JP2019051192A - Ultrasound medical apparatus - Google Patents

Abstract

To provide a technique more improved for measuring tissue coagulation by using ultrasound medical apparatus.SOLUTION: A displacement measurement unit 22 measures tissue displacement in a coagulation region of interest and tissue displacement in a reference coagulation region. A displacement comparison unit 24 compares the time change in the tissue displacement in the coagulation region of interest and the time change in the tissue displacement in the reference coagulation region to obtain displacement comparison information. A coagulation measurement unit 26 obtains a measurement result relating to the joining state between the coagulation region of interest and the reference coagulation region based on the displacement comparison information.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasonic medical apparatus for measuring tissue coagulation.

  A treatment method is known in which, for example, a living body is irradiated with high intensity focused ultrasound (HIFU), and a treatment site such as a tumor is heated and coagulated using the acoustic energy.

  It is known that when a tissue is heated and solidified, the elastic modulus (Young's modulus) of the tissue increases before and after the solidification. In addition, since relatively strong ultrasonic waves such as HIFU generate radiation force in the traveling direction, for example, a displacement of about 10 to 100 μm (micrometer) is applied to the tissue at the focal point of the ultrasonic beam of HIFU. Can be given. Therefore, it is possible to observe the coagulation of the tissue by applying a displacement to the tissue with relatively strong ultrasonic waves such as HIFU and measuring the decrease in the displacement due to the increase in the elastic modulus.

  For example, Patent Document 1 discloses an invention in which a displacement ultrasonic wave is modulated using a relatively high modulation frequency and a relatively low modulation frequency, and a tissue displacement at a treatment site is measured for each modulation frequency. ing. According to the invention of Patent Document 1, local coagulation at a treatment site is measured based on a measurement result of a displacement with a relatively high modulation frequency, and a wide area at the treatment site is measured based on a measurement result of a displacement with a relatively low modulation frequency. Thus, for example, the presence or absence of local coagulation immediately after the occurrence can be measured with high accuracy, and further, for example, the size of a wide range of coagulation after progress can be measured with high accuracy.

  Further, in Patent Document 2, ultrasonic waves for displacement generation are transmitted toward the treatment site to generate radiation force at the treatment site to displace the tissue, and measurement ultrasonic waves toward the treatment site. To measure the displacement at the treatment site, form a displacement map indicating the periodic change of the displacement based on the measured displacement, and measure the coagulation of the tissue at the treatment site based on the displacement map Is disclosed.

Japanese Patent No. 5590493 Japanese Patent No. 5954841

  The inventors of the present application have conducted research and development on further improvements of the ground-breaking invention disclosed in Patent Documents 1 and 2.

  An object of this invention is to provide the further improvement technique of the ultrasonic medical device which measures coagulation | solidification of a structure | tissue.

  An ultrasonic medical device suitable as an aspect of the present invention includes a displacement measuring unit that measures tissue displacement in a target coagulation region and tissue displacement in a reference coagulation region due to vibration caused by ultrasonic waves, and temporal change of tissue displacement in the target coagulation region. A displacement comparison unit that obtains displacement comparison information by comparing the time variation of the tissue displacement in the reference coagulation region and a measurement result relating to the joint state of the attention coagulation region and the reference coagulation region based on the displacement comparison information And a coagulation measuring unit for obtaining

  The ultrasonic medical device having the above-described configuration transmits and receives measurement ultrasonic waves having characteristics (frequency, waveform, intensity) similar to those of diagnostic ultrasonic waves in a general ultrasonic diagnostic apparatus, for example, to reduce tissue displacement. A function for obtaining a received signal for measurement is provided. Furthermore, it is desirable that the ultrasonic medical apparatus having the above-described configuration has a function of transmitting a displacement ultrasonic wave having a relatively high intensity enough to displace the tissue by the radiation force. The ultrasonic waves for displacement have a higher intensity than the ultrasonic waves for measurement. For example, high intensity focused ultrasonic waves (HIFU) are suitable specific examples of ultrasonic waves for displacement. In addition, when using intense focused ultrasound (HIFU) as the ultrasound for displacement, the tissue may be heated and solidified while the tissue is displaced by the intense focused ultrasound (HIFU). According to the ultrasonic medical device having the above-described configuration, it is possible to obtain a measurement result relating to the joining state of the attention coagulation region and the reference coagulation region.

  For example, in the treatment in which a coagulation region is formed for each of a plurality of treatment locations, the coagulation measurement unit determines a coagulation region corresponding to the closest treatment location in the direction of interest from the treatment location corresponding to the attention coagulation region. It is desirable to obtain a measurement result relating to a joint state between the target solidification region and the reference solidification region as the reference solidification region.

  Further, for example, the displacement measuring unit measures tissue displacement at a plurality of depths of the attention coagulation region and tissue displacement at a plurality of depths of the reference coagulation region, and the displacement comparison unit includes the attention coagulation region and the reference. The displacement comparison information is derived for each depth of a plurality of depths by comparing temporal changes in tissue displacement at corresponding depths of the coagulation region, and the coagulation measurement unit is configured to measure each depth of the plurality of depths. It is desirable to obtain a measurement result relating to the joining state of the focused solidification region and the reference solidification region based on the displacement comparison information obtained for each.

  Further, for example, the coagulation measurement unit derives the measurement result indicating whether or not the target coagulation region and the reference coagulation region are joined in the treatment by irradiating ultrasonic waves to the treatment site corresponding to the target coagulation region. When the measurement result indicating that the target coagulation region and the reference coagulation region are joined is obtained, it is desirable to stop the irradiation of ultrasonic waves to the treatment site corresponding to the target coagulation region.

  In addition, for example, the displacement comparison unit may calculate a phase difference between tissue displacements in the attention coagulation region and the reference coagulation region as the displacement comparison information based on a temporal change in tissue displacement in the attention coagulation region and the reference coagulation region. It is preferable that the solidification measurement unit obtains the measurement result indicating that the target solidification region and the reference solidification region are joined when the determination condition indicating that the phase difference is small is satisfied.

  According to the present invention, a further improvement technique of an ultrasonic medical device for measuring tissue coagulation is provided. For example, according to a preferred aspect of the present invention, it is possible to obtain a measurement result relating to the bonding state of the target coagulation region and the reference coagulation region.

1 is a diagram showing an overall configuration of an ultrasonic medical apparatus suitable for implementing the present invention. It is a figure which shows the specific example of the tissue displacement by the HIFU signal by which the modulation process was carried out. It is a figure which shows one of the suitable operation examples which the ultrasonic medical device of FIG. 1 performs. It is a figure which shows the specific example of a two-dimensional displacement amount map. It is a figure which shows the specific example of the displacement amount map formed over several diagnostic time. It is a figure which shows the specific example of the coagulation area | region formed in a some treatment location. It is a figure which shows the specific example of a displacement change map. It is a figure which shows the specific example of the time change of phase delay d (theta). It is a figure which shows the specific example of several observation line KL. It is a figure which shows the specific example of a direction of interest.

  FIG. 1 is an overall configuration diagram of an ultrasonic medical device suitable for carrying out the present invention. The ultrasonic medical apparatus of FIG. 1 includes a composite ultrasonic transducer 10, and the ultrasonic transducer 10 includes a HIFU transducer 10H and a diagnostic transducer 10D.

  The HIFU vibrator 10H is a vibrator that transmits strong focused ultrasound (HIFU), and includes, for example, a plurality of vibration elements arranged two-dimensionally. For example, the HIFU transducer 10H forms a therapeutic ultrasonic beam TB toward the treatment site P such as cancer or tumor, transmits a strong focused ultrasound, and heats and treats the treatment site P. Used.

  Further, the HIFU transducer 10H forms a displacement ultrasonic beam EB toward the treatment site P and transmits an ultrasonic wave for generating displacement, and generates a radiation force at the treatment site P to displace the tissue. The displacement ultrasonic beam EB is a beam formed with an intensity that generates an effective radiation force at the treatment site P. In the specific example shown in FIG. 1, the treatment ultrasonic beam TB is the displacement ultrasonic beam. Used as EB. Of course, a displacement ultrasonic beam EB different from the therapeutic ultrasonic beam TB may be used.

  On the other hand, the diagnostic transducer 10D includes, for example, a plurality of vibration elements arranged two-dimensionally. For example, a comparison for forming an ultrasound image on a subject (patient) having a treatment site P is performed. Send and receive weak ultrasonic waves. That is, ultrasonic waves having the same intensity (energy) as that of a known general ultrasonic diagnostic apparatus are transmitted and received.

  In addition, the diagnostic transducer 10D forms a measurement ultrasonic beam MB toward the treatment site P, transmits and receives measurement ultrasonic waves, and obtains a reception signal along the measurement ultrasonic beam MB. The received signal obtained along the measurement ultrasonic beam MB is used to measure the displacement at the treatment site P due to the radiation force of the displacement ultrasonic beam EB.

  In addition, the ultrasonic transducer | vibrator 10 makes the inside surface dented in bowl shape the vibrator surface, for example. Then, for example, the diagnostic transducer 10D is provided at the bottom portion located in the center of the inside which is recessed in the bowl shape, and the HIFU transducer 10H is provided so as to surround the diagnostic transducer 10D. Note that the shape of the transducer surface of the ultrasonic transducer 10 is not limited to a bowl shape, and it is desirable that the shape be adapted to, for example, a therapeutic application. Moreover, all the vibration elements or some vibration elements may be used in combination for both HIFU use and diagnosis use.

  The measurement diagnosis block 20 includes a transmission / reception unit 21 that controls transmission / reception of the diagnostic transducer 10D. The transmission / reception unit 21 outputs a transmission signal corresponding to each of the plurality of vibration elements constituting the diagnostic transducer 10D, thereby controlling the diagnostic transducer 10D to form a transmission beam. A received signal is obtained along the received beam by performing a phasing addition process on the received signal obtained from each of the vibration elements. That is, the transmission / reception unit 21 has a function of a transmission unit (transmission beamformer) and a function of a reception unit (reception beamformer).

  The transmission / reception unit 21 scans a diagnostic ultrasonic beam in a three-dimensional space or cross section including the treatment site P and collects reception signals for images. Then, based on the collected received signals, the ultrasonic image forming unit 28 forms image data of a three-dimensional ultrasonic image or a two-dimensional tomographic image, and an ultrasonic image corresponding to the image data is displayed on the display unit. 50.

  A user such as a doctor or a laboratory technician confirms the position of the treatment site P from the ultrasonic image displayed on the display unit 50, and uses the operation device or the like not shown to obtain the position information of the treatment site P in FIG. Enter into the ultrasonic medical device. Of course, the ultrasonic medical apparatus in FIG. 1 may obtain the position information by confirming the position of the treatment site P by image analysis processing or the like on the ultrasonic image.

  Further, the transmitting / receiving unit 21 controls the diagnostic transducer 10D to form the measurement ultrasonic beam MB, and obtains a reception signal along the measurement ultrasonic beam MB. Then, the displacement measuring unit 22 measures the tissue displacement at the treatment site P based on the received signal obtained along the measurement ultrasonic beam MB. Further, the displacement comparison unit 24 obtains displacement comparison information based on the temporal change of the tissue displacement measured by the displacement measurement unit 22. Then, the coagulation measurement unit 26 obtains a measurement result regarding the coagulation state of the tissue at the treatment site P in the subject based on the displacement comparison information. Specific processing realized by the displacement measuring unit 22, the displacement comparing unit 24, and the coagulation measuring unit 26 will be described in detail later.

  On the other hand, the therapeutic radiation block 30 includes a transmission unit 32, and the transmission unit 32 outputs a transmission signal corresponding to each of the plurality of vibration elements constituting the HIFU transducer 10H, whereby the HIFU transducer 10H. Is controlled to form a therapeutic ultrasonic beam TB. The transmission unit 32 is controlled by the control unit 40, and for example, a therapeutic ultrasonic beam TB is formed with a focus set on each of a plurality of treatment sites in the treatment site P.

  Further, the transmission unit 32 outputs a transmission signal corresponding to each of the plurality of vibration elements constituting the HIFU transducer 10H, thereby controlling the HIFU transducer 10H to form the displacement ultrasonic beam EB. The displacement ultrasonic beam EB is subjected to a modulation process. In the specific example shown in FIG. 1, the therapeutic ultrasonic beam TB is used as the displacement ultrasonic beam EB. That is, the displacement ultrasonic beam EB (= therapeutic ultrasonic beam TB) is formed based on the transmission signal modulated by the modulation processing unit 36 using, for example, a rectangular wave. The modulation processing unit 36 is controlled by the control unit 40.

  When intense focused ultrasound (HIFU) is transmitted along the therapeutic ultrasound beam TB and the treatment site P is heated, the tissue of the treatment site P is coagulated. It is known that the elastic modulus (Young's modulus) of the tissue increases before and after the solidification. Then, in order to know the change in the elastic modulus of the tissue, the ultrasonic medical device in FIG. 1 transmits an ultrasonic wave along the displacement ultrasonic beam EB to generate a radiation force, and a treatment site by the radiation force. The tissue displacement at P is measured. For example, the treatment ultrasonic beam TB is modulated into a rectangular shape and used as the displacement ultrasonic beam EB. The displacement is measured based on the received signal obtained along the measurement ultrasonic beam MB.

  Each unit in the measurement diagnosis block 20 and each unit in the treatment radiation block 30 can be realized by using hardware such as a processor or an electronic circuit, for example. The control unit 40 is configured by, for example, hardware having a calculation function and software (program) that defines the operation thereof. The display unit 50 can be realized by, for example, a liquid crystal display or an organic EL (electroluminescence) display.

  The measurement diagnostic block 20 may be realized by a general ultrasonic diagnostic apparatus. The ultrasonic medical apparatus of FIG. 1 may be realized by a system that combines an ultrasonic therapeutic apparatus corresponding to the therapeutic radiation block 30 and an ultrasonic diagnostic apparatus corresponding to the measurement diagnostic block 20.

  The overall configuration of the ultrasonic medical apparatus in FIG. 1 is as described above. Next, functions and the like realized by the ultrasonic medical apparatus in FIG. 1 will be described. In addition, about the structure (each part which attached | subjected the code | symbol) shown in FIG. 1, the code | symbol of FIG. 1 is utilized in the following description.

FIG. 2 is a diagram illustrating a specific example of tissue displacement caused by a modulated HIFU signal. One preferred specific example of the modulation processing is amplitude modulation processing using a rectangular wave. FIG. 2 shows a specific example of tissue displacement due to a HIFU signal subjected to amplitude modulation processing in a rectangular shape. The HIFU (High Power Focused Ultrasound) signal is a transmission signal of the therapeutic ultrasonic beam TB used as the displacement ultrasonic beam EB, and the amplitude ON period during which the irradiation power is output and the irradiation power are output. The period of amplitude OFF (off) that is not performed is repeated. The HIFU signal is a transmission signal modulated by the modulation processing unit 36 using a rectangular wave. For example, the HIFU signal shown in FIG. 2 can be obtained by subjecting a continuous wave having a frequency of about 2 MHz (megahertz) to amplitude modulation processing using a rectangular wave modulation signal. The fundamental frequency _{f 0} of the modulated signal of a rectangular wave, for example, about 30～200Hz (Hz), preferably is below 100Hz.

  The tissue displacement shown in FIG. 2 is a specific example of the tissue displacement accompanying irradiation of the HIFU signal. When the therapeutic ultrasonic beam TB (displacement ultrasonic beam EB) based on the HIFU signal shown in FIG. 2 is transmitted from the ultrasonic transducer 10 toward the treatment site P, the therapeutic ultrasonic beam TB (displacement) Due to the radiation force of the ultrasonic beam EB), for example, the tissue of the treatment site P is displaced according to the tissue displacement shown in FIG.

  That is, in the period of the amplitude ON when the irradiation power is output, the positive direction (positive direction) that is the direction away from the ultrasonic transducer 10 due to the radiation force of HIFU (therapeutic ultrasonic beam TB = displacement ultrasonic beam EB). ) And the tissue is returned in the negative direction, which is the direction approaching the ultrasonic transducer 10 during the amplitude OFF period when the irradiation power is not output.

  Accordingly, as in the specific example shown in FIG. 2, the tissue is displaced in the + direction (deep side) corresponding to the amplitude ON period of the HIFU signal, and the tissue is moved in the − direction (corresponding to the amplitude OFF period of the HIFU signal). A tissue displacement that is displaced to the shallow side) is obtained. Note that there are cases where the tissue displacement changes in the + direction and the − direction from the change timing of the amplitude ON / OFF of the HIFU signal, for example, with a delay due to the propagation time of the ultrasonic wave.

  The ultrasonic medical apparatus in FIG. 1 obtains effective displacement data (effective displacement data) from the tissue displacement corresponding to the period in which the amplitude of the displacement ultrasound is off. That is, in FIG. 2, effective displacement data is obtained from the tissue displacement during the period when the amplitude of the HIFU signal is OFF. The ultrasonic medical apparatus in FIG. 1 obtains effective displacement data from tissue displacement in a period in which the amplitude of the HIFU signal is OFF, for example, by an operation example described below.

  FIG. 3 is a diagram (timing chart) showing one example of a preferable operation executed by the ultrasonic medical apparatus of FIG. In FIG. 3, the main trigger is a signal indicating the start timing of treatment by high intensity focused ultrasound (HIFU). For example, the ultrasonic medical device shown in FIG. It is output to each part in the device.

  The frame trigger is a signal indicating the start of a frame (measurement frame) of the measurement ultrasonic beam MB. The transmission / reception unit 21 sequentially forms a plurality of measurement ultrasonic beams MB toward the treatment site P in each frame period that starts, for example, every time the frame trigger falls. For example, for each frame period (every frame trigger fall), about 10 to 100 measuring ultrasonic beams MB are sequentially formed toward the treatment site P while being shifted in position. A frame is formed. Note that when forming the measurement ultrasonic beam MB (a set of a transmission beam and a reception beam), a plurality of (for example, two) reception beams may be formed for one transmission beam.

  The heating period signal is a signal indicating a heating process period of the treatment site P by the therapeutic ultrasonic beam TB. In the period from the rising edge to the falling edge of the heating period signal, for example, each treatment area in the treatment area P is focused. A therapeutic ultrasonic beam TB is formed.

  The modulation signal is a rectangular wave modulation signal used for modulation processing of the therapeutic ultrasonic beam TB (= displacement ultrasonic beam EB). The HIFU signal is a transmission signal of the therapeutic ultrasonic beam TB (= displacement ultrasonic beam EB), and the modulation processing unit 36 amplitude-modulates a continuous wave having a frequency of about 2 MHz, for example, according to a rectangular wave modulation signal. Is obtained. The tissue displacement shows a specific example (see FIG. 2) of the tissue displacement accompanying irradiation of the HIFU signal.

  In the operation example shown in FIG. 3, the displacement is measured in a plurality of frames for each period in which the amplitude of the HIFU signal is OFF. Further, the displacement corresponding to the same phase is repeatedly measured in a plurality of periods when the amplitude of the HIFU signal is OFF. For example, as shown in FIG. 3, a plurality of frame triggers are generated and displacements are measured in a plurality of frames for each of periods 1 to 4 in which the amplitude of the HIFU signal is OFF. And the displacement corresponding to each of phase (theta) 1, (theta) 2, (theta) 3, (theta) 4, (theta) 5 is repeatedly measured in several periods 1-4.

  Note that the specific example shown in FIG. 3 is only one of the preferable operation examples, and the ultrasonic medical apparatus in FIG. 1 is effective from the tissue displacement during the period when the amplitude of the HIFU signal is OFF by the operation example other than FIG. Data may be obtained. For example, the tissue displacement is measured using a HIFU signal modulated by a sinusoidal modulation signal, as in the specific example described using FIG. 2 of Patent Document 2 (Japanese Patent No. 5954841). Also good.

  In this way, for example, the displacement is measured in a period in which the amplitude of the HIFU signal is OFF by any operation example including the specific example shown in FIG. The displacement is measured for each of a plurality of beams constituting each frame (each measurement frame). That is, about 10 to 100 measurement ultrasonic beams MB are formed one after another while shifting the position in each frame, and the displacement measurement unit 22 converts the received signal obtained along the measurement ultrasonic beam MB into a received signal. Based on this, the displacement at the treatment site P is measured. Thereby, the displacement is measured two-dimensionally in each frame.

  For example, the displacement measuring unit 22 measures the displacement at each sampling point (each depth) for a plurality of sampling points arranged in the depth direction of the measurement ultrasonic beam MB. For example, for each sampling point, data corresponding to time phases (phases) adjacent to each other are compared by a cross-correlation calculation or the like, and a displacement is calculated for each sampling point (each depth). For example, in the specific example of FIG. 3, the data corresponding to the phase θ1 and the phase θ2 are compared, the data corresponding to the phase θ2 and the phase θ3 are compared, the data corresponding to the phase θ3 and the phase θ4 are compared, and the phase Data corresponding to θ4 and phase θ5 are compared. Further, for example, for 1024 sampling points arranged in the depth direction, the displacement is calculated for each sampling point with the correlation window of the correlation calculation being 64 sampling points.

  Further, for example, the displacement may be calculated by comparing a time phase that is a reference before the heat treatment and the latest time phase. For example, the position of the tissue in the reference time phase before irradiation with the HIFU is set as a steady position (reference position of zero displacement), and the data corresponding to the reference time phase and each time phase (each phase) are calculated by cross-correlation calculation etc. The displacement corresponding to each time phase (each phase) may be calculated by comparison. Prior to the calculation of the displacement, a baseband removal process, a noise removal process, or the like may be performed as necessary.

  And the displacement measurement part 22 derives | leads-out the displacement amount corresponding to the depth for every depth from the displacement of the several time phase (plural phases) measured for every depth (each sampling point). For example, the root mean square (RMS) or effective value of the displacement is calculated from the change in displacement obtained over one period of the modulation signal (rectangular wave) at each depth, and the effective value is calculated as the depth. It may be the amount of displacement.

  The displacement measuring unit 22 calculates the amount of tissue displacement (for example, RMS amplitude) at each depth for each line for all lines constituting the measurement frame. Furthermore, the displacement measuring unit 22 forms a two-dimensional displacement map corresponding to the measurement frame based on the calculated tissue displacement.

  FIG. 4 is a diagram showing a specific example of a two-dimensional displacement amount map. FIG. 4 shows a specific example of a displacement (RMS amplitude) map corresponding to a measurement frame at an arbitrary diagnosis time (After0s).

  In the specific example shown in FIG. 4, the vertical axis of the displacement amount map is the depth direction. In addition, the horizontal axis of the displacement amount map is an arrangement direction (azimuth direction = lateral direction) of a plurality of lines constituting the measurement frame. The displacement amount (RMS amplitude) at each of a plurality of positions arranged two-dimensionally in the vertical axis direction and the horizontal axis direction in the displacement amount map is expressed by, for example, a color difference. In FIG. 4, the color bar indicates the correspondence between the amount of displacement (RMS amplitude) and the color (color). Note that the displacement amount (RMS amplitude) at each position may be expressed by, for example, a difference in luminance instead of or together with the color expression.

  4, for example, if the measurement frame is set to a cross section including the treatment site P (see FIG. 1), a two-dimensional displacement map corresponding to the cross section including the treatment site P is obtained. It is done. The two-dimensional displacement amount map formed by the displacement measuring unit 22 is displayed on the display unit 50.

  In addition, a two-dimensional displacement amount map can be formed for each diagnosis time over a plurality of diagnosis times. For example, two-dimensionally corresponding to a cross section including the treatment site P periodically (for example, at intervals of about 1 to 2 seconds) immediately before or after the start of the heat treatment of the treatment site P by the therapeutic ultrasonic beam TB. A simple displacement map is formed.

  FIG. 5 is a diagram illustrating a specific example of a displacement amount map formed over a plurality of diagnosis times. FIG. 5 shows a displacement amount map formed one after another over a plurality of diagnosis times at intervals of 2 seconds from the diagnosis time 0 seconds to the diagnosis time 26 seconds. For example, the start time of the heat treatment of the treatment site P by the treatment ultrasonic beam TB corresponds to the diagnosis time 0 seconds, and the diagnosis time N seconds corresponds to N seconds after the treatment start.

  The displacement measuring unit 22 forms a displacement amount map over a plurality of diagnosis times, for example, as in the specific example shown in FIG. The formed displacement amount map is displayed on the display unit 50. It is desirable that the two-dimensional displacement amount map obtained over a plurality of diagnosis times is displayed dynamically.

  For example, a displacement amount map display area is provided in the display screen displayed on the display unit 50, and the displacement amount maps from the diagnosis time 0 second to the diagnosis time 26 seconds shown in FIG. Is displayed. As a result, a moving image of a two-dimensional displacement amount map is displayed on the display unit 50. Of course, a two-dimensional displacement map corresponding to a plurality of diagnosis times may be displayed in a frame feed, or a two-dimensional displacement map at a diagnosis time designated by a user such as a doctor or a laboratory technician is a still image. May be displayed.

  In the treatment using the ultrasonic medical apparatus of FIG. 1, for example, a plurality of treatment locations (target locations for treatment) are set in the treatment site P (treatment target region). Then, a therapeutic ultrasonic beam TB having a focus on each of the plurality of treatment locations is formed, and heat treatment is performed for each treatment location to form a coagulation region. In the treatment of a treatment site P such as a tumor, it is desirable to coagulate the entire treatment site P (region to be treated), for example. That is, it is desirable to eliminate a gap (a non-coagulated region) in the coagulation region between each treatment site and the treatment site adjacent thereto. On the other hand, it is not desirable to carry out excessive irradiation of the therapeutic ultrasonic beam TB at each treatment site in terms of safety of treatment and time burden on the patient.

  Therefore, the ultrasonic medical apparatus in FIG. 1 measures the bonding state of coagulation regions formed at a plurality of treatment locations. For example, according to a specific example described in detail below, a measurement result indicating whether or not a plurality of solidified regions are joined is obtained.

  FIG. 6 is a diagram illustrating a specific example of a coagulation region formed in a plurality of treatment locations. FIG. 6 shows a specific example of the coagulation state of the coagulation region formed at the two treatment locations P1 and P2 from the start of irradiation of the therapeutic ultrasonic beam TB (a) to 50 seconds after irradiation (f). Has been. In the specific example shown in FIG. 6, as in the displacement map (see FIG. 4), the vertical axis corresponds to the depth direction, and the horizontal axis corresponds to the azimuth direction (arrangement direction of a plurality of lines). Yes.

  The specific example shown in FIG. 6 corresponds to a specific example in which the coagulation region is formed at the treatment site P2 by irradiating the treatment site P2 with the therapeutic ultrasound beam TB after the coagulation region is formed at the treatment site P1. Yes.

  In the specific example shown in FIG. 6, at the start of irradiation (a), a coagulation region is not formed at the treatment site P2, but after 10 seconds from irradiation (b), a coagulation region around the treatment site P2 is formed, The range of the coagulation region corresponding to the treatment site P2 increases as the irradiation time elapses 20 seconds after irradiation (c) and 30 seconds after irradiation (d). Then, the coagulation region of the treatment site P1 and the treatment site P2 starts to be joined 40 seconds after irradiation (e), and the coagulation region of the treatment site P1 and the treatment site P2 partially overlaps after 50 seconds of irradiation (f). .

  For example, in the specific example shown in FIG. 6, in order to confirm the joining state of the coagulation region of the treatment site P1 and the coagulation region of the treatment site P2, a displacement amount map in a cross section including the treatment site P1 and the treatment site P2 (FIG. 4). Is formed. Furthermore, after the irradiation of the therapeutic ultrasound beam TB is started on the treatment site P2, displacement amount maps are successively formed periodically (at intervals of 10 seconds in the specific example of FIG. 6).

  Moreover, when confirming the joining state of the solidified region, the observation line KL is set to the depth to be observed. The observation line KL is set to a depth at which the coagulation regions at the treatment points P1 and P2 can be confirmed. For example, the observation line KL is set so as to pass through the treatment location P1 and the treatment location P2. Although the observation line KL is desirably set parallel to the azimuth direction, it may be set to have an angle with respect to the azimuth direction. Then, a displacement change map corresponding to the depth at which the observation line KL is set is formed.

  FIG. 7 is a diagram showing a specific example of the displacement change map. The displacement change map shown in FIG. 7 corresponds to a specific example of the coagulation region corresponding to the two treatment locations P1 and P2 shown in FIG. That is, FIG. 7 shows a specific example of the displacement change map obtained from the start of irradiation (a) to 50 seconds after irradiation (f) on the observation line KL in FIG.

  The displacement comparison unit 24 generates a displacement change map from, for example, a displacement amount map (see FIG. 4). In the displacement map (see FIG. 4), the root mean square (RMS) of displacement obtained over one period or more of the modulation signal (rectangular wave) for each depth is used as the displacement. On the other hand, the displacement change map of FIG. 7 shows the change of displacement obtained over one period of the modulation signal (rectangular wave) at the depth corresponding to the observation line KL.

  In the specific example shown in FIG. 7, the vertical axis of the displacement change map corresponds to the azimuth direction (each position on the observation line KL), and the horizontal axis represents the frame (each time phase within one period of the modulation signal). It corresponds. In the displacement change map, the displacement of each pixel of a plurality of pixels (a plurality of display samples) arranged two-dimensionally in the vertical axis direction and the horizontal axis direction is expressed by, for example, a difference in luminance. For example, a pixel corresponding to low luminance (black) corresponds to a displacement in the positive direction (deep direction), and a pixel corresponding to high luminance (white) corresponds to a displacement in the negative direction (shallow direction).

  The displacement change map in FIG. 7 shows the change in displacement obtained over one period of the modulation signal (for example, a rectangular wave) at the depth corresponding to the observation line KL. Therefore, in the displacement change map corresponding to each diagnosis time from the irradiation start time (a) to 50 seconds after the irradiation (f), the displacement at each position in the azimuth direction changes periodically over one period in the frame direction. doing.

  When the displacement change map is formed, the displacement comparison unit 24 obtains displacement comparison information by comparing temporal changes in tissue displacement at a plurality of treatment locations based on the displacement change map. For example, in the case of the specific examples shown in FIGS. 6 and 7, the displacement comparison unit 24 compares temporal changes in tissue displacement at the treatment location P1 and the treatment location P2 based on the displacement change map of FIG. As described above, the phase delay of the tissue displacement at the treatment location P1 with respect to the tissue displacement at the treatment location P2 is derived.

  The displacement comparison unit 24, for example, performs a complex FFT (a temporal change in the tissue displacement at the treatment location P2 (a change in the horizontal frame direction) and a temporal change in the tissue displacement at the treatment location P1 (a change in the horizontal axis direction). (Fast Fourier transform) analysis is performed to calculate a phase lag dθ of the tissue displacement at the treatment location P1 with respect to the tissue displacement at the treatment location P2 (phase difference between the tissue displacement at the treatment location P2 and the treatment location P1). In the specific examples shown in FIGS. 6 and 7, the displacement comparison unit 24 calculates the phase delay dθ at each diagnosis time from the start of irradiation (a) to 50 seconds after irradiation (f).

  In the specific examples of FIGS. 6 and 7, after the coagulation region is formed at the treatment location P1, that is, in the state where the coagulation region corresponding to the treatment location P1 has already been formed, the therapeutic ultrasonic beam TB is applied to the treatment location P2. Is irradiated. When the therapeutic ultrasound beam TB is irradiated to the treatment site P2, the tissue at the treatment site P2 is periodically displaced by the modulated HIFU signal (see FIGS. 2 and 3).

  When the tissue at the treatment location P2 is periodically displaced, the tissue at the treatment location P1 in the vicinity of the treatment location P2 is periodically displaced so as to follow the tissue at the treatment location P2. If the coagulation region at the treatment site P2 is small and there is a gap in the coagulation region (non-coagulated region) between the treatment site P2 and the treatment site P1, the tissue in the gap is relatively soft. The tissue displacement of the treatment site P1 follows the displacement with a delay. As the coagulation region at the treatment site P2 becomes larger due to the irradiation with the therapeutic ultrasonic beam TB, the gap between the treatment site P2 and the treatment site P1 becomes smaller, so that the treatment site P1 with respect to the tissue displacement of the treatment site P2 The follow-up ability of the tissue displacement becomes higher. When the coagulation region at the treatment location P2 becomes large and is joined to the coagulation region at the treatment location P1, the region from the treatment location P2 to the treatment location P1 becomes substantially one large coagulation region, and the tissue displacement of the treatment location P2 is reduced. The delay in tissue displacement at the treatment site P1 is extremely small.

  Thus, when the coagulation region at the treatment location P2 is small, the tissue displacement at the treatment location P1 follows the tissue displacement at the treatment location P2 with a delay, so the phase delay dθ is relatively large. Further, as the coagulation region at the treatment location P2 increases, the followability of the tissue displacement at the treatment location P1 increases, and therefore the phase delay dθ gradually decreases. Furthermore, when the coagulation region at the treatment point P2 becomes large and is joined to the coagulation region at the treatment point P1, the phase delay dθ becomes extremely small.

  FIG. 8 is a diagram illustrating a specific example of the time change of the phase delay dθ. In FIG. 8, the horizontal axis is the time axis, and the vertical axis is the phase delay dθ. In the specific example shown in FIG. 8, the phase delay dθ immediately after the start of irradiation of the therapeutic ultrasonic beam TB is about 25 degrees, and the phase difference between the treatment location P1 and the treatment location P2 is detected significantly. However, the phase delay dθ decreases with the passage of time, and the phase delay dθ decreases to about 12 degrees in about 20 seconds from the start of the irradiation of the therapeutic ultrasonic beam TB. In this way, the case where the initial phase delay dθ has changed to a value that can be regarded as sufficiently small, or the case where the change on the time axis has become sufficiently small, is determined by, for example, comparison with a preset threshold value. By doing, it can be determined whether the coagulation | solidification area | region of the treatment location P1 and the treatment location P2 joined without a gap.

  Therefore, the coagulation measurement unit 26 obtains a measurement result relating to the joining state of the coagulation regions formed at a plurality of treatment locations based on the displacement comparison information obtained from the displacement comparison unit 24. For example, in the specific examples shown in FIGS. 6 and 7, the coagulation measuring unit 26 is based on the phase lag dθ obtained from the displacement comparing unit 24 to determine the bonding state of the coagulation region at the treatment site P1 and the coagulation region at the treatment site P2. Obtain the judgment result.

  The coagulation measurement unit 26 compares, for example, the phase delay dθ obtained at each diagnosis time from the start of irradiation (a) to 50 seconds after irradiation (f) with a determination threshold, and the phase delay dθ is equal to or less than the determination threshold ( Or, it is determined that the coagulation region at the treatment location P1 and the coagulation region at the treatment location P2 are joined at the diagnosis time that is smaller than the determination threshold. Note that the determination threshold is set based on, for example, a large number of measurement results performed in the past. For example, the determination threshold value corresponding to one of the bonding states of 30 seconds after irradiation (d), 40 seconds after irradiation (e), and 50 seconds after irradiation (f) in FIG. 6 is set. Of course, for example, a user such as a doctor or a laboratory technician may adjust the determination threshold.

  Further, the coagulation measurement unit 26 uses the displacement change map obtained from the displacement comparison unit 24 as displacement comparison information, and based on the displacement change map, the measurement result relating to the bonding state of the coagulation regions formed at a plurality of treatment locations. May be obtained. For example, in the specific examples shown in FIGS. 6 and 7, the coagulation measuring unit 26 uses a displacement change map obtained at each diagnosis time from the start of irradiation (a) to 50 seconds after irradiation (f) and a joint determination. The coagulation region at the treatment location P1 and the coagulation region at the treatment location P2 are joined at the diagnosis time when the displacement change map that matches the reference map (which has a large correlation with the reference map) is obtained. May be determined. The reference map is formed based on, for example, a large number of measurement results performed in the past.

  Thus, when the coagulation measurement unit 26 determines that the coagulation region of the treatment site P1 and the coagulation region of the treatment site P2 are joined, for example, the control unit 40 controls the transmission unit 32 to treat the treatment site P2. Irradiation of the ultrasonic beam TB for use is stopped. As a result, while suppressing excessive irradiation of the therapeutic ultrasound beam TB to the treatment location P2, the gap between the coagulation region at the treatment location P1 and the treatment location P2 can be made as small as possible, and preferably the gap can be eliminated. .

  In the treatment using the ultrasonic medical apparatus of FIG. 1, for example, a therapeutic ultrasonic beam TB is formed with each of a plurality of treatment sites set in the treatment site P as a focal point. At that time, for each treatment site where the therapeutic ultrasound beam TB is formed, the bonding state between the coagulation region at the treatment site and the coagulation region at the treatment site adjacent to the treatment site is determined.

  Further, during the period in which the treatment ultrasonic beam TB is irradiated to each treatment site, the displacement corresponding to the cross section including the treatment site and the treatment site adjacent to the treatment site (the treatment site for which the bonding state is determined) It is desirable to display the quantity map (FIGS. 4 and 5) on the display unit 50.

  Moreover, in the specific examples shown in FIGS. 6 and 7, the joint state of the coagulation region at the treatment location P1 and the treatment location P2 is determined at the depth corresponding to one observation line KL. A plurality of observed lines KL may be set, and based on determination results at a plurality of depths, the joint state of the coagulation region at the treatment location P1 and the treatment location P2 may be comprehensively determined.

  FIG. 9 is a diagram illustrating a specific example of a plurality of observation lines KL. FIG. 9 illustrates a preferred specific example of a plurality of observation lines KL (KLu, KLc, KLd) used when determining the joining state of the coagulation regions formed at the two treatment locations P1, P2. Yes.

  The plurality of observation lines KL are set to a plurality of depths at which the coagulation regions at the treatment points P1 and P2 can be confirmed. In the specific example shown in FIG. 9, the central observation line KLc is set so as to pass through the treatment spot P1 and the treatment spot P2, and the upper observation line KLu is set at a position shallower than the central observation line KLc. A lower observation line KLd is set at a position deeper than the line KLc. The interval between the observation lines KL adjacent to each other may be a predetermined fixed value, for example, or may be changed to an interval according to a treatment target (observation target) or the like.

  Then, a displacement change map (FIG. 7) is formed for each depth for which each observation line KLc, KLu, KLd is set, and the coagulation region at the treatment site P1 and the coagulation region at the treatment site P2 are joined at each depth. It is determined whether or not. Thus, for example, in the case where all of the three depths corresponding to the observation lines KLc, KLu, and KLd have been confirmed to have joined the coagulation region at the treatment location P1 and the treatment location P2, the coagulation at the treatment location P1 and the treatment location P2 is confirmed. It is comprehensively determined that the regions are joined.

  For example, when the junction can be confirmed at the depth corresponding to the observation line KLc and the junction is not confirmed at the depth corresponding to the observation line KLu and the observation line KLd, the therapeutic ultrasonic beam for the treatment location P2 is used. The focal point of TB may be changed to a depth corresponding to the observation line KLu or the observation line KLd, and irradiation of the therapeutic ultrasound beam TB to the treatment site P2 may be resumed.

  In the treatment of irradiating each of the plurality of treatment locations with the therapeutic ultrasound beam TB, the coagulation region at the nearest treatment location in the direction of interest is determined from the treatment location irradiated with the treatment ultrasound beam TB. As an object, it is desirable to determine the joining state.

  FIG. 10 is a diagram illustrating a specific example of the direction of interest. FIG. 10 illustrates a specific example of a plurality of treatment locations P1 to P14 and Pn set in the treatment site P (treatment target region), for example. Further, FIG. 10 shows specific examples (D1 to D6) of the direction of interest when the therapeutic ultrasonic beam TB is irradiated to the treatment site Pn.

  In the specific example shown in FIG. 10, in the case of the treatment in which the treatment ultrasound beam TB is irradiated to the treatment site Pn, for example, if the direction of interest is D1, it is already formed at the nearest treatment site P1 in the direction of D1. The solidified region that is being treated is determined as a joint state determination target, and the joint state between the solidified region formed at the treatment location Pn and the solidification region at the treatment location P1 is determined.

  In the specific example shown in FIG. 10, for example, if the direction of interest is D2, the coagulation region of the closest treatment site P2 in the direction D2 is determined as the determination target of the joint state. Similarly, if the direction of interest is any one of D3 to D6, any one of the coagulation regions of the treatment locations P3 to P6 corresponding to each direction is determined as a joining state determination target.

  In the specific example shown in FIG. 10, if a coagulation region has already been formed at the treatment site P7 or the treatment site P8, the coagulation region at the treatment site P7 or the treatment site P8 may be determined as a joint state determination target.

  As mentioned above, although preferred embodiment of this invention was described, embodiment mentioned above is only a mere illustration in all the points, and does not limit the scope of the present invention. The present invention includes various modifications without departing from the essence thereof. Needless to say, treatment using the ultrasonic medical device according to the present invention should be performed with sufficient care under the guidance of a specialist such as a doctor.

  DESCRIPTION OF SYMBOLS 10 Ultrasonic transducer, 20 Measurement diagnostic block, 21 Transmission / reception part, 22 Displacement measurement part, 24 Displacement comparison part, 26 Coagulation measurement part, 28 Ultrasound image formation part, 30 Treatment radiation block, 32 Transmission part, 36 Modulation process part , 40 control unit, 50 display unit.

Claims (5)

A displacement measuring unit for measuring tissue displacement in a noticeable coagulation region and tissue displacement in a reference coagulation region due to vibration by ultrasonic waves;
A displacement comparison unit that obtains displacement comparison information by comparing the time change of the tissue displacement in the focused coagulation region and the time change of the tissue displacement in the reference coagulation region;
A coagulation measuring unit for obtaining a measurement result relating to a joining state of the focused solidification region and the reference solidification region based on the displacement comparison information;
Having
An ultrasonic medical device. The ultrasonic medical device according to claim 1,
In the treatment in which a coagulation region is formed for each of a plurality of treatment locations, the coagulation measurement unit refers to the coagulation region corresponding to the closest treatment location in the direction of interest from the treatment location corresponding to the attention coagulation region. As a solidification region, to obtain a measurement result relating to the bonding state of the attention solidification region and the reference solidification region,
An ultrasonic medical device. The ultrasonic medical device according to claim 1 or 2,
The displacement measuring unit measures tissue displacement at a plurality of depths of the focused coagulation region and tissue displacement at a plurality of depths of the reference coagulation region,
The displacement comparison unit derives the displacement comparison information for each depth of a plurality of depths by comparing the temporal change of the tissue displacement at the corresponding depths of the attention coagulation region and the reference coagulation region,
The solidification measurement unit obtains a measurement result relating to a bonding state of the target solidification region and the reference solidification region based on the displacement comparison information obtained for each depth of a plurality of depths.
An ultrasonic medical device. The ultrasonic medical device according to any one of claims 1 to 3,
The coagulation measurement unit derives the measurement result indicating whether or not the target coagulation region and the reference coagulation region are joined in the treatment by irradiation of ultrasonic waves to the treatment site corresponding to the target coagulation region,
When the measurement result indicating that the target coagulation region and the reference coagulation region are bonded is obtained, the irradiation of ultrasonic waves to the treatment site corresponding to the target coagulation region is stopped.
An ultrasonic medical device. The ultrasonic medical device according to any one of claims 1 to 4,
The displacement comparison unit derives a phase difference of tissue displacement in the attention coagulation region and the reference coagulation region as the displacement comparison information based on a temporal change in tissue displacement in the attention coagulation region and the reference coagulation region,
The solidification measurement unit obtains the measurement result indicating that the target solidification region and the reference solidification region are joined when the determination condition indicating that the phase difference is small is satisfied.
An ultrasonic medical device.