiation section 101, an ultrasonic probe 102, an input interface 103, and a display 104. The light irradiation unit 101, the ultrasound probe 102, the input interface 103, and the display 104 are communicably connected to the apparatus main body 100. FIG. Note that the subject P is not included in the configuration of the photoultrasonic diagnostic apparatus 1 .

The light irradiation unit 101 is configured by an optical system (light propagation member) such as an optical fiber and a lens. The light irradiation unit 101 irradiates the subject P with light (pulsed light) generated by a light source 110 which will be described later. For example, it is preferable that the light irradiation unit 101 irradiate pulsed light to a part of the subject P, such as a finger, an extremity, or a breast, which has little body movement. The irradiated pulsed light propagates and diffuses inside the subject P, and is absorbed by substances present in the subject P. FIG. Such a light-absorbing substance (light absorber) absorbs the energy of pulsed light of each wavelength and generates photoultrasonic waves. The light irradiation unit 101 is an example of an irradiation unit.

Examples of light absorbers include substances such as melanin and blood vessels (for example, capillaries) that are contained in living organisms. Each optical absorber absorbs the energy of pulsed light having a specific wavelength corresponding to the type of each optical absorber to generate photoultrasonic waves. The generated optical ultrasound propagates through the subject P and is received by a plurality of transducers included in the ultrasound probe 102, which will be described later. Note that the light absorber is not limited to the above substances, and any substance that can absorb the energy of the pulsed light can be applied. For example, not only in vivo substances, but also dyes such as methylene blue and indochine green, fine gold particles, and substances (or drugs) obtained by accumulating or chemically modifying them are also administered into the subject P. Therefore, it can be used as a light absorber.

The light irradiation unit 101 according to the first embodiment sequentially irradiates each position included in the PAI target area with converged pulsed light. The PAI target area may be a two-dimensional area (corresponding to a cross section within the subject P) or a three-dimensional area.

The ultrasonic probe 102 is a probe having a plurality of transducers (for example, piezoelectric transducers), a preamplifier, an A/D (Analog/Digital) converter, and the like. The plurality of transducers receive optical ultrasound waves generated within the subject P. FIG. The preamplifier amplifies the received optical ultrasound for each channel. The A/D converter A/D-converts the photoultrasonic wave, which is an amplified analog signal, and outputs a digital electric signal. The ultrasonic probe 102 transmits a digital electric signal output by the A/D converter as a detection signal to the receiving circuit 120, which will be described later.

The photoacoustic wave receiving surface of the ultrasound probe 102 may be a flat surface or a curved surface that conforms to the body surface of the subject P. FIG. As an example, the plurality of vibrators are linearly arranged on a plane at predetermined intervals. As another example, the plurality of vibrators are arranged in a two-dimensional array (lattice) or concentric circles. Alternatively, the ultrasonic wave receiving surface may be formed in a hemispherical shape, and a plurality of transducers may be arranged concentrically or spirally on this hemispherical curved surface. A hemispherical photoacoustic wave receiving surface is suitable for breast imaging. Alternatively, the ultrasonic wave receiving surface may be formed in a cylindrical or semi-cylindrical shape, and a plurality of transducers may be arranged on this surface. Cylindrical or semi-cylindrical photoacoustic receiving surfaces are suitable for extremity imaging. In order to improve resolution, the ultrasonic probe 102 according to the first embodiment preferably has a configuration capable of receiving high-frequency optical ultrasonic waves. The ultrasonic probe 102 is an example of a receiving unit that receives optical ultrasonic waves generated by a light absorber in the subject P due to light irradiation.

The input interface 103 is implemented by a mouse, keyboard, button, panel switch, touch command screen, foot switch, trackball, joystick, and the like. For example, the input interface 103 receives various setting requests from the operator of the photoultrasonic diagnostic apparatus 1 and transfers the received various setting requests to the apparatus main body 100 .

The display 104 displays a GUI (Graphical User Interface) for the operator of the photoultrasonic diagnostic apparatus 1 to input various setting requests using the input interface 103, and displays image data generated in the apparatus main body 100. Display images, etc. For example, the display 104 is realized by a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, a touch panel, or the like.

The device main body 100 is a device that generates image data based on photoacoustic waves received by the ultrasonic probe 102 . As shown in FIG. 1, the apparatus body 100 has a light source 110, a receiving circuit 120, a signal processing circuit 130, an image generating circuit 140, a memory circuit 150, and a processing circuit 160. The light source 110, the receiving circuit 120, the signal processing circuit 130, the image generating circuit 140, the storage circuit 150, and the processing circuit 160 are communicably connected to each other.

The light source 110 emits light (pulsed light). For example, the light source 110 is a laser light source that generates light with high power. Examples of laser light sources include solid-state lasers, gas lasers, dye lasers, and semiconductor lasers. As the light source 110, a light source capable of emitting light of an arbitrary wavelength can be appropriately used according to the type of light absorber to be PAI-targeted. In addition, the light source 110 can adjust the irradiation timing, pulse width, intensity, etc. of the light under the control of the processing circuit 160, which will be described later.

The light source 110 preferably has a strong output and can continuously change the wavelength, but may be composed of a plurality of single-wavelength lasers having different wavelengths. Moreover, the light source 110 is not limited to a laser light source, and may be configured by a light emitting diode, a flash lamp, or the like. Further, the light source 110 may be provided in a separate housing installed outside the apparatus main body 100 or may be provided inside the light irradiation section 101, for example. Light source 110 is an example of a light irradiation unit.

The reception circuit 120 has a reception delay unit, an adder, and the like, and performs various processes on the detection signal transmitted from the ultrasonic probe 102 to generate detection data (reception data). The reception delay section gives the detection signal a delay time necessary to determine the reception directivity. The adder adds the detection signals processed by the reception delay unit to generate detection data. In this specification, the detection data generated by the receiving circuit 120 is included in the detection signal. The receiving circuit 120 transmits the generated detection data to the signal processing circuit 130 . The receiving circuit 120 is an example of a generator.

The signal processing circuit 130 receives the detection data transmitted by the receiving circuit 120 and generates distribution data of characteristic values within the subject P using the received detection data. For example, the signal processing circuit 130 performs image reconstruction using time-series detection data for each channel, thereby corresponding to each position on the spatial coordinates of the PAI target area (two-dimensional or three-dimensional area). Obtain distribution data of characteristic values. As the image reconstruction method, a known reconstruction method can be used as appropriate.

The image generation circuit 140 generates image data from the distribution data generated by the signal processing circuit 130 . For example, from the distribution data generated by the signal processing circuit 130, the image generation circuit 140 generates image data representing the intensity of the photoultrasonic waves in luminance. The image generation circuit 140 generates two-dimensional image data when the PAI target area is a two-dimensional area, and generates three-dimensional image data when the PAI target area is a three-dimensional area. Note that the image generation circuit 140 is an example of an image generation unit.

The image generation circuit 140 can also perform various image processing on the generated image data. For example, the image generation circuit 140 executes various image processing such as smoothing processing and edge enhancement processing in response to requests from the operator. In addition, the image generation circuit 140 attaches supplementary information (character information of various parameters, scales, body marks, etc.) to the image data, and stores the supplementary information in the storage circuit 150 .

The storage circuit 150 stores control programs for performing PAI, various image processing, display processing, etc., diagnostic information (for example, patient ID, doctor's findings, etc.), diagnostic protocols, various data such as various body marks. do. The storage circuit 150 also stores the image data generated by the image generation circuit 140 together with the additional information. Data stored in the storage circuit 150 can be transferred to an external device via a communication interface (not shown). For example, the storage circuit 150 is implemented by a semiconductor memory device such as a RAM (Random Access Memory) or flash memory, a hard disk, an optical disk, or the like.

The processing circuit 160 controls the entire processing of the photoultrasonic diagnostic apparatus 1 . The processing circuit 160 has a control function 161 and an output control function 162, as shown in FIG. Here, the control function 161 is an example of a control unit. Also, the output control function 162 is an example of a display control unit.

Here, for example, each processing function of the control function 161 and the output control function 162, which are components of the processing circuit 160 shown in FIG. For example, it is recorded in the storage circuit 150). The processing circuit 160 is a processor that reads each program from a storage device and executes each read program to realize each function corresponding to each program. In other words, the processing circuit 160 with each program read has each function shown in the processing circuit 160 of FIG.

For example, the control function 161 controls the light source 110, the receiving circuit 120, and the signal processing circuit based on various setting requests input by the operator via the input interface 103 and various control programs and various data read from the storage circuit 150. 130 and image generation circuit 140 processing. In addition, the output control function 162 reads the image data stored in the storage circuit 150 and causes the display 104 to display an image based on the read image data.

An example of the configuration of the photoultrasonic diagnostic apparatus 1 according to the first embodiment has been described above. With such a configuration, the photoacoustic diagnostic apparatus 1 according to the first embodiment executes various processes described below in order to obtain accurate data on the light absorber located in the deep part.

Processing in the photoultrasonic diagnostic apparatus 1 according to the first embodiment will be specifically described with reference to FIG. FIG. 2 is a flow chart showing an example of the flow of processing executed by the photoultrasonic diagnostic apparatus 1 according to the first embodiment. 3A to 5 are diagrams for explaining an example of processing executed by the photoacoustic diagnostic apparatus 1 according to the first embodiment.

For example, the processing shown in FIG. 2 is performed in order for a user such as a doctor to evaluate the second light absorber 13 positioned deeper than the first light absorber 12 shown in FIG. First, it is executed when the photoacoustic diagnostic apparatus 1 generates image data in which the second light absorber 13 is visualized. The first light absorber 12 is, for example, melanin. Melanin is located in the epithelium of the subject P's dermis 14 . Also, the second light absorber 13 is, for example, a blood vessel, more specifically a capillary. Such blood vessels are located in the subject P's dermis 14 .

(Step S101)
As shown in FIGS. 2, 3A, and 3B, in step S101, the photoacoustic diagnostic apparatus 1 acquires first detection data 18 of the light absorber group 11 by irradiation with the first light 15. FIG. The processing in step S101 will be described with a specific example. For example, the control function 161 transmits light from the first light absorber 12 to the light absorber group 11 including the first light absorber 12 and the second light absorber 13 from the dermis 14 side of the subject P. The light source 110 is controlled so as to irradiate the first light 15 that lowers the absorptance. Accordingly, the light source 110 and the light irradiation unit 101 irradiate the light absorber group 11 with the first light 15 from the dermis 14 side, as shown in FIG. 3A. The first light 15 is light including pulsed light 16, for example.

Here, it is known that the light absorption rate of the light absorber temporarily decreases by irradiating the light absorber with pulsed light to induce light saturation. Therefore, in the present embodiment, the light source 110 and the light irradiation unit 101 irradiate the first light absorber 12 with the first light 15 including the pulsed light 16 to induce light saturation. Temporarily lowers the light absorption rate of the body 12.

Then, the ultrasonic probe 102 receives the first optical ultrasonic waves 17 generated in the light absorber group 11 by the irradiation of the first light 15, and the detection signal based on the first optical ultrasonic waves 17 is received by the receiving circuit 120. Send to Then, the receiving circuit 120 receives the detection signal based on the first photoultrasonic wave 17 transmitted from the ultrasonic probe 102, and generates the first detection data 18 (see FIG. 3B) based on the received detection signal. do. That is, the first detection data 18 is data based on the first photoultrasonic waves 17 . Thus, the receiving circuit 120 generates the first detection data 18 as the first data.

The first detection data 18 shown in FIG. 3B indicates a time waveform. For example, in FIG. 3B, the horizontal axis indicates the time after the first light 15 is emitted from the light irradiation unit 101, and the vertical axis indicates the intensity (signal intensity) of the first detection data 18. FIG. The waveform 18a in the first detection data 18 is based on the optical ultrasound generated by the first optical absorber 12, and the waveform 18b is based on the optical ultrasound generated by the second optical absorber 13. It is based on As shown in FIG. 3B, the signal intensity represented by waveform 18a is optically saturated.

(Step S102)
Then, in step S<b>102 , the receiving circuit 120 records the first detection data 18 by storing the first detection data 18 in the storage circuit 150 .

(Step S103)
Then, as shown in FIGS. 2, 4A, and 4B, in step S103, the photoultrasonic diagnostic apparatus 1 acquires second detection data 28 of the light absorber group 11 by irradiation with the second light. The processing in step S103 will be described with a specific example. For example, the control function 161 controls the dermis of the subject P while the light absorptance of the first light absorber 12 is being reduced (while the light absorptance of the first light absorber 12 is being reduced). The light source 110 is controlled so as to irradiate the light absorber group 11 with the second light from the 14 side. Accordingly, the light source 110 and the light irradiation unit 101 irradiate the light absorber group 11 with the second light from the dermis 14 side, as shown in FIG. 4A. Here, the second light is light including light 20 and light 21 . Light 20 is light containing first pulsed light 22 , and light 21 is light containing second pulsed light 23 .

The first pulsed light 22 is pulsed light having the same frequency as the frequency of the first light 15 (pulsed light 16). The second pulsed light 23 is pulsed light irradiated after the first pulsed light 22 .

The ultrasonic probe 102 receives the optical ultrasonic waves 24 generated in the light absorber group 11 by the irradiation of the first pulsed light 22 and transmits a detection signal based on the optical ultrasonic waves 24 to the receiving circuit 120 . The receiving circuit 120 receives a detection signal based on the optical ultrasound 24 transmitted from the ultrasonic probe 102 and generates detection data 26 (see FIG. 4B) based on the received detection signal. That is, the detection data 26 is data based on the photoultrasonic waves 24 .

The detection data 26 shown in FIG. 4B indicates a time waveform. For example, in FIG. 4B, the horizontal axis indicates the time after the first pulsed light 22 is emitted from the light irradiation section 101, and the vertical axis indicates the signal intensity of the detection data 26. As shown in FIG. The waveform 26a in the detection data 26 is based on the optical ultrasonic waves generated by the first optical absorber 12, and the waveform 26b is based on the optical ultrasonic waves generated by the second optical absorber 13. be. As shown in FIG. 4B, the signal intensity represented by waveform 26a is optically saturated.

The ultrasonic probe 102 receives the optical ultrasonic waves 25 generated by the optical absorber group 11 by the irradiation of the second pulsed light 23 and transmits a detection signal based on the optical ultrasonic waves 25 to the receiving circuit 120 . The receiving circuit 120 receives a detection signal based on the optical ultrasound 25 transmitted from the ultrasonic probe 102 and generates detection data 27 (see FIG. 4B) based on the received detection signal. That is, the detection data 27 is data based on the photoultrasonic waves 25 .

The detection data 27 shown in FIG. 4B indicates a time waveform. For example, in FIG. 4B, the horizontal axis indicates the time after the second pulsed light 23 is emitted from the light irradiation section 101, and the vertical axis indicates the signal intensity of the detection data 27. As shown in FIG. A waveform 27a in the detection data 27 is based on the optical ultrasonic waves generated by the first optical absorber 12, and a waveform 27b is based on the optical ultrasonic waves generated by the second optical absorber 13. be.

Comparing the detection data 26 and the detection data 27 , the detection data 27 has a higher signal intensity based on the photoultrasonic wave generated by the second light absorber 13 .

Then, the receiving circuit 120 generates the second detection data 28 by synthesizing the detection data 26 and the detection data 27, as shown in FIG. 4B. The receiving circuit 120 synthesizes the detection data 26 and the detection data 27 by combining the time indicated by the horizontal axis of the detection data 26 and the time indicated by the horizontal axis of the detection data 27 . Here, as described above, the time indicated by the horizontal axis in the detection data 26 is the time after the first pulsed light 22 is emitted from the light irradiation section 101 . The time indicated by the horizontal axis in the detection data 27 is the time after the second pulsed light 23 is emitted from the light irradiation section 101 . The receiving circuit 120 generates the second detection data 28 as the second data by the method as described above.

The second detection data 28 shown in FIG. 4B indicates a time waveform. For example, in FIG. 4B, the horizontal axis indicates the time after the first pulsed light 22 and the second pulsed light 23 are emitted from the light irradiation unit 101, and the vertical axis indicates the signal of the second detection data 28. Show strength. The waveform 28a in the second detection data 28 is based on the optical ultrasonic waves generated by the first optical absorber 12, and the waveform 28b is based on the optical ultrasonic waves generated by the second optical absorber 13. It is based on

As described above, in step S103, the ultrasonic probe 102 receives the second optical ultrasonic waves generated in the light absorber group 11 by irradiation with the second light. The second optical ultrasound referred to here is optical ultrasound including the optical ultrasound 24 and the optical ultrasound 25 . The receiving circuit 120 then generates second detection data 28 based on the second optical ultrasound.

(Step S104)
Then, in step S<b>104 , the receiving circuit 120 records the second detection data 28 by storing the second detection data 28 in the storage circuit 150 .

(Step S105)
Then, in step S105, the receiving circuit 120 obtains the third detection data 29 shown in FIG. 5 by taking the difference between the first detection data 18 and the second detection data 28. FIG. The processing in step S105 will be described with a specific example. For example, receiver circuit 120 generates third sensed data 29 by subtracting first sensed data 18 from second sensed data 28 . The third detection data 29 indicates a time waveform.

Note that the receiving circuit 120 combines the time indicated by the horizontal axis of the second detection data 28 with the time indicated by the horizontal axis of the first detection data 18 to convert the second detection data 28 to the first detection data. Subtract 18. Here, the time indicated by the horizontal axis in the first detection data 18 is the time after the first light 15 (pulsed light 16) is emitted from the light irradiation section 101, and the horizontal axis in the second detection data 28 is the time. The time indicated by the axis is the time after the first pulsed light 22 and the second pulsed light 23 are emitted from the light irradiation section 101 .

Since the first detection data 18 is subtracted from the second detection data 28, the third detection data 29, as shown in FIG. The signal strength exhibited by waveform 29a is relatively small. On the other hand, the signal intensity indicated by the waveform 29b based on the photoultrasonic waves generated by the second optical absorber 13 is relatively large. In the first embodiment, the light absorber group 11 is irradiated with the second pulsed light 23 while the light absorbance of the first light absorber 12 is temporarily lowered. Therefore, the second pulsed light 23 can be irradiated onto the second light absorber 13 which is a desired target without being absorbed by the first light absorber 12 . Therefore, it is possible to obtain image data and detection data in which the second light absorber 13 positioned directly below the first light absorber 12 is clearly rendered with the influence of the first light absorber 12 suppressed. . Therefore, according to the photoacoustic diagnostic apparatus 1 according to the first embodiment, it is possible to obtain the third detection data 29 with high accuracy regarding the second light absorber 13 located in the deep part. The receiving circuit 120 generates the third detection data 29 as the third data by the method described above.

(Step S106)
Then, in step S106, the receiving circuit 120 records the third detection data 29 by storing the third detection data 29 in the storage circuit 150, and ends the processing shown in FIG.

After the processing shown in FIG. 2 is completed, the signal processing circuit 130 and the image generation circuit 140 generate image data (hereinafter referred to as third image data) from the third detection data 29 . That is, the signal processing circuit 130 and the image generation circuit 140 generate third image data based on the third detection data 29 . Then, the output control function 162 causes the display 104 to display an image based on the third image data.

Also, the signal processing circuit 130 and the image generation circuit 140 may generate image data (hereinafter referred to as first image data) from the first detection data 18 . That is, the signal processing circuit 130 and the image generation circuit 140 may generate first image data based on the first detection data 18 . Similarly, the signal processing circuit 130 and the image generation circuit 140 may generate image data based on the second detection data 28 (hereinafter referred to as second image data). Then, the output control function 162 may cause the display 104 to display at least one of the image based on the first image data and the image based on the second image data, and the image based on the third image data. . At this time, the output control function 162 displays at least one of the image based on the first image data and the image based on the second image data in a different display manner from the image based on the third image data. may be controlled.

An example of display control of various images will be described with reference to FIGS. 6A to 6C. 6A is a diagram showing an example of an image based on second image data according to the first embodiment; FIG. 6B is a diagram illustrating an example of an image based on first image data according to the first embodiment; FIG. 6C is a diagram illustrating an example of an image based on third image data according to the first embodiment; FIG. In the three images shown in FIGS. 6A-6C, the reference numeral “30” refers to the image showing the first light absorber 12 and the reference numeral “30” refers to the image showing the first light absorber 12. FIG. Moreover, the code|symbol "31" indicates the artifact resulting from the multiple reflection of an optical ultrasonic wave. Also, reference numeral “32” indicates an image showing the second light absorber 13 .

For example, the output control function 162 causes the display 104 to display an image based on the third image data shown in FIG. 6C among the three images shown in FIGS. 6A to 6C. In addition, the output control function 162 outputs at least one of the image based on the first image data shown in FIG. 6B and the image based on the second image data shown in FIG. 6A and the third image data shown in FIG. 6C. The image based on the image may be displayed on the display 104 . At this time, the output control function 162 displays at least one of the image based on the first image data and the image based on the second image data in a different display manner from the image based on the third image data. may be controlled. For example, the output control function 162 performs display control so that the image based on the third image data is emphasized more than at least one image based on the first image data and the image based on the second image data. You may Specifically, for example, the output control function 162 may perform display control so that the edge color of the image based on the third image data is a specific color (eg, red).

The photoultrasonic diagnostic apparatus 1 according to the first embodiment has been described above. According to the photoacoustic diagnostic apparatus 1 according to the first embodiment, as described above, it is possible to obtain the third detection data 29 with high accuracy regarding the second light absorber 13 located in the deep part.

Note that in the first embodiment, the receiving circuit 120 generates the first detection data 18 as the first data, the second detection data 28 as the second data, and the second detection data 28 as the third data. 3 detection data 29 is generated. However, the image generation circuit 140 may generate the first image data described above as the first data and the second image data described above as the second data. In this case, the image generation circuit 140 may generate the third image data as the third data by taking the difference between the first image data and the second image data. For example, the image generation circuit 140 may generate third image data by subtracting the first image data from the second image data.

(Second embodiment)
In the first embodiment, the case where the photoacoustic diagnostic apparatus 1 irradiates the light absorber group 11 with light including the light 20 and the light 21 as the second light has been described. However, the photoacoustic diagnostic apparatus 1 may irradiate the light absorber group 11 with other light as the second light. Accordingly, the photoacoustic diagnostic apparatus 1 irradiates the light absorber group 11 with another light as the second light will be described as a second embodiment and a third embodiment. First, the second embodiment will be described. It should be noted that in the description of the second embodiment, differences from the first embodiment will be mainly described, and descriptions of configurations similar to those of the first embodiment may be omitted.

7A to 9 are diagrams for explaining an example of processing executed by the photoacoustic diagnostic apparatus 1 according to the second embodiment. As shown in FIGS. 7A and 7B, the photoacoustic diagnostic apparatus 1 according to the second embodiment, similarly to the first embodiment, emits the first light 15 to the first light absorber group 11 . is acquired.

Then, as shown in FIGS. 8A and 8B, the photoultrasonic diagnostic apparatus 1 obtains second detection data 43 of the light absorber group 11 by irradiation with the second light 40 . The process of acquiring the second detection data 43 will be described with a specific example. For example, the control function 161 irradiates the light absorber group 11 with the second light 40 from the dermis 14 side of the subject P while the light absorbance of the first light absorber 12 is reduced. The light source 110 is controlled so as to Thereby, the light source 110 and the light irradiation unit 101 irradiate the light absorber group 11 with the second light 40 from the dermis 14 side. Here, the second light 40 is light including pulsed light 41 .

The pulsed light 41 is pulsed light having the same frequency as that of the first light 15 (pulsed light 16 ) and having a light intensity higher than that of the first light 15 .

Then, the ultrasonic probe 102 receives the optical ultrasonic waves 42 generated in the light absorber group 11 by the irradiation of the second light 40 (pulsed light 41), and transmits a detection signal based on the optical ultrasonic waves 42 to the receiving circuit 120. Send. The receiving circuit 120 receives a detection signal based on the optical ultrasound 42 transmitted from the ultrasonic probe 102 and generates second detection data 43 (see FIG. 8B) based on the received detection signal. That is, the second detection data 43 is data based on the photoultrasonic wave 42 . The receiving circuit 120 generates the second detection data 43 as the second data by the method as described above.

The second detection data 43 shown in FIG. 8B indicates a time waveform. For example, in FIG. 8B, the horizontal axis indicates the time after the pulsed light 41 is emitted from the light irradiation section 101, and the vertical axis indicates the signal intensity of the second detection data 43. As shown in FIG. A waveform 43a in the second detection data 43 is based on the optical ultrasonic waves generated by the first optical absorber 12, and a waveform 43b is based on the optical ultrasonic waves generated by the second optical absorber 13. It is based on As shown in FIG. 8B, the signal intensity represented by waveform 43a is optically saturated.

When the first detection data 18 and the second detection data 43 are compared, both the signal intensity indicated by the waveform 18a and the signal intensity indicated by the waveform 43a are optically saturated.

As described above, in the second embodiment, the ultrasonic probe 102 receives the second optical ultrasonic waves 42 generated in the light absorber group 11 by irradiation with the second light 40 . The receiving circuit 120 then generates second detection data 43 based on the second photoultrasonic wave 42 .

Then, the receiving circuit 120 records the second detection data 43 by storing the second detection data 43 in the storage circuit 150 .

The receiving circuit 120 obtains the third detection data 44 shown in FIG. 9 by taking the difference between the first detection data 18 and the second detection data 43 . The process of acquiring the third detection data 44 will be described with a specific example. For example, receiver circuit 120 generates third sensed data 44 by subtracting first sensed data 18 from second sensed data 43 . The third detection data 44 indicates a time waveform.

Note that the reception circuit 120 combines the time indicated by the horizontal axis of the second detection data 43 with the time indicated by the horizontal axis of the first detection data 18 to convert the second detection data 43 to the first detection data. Subtract 18. Here, the time indicated by the horizontal axis in the second detection data 43 is the time after the pulsed light 41 is emitted from the light irradiation section 101 .

Since the first detection data 18 is subtracted from the second detection data 43, the third detection data 44, as shown in FIG. The signal strength exhibited by the waveform is zero or nearly zero. On the other hand, the signal intensity indicated by the waveform 44a based on the photoultrasonic waves generated by the second optical absorber 13 is relatively large. In the second embodiment, the light absorber group 11 is irradiated with the second light 40 (pulsed light 41) while the light absorbance of the first light absorber 12 is temporarily lowered. Therefore, the second light 40 can be irradiated onto the second light absorber 13 which is a desired target without being absorbed by the first light absorber 12 . Therefore, it is possible to obtain image data and detection data in which the second light absorber 13 positioned directly below the first light absorber 12 is clearly rendered with the influence of the first light absorber 12 suppressed. . Therefore, according to the photoacoustic diagnostic apparatus 1 according to the second embodiment, similarly to the first embodiment, the accurate third detection data 44 regarding the second light absorber 13 located in the deep part can be obtained. Obtainable. The receiving circuit 120 generates the third detection data 44 as the third data by the method as described above.

Then, the receiving circuit 120 records the third detection data 44 by storing the third detection data 44 in the storage circuit 150 .

The photoultrasonic diagnostic apparatus 1 according to the second embodiment has been described above. According to the photoacoustic diagnostic apparatus 1 according to the second embodiment, as described above, it is possible to obtain the third detection data 44 with high precision regarding the second light absorber 13 located in the deep part.

In the second embodiment, the image generating circuit 140 generates first image data as first data and second image data as second data by the same method as in the first embodiment. may be generated. In this case, the image generation circuit 140 may generate the third image data as the third data by taking the difference between the first image data and the second image data. For example, the image generation circuit 140 may generate third image data by subtracting the first image data from the second image data.

(Third embodiment)
Next, a third embodiment will be described. In the description of the third embodiment, differences from the first embodiment will be mainly described, and the description of the same configuration as the first embodiment may be omitted.

10A to 12 are diagrams for explaining an example of processing executed by the photoultrasonic diagnostic apparatus 1 according to the third embodiment. As shown in FIGS. 10A and 10B, the photoultrasonic diagnostic apparatus 1 according to the third embodiment absorbs light by irradiation with the first light 15, as in the first embodiment and the second embodiment. First detection data 18 of the body group 11 are obtained. However, the first light 15 (pulsed light 16) is light having a first wavelength that the first light absorber 12 specifically absorbs.

Then, as shown in FIGS. 11A and 11B, the photoultrasonic diagnostic apparatus 1 obtains second detection data 58 of the light absorber group 11 by irradiation with the second light. The process of acquiring the second detection data 58 will be described with a specific example. For example, the control function 161 irradiates the light absorber group 11 from the dermis 14 side of the subject P with the second light while the light absorbance of the first light absorber 12 is reduced. to control the light source 110 . Accordingly, the light source 110 and the light irradiation unit 101 irradiate the light absorber group 11 with the second light from the dermis 14 side, as shown in FIG. 11A. Here, the second light is light including light 50 and light 51 . Light 50 is light containing first pulsed light 52 , and light 51 is light containing second pulsed light 53 .

The first pulsed light 52 is pulsed light having the same wavelength as the first wavelength described above. The second pulsed light 53 is pulsed light irradiated after the first pulsed light 52 . The second pulsed light 53 is light (pulsed light) having a second wavelength specifically absorbed by the second light absorber 13 .

The ultrasonic probe 102 receives the optical ultrasonic waves 54 generated in the light absorber group 11 by the irradiation of the first pulsed light 52 and transmits detection signals based on the optical ultrasonic waves 54 to the receiving circuit 120 . The receiving circuit 120 receives a detection signal based on the optical ultrasound 54 transmitted from the ultrasonic probe 102 and generates detection data 56 (see FIG. 11B) based on the received detection signal. That is, the detection data 56 is data based on the photoultrasonic waves 54 .

The detection data 56 shown in FIG. 11B shows a time waveform. For example, in FIG. 11B, the horizontal axis indicates the time after the first pulsed light 52 is emitted from the light irradiation section 101, and the vertical axis indicates the signal intensity of the detection data 56. As shown in FIG. A waveform 56a in the detection data 56 is based on the optical ultrasonic waves generated by the first optical absorber 12, and a waveform 56b is based on the optical ultrasonic waves generated by the second optical absorber 13. be. As shown in FIG. 11B, the signal intensity represented by waveform 56a is optically saturated.

The ultrasonic probe 102 receives the optical ultrasonic waves 55 generated in the light absorber group 11 by the irradiation of the second pulsed light 53 and transmits a detection signal based on the optical ultrasonic waves 55 to the receiving circuit 120 . The receiving circuit 120 receives a detection signal based on the optical ultrasound 55 transmitted from the ultrasonic probe 102 and generates detection data 57 (see FIG. 11B) based on the received detection signal. That is, the detection data 57 is data based on the photoultrasonic waves 55 .

Detected data 57 shown in FIG. 11B indicates a time waveform. For example, in FIG. 11B, the horizontal axis indicates the time after the second pulsed light 53 is emitted from the light irradiation section 101, and the vertical axis indicates the signal intensity of the detection data 57. FIG. A waveform 57a in the detection data 57 is based on the optical ultrasonic waves generated by the first optical absorber 12, and a waveform 57b is based on the optical ultrasonic waves generated by the second optical absorber 13. be.

Comparing the detection data 56 and the detection data 57 , the detection data 57 has a higher signal intensity based on the photoultrasonic wave generated by the second light absorber 13 .

Then, the receiving circuit 120 generates the second detection data 58 by synthesizing the detection data 56 and the detection data 57, as shown in FIG. 11B. The receiving circuit 120 synthesizes the detection data 56 and the detection data 57 by combining the time indicated by the horizontal axis of the detection data 56 and the time indicated by the horizontal axis of the detection data 57 . Here, as described above, the time indicated by the horizontal axis in the detection data 56 is the time after the first pulsed light 52 is emitted from the light irradiation section 101 . The time indicated by the horizontal axis in the detection data 57 is the time after the second pulsed light 53 is emitted from the light irradiation section 101 . The receiving circuit 120 generates the second detection data 58 as the second data by the method as described above.

The detection data 58 shown in FIG. 11B shows a time waveform. For example, in FIG. 11B, the horizontal axis indicates the time after the first pulsed light 52 and the second pulsed light 53 are emitted from the light irradiation unit 101, and the vertical axis indicates the signal intensity of the detection data 58. . The waveform 58a in the detection data 58 is based on the optical ultrasound generated by the first optical absorber 12, and the waveform 58b is based on the optical ultrasound generated by the second optical absorber 13. be.

As described above, the ultrasonic probe 102 receives the second optical ultrasonic waves generated in the light absorber group 11 by irradiation with the second light. The second optical ultrasonic waves referred to here are optical ultrasonic waves including the optical ultrasonic waves 54 and the optical ultrasonic waves 55 . The receiving circuit 120 then generates second detection data 58 based on the second optical ultrasound.

Then, the receiving circuit 120 records the second detection data 58 by storing the second detection data 58 in the storage circuit 150 .

The receiving circuit 120 obtains the third detection data 59 shown in FIG. 12 by taking the difference between the first detection data 18 and the second detection data 58 . A specific example of the process of acquiring the third detection data 59 will be described. For example, receiver circuit 120 generates third sensed data 59 by subtracting first sensed data 18 from second sensed data 58 . The third detection data 59 indicates a time waveform.

Note that the receiving circuit 120 combines the time indicated by the horizontal axis of the second detection data 58 with the time indicated by the horizontal axis of the first detection data 18 to convert the second detection data 58 to the first detection data. Subtract 18. Here, as described above, the time indicated by the horizontal axis in the second detection data 28 is the time after the first pulsed light 52 and the second pulsed light 53 are emitted from the light irradiation section 101 .

Since the first detection data 18 is subtracted from the second detection data 58, the third detection data 59, as shown in FIG. The signal strength exhibited by waveform 59a is relatively small. On the other hand, the signal intensity indicated by the waveform 59b based on the photoultrasonic waves generated by the second optical absorber 13 is relatively large. In the third embodiment, the light absorber group 11 is irradiated with the second pulsed light 53 while the light absorbance of the first light absorber 12 is temporarily lowered. Therefore, the second pulsed light 53 can be irradiated onto the second light absorber 13 as a desired target without being absorbed by the first light absorber 12 . Therefore, it is possible to obtain image data and detection data in which the second light absorber 13 positioned directly below the first light absorber 12 is clearly rendered with the influence of the first light absorber 12 suppressed. . Therefore, according to the photoacoustic diagnostic apparatus 1 according to the third embodiment, it is possible to obtain the third detection data 59 with high accuracy regarding the second light absorber 13 located in the deep part. The receiving circuit 120 generates the third detection data 59 as the third data by the method as described above.

Then, the receiving circuit 120 records the third detection data 59 by storing the third detection data 59 in the storage circuit 150 .

The photoultrasonic diagnostic apparatus 1 according to the third embodiment has been described above. According to the photoacoustic diagnostic apparatus 1 according to the third embodiment, as described above, it is possible to obtain the third detection data 59 with high accuracy regarding the second light absorber 13 located in the deep part.

Note that in the third embodiment, the image generation circuit 140 generates first image data as first data by the same method as in the first and second embodiments, and generates second data. You may generate|occur|produce the 2nd image data as. In this case, the image generation circuit 140 may generate the third image data as the third data by taking the difference between the first image data and the second image data. For example, the image generation circuit 140 may generate third image data by subtracting the first image data from the second image data.

(Other embodiments)
Various different forms may be implemented in addition to the embodiments described above. For example, in the above-described embodiment, the control function 161 performs the first The light source 110 may be controlled to irradiate the light absorber group 11 with the second light in a state where the light absorbance of the light absorber 12 is lowered. In this case, the photoacoustic diagnostic apparatus 1 may perform processing after irradiating the second light, as described above. On the other hand, the control function 161 may control the light source 110 so as not to irradiate the light absorber group 11 with the second light when the signal intensity is less than the threshold. In this case, the photoacoustic diagnostic apparatus 1 does not perform the above-described processing after irradiating the second light.

In the above-described embodiment, the state in which the light absorption rate of the first light absorber 12 is reduced may be a state of complete light saturation, or a state in which light absorption is reduced to a desired level. It may be in a state where When the irradiation of the first light 15 is to induce a completely saturated state of light, the following procedure is performed in advance before the irradiation of the first light 15 so that the storage circuit 150 of the photoultrasonic diagnostic apparatus 1 is completely stored. The irradiation intensity of the first light 15 for inducing a more saturated state of light may be stored.

For example, the photoacoustic diagnostic apparatus 1 acquires photoacoustic signals while changing the light irradiation intensity so that the light irradiation intensity gradually increases. At this time, the photoacoustic diagnostic apparatus 1 plots the measurement results with the irradiation intensity of light on the horizontal axis and the detection intensity of the photoacoustic wave on the vertical axis. The photoacoustic diagnostic apparatus 1 stops light irradiation when the change in the detected intensity of the photoacoustic wave falls below a certain threshold value, the light absorption of the light absorber is saturated, and the irradiation intensity of the light at that time is stored in the storage circuit 150 . Then, the photoacoustic diagnostic apparatus 1 reads the irradiation intensity stored in the storage circuit 150 and irradiates the light absorber group 11 with the first light 15 having the read irradiation intensity.

In the above-described embodiment, each processing function is realized by a single processing circuit 160, but a processing circuit is configured by combining a plurality of independent processors, and each processor executes a program. The function may be realized by executing it.

The term "processor" used in the above description is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an application specific integrated circuit (ASIC), a programmable logic device (e.g., Circuits such as Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)). The processor implements its functions by reading and executing programs stored in the storage circuit 150 . Note that instead of storing the program in the memory circuit 150, the program may be configured to be directly installed in the circuit of the processor. In this case, the processor implements its functions by reading and executing the program embedded in the circuit. Note that each processor of the present embodiment is not limited to being configured as a single circuit for each processor, and may be configured as one processor by combining a plurality of independent circuits to realize its function. good.

Also, each component of each device illustrated is functionally conceptual, and does not necessarily need to be physically configured as illustrated. In other words, the specific form of distribution and integration of each device is not limited to the illustrated one, and all or part of them can be functionally or physically distributed and integrated in arbitrary units according to various loads and usage conditions. Can be integrated and configured. Furthermore, each processing function performed by each device may be implemented in whole or in part by a CPU and a program analyzed and executed by the CPU, or implemented as hardware based on wired logic.

Further, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or the processes described as being performed manually can be performed manually. can also be performed automatically by known methods. In addition, information including processing procedures, control procedures, specific names, and various data and parameters shown in the above documents and drawings can be arbitrarily changed unless otherwise specified.

In addition, the technique described in this specification can also be applied to non-destructive inspection using laser-excited ultrasonic waves in the industrial field. For example, in a non-destructive inspection using laser-excited ultrasonic waves, when evaluating fiber reinforced plastic (FRP), light saturation is induced by first irradiation on the FRP surface coating part, and then second irradiation is performed. , the light may be irradiated to a deeper portion than the coated portion.

According to at least one of the embodiments described above, it is possible to obtain highly accurate data on the light absorber positioned deep.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

1 Optical Ultrasound Diagnostic Apparatus 101 Light Irradiation Unit 102 Ultrasound Probe 110 Light Source 120 Receiving Circuit 140 Image Generation Circuit 160 Processing Circuit 161 Control Function 162 Output Control Function

Claims (9)

an irradiation unit that irradiates a light absorber group including a first light absorber and a second light absorber positioned deeper than the first light absorber with light;
controlling the irradiating unit so as to irradiate the group of light absorbers with first light that reduces the light absorption rate of the first light absorber, and reducing the light absorption rate of the first light absorber; a control unit that controls the irradiation unit to irradiate the light absorber group with the second light in the state of
Receiving first optical ultrasound waves generated in the light absorber group by irradiation with the first light and second light ultrasound waves generated in the light absorber group by irradiation with the second light a receiver;
a generation unit that generates third data by taking a difference between first data based on the first optical ultrasound and second data based on the second optical ultrasound;
An optical ultrasound diagnostic device comprising: The control unit controls the second light including first pulsed light having the same frequency as the frequency of the first light and second pulsed light irradiated after the first pulsed light. The irradiation unit is controlled to irradiate the light absorber group in a state where the light absorption rate of the first light absorber is reduced,
The photoultrasonic diagnostic apparatus according to claim 1. The control unit controls the second light including pulsed light having the same frequency as that of the first light and having a light intensity higher than that of the first light. controlling the irradiation unit to irradiate the light absorber group in a state where the light absorbance of the light absorber of 1 is reduced;
The photoultrasonic diagnostic apparatus according to claim 1. The control unit controls the irradiation unit to irradiate the group of light absorbers with the first light having a first wavelength that is absorbed by the first light absorber, and a second pulsed light that is irradiated after the first pulsed light and has a second wavelength that the second light absorber absorbs light controlling the irradiation unit to irradiate the light absorber group with the second light including the pulsed light of 2 in a state where the light absorption rate of the first light absorber is reduced;
The photoultrasonic diagnostic apparatus according to claim 1. The generating unit generates data based on the photoacoustic waves generated in the light absorber group by the irradiation of the first pulsed light and the photoultrasonic waves generated in the light absorber group by the irradiation of the second pulsed light. generating the second data by combining data based on
The photoultrasonic diagnostic apparatus according to claim 2 or 4. The generation unit generates a detection signal indicating a time waveform or image data as the third data,
The photoultrasonic diagnostic apparatus according to any one of claims 1 to 5. When the intensity of the detection signal based on the first photoultrasonic wave is equal to or higher than a threshold, the control unit emits the second light in a state where the light absorption rate of the first light absorber is reduced. controlling the irradiation unit to irradiate the light absorber group, and controlling the irradiation unit not to irradiate the light absorber group with the second light when the intensity is less than the threshold value; ,
The photoultrasonic diagnostic apparatus according to any one of claims 1 to 6. Further comprising a display control unit that causes a display unit to display an image based on the third data,
The photoultrasonic diagnostic apparatus according to any one of claims 1 to 7. The display control unit further controls at least one of the image based on the first data and the image based on the second data in a display mode of the at least one image and the image based on the third data. are displayed on the display unit so that
The photoultrasonic diagnostic apparatus according to claim 8.

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