JP2014161428A - Photoacoustic measuring apparatus and photoacoustic measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more precisely recognize a positional relationship between a specific light absorber of interest and a scan plane in photoacoustic measurement.SOLUTION: A photoacoustic measuring apparatus 10, which measures a signal of a photoacoustic wave generated within a subject M, comprises: determination means (shift detection means 33) for determining a magnitude relation between the intensity of a photoacoustic signal from a blood vessel of interest in the subject M, which is caused to be generated by measuring light emitted from a light emission part (light guide plate 44) on one side of both sides of an ultrasonic vibrator 20 where a plurality of light emission parts (light guide plates 44) are disposed, and the intensity of a photoacoustic signal from the blood vessel of interest in the subject M, which is caused to be generated by measuring light emitted from a light emission part (light guide plate 44) on the other side of both sides of the ultrasonic vibrator 20; and notification means (display control means 36 and notification sound producing means) for notifying a result obtained by the determination means of a user.

Description

  The present invention relates to a photoacoustic measurement apparatus and a photoacoustic measurement method for measuring in a subject based on a photoacoustic signal generated in the subject.

  Conventionally, as a method for acquiring a tomographic image inside a subject, an ultrasonic image is generated by detecting ultrasonic waves reflected in the subject by irradiating the subject with ultrasonic waves. Ultrasonic imaging for obtaining a morphological tomographic image is known. On the other hand, in the examination of a subject, development of an apparatus that displays not only a morphological tomographic image but also a functional tomographic image has been advanced in recent years. One of such devices is a device using a photoacoustic analysis method. This photoacoustic analysis method irradiates a subject with pulsed light having a predetermined wavelength (for example, wavelength band of visible light, near-infrared light, or mid-infrared light), and a specific substance in the subject is irradiated with the pulsed light. The photoacoustic wave, which is an elastic wave generated as a result of absorption of the energy, is detected, and the concentration of the specific substance is quantitatively measured. The specific substance in the subject is, for example, glucose or hemoglobin contained in blood. Such a technique for detecting a photoacoustic wave and generating a photoacoustic image based on the detection signal is called photoacoustic imaging (PAI) or photoacoustic tomography (PAT).

  Currently, in such photoacoustic measurement, a probe (probe) having a transducer array including a plurality of acoustic detection elements (for example, ultrasonic transducers) and a light irradiation unit such as an optical fiber is often used ( For example, Patent Document 1).

JP 2010-12295 A

  However, the conventional measurement method such as Patent Document 1 may cause a problem that the specific tissue of interest represented in the photoacoustic image acquired for the specific scan plane does not necessarily exist on the scan plane. This is because the transducer array has a width in a direction (elevation direction) perpendicular to the array direction of the transducer array (direction in which a plurality of ultrasonic transducers are arranged) and parallel to the detection surface. This is because an error is included in the source position of the photoacoustic wave.

  Such a problem is not only when checking the tissue structure of the subject originally present in the subject, but also when checking the position of the light absorber inserted in the subject like a puncture needle. Can cause similar problems.

  The present invention has been made in view of the above problems, and in photoacoustic measurement, a photoacoustic measurement apparatus and a photoacoustic measurement method that enable a more accurate grasp of the positional relationship between a specific light absorber of interest and a scan surface. Is intended to provide.

In order to solve the above problems, the photoacoustic measurement device of the present invention is:
In a photoacoustic measurement device that measures a signal of a photoacoustic wave generated in a subject,
Among the plurality of light emitting units arranged on both sides of the acoustic detection element, the intensity of the photoacoustic signal generated from the light absorber of interest in the subject caused by the measurement light emitted from the light emitting unit on one side, and the other Determining means for determining a magnitude relationship with the intensity of the photoacoustic signal generated from the light absorber of interest generated by the measurement light emitted from the light emitting portion on the side of
And a notification means for notifying the user of the determination result obtained by the determination means.

  In the present specification, the “magnitude relationship” means a relationship that one is large or small and also a relationship that both are equal.

  And in the photoacoustic measuring device of this invention, it is preferable that a notification means changes a notification aspect according to the grade of the magnitude relationship of the said determination result.

  In the photoacoustic measurement apparatus of the present invention, the notifying unit may be a display control unit that notifies the determination result by controlling the display unit so that the determination result is expressed on the display unit of the display unit. preferable. In this case, it is preferable that the display control means causes the display unit to display a sign or meter display corresponding to the determination result. Alternatively, the display control unit may display all or a part of the display unit with a color according to the determination result, or a plurality of photoacoustic images generated based on the respective photoacoustic signals. May be alternately displayed on the display unit.

  In the photoacoustic measurement device of the present invention, the notification unit may be a notification sound generation unit that notifies the determination result by emitting a sound according to the determination result.

  In addition, the photoacoustic measurement apparatus of the present invention preferably further includes a probe having an acoustic detection element and a plurality of light emitting units arranged on both sides of the acoustic detection element. In this case, the notifying means may be a vibration generating means provided in the probe for notifying the determination result by emitting a vibration corresponding to the determination result.

  Moreover, in the photoacoustic measuring device of this invention, it is preferable that a probe has a puncture adapter which assists insertion of a puncture needle.

  Moreover, it is preferable that the photoacoustic measuring device of this invention is further provided with the photoacoustic image generation means which produces | generates a photoacoustic image based on a photoacoustic signal.

  In addition, the photoacoustic measurement apparatus of the present invention preferably further includes a reflected acoustic image generation unit that generates a reflected acoustic image based on the reflected acoustic wave reflected in the subject.

The photoacoustic measurement method of the present invention is
In a photoacoustic measurement method for measuring a photoacoustic wave signal generated in a subject,
Among the plurality of light emitting units arranged on both sides of the acoustic detection element, the intensity of the photoacoustic signal generated from the light absorber of interest in the subject caused by the measurement light emitted from the light emitting unit on one side, and the other Determining the magnitude relationship with the intensity of the photoacoustic signal generated from the noted light absorber due to the measurement light emitted from the light emitting portion on the side of
The obtained determination result is notified to the user by a notification means.

  And in the photoacoustic measuring method of this invention, it is preferable to change a notification aspect according to the grade of the magnitude relationship of a determination result.

  Further, in the photoacoustic measurement method of the present invention, the determination result is notified by controlling the display means so that the determination result is displayed on the display unit of the display means using the display control means as the notification means. It is preferable to do. In this case, it is preferable to display a sign or a meter display corresponding to the determination result on the display unit. Alternatively, all or part of the display unit may be displayed in a color according to the determination result, or a plurality of photoacoustic images generated based on the respective photoacoustic signals are alternately displayed on the display unit. May be.

  In the photoacoustic measurement method of the present invention, the determination result may be notified by emitting a sound according to the determination result using a notification sound generation unit as a notification unit. You may notify the said determination result by emitting the vibration according to the said determination result using the provided vibration generation means.

  The photoacoustic measurement device and the photoacoustic measurement method of the present invention include a plurality of light emitting units arranged on both sides of the acoustic detection element, and the inside of the subject caused by the measurement light emitted from the light emitting unit on one side. It is obtained by determining the magnitude relationship between the intensity of the photoacoustic signal generated from the focused light absorber and the intensity of the photoacoustic signal generated from the focused light absorber due to the measurement light emitted from the light emitting portion on the other side. The determination result is notified to the user. Since this magnitude relationship is related to the distance between the light absorber of interest and the light emitting part on each side, the user can indicate in which direction the light absorber of interest is in relation to the scan plane by this notification. Can be known more accurately than in the past. As a result, in photoacoustic measurement, a more accurate positional relationship between the specific light absorber of interest and the scan surface can be grasped.

It is the schematic which shows the structure of the photoacoustic measuring device of 1st Embodiment. It is a schematic front view which shows the structure of the probe of 1st Embodiment. It is a schematic side view which shows the structure of the probe of 1st Embodiment. It is the schematic which shows a mode when measuring light is separately radiate | emitted from the light emission part of each side. (A) a photoacoustic image based on a photoacoustic signal caused by measurement light emitted from a light emitting part on the near side, and (b) a light based on a photoacoustic signal caused by measuring light emitted from a light emitting part on a far side. It is the schematic which shows an acoustic image. (A) a display unit that displays a sign indicating that the target tissue is shifted to the front side of the scan plane and a photoacoustic image; and (b) a label indicating that the target tissue is shifted to the rear side of the scan plane. It is the schematic which shows the display part which displayed the photoacoustic image, and the label | marker which shows that (c) attention tissue exists on a scanning surface. It is the schematic which shows the display part which displayed the meter display and photoacoustic image which show the positional relationship of an attention structure | tissue and a scanning surface. It is the schematic which shows a mode that the puncture needle was inserted using the puncture adapter. It is the schematic which shows the structure of the photoacoustic measuring device of 2nd Embodiment. It is the schematic which shows the structure of the probe of 3rd Embodiment. It is the schematic which shows the structure of the photoacoustic measuring device of 4th Embodiment. It is the schematic which shows the display part which displayed the meter display which shows the positional relationship of an attention structure | tissue, and a scanning surface, and a synthesized image.

  Hereinafter, although an embodiment of the present invention is described using a drawing, the present invention is not limited to this. In addition, for easy visual recognition, the scale of each component in the drawings is appropriately changed from the actual one.

“First Embodiment”
First, a first embodiment of the photoacoustic measurement apparatus and photoacoustic measurement method of the present invention will be described. FIG. 1 is a schematic diagram showing the configuration of the photoacoustic measurement apparatus of the first embodiment, FIG. 2 is a schematic front view showing the configuration of the probe of the first embodiment, and FIG. It is a schematic side view which shows the structure of the probe of embodiment. In the following, a case where a tissue in a subject (living body), particularly a blood vessel, is employed as the light absorber will be described.

  The photoacoustic measuring device 10 of this embodiment has a photoacoustic image generation function. Specifically, as shown in FIG. 1, the photoacoustic measurement apparatus 10 includes a probe (ultrasonic probe) 11, an ultrasonic unit 12, a laser unit 13, a display unit 14, and an input unit 16.

<Probe>
The probe 11 irradiates the subject with ultrasonic waves or detects an acoustic wave propagating through the subject M. That is, the probe 11 can perform irradiation (transmission) of ultrasonic waves to the subject M and detection (reception) of reflected ultrasonic waves (reflected acoustic waves) that have been reflected back from the subject M. Furthermore, the probe 11 can also detect a photoacoustic wave generated in the subject M when the imaging target (for example, blood vessel) in the subject M absorbs the laser light. In this specification, “acoustic wave” means an ultrasonic wave and a photoacoustic wave. Here, “ultrasonic wave” means an elastic wave reflected by the boundary surface of the tissue in the subject M and the like, and the “photoacoustic wave” means a photoacoustic wave generated by irradiation of measurement light. It means an elastic wave generated in the subject M due to the effect.

  The probe 11 of the present embodiment includes a transducer array 20, an optical fiber 43, and a light guide plate 44, as shown in FIGS. 2 and 3, for example. For example, the transducer array 20 includes a plurality of ultrasonic transducers 20a (acoustic detection elements) arranged one-dimensionally or two-dimensionally. The ultrasonic transducer 20a is a piezoelectric element made of a polymer film such as piezoelectric ceramics or polyvinylidene fluoride (PVDF). The ultrasonic transducer 20a has a function of converting a received signal into an electric signal when an acoustic wave is received. This electrical signal is output to the receiving circuit 21 described later. The probe 11 is selected according to the imaging region from among sector scanning, linear scanning, and convex scanning.

  The optical fiber 43 guides the laser light L from the laser unit 13 to the light guide plate 44. The optical fiber 43 is not particularly limited, and a known fiber such as a quartz fiber can be used.

  The light guide plate 44 is a plate that performs special processing on the surface of an acrylic plate or a quartz plate, for example, and uniformly emits light from one end surface from the other end surface. This corresponds to the light emitting portion of the present invention. As shown in FIG. 3, in the present embodiment, two light guide plates 44 are arranged on both sides of the transducer array 20 in the elevation direction so as to face each other with the transducer array 20 interposed therebetween. In general, the front and the rear are defined along the elevation direction in the probe. For example, the light guide plate 44a disposed on one side of the plurality of light guide plates 44 (light emitting portions) is provided with “ The light guide plate on the front side and the light guide plate 44b disposed on the other side are referred to as the light guide plate on the rear side. The optical fiber 43 and the light guide plate 44 are optically coupled to each other.

  The portion of the light guide plate 44 on the side coupled to the optical fiber 43 is formed in a tapered shape, for example, as shown in FIG. Thereby, the irradiation range of measurement light can be expanded efficiently. Further, the portion of the light guide plate 44 coupled to the optical fiber 43 is preferably formed of a glass material in order to avoid damage due to light energy. On the other hand, other portions are formed of a resin material such as acrylic.

  The laser light L guided by the optical fiber 43 is incident on the light guide plate 44 and then irradiated to the subject M from the opposite end. The light guide plate 44 has a mechanism for diffusing light at the tip thereof (such as a resin containing scattering particles) or a light traveling direction on the transducer array 20 side so that a wider range of the subject M can be irradiated with the laser light L. There may be a mechanism (such as a notch for refracting light) to be directed.

  By configuring the probe 11 as described above, it is possible to accurately generate an ultrasonic image and a photoacoustic image as reflected acoustic images for the same imaging range. As a result, a complicated alignment process between the ultrasonic image and the photoacoustic image may be unnecessary.

  The probe 11 can also include a puncture adapter 46 having a guide portion 46 a for guiding puncture of the puncture needle 60. Usually, the puncturing performed while referring to the tomographic image is performed based on the scanning surface of the probe (cross section passing through the center of the transducer array). Therefore, the present invention is particularly useful when performing puncturing while referring to a photoacoustic image.

<Laser unit>
The laser unit 13 is a light source that emits laser light L to be irradiated on the subject M as measurement light. As the subject M absorbs the laser light, a photoacoustic wave is generated in the subject M. The laser light emitted from the laser unit 13 is guided to the tip of the probe 11 using a light guide means such as an optical fiber 43 and is irradiated from the probe 11 to the subject M.

  For example, in the present embodiment, the laser unit 13 includes a Q switch laser 40 such as a Q switch alexandrite laser, and a switching unit 42 that connects the laser light L emitted from the Q switch laser 40 to the optical fiber 43. When the switching unit 42 appropriately selects the optical fiber 43 to which the laser light L is connected in accordance with a command from the control unit 29, and (i) guides the laser light L only to the light guide plate 44 on the front side, ii) The optical path is switched when the light is guided only to the rear light guide plate 44 and (iii) when the light is guided to the light guide plates 44 on both sides. The switching of the optical path as described above can be realized by an existing optical switching technique using, for example, a driving optical element (mirror or prism) or an optical switch. When the trigger control circuit 30 in the control means 29 outputs a light trigger signal, the laser unit 13 turns on the flash lamp and excites the Q switch laser. For example, in the present embodiment, the laser unit 13 preferably outputs pulsed light having a pulse width of 1 to 100 nsec as laser light. The wavelength of the laser light is appropriately determined according to the light absorption characteristics of the substance in the subject to be measured. In general, hemoglobin in a living body absorbs light of 360 to 1000 nm, although the optical absorption characteristics differ depending on the state (oxygenated hemoglobin, deoxygenated hemoglobin, methemoglobin, etc.). Therefore, when measuring hemoglobin in a living body, it is preferable to set the thickness to about 600 to 1000 nm with relatively little absorption of other biological substances. Further, from the viewpoint of reaching deeper in the subject in the living body, the wavelength of the laser light is preferably 700 to 1000 nm, and particularly preferably in the near infrared wavelength region (700 to 850 nm).

  The laser unit 13 may be a light emitting element such as a semiconductor laser (LD), a solid-state laser, or a gas laser that generates a specific wavelength component or monochromatic light including the component.

<Ultrasonic unit>
The ultrasonic unit 12 includes a reception circuit 21, an AD conversion unit 22, a reception memory 23, a data separation unit 24, photoacoustic data reconstruction units A25a and B25b, detection units A26a and B26b, logarithmic conversion units A27a and B27b, and control unit 29. , Data addition means 31, photoacoustic image construction means 32, deviation amount detection means 33, target tissue determination means 34, and display control means 36. For example, photoacoustic data reconstruction means A25a and B25b, detection means A26a and B26b, logarithmic conversion means A27a and B27b, data addition means 31, and photoacoustic image construction means 32 correspond to the photoacoustic image generation means in the present invention.

  The control means 29 controls each part of the photoacoustic measuring device 10, and includes, for example, a trigger control circuit 30 in this embodiment. The trigger control circuit 30 sends an optical trigger signal to the laser unit 13 when the photoacoustic measurement device is activated, for example. As a result, the flash lamp is turned on in the laser unit 13 and the excitation of the laser rod is started. And the excitation state of a laser rod is maintained and the laser unit 13 will be in the state which can output a laser beam.

  The control unit 29 then transmits a Qsw trigger signal from the trigger control circuit 30 to the laser unit 13. That is, the control means 29 controls the output timing of the laser light from the laser unit 13 by this Qsw trigger signal. For example, the control means 29 can be configured to start transmission of a Qsw trigger signal when a predetermined switch provided on the probe 11 is pressed. If comprised in this way, the position of the probe 11 when a switch is pushed can be handled as a starting point of probe scanning. Further, if the transmission of the Qsw trigger signal is terminated when the switch is pressed next time, the position of the probe 11 at that time can be handled as the end point of the probe scan. In the present embodiment, the control unit 29 transmits the sampling trigger signal to the AD conversion unit 22 simultaneously with the transmission of the Qsw trigger signal. The sampling trigger signal serves as a cue for the start timing of the photoacoustic signal sampling in the AD conversion means 22. As described above, by using the sampling trigger signal, it is possible to sample the photoacoustic signal in synchronization with the output of the laser beam.

  The receiving circuit 21 receives the photoacoustic signal detected by the probe 11. The photoacoustic signal received by the receiving circuit 21 is transmitted to the AD conversion means 22.

  The AD conversion means 22 is a sampling means, which samples the photoacoustic signal received by the receiving circuit 21 and converts it into a digital signal. For example, the AD conversion unit 22 includes a sampling control unit and an AD converter. The reception signal received by the reception circuit 21 is converted into a sampling signal digitized by an AD converter. The AD converter is controlled by a sampling control unit, and is configured to perform sampling when the sampling control unit receives a sampling trigger signal. The AD converter 22 samples the received signal at a predetermined sampling period based on, for example, an AD clock signal having a predetermined frequency input from the outside.

  The reception memory 23 stores the photoacoustic signal sampled by the AD conversion means 22 (that is, the sampling signal). Then, the reception memory 23 outputs the photoacoustic signal detected by the probe 11 to the data separation unit 24.

  The data separation means 24 transmits photoacoustic signal data (first photoacoustic signal data) resulting from the laser light emitted from the front light guide plate 44 to the photoacoustic data reconstruction means A, and guides the rear side. Photoacoustic signal data (second photoacoustic signal data) resulting from the laser light emitted from the optical plate 44 is transmitted to the photoacoustic data reconstruction unit B.

  The photoacoustic data reconstruction unit A25a reconstructs the first photoacoustic signal data received from the data separation unit 24, and generates signal data for each line in the imaging range. Specifically, the photoacoustic data reconstruction unit A25a adds signal data from each ultrasonic transducer 20a with a delay time corresponding to the position of each ultrasonic transducer 20a to generate signal data for one line ( Delayed addition method). The photoacoustic data reconstruction unit A25a may perform reconstruction by the CBP method (Circular Back Projection) instead of the delay addition method. Alternatively, the photoacoustic data reconstruction unit A25a may perform reconstruction using the Hough transform method or the Fourier transform method. The reconstructed signal data is transmitted to the detection means 26a. On the other hand, the photoacoustic data reconstruction unit B25b reconstructs the second photoacoustic signal data received from the data separation unit 24, and generates signal data for each line in the imaging range. The reconstructed signal data is transmitted to the detection means 26b. Other signal processing is the same as that of the photoacoustic data reconstruction unit A25a.

  Each of the detection means A26a and B26b performs detection and extracts a photoacoustic signal from the reconstructed signal data. The detection means 26a and 26b transmit the detected signal data to the logarithmic conversion means A27a or B27b for photoacoustic image generation and to the deviation amount detection means 33 for deviation amount detection.

  The logarithmic conversion means A27a or B27b performs logarithmic conversion on the detected signal data. The logarithmically converted signal data is transmitted to the data adding means 31. The data adding means 31 adds two logarithmically converted signal data, generates one photoacoustic signal data, and transmits the data to the photoacoustic image construction means 32. The photoacoustic image construction unit 32 generates photoacoustic image data by associating the time axis of the photoacoustic signal data generated by the data addition unit 31 with the depth axis. The photoacoustic image data is transmitted to the display control means 36.

  On the other hand, the deviation amount detection means 33 includes the intensity (first intensity) of the portion of the signal data received from the detection means A26a due to the tissue of interest (that is, the attention light absorber) and the signal data received from the detection means B26b. The magnitude relationship is determined by comparing the strength (second strength) of the portion caused by the target tissue. That is, the deviation amount detection means 33 corresponds to the determination means in the present invention. The determination method can be performed, for example, by taking a ratio or difference between the first intensity and the second intensity. Of the signal data, the “part resulting from the tissue of interest” can be extracted based on the position information of the tissue of interest. The position information of the target tissue is given by the target tissue determination unit 34. The tissue-of-interest determination means 34 automatically sets a tissue of interest in accordance with a predetermined condition from among the tissues shown in the photoacoustic image generated in advance or at present, and automatically sets the position information of the tissue of interest that has been set. Get in. Here, for example, the target tissue set automatically using the input unit 16 may be manually changed, or the setting of the target tissue itself may be performed using the input unit 16. The “intensity” of the portion caused by the tissue of interest is, for example, a representative value such as an average value, maximum value, mode value, or median value of the portion of the signal data caused by the tissue of interest.

  Based on this magnitude relationship, it is possible to grasp whether the target tissue is displaced forward or backward with respect to the scan plane. Note that the tissue of interest (or light absorber of interest) is a tissue (or light absorber) that is a target of grasping the positional relationship with respect to the scan plane among tissues (or light absorbers) having light absorption characteristics. Examples of such tissues include blood vessels and lymph nodes.

  Specifically, it is as follows. For example, consider a case where the target tissue is a blood vessel 65. FIG. 4A is a schematic view showing a state when the laser light L1 is emitted only from the front light guide plate 44a, and FIG. 4B is a view when the laser light L2 is emitted only from the rear light guide plate 44b. It is the schematic which shows a mode. When the target blood vessel 65 is displaced forward from the scan plane S, the distance between the light guide plate 44a and the target blood vessel 65 is shorter than the distance between the light guide plate 44b and the target blood vessel 65. Therefore, since the intensity of light or acoustic wave depends on the propagation distance, the intensity of the photoacoustic signal from the target blood vessel 65 detected by the transducer array 20 in the case of FIG. 4a is higher than that in the case of FIG. 4b. growing. If a photoacoustic image is produced | generated from each photoacoustic signal, it will become like FIG. 5, for example. FIG. 5a is a schematic diagram showing a photoacoustic image 66a based on a photoacoustic signal resulting from the laser light emitted from the front light guide plate 44a, and FIG. 5b shows the laser light emitted from the rear light guide plate 44b. It is the schematic which shows the photoacoustic image 66b based on the resulting photoacoustic signal. In FIG. 5b, the blood vessel 65b in the photoacoustic image 66b is thinner than the blood vessel 65a in the photoacoustic image 66a because the signal intensity is weak.

  Thus, since the magnitude relationship has a correlation with the shift of the target blood vessel with respect to the scan plane, it is possible to grasp the shift of the target blood vessel with respect to the scan plane by knowing the magnitude relationship. Furthermore, since the difference between the two distances increases as the target blood vessel moves away from the scan plane, the amount of shift of the target blood vessel from the scan plane can be detected by detecting the magnitude relationship. Then, the determination result of the magnitude relationship acquired by the deviation amount detection unit 33 is transmitted to the display control unit 36.

  The display control unit 36 displays the display content on the display unit of the display unit 14. For example, the display control unit 36 displays the photoacoustic image on the display unit of the display unit 14 based on the photoacoustic image data generated by the photoacoustic image construction unit 32. Further, the display control unit 36 controls the display unit based on the determination result so that the determination result is expressed on the display unit. That is, in the present embodiment, the display control unit 36 corresponds to the notification unit of the present invention. For example, FIG. 6 shows a state in which the determination result is represented by an arrow. Specifically, in FIG. 6a, a photoacoustic image 68 showing the blood vessel 65 and an upward arrow 69a are displayed on the display unit 67, and the target blood vessel 65 is displaced forward with respect to the scan plane by the arrow 69a. The determination result is notified. In this case, in order to align the position of the target blood vessel 65 on the scan plane, the probe may be moved forward. On the other hand, FIG. 6B shows that the photoacoustic image 68 and the downward arrow 69b are displayed on the display unit 67, and the arrow 69b expresses that, for example, the blood vessel 65 of interest is displaced backward with respect to the scan plane. The judgment result is notified. In this case, in order to align the position of the target blood vessel 65 on the scan plane, the probe may be moved backward.

  As described above, the user of this apparatus (including the person who exists in the vicinity of the measurement operator and the like, in addition to the actual operator of the apparatus) can recognize the target blood vessel 65 and the scan plane based on the direction of the arrow. As a result, the position of the blood vessel 65 of interest can be easily aligned on the scan plane by moving the probe 11 back and forth. When the position of the target blood vessel 65 has reached the scan plane, for example, as shown in FIG. 6c, a sign indicating that the target blood vessel exists on the scan plane is displayed. Thereby, the user of this apparatus can easily know that the position of the target blood vessel 65 has reached the scan plane. Note that the display object for notifying the determination result is not limited to the above-described arrow, and other figures, characters, symbols, or a combination thereof can be employed. Further, not limited to the sign, as shown in FIG. 7, for example, a meter display 70 including a scale 70a and an indicator 70b may be employed. In this case, when the position of the blood vessel 65 of interest reaches the scan plane, the indicator 70b is set to come to the reference point 70c of the scale 70a.

  Here, it is preferable that the display control unit 36 serving as a notification unit changes the notification mode of the determination result according to the degree of the magnitude relationship of the determination result. Although FIG. 6c and FIG. 7 are examples thereof, other modes in which the size, color, or shape of the sign changes depending on the magnitude of the magnitude relationship are conceivable.

  Or the display control means 36 shall display all or one part of a display part by the color according to the said determination result. For example, if the target tissue is displaced forward with respect to the scan plane, the entire screen or a part of the screen is colored in red, and if the target tissue is shifted backward with respect to the scan plane A mode in which the entire screen or a part thereof is arranged in a blue color scheme is conceivable. According to such an aspect, the determination result can be notified to the user by the color of the screen (display unit). In this case, as an example of a mode in which the determination result notification mode is changed according to the level of the determination result, the brightness and hue of the color scheme of the screen are changed according to the level of the determination result. Can be mentioned. Further, the display control means 36 may alternately display a plurality of photoacoustic images generated based on the respective photoacoustic signals on the display unit. For example, a mode in which the photoacoustic images of FIGS. 5a and 5b are alternately displayed on the screen is conceivable. According to such an aspect, since images with different pixel values (signal intensity) are alternately displayed, the image region of the target tissue is blinking when the position of the target tissue is shifted from the scan plane. The user can be notified of the determination result by this blinking. Also in this case, since the difference in pixel value increases as the position of the target tissue deviates from the scan plane, the determination result notification mode changes according to the magnitude of the determination result.

  Hereinafter, the function and effect of the present invention will be described. In general, when an acoustic wave is detected by an acoustic detection element such as an ultrasonic transducer, an acoustic wave detection range R corresponding to the width of the acoustic detection element (for example, the horizontal length in FIG. 3). There will be a width. Therefore, for example, as shown in FIG. 3, even a specific tissue of interest (blood vessel 65 in the present embodiment) represented in the photoacoustic image acquired for a specific scan plane defined by the transducer array, Actually, there may be a case where it does not exist on the scan plane S. In such a case, for example, even if the puncture needle 60 is inserted toward the target tissue while referring to the photoacoustic image (that is, based on the scan plane S), the target tissue cannot be captured by the puncture needle 60. It becomes. Therefore, for example, when puncturing is performed, it is necessary to grasp a more accurate positional relationship between a specific target tissue to be punctured and a scan plane.

  And according to this invention, it can respond to the said request. The photoacoustic measurement device and the photoacoustic measurement method according to the present embodiment include a plurality of light emitting units arranged on both sides of the acoustic detection element, and the inside of the subject caused by the measurement light emitted from the light emitting unit on one side. Determination result obtained by determining the magnitude relationship between the intensity of the photoacoustic signal generated from the target tissue and the intensity of the photoacoustic signal generated from the target tissue due to the measurement light emitted from the light emitting unit on the other side Is notified to the user. As described above, this magnitude relationship is related to the distance between the target tissue and the light emitting part on each side. It is possible to know whether there is more accurately than in the past. As a result, in photoacoustic measurement, it is possible to grasp a more accurate positional relationship between a specific target tissue and a scan surface, and the position adjustment of the probe is facilitated. If the user performs the puncturing operation after adjusting the position of the probe, the user can puncture the tissue of interest more accurately.

  In the above description, the case where the photoacoustic image is generated by adding the first and second photoacoustic signal data has been described, but the present invention is not limited to this. For example, the photoacoustic image may be generated based on a photoacoustic signal (third photoacoustic signal data) caused by laser light emitted from the light guide plates 44 on both sides. In this case, the first and second photoacoustic signal data obtained by irradiation on only one side are used only for determination of the magnitude relationship, and the third photoacoustic signal data obtained by irradiation on both sides is photoacoustic. It will be used only for image generation.

  In the above description, the case is described in which the magnitude relationship between the photoacoustic signals is determined based on the signal data after detection and before logarithmic conversion. However, the present invention is not limited to this. For example, the magnitude relationship between the photoacoustic signals can be determined based on raw data before detection or signal data after logarithmic conversion.

  In the above description, the case where the tissue in the subject (living body) is employed as the light absorber has been described, but the present invention is not limited to this. For example, the present invention can also be applied when it is desired to confirm the position of a device (for example, a puncture needle or a stent) manufactured from a material having a property of absorbing light (for example, metal, stainless steel, or plastic).

“Second Embodiment”
Next, a second embodiment of the photoacoustic measurement apparatus and photoacoustic measurement method of the present invention will be described. FIG. 9 is a schematic diagram illustrating the configuration of the photoacoustic measurement apparatus according to the second embodiment. This embodiment is different from the first embodiment in that the notification unit is a notification sound generation unit. Therefore, a detailed description of the same components as those in the first embodiment will be omitted unless particularly necessary.

  As shown in FIG. 9, the photoacoustic measurement apparatus 10 of the present embodiment includes a probe 11, an ultrasonic unit 12, a laser unit 13, a display unit 14, and an input unit 16. The ultrasonic unit 12 includes a receiving circuit 21, an AD converting means 22, a receiving memory 23, a data separating means 24, photoacoustic data reconstruction means A25a and B25b, detecting means A26a and B26b, logarithmic converting means A27a and B27b, control. Means 29, data addition means 31, photoacoustic image construction means 32, deviation amount detection means 33, target tissue determination means 34, notification sound generation means 35, and display control means 36.

  In the present embodiment, the determination result of the magnitude relationship acquired by the deviation amount detection unit 33 is transmitted to the notification sound generation unit 35. The notification sound generator 35 notifies the determination result by emitting a sound according to the determination result. For example, a mode in which the pitch, loudness, or melody of the sound is changed according to the position of the target tissue with respect to the scan surface can be considered. In this case, as an example of a mode of changing the notification mode of the determination result according to the degree of the magnitude relation of the determination result, the pitch, loudness or generation cycle of the sound is continuously changed according to the level. Can be mentioned.

  As described above, the photoacoustic measurement apparatus and the photoacoustic measurement method of the present embodiment are characterized by determining the magnitude relationship and notifying the obtained determination result to the user by the notification sound generating means. Therefore, the present embodiment can provide the same effects as those of the first embodiment.

  In this embodiment, the display control unit 36 does not need to function as a notification unit, but may function as a notification unit together with the notification sound generation unit 35.

“Third Embodiment”
Next, a third embodiment of the photoacoustic measurement apparatus and photoacoustic measurement method of the present invention will be described. FIG. 10 is a schematic diagram illustrating the configuration of the probe according to the third embodiment. This embodiment is different from the first embodiment in that the notifying means is a vibration generating means. Therefore, a detailed description of the same components as those in the first embodiment will be omitted unless particularly necessary.

  As shown in FIG. 1, the photoacoustic measurement apparatus of the present embodiment includes a probe 11, an ultrasonic unit 12, a laser unit 13, a display unit 14, and an input unit 16. The probe 11 has two vibration motors 47 a and 47 b in the probe housing 45. One vibration motor 47a is provided on the front side in the housing 45, and the other vibration motor 47b is provided on the rear side.

  In the present embodiment, the magnitude relation determination result acquired by the deviation amount detection unit 33 is transmitted to the control unit 29, for example. The control means 29 and the vibration motors 47a and 47b are connected, and the control means 29 vibrates both or one of the vibration motors 47a and 47b according to the determination result. That is, in this embodiment, the control means 29 and the vibration motors 47a and 47b correspond to the vibration generating means in the present invention. The vibration generating means notifies the determination result by emitting a vibration according to the determination result. For example, as shown in FIG. 10, when the target tissue is displaced forward with respect to the scan surface, the control unit 29 drives the vibration motor 47a to generate vibration 48 on the front side (FIG. 10a). In the case where the target tissue is displaced rearward with respect to the scan surface, a mode in which the control means 29 drives the vibration motor 47b to generate the vibration 48 rearward (FIG. 10b) is conceivable. In this case, as an example of a mode in which the determination result notification mode is changed according to the magnitude relation of the determination result, continuously changing the magnitude or generation period of the vibration according to the level. It is done.

  As described above, the photoacoustic measurement apparatus and the photoacoustic measurement method of the present embodiment are characterized by determining the magnitude relationship and notifying the user of the obtained determination result by vibration generating means. Therefore, the present embodiment can provide the same effects as those of the first embodiment.

  In the present embodiment, the display control unit 36 does not need to function as a notification unit, but may function as a notification unit together with the vibration generation unit.

“Fourth Embodiment”
Next, a fourth embodiment of the photoacoustic measurement apparatus and photoacoustic measurement method of the present invention will be described. FIG. 11 is a schematic diagram illustrating the configuration of the photoacoustic measurement apparatus according to the fourth embodiment. This embodiment is different from the first embodiment in that it also has an ultrasonic image generation function. Therefore, a detailed description of the same components as those in the first embodiment will be omitted unless particularly necessary.

  As shown in FIG. 11, the photoacoustic measurement apparatus 10 of the present embodiment includes a probe 11, an ultrasonic unit 12, a laser unit 13, a display unit 14, and an input unit 16. The ultrasonic unit 12 includes a receiving circuit 21, an AD converting means 22, a receiving memory 23, a data separating means 24, photoacoustic data reconstruction means A25a and B25b, detecting means A26a and B26b, logarithmic converting means A27a and B27b, control. Means 29, data addition means 31, photoacoustic image construction means 32, deviation amount detection means 33, target tissue determination means 34 and display control means 36, ultrasound data reconstruction means 25c, detection / logarithm conversion means 26c, ultrasound An image construction unit 39, an image composition unit 38, and a transmission control circuit 50 are included. The ultrasonic data reconstruction means 25c, the detection / logarithm conversion means 26c, and the ultrasonic image construction means 39 correspond to the reflected acoustic image generation means in the present invention.

  In the present embodiment, in addition to the detection of the photoacoustic signal, the probe 11 outputs (transmits) ultrasonic waves to the subject and detects reflected ultrasonic waves (reflected acoustic waves) from the subject with respect to the transmitted ultrasonic waves (reflected acoustic waves). Receive). As the acoustic detection element for transmitting and receiving ultrasonic waves, the above-described detection element array 20 may be used, or a new detection element array provided separately in the probe 11 for ultrasonic transmission and reception may be used. Good. In addition, transmission and reception of ultrasonic waves may be separated. For example, ultrasonic waves may be transmitted from a position different from the probe 11, and reflected ultrasonic waves with respect to the transmitted ultrasonic waves may be received by the probe 11.

  When generating an ultrasonic image (reflection acoustic image), the trigger control circuit 30 sends an ultrasonic transmission trigger signal to the transmission control circuit 50 to instruct ultrasonic transmission. When receiving the trigger signal, the transmission control circuit 50 transmits an ultrasonic wave from the probe 11. The probe 11 detects the reflected ultrasonic wave from the subject after transmitting the ultrasonic wave.

  The reflected ultrasonic wave detected by the probe 11 is input to the AD conversion means 22 via the receiving circuit 21. The trigger control circuit 30 sends a sampling trigger signal to the AD conversion means 22 in synchronization with the timing of ultrasonic transmission, and starts sampling of reflected ultrasonic waves. The AD conversion means 22 stores the reflected ultrasonic sampling signal in the reception memory 23. Either sampling of the photoacoustic signal or sampling of the reflected ultrasonic wave may be performed first.

  The data separation unit 24 separates the photoacoustic signal sampling signal and the reflected ultrasonic sampling signal stored in the reception memory 23. The data separation unit 24 transmits the first photoacoustic signal data to the photoacoustic data reconstruction unit A25a, transmits the second photoacoustic signal data to the photoacoustic data reconstruction unit B25b, and receives reflected ultrasonic signal data. Is transmitted to the ultrasonic data reconstruction means 25c.

  The ultrasonic data reconstruction unit 25 c generates data of each line of the ultrasonic image based on the reflected ultrasonic waves (its sampling signals) detected by the plurality of acoustic detection elements of the probe 11. For the generation of the data of each line, a delay addition method or the like can be used as in the generation of the data of each line in the photoacoustic data reconstruction unit. The detection / logarithm conversion means 26c obtains an envelope of the data of each line output from the ultrasonic data reconstruction means 25c, and logarithmically converts the obtained envelope.

  The ultrasonic image construction unit 39 generates an ultrasonic image based on the data of each line subjected to logarithmic transformation.

  The image synthesis means 38 synthesizes, for example, a photoacoustic image and an ultrasonic image (FIG. 12). The image composition unit 38 performs image composition by superimposing a photoacoustic image and an ultrasonic image, for example. The synthesized image is output to the display control unit 36 and displayed on the display unit 14. It is also possible to display the photoacoustic image and the ultrasonic image side by side on the display unit 14 without performing image synthesis, or to switch between the photoacoustic image and the ultrasonic image.

  As described above, the photoacoustic measurement device and the photoacoustic measurement method according to the present embodiment generate an ultrasonic image in addition to the photoacoustic image. Therefore, by referring to the ultrasonic image, there is also an effect that a portion that cannot be imaged by the photoacoustic image can be observed (FIG. 12).

DESCRIPTION OF SYMBOLS 10 Photoacoustic measuring device 11 Probe 12 Ultrasonic unit 13 Laser unit 14 Display means 16 Input means 20 Transducer array 20a Ultrasonic vibrator 40 Switch laser 42 Switching part 43 Optical fiber 44 Light guide plate 45 Housing 46 Puncture adapter 46a Guide part 47a Vibration motor 47b Vibration motor 48 Vibration 50 Transmission control circuit 60 Puncture needle 65 Blood vessel 25a Photoacoustic data reconstruction means A
25b Photoacoustic data reconstruction means B
L Laser beam M Subject R Detection range S Scan plane

Claims (20)

In a photoacoustic measurement device that measures a signal of a photoacoustic wave generated in a subject,
Among the plurality of light emitting units arranged on both sides of the acoustic detection element, the intensity of the photoacoustic signal generated from the light absorber of interest in the subject caused by the measurement light emitted from the light emitting unit on one side, and the other Determination means for determining a magnitude relationship with the intensity of the photoacoustic signal generated from the light absorber of interest caused by the measurement light emitted from the light emitting portion on the side of
A photoacoustic measurement device comprising: notification means for notifying a user of a determination result obtained by the determination means.   The photoacoustic measurement device according to claim 1, wherein the notification unit changes a notification mode according to a degree of the magnitude relation of the determination result.   3. The display means for notifying the determination result by controlling the display means so that the determination result is expressed on a display unit of the display means. The photoacoustic measuring device of description.   The photoacoustic measuring device according to claim 3, wherein the display control means displays a sign or a meter display corresponding to the determination result on the display unit.   4. The photoacoustic measurement apparatus according to claim 3, wherein the display control unit displays all or a part of the display unit in a color corresponding to the determination result.   4. The photoacoustic measurement apparatus according to claim 3, wherein the display control unit is configured to alternately display a plurality of photoacoustic images generated based on the respective photoacoustic signals on the display unit. .   The photoacoustic measuring device according to claim 1, wherein the notification unit is a notification sound generation unit that notifies the determination result by emitting a sound according to the determination result.   The photoacoustic measurement apparatus according to claim 1, further comprising a probe having an acoustic detection element and a plurality of light emitting portions arranged on both sides of the acoustic detection element.   9. The photoacoustic measurement apparatus according to claim 8, wherein the notifying unit is a vibration generating unit provided in the probe for notifying the determination result by emitting a vibration corresponding to the determination result. .   The photoacoustic measuring device according to claim 8 or 9, wherein the probe has a puncture adapter that assists insertion of a puncture needle.   The photoacoustic measurement device according to claim 1, further comprising photoacoustic image generation means for generating a photoacoustic image based on a photoacoustic signal.   The photoacoustic measurement apparatus according to claim 1, further comprising a reflected acoustic image generation unit configured to generate a reflected acoustic image based on a reflected acoustic wave reflected within the subject. In a photoacoustic measurement method for measuring a photoacoustic wave signal generated in a subject,
Among the plurality of light emitting units arranged on both sides of the acoustic detection element, the intensity of the photoacoustic signal generated from the light absorber of interest in the subject caused by the measurement light emitted from the light emitting unit on one side, and the other Determining the magnitude relationship with the intensity of the photoacoustic signal generated from the light absorber of interest due to the measurement light emitted from the light emitting part on the side of
A photoacoustic measurement method characterized by notifying a user of the obtained determination result by a notification means.   The photoacoustic measurement method according to claim 13, wherein a notification mode is changed according to a degree of magnitude relation of the determination result.   14. The determination result is notified by controlling the display unit using a display control unit as the notification unit so that the determination result is represented on a display unit of the display unit. Or the photoacoustic measuring method of 14.   The photoacoustic measurement method according to claim 15, wherein a sign or a meter display corresponding to the determination result is displayed on the display unit.   The photoacoustic measurement method according to claim 15, wherein all or part of the display unit is displayed in a color corresponding to the determination result.   The photoacoustic measurement method according to claim 15, wherein a plurality of photoacoustic images generated based on the respective photoacoustic signals are alternately displayed on the display unit.   15. The photoacoustic measurement method according to claim 13, wherein the determination result is notified by emitting a sound corresponding to the determination result using a notification sound generating unit as the notification unit.   The photoacoustic measurement according to claim 13 or 14, wherein the determination result is notified by emitting a vibration according to the determination result by using a vibration generating means provided in a probe as the notification means. Method.

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