JP2017023498A - Ultrasonic medical apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved technology for transmitting and receiving a diagnostic ultrasonic wave to form an ultrasonic image while transmitting a medical ultrasonic wave.SOLUTION: An HIFU vibrator 10H transmits a medical ultrasonic wave and a diagnostic vibrator 10D transmits a diagnostic ultrasonic wave. The diagnostic vibrator 10D also receives a first ultrasonic wave obtained by transmitting the medical ultrasonic wave to a treatment portion P and a second ultrasonic wave obtained by transmitting the diagnostic ultrasonic wave to the treatment portion P together with the medical ultrasonic wave. A difference arithmetic processing unit 22 obtains difference information by difference processing based on reception information obtained by receiving the second ultrasonic wave and reception information obtained by receiving the first ultrasonic wave. An ultrasonic image of the treatment portion P is formed based on the difference information.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasonic medical apparatus for transmitting therapeutic ultrasonic waves.

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

  In treatment using therapeutic ultrasound, it is desirable to confirm the progress of coagulation at the treatment site due to heating. For example, since the acoustic characteristics and the like change when the tissue coagulates, a method of measuring the coagulation region by extracting the change from the received signal (RF signal) of the ultrasonic diagnostic apparatus and mapping it on the image. Is known (see Non-Patent Documents 1 and 2).

  In treatments using therapeutic ultrasound, an interval (the period for stopping the transmission of therapeutic ultrasound) can be set, and diagnostic ultrasound can be sent and received during that interval to check the image. Cannot confirm the tissue state at the time of transmitting therapeutic ultrasonic waves. In particular, when a tissue state is confirmed by a three-dimensional ultrasonic image, it takes time to transmit and receive ultrasonic waves for forming a three-dimensional ultrasonic image. Period) is relatively long.

  Therefore, it is desirable to be able to form an ultrasound image by transmitting and receiving diagnostic ultrasound while irradiating therapeutic ultrasound. For example, in Patent Document 1 and Non-Patent Document 3, ultrasonic waves for image formation are transmitted and received while irradiating therapeutic ultrasonic waves, and therapeutic ultrasonic waves are generated by a notch filter having a frequency corresponding to therapeutic ultrasonic waves (HIFU). A method for removing a component of sound waves has been proposed. Further, in Non-Patent Document 4, ultrasonic waves for image formation are transmitted and received while irradiating therapeutic ultrasonic waves, and a therapeutic ultrasonic wave is applied by applying a pulse inversion method to irradiation of therapeutic ultrasonic waves (HIFU). There has been proposed a method for removing these components.

US Patent Application Publication No. 2009/0240148

Ryo Matsuzawa and three others, "Monitoring of Lesion Induced by High-Intensity Focused Ultrasound Using Correlation Method Based on Block Matching", Japanese Journal of Applied Physics 51 (2012) 07GF26 Shoya Sasaki and 4 others, “Monitoring of high-intensity focused ultrasound lesion formation using decorrelation between high-speed ultrasonic images by parallel beamforming”, Japanese Journal of Applied Physics 53, 07KF10 (2014) Jong Seob Jeong and two others, "Adaptive HIFU noise cancellation for simultaneous therapy and imaging using an integrated HIFU / imaging transducer", Physics In Medicine and Biology 55 (2010) 1889-1902 Jae Hee Song, 3 others, “Real-time monitoring of HIFU treatment using pulse inversion”, Physics In Medicine and Biology 58 (2013) 5333-5350

  However, in the method of removing the therapeutic ultrasonic wave (HIFU) component by the notch filter, in order to set the optimal notch filter according to the therapeutic ultrasonic wave component that changes momentarily according to the irradiation situation, it is complicated. An algorithm or the like is required, and for example, real-time performance may be impaired. In addition, in the technique of applying the pulse inversion method to the irradiation of therapeutic ultrasonic waves (HIFU) and removing the components of therapeutic ultrasonic waves, a pair of frequency bands of therapeutic ultrasonic waves and diagnostic ultrasonic waves is used. Appropriate combinations must be made and applicable cases may be limited.

  As described above, there are some problems to be solved in the conventional technique of forming ultrasonic images by transmitting and receiving diagnostic ultrasonic waves for image formation while irradiating therapeutic ultrasonic waves.

  An object of the present invention is to provide an improved technique for forming an ultrasound image by transmitting and receiving diagnostic ultrasound while transmitting therapeutic ultrasound.

  A suitable ultrasonic medical apparatus that meets the above-described purpose transmits a first ultrasonic wave obtained by transmitting a therapeutic ultrasonic wave to a treatment site and a diagnostic ultrasonic wave together with the therapeutic ultrasonic wave to the treatment site. A plurality of vibration elements for receiving the second ultrasonic wave obtained by the above, reception information obtained by receiving the second ultrasonic wave, and reception information obtained by receiving the first ultrasonic wave, And a difference processing unit that obtains difference information by difference processing based on, and forming an ultrasonic image of the treatment site based on the difference information.

  In the above configuration, the diagnostic ultrasound has the same characteristics (frequency, waveform, intensity) as the ultrasound for image formation in a general ultrasound diagnostic apparatus, and uses a plurality of diagnostic vibration elements. You can send and receive. On the other hand, therapeutic ultrasonic waves are ultrasonic waves having a relatively high intensity that can heat-treat a treatment site. The therapeutic ultrasound has a higher intensity than, for example, diagnostic ultrasound, and particularly high intensity focused ultrasound (HIFU) is a preferred specific example of therapeutic ultrasound.

  According to the ultrasonic medical device having the above configuration, an ultrasonic image of a treatment site can be formed based on difference information obtained by transmitting and receiving diagnostic ultrasonic waves while transmitting therapeutic ultrasonic waves. Accordingly, for example, a user such as a doctor can perform treatment while confirming the state of the treatment site with an ultrasonic image while irradiating therapeutic ultrasonic waves.

  In a preferred embodiment, the ultrasonic medical device obtains a second reception signal corresponding to the second ultrasonic wave and a first reception signal corresponding to the first ultrasonic wave for each vibration element of the plurality of vibration elements. The difference processing unit forms a difference signal by performing a difference process on the second reception signal and the first reception signal of the vibration element for each vibration element of the plurality of vibration elements, An ultrasonic image of the treatment site is formed based on a plurality of differential signals corresponding to the plurality of vibration elements.

  In a preferred embodiment, the ultrasonic medical device includes a phasing addition processing unit that obtains a beam signal of a plurality of beams by performing a phasing addition process on the plurality of difference signals, and the treatment based on the beam signal of the plurality of beams. It further has an image forming part which forms an ultrasonic image of a part.

  In a preferred embodiment, the ultrasonic medical device obtains a second reception signal corresponding to the second ultrasonic wave and a first reception signal corresponding to the first ultrasonic wave for each vibration element of the plurality of vibration elements. The receiving unit and a plurality of second reception signals corresponding to the plurality of vibration elements are subjected to phasing addition processing to form a second reception beam signal for each of the plurality of beams, and corresponding to the plurality of vibration elements A phasing addition processing unit that forms a first reception beam signal for each of the plurality of beams by performing phasing addition processing on the plurality of first reception signals, and the difference processing unit includes each of the plurality of beams. A differential beam signal is formed by performing differential processing on the second received beam signal and the first received beam signal for each beam, and an ultrasonic image of the treatment site based on a plurality of differential beam signals corresponding to the plurality of beams. Formed, characterized in that.

  In a preferred embodiment, the ultrasonic medical device receives the first ultrasonic wave by sequentially forming a therapeutic beam for a plurality of positions in the treatment site and transmitting the therapeutic ultrasonic wave. Further, the second ultrasonic wave is formed by sequentially forming a therapeutic beam for the plurality of positions and transmitting the therapeutic ultrasonic wave and scanning the diagnostic beam to transmit the diagnostic ultrasonic wave. The difference processing unit obtains difference information for each position of the plurality of positions by difference processing based on the reception information of the second ultrasonic wave and the reception information of the first ultrasonic wave corresponding to the position. It is characterized by acquiring.

  According to the present invention, there is provided an improved technique for forming an ultrasound image by transmitting and receiving diagnostic ultrasound while transmitting therapeutic ultrasound. For example, according to a preferred aspect of the present invention, an ultrasonic image of a treatment site can be formed based on difference information obtained by transmitting and receiving diagnostic ultrasonic waves while transmitting therapeutic ultrasonic waves.

1 is a diagram showing an overall configuration of an ultrasonic medical apparatus suitable for implementing the present invention. It is a figure for demonstrating the specific example 1 of a difference process. It is a figure for demonstrating the specific example 1 of a received signal process. It is a figure which shows the specific example of an ultrasonic image. It is a figure which shows the specific example of a coagulation | solidification area | region estimation image. FIG. 6 is a diagram for explaining an operation example 1 of the ultrasonic medical apparatus in FIG. 1. It is a figure for demonstrating the specific example 2 of a difference process. It is a figure for demonstrating the specific example 2 of a received signal process. FIG. 6 is a diagram for explaining an operation example 2 of the ultrasonic medical apparatus in FIG. 1. It is a figure which shows the specific example of the focus of a treatment beam. It is a figure which shows the specific example of the focus movement of a therapeutic beam, and a reception process. It is a figure which shows the general example of the focus movement of a therapeutic beam, and a reception process. It is a figure which shows another specific example of the focus movement of a therapeutic beam, and a reception process. 3 is a flowchart showing a preferred operation example of the ultrasonic medical apparatus in FIG. 1.

  FIG. 1 is an overall configuration diagram of an ultrasonic medical apparatus (the present ultrasonic medical apparatus) suitable for implementing the present invention. This ultrasonic medical apparatus has a composite ultrasonic transducer 10, and the ultrasonic transducer 10 includes a HIFU transducer 10H and a diagnostic transducer 10D.

  The HIFU transducer 10H is a transducer that transmits strong focused ultrasound (HIFU), which is a preferred specific example of therapeutic ultrasound, and includes, for example, a plurality of transducer 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.

  On the other hand, the diagnostic transducer 10D includes, for example, a plurality of vibration elements arranged one-dimensionally, and for example, a comparison for forming an ultrasound image on a subject (patient) having a treatment site P. Send and receive weak ultrasonic waves. That is, ultrasonic waves having the same intensity (energy) as that of ultrasonic waves used when forming an ultrasonic image in a known general ultrasonic diagnostic apparatus are transmitted and received. The diagnostic transducer 10D scans the diagnostic ultrasonic beam DB within a cross section including the treatment site P. Note that the diagnostic transducer 10D includes, for example, a plurality of vibration elements arranged two-dimensionally, so that the diagnostic ultrasonic beam DB can be scanned three-dimensionally in the space including the treatment site P. Good.

  The ultrasonic transducer | vibrator 10 makes the inside surface dented in bowl shape like a 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. Further, the HIFU transducer 10H and the diagnostic transducer 10D may constitute an integrated ultrasonic transducer 10 as shown in FIG. 1, or may be separate types that are physically separated from each other. .

  The transmission / reception unit 12 controls the HIFU transducer 10H by outputting a transmission signal (transmission signal of therapeutic ultrasonic waves) corresponding to each of the plurality of transducer elements constituting the HIFU transducer 10H, thereby treating the HIFU transducer 10H. An ultrasonic beam TB is formed. Further, the transmission / reception unit 12 controls the diagnostic transducer 10D by outputting a transmission signal (transmission signal of diagnostic ultrasonic waves) corresponding to each of the plurality of vibration elements constituting the diagnostic transducer 10D. A diagnostic ultrasonic transmission beam is formed, and an ultrasonic reception signal is obtained from each of the plurality of vibration elements.

  The reception signal processing block 20 is a block for processing reception signals obtained from a plurality of vibration elements constituting the diagnostic transducer 10D. The reception signal processing block 20 includes a difference calculation processing unit 22, a phasing addition processing unit 24, and a notch filter processing unit 26. Composed. The processing in the reception signal processing block 20 will be described in detail later.

  The ultrasonic image forming unit 30 forms an ultrasonic image of the treatment site P based on reception information (signal or data) after reception processing obtained from the reception signal processing block 20. The ultrasonic image forming unit 30 forms a B-mode image of the treatment site P, for example. In addition, when the diagnostic transducer 10D includes a plurality of vibration elements arranged two-dimensionally, a three-dimensional ultrasonic image in which the treatment site P is three-dimensionally displayed may be formed. The ultrasonic image formed in the ultrasonic image forming unit 30 is displayed on the display unit 32.

  The ultrasonic image forming unit 30 forms an ultrasonic image over a plurality of frames (a plurality of time phases) during a treatment period in which the treatment site P is heated and treated with intense focused ultrasound (HIFU). The cross-correlation processing unit 40 applies cross-correlation processing such as block matching (pattern matching) between the frames of ultrasonic images obtained over a plurality of frames. When the tissue is heated and solidified, the acoustic characteristics of the tissue change, so that an image difference accompanying the change occurs between frames of the ultrasonic image. An image difference between the frames is detected by cross-correlation processing. For example, the measurement principle disclosed in Non-Patent Documents 1 and 2 can be applied to the processing in the cross-correlation processing unit 40.

  The solidified region estimation unit 50 estimates a solidified region that is considered to have been solidified by heating, based on the calculation result in the cross correlation processing unit 40. For example, the coagulation region estimation unit 50 may form a coagulation region estimation image that indicates the degree of coagulation in color in a cross section corresponding to the ultrasonic image or as an image different from the ultrasonic image. The solidified region estimation image is displayed on the display unit 32.

  The control unit 70 generally controls the inside of the ultrasonic medical apparatus in FIG. The overall control by the control unit 70 also reflects an instruction received from a user such as a doctor or a laboratory technician via the operation device 60.

  Among the configurations shown in FIG. 1 (respectively assigned parts), the transmission / reception unit 12, the difference calculation processing unit 22, the phasing addition processing unit 24, the notch filter processing unit 26, the ultrasonic image forming unit 30, and the cross correlation processing unit. 40 and each part of the coagulation area | region estimation part 50 can be implement | achieved using hardware, such as an electrical and electronic circuit and a processor, for example, and devices, such as a memory, may be utilized for the implementation | achievement as needed. In addition, at least some of the functions corresponding to the above-described units may be realized by a computer. That is, at least a part of the functions corresponding to the above-described units may be realized by cooperation between hardware such as a CPU, a processor, and a memory and software (program) that defines the operation of the CPU and the processor.

  A suitable specific example of the display unit 32 is a liquid crystal display or the like, and the operation device 60 can be realized by at least one of a mouse, a keyboard, a trackball, a touch panel, and other switches, for example. And the control part 70 is realizable by cooperation with hardware (CPU, a processor, memory, etc.) and the software (program) which prescribes | regulates operation | movement of CPU, a processor, for example.

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

  This ultrasonic medical device performs treatment of the treatment site P by irradiating the intense focused ultrasound (HIFU), which is a preferable specific example of the treatment ultrasound, and transmits and receives diagnostic ultrasound to the treatment site P. An ultrasound image is formed. Specifically, the first ultrasonic wave obtained by transmitting the therapeutic ultrasonic wave (strongly focused ultrasonic wave) to the treatment site P and the diagnostic ultrasonic wave together with the therapeutic ultrasonic wave are transmitted to the treatment site P. The 2nd ultrasonic wave obtained by this is received, and the difference process based on the receiving information corresponding to a 2nd ultrasonic wave and the receiving information corresponding to a 1st ultrasonic wave is performed.

  FIG. 2 is a diagram for explaining a specific example 1 of the difference processing. FIG. 2A illustrates a first reception signal obtained by transmitting a HIFU that is a therapeutic ultrasonic wave to the treatment site P. The first received signal in FIG. 2 (1) transmits the HIFU from the HIFU transducer 10H to the treatment site P without transmitting the diagnostic ultrasound from the diagnostic transducer 10D. It corresponds to the received signal obtained for each 10D vibrating element.

  FIG. 2 (2) shows a second received signal obtained by transmitting HIFU to the treatment site P and transmitting diagnostic ultrasonic waves. The second received signal in FIG. 2 (2) is used for diagnosis by transmitting diagnostic ultrasound from the diagnostic transducer 10D while transmitting the HIFU from the HIFU transducer 10H to the treatment site P. This corresponds to a received signal obtained for each vibration element of the vibrator 10D. The second received signal in FIG. 2 (2) includes a HIFU response period, which is a period of a received signal obtained by transmitting only the HIFU without transmitting diagnostic ultrasonic waves, and a diagnostic signal together with the HIFU. A HIFU + diagnostic response period, which is a period of a reception signal obtained by transmitting an ultrasonic wave, is included.

  FIG. 2 (3) shows a differential signal obtained by subtracting the first received signal from the second received signal (difference processing). In Specific Example 1 shown in FIG. 2, the difference calculation processing unit 22 forms a difference signal by subtracting the first reception signal from the second reception signal for each vibration element of the diagnostic transducer 10 </ b> D.

  Since the second received signal is a received signal obtained by transmitting diagnostic ultrasound together with HIFU that is therapeutic ultrasound, the second received signal includes a received signal component associated with the diagnostic ultrasound and a received signal component associated with the HIFU. Yes. On the other hand, since the first reception signal is a reception signal obtained by transmitting only the HIFU, only the reception signal component accompanying the HIFU is included. Therefore, by subtracting the first received signal from the second received signal, the received signal component associated with the diagnostic ultrasound is dominant, and preferably, the differential signal is only the received signal component associated with the diagnostic ultrasound. Is obtained.

  For example, based on the waveform of the second received signal in the HIFU response period and the waveform of the first received signal, the difference calculation processing unit 22 executes the difference processing after aligning the phases and amplitudes of these two waveforms with each other. Is desirable. The first received signal may be formed based on the waveform of the second received signal in the HIFU response period. That is, the HIFU response period of the second received signal may be used as the first received signal.

  Further, the notch filter processing unit 26 may execute notch filter processing. That is, notch filter processing (band elimination filter processing) for removing frequencies corresponding to therapeutic ultrasound (HIFU) may be performed. The notch filter is designed, for example, to remove frequencies corresponding to the fundamental wave, the second harmonic, and the third harmonic of the HIFU. For example, the notch filter processing unit 26 performs notch filter processing on the difference signal obtained by subtracting the first reception signal from the second reception signal, thereby receiving the received signal component accompanying the HIFU remaining in the difference signal. Remove. Note that the notch filter processing unit 26 may remove the received signal component associated with the HIFU by performing notch filter processing on the second received signal.

  FIG. 3 is a diagram for explaining a specific example 1 of the received signal processing. FIG. 3 shows a second received signal set composed of a plurality of second received signals (FIG. 2 (2)) corresponding to a plurality of vibrating elements (all elements) of the diagnostic transducer 10D, and the plurality of vibrating elements ( A first received signal set composed of a plurality of first received signals (FIG. 2 (1)) corresponding to all elements) and a plurality of differential signals (FIG. 2 (3) corresponding to the plurality of vibration elements (all elements)). ) Is shown.

  When the difference signal set is obtained by the difference processing in the difference calculation processing unit 22, the phasing addition processing unit 24 includes a plurality of difference signals constituting the difference signal set, that is, a plurality of vibration elements (all elements) of the diagnostic transducer 10D. ), A known phasing addition process (beam forming) is executed on the plurality of differential signals corresponding to () to form beam data for each received beam.

  For example, when a plurality of ultrasonic beams are formed by scanning diagnostic ultrasonic waves, the second received signal set and the first received signal set are obtained for each transmitted beam of diagnostic ultrasonic waves, and differential processing is performed. Thus, a differential signal set is formed, and beam data of each reception beam corresponding to the transmission beam is formed by phasing addition processing on the differential signal set. Then, by scanning the diagnostic ultrasonic wave to obtain beam data of a plurality of reception beams corresponding to a plurality of transmission beams constituting one frame, the beam data corresponding to a plurality of reception beams constituting one frame is formed. A differential beam data set is formed.

  Note that parallel reception for forming beam data of a plurality of reception beams may be executed for each transmission beam of diagnostic ultrasound, or a known transmission that transmits a plane wave of diagnostic ultrasound multiple times at different angles. A compound may be executed.

  The difference beam data set is successively formed over a plurality of frames for each frame, and image data of an ultrasound image is formed by the ultrasound image forming unit 30 based on the difference beam data set.

  FIG. 4 is a diagram illustrating a specific example of an ultrasonic image. The ultrasonic image forming unit 30 forms an ultrasonic image for each frame based on the differential beam data set of a plurality of frames obtained by the processing in the reception signal processing block 20. For example, a B-mode image is a preferable specific example as an ultrasonic image.

  In the specific example shown in FIG. 4, the ultrasound image 34 is a B-mode image corresponding to a cross section including the treatment site P, that is, a scanning plane (ZX plane) realized by the diagnostic transducer 10D. An ultrasonic acoustic medium (for example, water) is inserted between the ultrasonic transducer 10 and the subject. In the ultrasonic image shown in FIG. 4, a tomographic image of the living body (subject) 36 including the treatment site P and the acoustic medium (water) 35 is displayed.

  The ultrasonic image forming unit 30 forms an ultrasonic image 34 that reflects the treatment site P and the vicinity thereof for each frame over a plurality of frames. The formed ultrasonic image 34 is displayed on the display unit 32.

  According to the ultrasonic medical device (FIG. 1), an ultrasonic image showing the treatment site P and the vicinity thereof can be displayed on the display unit 32 while the treatment site P is irradiated with the HIFU that is the treatment ultrasound. it can. Therefore, for example, a user such as a doctor can check an ultrasonic image of the treatment site P while irradiating the treatment site P with HIFU. Therefore, for example, if there is an abnormality such as the occurrence of unintentional cavitation in the vicinity of the treatment site P while irradiating HIFU, a user such as a doctor may operate the operation device 60 to stop HIFU irradiation. Can do. Of course, a user such as a doctor can also stop the irradiation of the HIFU by operating the operation device 60 when the treatment of the treatment site P reaches the intended state.

  In addition, the ultrasonic medical apparatus (FIG. 1) forms a coagulation region estimation image indicating the degree of coagulation in color within a cross section corresponding to the ultrasonic image 34 or as an image different from the ultrasonic image 34. To do.

  FIG. 5 is a diagram illustrating a specific example of a coagulation region estimation image. FIG. 5 shows a specific example of a coagulation region estimation image showing a coagulation state in the ultrasonic image 34. The solidified region estimation image is formed by the solidified region estimation unit 50 based on the result of the correlation calculation in the cross correlation processing unit 40.

  The cross-correlation processing unit 40 performs cross-correlation processing such as block matching (pattern matching) between frames of the ultrasonic image 34 obtained over a plurality of frames. When the tissue is heated and coagulated, the acoustic characteristics of the tissue change, so that an image difference due to the change occurs between the frames of the ultrasonic image 34. An image difference (for example, a luminance difference) between the frames is detected by cross-correlation processing.

  The cross-correlation processing unit 40 applies cross-correlation processing within the region of interest ROI set in the ultrasonic image 34, for example. The region of interest ROI may be set by using the operation device 60 by the user who has confirmed the ultrasonic image 34 displayed on the display unit 32. For example, the position of the treatment site P is surrounded by the ultrasonic medical apparatus. In this way, the ultrasonic image 34 may be set.

  The solidified region estimation unit 50 estimates a solidified region that is considered to have been solidified by heating, based on the calculation result in the cross correlation processing unit 40. For example, in the region of interest ROI set in the ultrasonic image 34, the coagulation region estimation unit 50 forms, for example, a coagulation region estimation image indicating a color corresponding to the correlation value, that is, indicating the degree of coagulation in color. To do. The formed solidified region estimation image is displayed on the display unit 32.

  The solidified region estimation unit 50 may determine whether or not the solidified region has reached a target state based on the calculation result in the cross correlation processing unit 40. For example, the coagulation region estimation unit 50 determines whether or not the target coagulation region has been reached based on whether or not the average value of the correlation coefficient (correlation value) in the region of interest ROI has reached the determination value (threshold value). judge. Further, for example, a determination region may be set in the region of interest ROI, and it may be determined whether or not the target coagulation region has been reached based on an average value of correlation coefficients in the determination region.

  The determination result in the coagulation region estimation unit 50 is transmitted to the control unit 70, and when it is determined that the target coagulation region has been reached, the control unit 70, for example, controls the transmission / reception unit 12 to stop HIFU irradiation. Let

  FIG. 6 is a diagram for explaining an operation example 1 of the ultrasonic medical apparatus in FIG. 1. FIG. 6 shows a timing chart of a plurality of signals (triggers) in the ultrasonic medical apparatus of FIG.

  The main trigger is a signal indicating the start timing of treatment by high intensity focused ultrasound (HIFU). For example, in response to an operation of starting treatment by a user (examiner), the main trigger from the control unit 70 (FIG. 1) ) Is output to each part.

  The frame start trigger signal and the frame end trigger signal are signals indicating the start timing of one frame and the end timing of one frame, respectively, and are output for the first time after the frame start trigger signal is output. In the period up to, transmission / reception processing for one frame (for example, reception signal processing described with reference to FIG. 3) is performed.

  The difference calculation processing period trigger is a signal indicating a period during which the therapeutic ultrasound (HIFU) component is removed, and the process starts at the rising edge and ends at the falling edge. During this period, for example, the difference process of the received signal process described with reference to FIG. 3 is performed.

  The phasing addition process period trigger is a signal indicating a period during which the phasing addition process is performed, and the process starts at the rising edge and ends at the falling edge. In this period, for example, the phasing addition process of the reception signal process described with reference to FIG. 3 is performed.

  The cross-correlation calculation processing period trigger is a signal indicating a period during which cross-correlation calculation is performed between images, starts processing at the rising edge, and ends processing at the falling edge. In order to perform the cross-correlation process, two or more (two or more frames) ultrasonic images are required. Therefore, the trigger signal rises after two ultrasonic images are acquired. In other words, the processing is started from the time when the second difference calculation processing is completed.

  The heating period signal is a signal indicating the heating process period of the treatment site P by the therapeutic ultrasound beam TB, and in the period from the rise to the fall of the heating period signal, for example, the treatment ultrasound beam is focused on the treatment site P. TB is formed. When a user such as a doctor performs an operation to stop HIFU irradiation, HIFU irradiation (therapeutic ultrasonic beam TB) is immediately stopped. Also, when the coagulation region estimation unit 50 determines that the target coagulation region has been reached, the HIFU irradiation is stopped.

  The HIFU signal is a transmission signal of the therapeutic ultrasonic beam TB, and is output from the transmission / reception unit 12 to the plurality of vibration elements of the HIFU transducer 10H.

  FIG. 7 is a diagram for explaining a specific example 2 of the difference processing. FIG. 7A illustrates a first reception signal after phasing addition processing (first reception signal after phasing) obtained by transmitting HIFU, which is a therapeutic ultrasonic wave, to the treatment site P. ing. The first received signal after phasing in FIG. 7 (1) does not transmit diagnostic ultrasonic waves from the diagnostic transducer 10D, but transmits HIFU from the HIFU transducer 10H to the treatment site P to perform diagnosis. It is obtained by phasing and adding the received signal obtained for each vibration element of the vibrator 10D for use.

  In FIG. 7 (2), the second received signal after phasing addition processing (second received signal after phasing) obtained by transmitting HIFU to the treatment site P and transmitting diagnostic ultrasonic waves is shown. It is shown. The second received signal after phasing in FIG. 7 (2) is obtained by transmitting diagnostic ultrasound from the diagnostic transducer 10D while transmitting the HIFU from the HIFU transducer 10H to the treatment site P. It is obtained by phasing and adding the received signal obtained for each vibration element of the diagnostic transducer 10D. Note that the second received signal after phasing in FIG. 7 (2) includes the HIFU signal obtained by transmitting only the HIFU without transmitting the diagnostic ultrasound, and the diagnostic ultrasound along with the HIFU. A tissue signal that is superimposed on the HIFU signal by being waved is included.

  FIG. 7 (3) shows a post-phasing differential signal obtained by subtracting the post-phasing first reception signal from the post-phasing second reception signal (difference processing). In the second specific example shown in FIG. 7, the difference calculation processing unit 22 subtracts the first received signal after phasing from the second received signal after phasing from the second received signal after phasing obtained from the phasing addition processing unit 24. Form.

  Since the second received signal after phasing is a received signal obtained by transmitting diagnostic ultrasound together with HIFU that is therapeutic ultrasound, the component of the tissue signal accompanying diagnostic ultrasound and the HIFU signal accompanying HIFU Contains ingredients. On the other hand, since the first received signal after phasing is a received signal obtained by transmitting only the HIFU, only the HIFU signal component accompanying the HIFU is included. Therefore, by subtracting the first received signal after phasing from the second received signal after phasing, the component of the tissue signal accompanying the diagnostic ultrasound became dominant, preferably only the component of the tissue signal. After phasing, a differential signal is obtained.

  For example, based on the waveform of the second received signal after phasing in the period of only the HIFU signal and the waveform of the first received signal after phasing, the difference calculation processing unit 22 aligns the phases and amplitudes of these two waveforms with each other. It is desirable to execute the difference processing after that. The first received signal after phasing may be formed based on the waveform of the second received signal after phasing in the period of only the HIFU signal.

  Further, the notch filter processing unit 26 may execute notch filter processing. That is, notch filter processing (band elimination filter processing) for removing frequencies corresponding to therapeutic ultrasound (HIFU) may be performed. The notch filter is designed, for example, to remove frequencies corresponding to the fundamental wave, the second harmonic, and the third harmonic of the HIFU. The notch filter processing unit 26 removes a component of the HIFU signal remaining in the post-phasing differential signal by performing a notch filter process on the post-phasing differential signal, for example. Note that the notch filter processing unit 26 may remove the component of the HIFU signal by performing notch filter processing on the second received signal after phasing.

  FIG. 8 is a diagram for explaining a specific example 2 of the received signal processing. FIG. 8 shows a second received signal set composed of a plurality of second received signals (FIG. 2 (2)) corresponding to a plurality of vibrating elements (all elements) of the diagnostic transducer 10D, and the plurality of vibrating elements ( A first received signal set composed of a plurality of first received signals (FIG. 2 (1)) corresponding to all elements) is shown.

  In the specific example 2 of FIG. 8, the phasing addition process part 24 performs the phasing addition process with respect to each of a 2nd received signal set and a 1st received signal set. The phasing addition processing unit 24 performs known phasing addition processing (beam forming) on the plurality of second reception signals constituting the second reception signal set to form beam data for each reception beam. . Similarly, the phasing addition processing unit 24 performs a known phasing addition processing (beam forming) on the plurality of first reception signals constituting the first reception signal set to perform beam data for each reception beam. Form.

  For example, when a plurality of ultrasonic beams are formed by scanning diagnostic ultrasonic waves, a second received signal set and a first received signal set are obtained for each transmitted beam of diagnostic ultrasonic waves. By the addition process, a second beam data set and a first beam data set of each reception beam corresponding to the transmission beam are formed. Further, a differential beam data set is formed by differential processing based on the second beam data set and the first beam data set of each received beam. Then, by obtaining beam data (difference beam data) of a plurality of reception beams corresponding to a plurality of transmission beams of diagnostic ultrasonic waves constituting one frame, beam data corresponding to a plurality of reception beams constituting one frame A differential beam data set consisting of (differential beam data) is formed.

  Note that parallel reception for forming beam data of a plurality of reception beams may be executed for each transmission beam of diagnostic ultrasound, or a known transmission that transmits a plane wave of diagnostic ultrasound multiple times at different angles. A compound may be executed.

  The difference beam data set is successively formed over a plurality of frames for each frame, and an ultrasonic image (for example, the ultrasonic image 34 in FIG. 4) is generated by the ultrasonic image forming unit 30 based on the difference beam data set. Image data is formed. Furthermore, as described with reference to FIG. 5, a coagulation region estimation image may be formed by the coagulation region estimation unit 50, and whether or not the coagulation region has reached a target state by the coagulation region estimation unit 50. A determination may be made.

  FIG. 9 is a diagram for explaining an operation example 2 of the ultrasonic medical apparatus in FIG. 1. FIG. 9 shows a timing chart of a plurality of signals (triggers) in the ultrasonic medical apparatus of FIG.

  The main trigger is a signal indicating the start timing of treatment by high intensity focused ultrasound (HIFU). For example, in response to an operation of starting treatment by a user (examiner), the main trigger from the control unit 70 (FIG. 1) ) Is output to each part.

  The frame start trigger signal and the frame end trigger signal are signals indicating the start timing of one frame and the end timing of one frame, respectively, and are output for the first time after the frame start trigger signal is output. In the period up to, transmission / reception processing for one frame (for example, reception signal processing described with reference to FIG. 8) is performed.

  The phasing addition process period trigger is a signal indicating a period during which the phasing addition process is performed, and the process starts at the rising edge and ends at the falling edge. In this period, for example, the phasing addition process of the reception signal process described with reference to FIG. 8 is performed.

  The difference calculation processing period trigger is a signal indicating a period during which the therapeutic ultrasound (HIFU) component is removed, and the process starts at the rising edge and ends at the falling edge. In this period, for example, the difference process of the received signal process described with reference to FIG. 8 is performed.

  Since the cross correlation calculation processing period trigger, the heating period signal, and the HIFU signal in the specific example 2 shown in FIG. 9 are the same as the cross correlation calculation processing period trigger, the heating period signal, and the HIFU signal in the specific example 1 of FIG. The description is omitted here.

  In addition, the ultrasonic medical device of FIG. 1 can move the focal point of a therapeutic ultrasonic beam (therapeutic beam) to generate, for example, cavitation bubbles and enhance the heating effect to improve the treatment efficiency. Good.

  FIG. 10 is a diagram showing a specific example of the focus of the therapeutic beam. FIG. 10 shows an XY cross section (plane) including the treatment site P in the XYZ coordinate system (see FIG. 1). In the specific example of FIG. 10, the focus (focus position) of the treatment beam is in the order of position 1, position 2, position 3, position 4, position 5, and position 6 in the XY cross section including the treatment site P. The movement of positions 1 to 6 is periodically repeated. The diameter of the circumference is desirably determined according to, for example, the state of the treatment site P, and is, for example, about several mm to several cm.

  The transmission / reception unit 12 moves the focus of the therapeutic beam by, for example, performing phase modulation processing or the like on the transmission signals output to the plurality of vibration elements of the HIFU transducer 10H. Further, an amplitude modulation process or the like may be applied instead of the phase modulation process or together with the phase modulation process.

  When the HIFU transducer 10H and the diagnostic transducer 10D (FIG. 1) are separate types, for example, an ultrasonic image corresponding to the XY section (or a section parallel to this) shown in FIG. 10 can be formed. As described above, the diagnostic transducer 10 </ b> D may be arranged. Specifically, the transducer surfaces of the HIFU transducer 10H and the diagnostic transducer 10D may be arranged so as to be orthogonal to each other.

  FIG. 11 is a diagram illustrating a specific example of focus shift and reception processing of a therapeutic beam. FIG. 11 shows a reception process when the focus (focus position) of the therapeutic beam is moved in the order of positions 1 to 6 according to the specific example of FIG.

  First, in the first period, only the therapeutic ultrasonic wave is transmitted while moving the focus of the therapeutic beam in the order of positions 1 to 6, and the first received signal set (FIGS. 3 and 8) for each position. Reference) is obtained.

  Next, in the second period, the therapeutic ultrasound is transmitted while moving the focus of the therapeutic beam in the order of positions 1 to 6, and the diagnostic ultrasound is transmitted by scanning the diagnostic beam. Thus, a second received signal set (see FIGS. 3 and 8) is obtained for each position.

  Then, for each position, based on the second received signal set and the first received signal set obtained at that position, the received signal processing specific example 1 described using FIG. 3 or FIG. 8 is used. Specific example 2 of the received signal processing described above is executed, and a differential beam data set is obtained.

  Thus, an ultrasonic image is formed based on the difference beam data set for each position. Furthermore, for example, an ultrasonic image can be formed over a plurality of time phases for each position by alternately repeating the first period and the second period.

  FIG. 11 shows a specific example in which the second received signal set and the first received signal set are obtained for each position and an ultrasonic image is formed based on the difference beam data set. That is, a specific example in which the focus position of the therapeutic beam and the ultrasound image are associated with each other on a one-to-one basis has been described. .

  FIG. 12 is a diagram illustrating a general example of focus shift and reception processing of a therapeutic beam. FIG. 12 illustrates a reception process when the focus (focus position) of the therapeutic beam is moved in the order of positions 1 to 6 in accordance with the specific example of FIG.

In the general example shown in FIG. 12, first, the focus of the treatment beam is moved in the order of positions 1 to 6 in each of the first to Nth periods (N is a modulation period and a natural number) starting from time t _0. Only therapeutic ultrasound waves are transmitted. The time length of each cycle is a period T ₀ (T ₀ is the modulation repetition cycle of the therapeutic beam).

The first reception signal set from time t ₀ for each period (see FIGS. 3 and 8) is obtained. That is, the first received signal set (1), the first received signal set (2), ..., the first received signal for each period in the order of the periods Δt ₁₂ , Δt ₂₃ , ..., Δt _{n (n + 1).} N sets (n is the number of received signal sets and natural number) up to set (n) are obtained one after another.

Next, in each cycle of the (N + 1) th to (N) th 2N cycles starting from time t ₀ + N · T ₀ , therapeutic ultrasound is transmitted while moving the focus of the treatment beam in the order of positions 1 to 6 and diagnosis is performed. Diagnostic ultrasound is transmitted by scanning the beam. The time length of each period is a period T _0.

In addition, a second received signal set (see FIGS. 3 and 8) is obtained for each period from time t ₀ + N · T ₀ . In other words, the period Delta] t _12, Delta] t _23, ..., the second reception signal set for each period in the order of _{Δt n (n + 1) (} 1), second reception signal set (2), ..., the second received signal N sets up to set (n) are obtained one after another.

  Then, based on the second received signal set and the first received signal set corresponding to the same set number, the received signal processing example 1 described with reference to FIG. 3 or described with reference to FIG. Specific example 2 of the received signal processing is executed, and a differential beam data set is obtained. For example, a differential beam data set (1) is obtained based on the second received signal set (1) and the first received signal set (1), and the second received signal set (2) and the first received signal set (2). A differential beam data set (2) is obtained based on the second received signal set (n), and a differential beam data set (n) is obtained based on the second received signal set (n) and the first received signal set (n).

  An ultrasonic image can be formed based on the difference beam data set (n) obtained by the general example shown in FIG.

In the general example shown in FIG. 12, the time difference between the timing for starting acquisition of the first received signal set (time t ₀ ) and the timing for starting acquiring the second received signal set (time t ₀ + N · T ₀ ) It is set to a natural number multiple (N · T ₀ ) of the beam modulation repetition period T ₀ . Further, the second received signal set (n) and the first received signal set (n) corresponding to the same set number are obtained in the same period Δt _{n (n + 1)} .

Incidentally, in the general example shown in FIG. 12, the number of received signal sets is 6 (n = 6), the number of modulation periods is 1 (N = 1), and each period is 1/6 of the modulation repetition period of the therapeutic beam (periods). FIG. 11 shows a specific example in which Δt ₁₂ = Δt ₂₃ =... = Δt _{n (n + 1)} = T _0/6 ).

FIG. 13 is a diagram illustrating another specific example of focus shift and reception processing of a therapeutic beam. In the specific example shown in FIG. 13, in the general example shown in FIG. 12, the number of received signal sets is 4 (n = 4), the number of modulation periods is 2 (N = 2), and each period is Δt (period Δt ₁₂ = Δt ₂₃ =... = Δt _{n (n + 1)} = Δt).

  Also in the specific example shown in FIG. 13, based on the second received signal set and the first received signal set corresponding to the same set number, the specific example 1 or FIG. 8 of the received signal processing described using FIG. Specific example 2 of the received signal processing explained using the above is executed, and a differential beam data set is obtained. For example, a differential beam data set (1) is obtained based on the second received signal set (1) and the first received signal set (1), and the second received signal set (2) and the first received signal set (2). The differential beam data set (2) is obtained based on the second received signal set (3), the differential beam data set (3) is obtained based on the second received signal set (3) and the second received signal set (3). A difference beam data set (4) is obtained based on the signal set (4) and the first received signal set (4).

  FIG. 14 is a flowchart showing a preferred operation example of the ultrasonic medical apparatus of FIG. First, prior to irradiation with therapeutic ultrasonic waves (HIFU), diagnostic ultrasonic waves are transmitted and received by the diagnostic transducer 10D, and an ultrasonic image is formed by the ultrasonic image forming unit 30, and displayed on the display unit 32, for example. A user such as a doctor confirms the position and size of the treatment site P from the ultrasonic image in the subject (S1401). Next, a user such as a doctor uses the operation device 60 according to the confirmation result, for example, the region of interest ROI (FIG. 5), the position of the focus of the treatment beam (FIG. 10), and the treatment end condition. A treatment condition such as a threshold value (referred to by the coagulation region estimation unit 50) is set.

  Then, for example, when a user such as a doctor performs a start operation using the operation device 60, irradiation with therapeutic ultrasonic waves (HIFU) is started according to the treatment condition set in S1402 (S1403).

  While irradiating therapeutic ultrasonic waves (HIFU), diagnostic ultrasonic waves are transmitted and received (S1404), received signal processing for removing HIFU components is executed (S1405), and an ultrasonic image is formed and displayed (S1406). The solidification region is estimated (S1407) as described in detail with reference to FIGS.

  Furthermore, it is determined whether or not the coagulation region has reached the target state by the coagulation region estimation unit 50 (S1408), and the treatment ultrasonic wave (HIFU) is irradiated until the coagulation region reaches the target state. The process of S1408 is repeated.

  Then, when the coagulation region reaches a target state (S1408), the irradiation of therapeutic ultrasonic waves (HIFU) is stopped, and the flowchart of FIG. 14 is ended. Note that, when an operation for stopping irradiation of HIFU is performed by a user such as a doctor during the process according to the flowchart of FIG. 14, irradiation of HIFU is immediately stopped. If the irradiation time of HIFU is set in S1402, the irradiation of HIFU is stopped when the irradiation time has elapsed from the start of irradiation of HIFU in S1403.

  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, 12 Transmission / reception part, 20 Reception signal processing block, 22 Difference calculation processing part, 24 Phased addition process part, 26 Notch filter processing part, 30 Ultrasound image formation part, 32 Display part, 40 Cross correlation process Unit, 50 coagulation region estimation unit, 60 operation device, 70 control unit.

Claims (5)

A first ultrasonic wave obtained by transmitting therapeutic ultrasonic waves to the treatment site and a second ultrasonic wave obtained by transmitting diagnostic ultrasonic waves together with the therapeutic ultrasonic wave to the treatment site are received. A plurality of vibration elements;
A difference processing unit for obtaining difference information by difference processing based on reception information obtained by receiving the second ultrasonic wave and reception information obtained by receiving the first ultrasonic wave;
Have
Forming an ultrasound image of the treatment site based on the difference information;
An ultrasonic medical device. The ultrasonic medical device according to claim 1,
A receiving unit that obtains a second reception signal corresponding to the second ultrasonic wave and a first reception signal corresponding to the first ultrasonic wave for each vibration element of the plurality of vibration elements;
The differential processing unit forms a differential signal by performing differential processing on the second received signal and the first received signal of the vibrating element for each vibrating element of the plurality of vibrating elements,
Forming an ultrasonic image of the treatment site based on a plurality of differential signals corresponding to the plurality of vibration elements;
An ultrasonic medical device. The ultrasonic medical device according to claim 2,
A phasing addition processing unit for obtaining a beam signal of a plurality of beams by performing phasing addition processing on the plurality of differential signals;
An image forming unit that forms an ultrasonic image of the treatment site based on the beam signals of the plurality of beams;
Further having
An ultrasonic medical device. The ultrasonic medical device according to claim 1,
A receiving unit for obtaining a second received signal corresponding to the second ultrasonic wave and a first received signal corresponding to the first ultrasonic wave for each of the vibrating elements of the plurality of vibrating elements;
A plurality of second reception signals corresponding to the plurality of vibration elements are subjected to phasing addition processing, thereby forming a second reception beam signal for each of the plurality of beams, and a plurality of first reception signals corresponding to the plurality of vibration elements. A phasing addition processing unit that forms a first reception beam signal for each of the plurality of beams by performing phasing addition processing on the reception signal;
Have
The differential processing unit forms a differential beam signal by performing differential processing on the second received beam signal and the first received beam signal for each beam of the plurality of beams,
Forming an ultrasound image of the treatment site based on a plurality of differential beam signals corresponding to the plurality of beams;
An ultrasonic medical device. In the ultrasonic medical device according to any one of claims 1 to 4,
The first ultrasonic wave is received by forming a therapeutic beam in order for a plurality of positions in the treatment site and transmitting the therapeutic ultrasonic wave, and further for the treatment in order for the plurality of positions. Receiving the second ultrasound by forming a beam and transmitting the therapeutic ultrasound and scanning the diagnostic beam to transmit the diagnostic ultrasound;
The difference processing unit obtains difference information for each position of the plurality of positions by difference processing based on the reception information of the second ultrasonic wave corresponding to the position and the reception information of the first ultrasonic wave,
An ultrasonic medical device.

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