Ultrasonic therapeutic device

Abstract

The purpose of this invention is to facilitate confirmation of the application of therapeutic ultrasound to the affected area during treatment using an ultrasound therapy device. In the therapeutic ultrasound transmission process, an ultrasound vibrator 28 transmits therapeutic ultrasound 38. In the irradiation area image generation process, after the transmission of the therapeutic ultrasound 38, the ultrasound probe 16 transmits multiple imaging pulses 46 as multiple ultrasound waves at different times and phases. Reflected by biological tissue, multiple received signals based on the multiple reflected ultrasound waves received by the ultrasound probe 16 are summed to generate irradiation area data based on the nonlinear components of each received signal. In the auxiliary ultrasound transmission process, the ultrasound vibrator 28 transmits interleaved pulses 50 at the time points between two adjacent transmission times of the multiple imaging pulses 46 on the time axis.

Description

Ultrasonic treatment device The present invention relates to an ultrasonic treatment device, and more particularly to a device including an ultrasonic vibrator for treatment and an ultrasonic probe for image generation. Treatment devices using high-density focused ultrasound therapy have been widely used. This ultrasonic treatment device can be referred to as an HIFU irradiation device or an HIFU irradiation system (High Intensity Focused Ultrasound), and irradiates ultrasonic waves on a treatment site to cause tissue necrosis. Generally, an HIFU irradiation device includes a plurality of ultrasonic vibrators provided on a bowl-shaped surface. The plurality of ultrasonic vibrators are arranged such that the ultrasonic waves emitted from each of them irradiate a single point to form a focus. During treatment, ultrasonic waves are irradiated in such a way that the position of the focus coincides with the treatment site. The confirmation of the irradiation position uses an ultrasonic imaging device that shows the focus on an ultrasonic image. The following Patent Document 1 describes an ultrasonic treatment device that uses an ultrasonic imaging device showing a B-mode image (tomographic image) to observe the position of the focus. In this device, weak-level ultrasonic waves that have no effect on the tissue are emitted from the ultrasonic vibrator for treatment, and at the same time, a tomographic image is displayed by transmitting and receiving ultrasonic waves using an ultrasonic imaging probe. Since the acoustic characteristics of the tissue of the subject change in response to the temperature change of the tissue, the position of the focus appears in the tomographic image according to the intensity of the brightness. Patent Document 2 describes a technique for discriminating echo components generated by scattering through a microbubble-based contrast agent from components generated by non-linear propagation of transmitted pulses and imaging them as a technique related to the present invention. 『Patent Document』 《Patent Document 1》: Japanese Patent Laid-Open No. H8-71069 《Patent Document 2》: International Patent Publication No. 2005 / 087109 《Patent Document 3》: Japanese Patent Laid-Open No. 2023-79320 Generally, when strong treatment ultrasonic waves are irradiated on an affected part of biological tissue, bubbles (voids) are generated at the irradiation site due to cavitation. In the treatment using a conventional HIFU irradiation device, there is a method of using the observation of the position of bubbles generated through cavitation and the observation of the biological tissue of the patient as a method for confirming that the treatment ultrasonic waves are irradiated on the affected part. The observation of the position of the bubbles can be performed, for example, by harmonic imaging that transmits ultrasonic waves from an ultrasonic probe toward the affected part and receives higher harmonics generated around the bubbles, as described in Patent Document 3. And the observation of the biological tissue of the patient can be performed by obtaining a B-mode image by transmitting and receiving ultrasonic waves using an ultrasonic probe. In the treatment using a HIFU irradiation device, when the area such as the affected part is narrow, therapeutic ultrasonic waves are irradiated in the narrow range. Therefore, sometimes it becomes difficult to confirm that the therapeutic ultrasonic waves are irradiated to the affected part because the amount of generated bubbles is small. An object of the present invention is to make it easy to confirm that therapeutic ultrasonic waves are irradiated to an affected part during treatment using an ultrasonic treatment device. The present invention includes: a therapeutic ultrasonic oscillator, an ultrasonic probe, and a control unit that controls the ultrasonic oscillator and the ultrasonic probe, and is characterized in that the control unit executes: a therapeutic ultrasonic wave transmission process that causes the ultrasonic oscillator to transmit therapeutic ultrasonic waves; an auxiliary ultrasonic wave transmission process that causes the ultrasonic oscillator to transmit auxiliary ultrasonic waves; and an irradiation area image generation process that causes the ultrasonic probe to transmit a plurality of ultrasonic waves at different time points and different phases after the therapeutic ultrasonic waves are transmitted, reflects on biological tissue, synthesizes a plurality of received signals based on the plurality of reflected ultrasonic waves received by the ultrasonic probe, and thereby generates irradiation area data based on the non-linear components of each of the received signals; wherein the auxiliary ultrasonic wave transmission process includes: a process of causing the ultrasonic oscillator to transmit the auxiliary ultrasonic waves at a time point between two time points at which two adjacent ones among the plurality of ultrasonic waves are transmitted on the time axis. It is desirable that the auxiliary ultrasonic wave transmission process includes: a process of causing the ultrasonic oscillator to transmit the auxiliary ultrasonic waves at a time point earlier than the intermediate time point between two time points at which two adjacent ones among the plurality of ultrasonic waves are transmitted on the time axis. It is desirable that the auxiliary ultrasonic wave transmission process includes: a process of causing the ultrasonic oscillator to transmit the auxiliary ultrasonic waves at a time point earlier than the time points of the plurality of ultrasonic waves after the therapeutic ultrasonic waves are transmitted. It is desirable that the plurality of received signals are signals based on M channels of ultrasonic waves sequentially transmitted from the ultrasonic probe with a phase difference of 360° / M and based on the plurality of reflected ultrasonic waves received by the ultrasonic probe. It is desirable that the control unit executes: a B-mode image generation process that generates B-mode image data of the biological tissue using any one of the plurality of received signals. It is desirable that the control unit causes an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data to be displayed on a display device. It is desirable that the control unit causes the irradiation area image based on the irradiation area data and the B-mode image based on the B-mode image data to be overlapped and displayed on the display device. According to the present invention, it is possible to make it easy to confirm that therapeutic ultrasonic waves are irradiated to an affected part. Embodiments of the present invention will now be described with reference to the drawings. The same reference numerals are used to denote the same structural elements shown in multiple drawings to simplify the description. FIG. 1 shows the structure of a HIFU irradiation device 100 (ultrasonic treatment device) related to an embodiment of the present invention. The HIFU irradiation device 100 includes a HIFU vibrator unit 10, a HIFU drive circuit 14, an ultrasonic probe 16, a transceiver circuit 18, an imaging operation unit 20, a controller 22, a display device 24, and a drive device 26. The controller 22 can be a personal computer, a tablet computer, or the like. An operation device (not shown) used by a user to operate the HIFU irradiation device 100 is connected to the controller 22. The operation device can include a mouse, a touch panel integrated with the display device 24, a switch, a keyboard, and the like. The HIFU vibrator unit 10 includes a vibrator housing 12 having a concave surface 4 with an opening facing downward, and a plurality of ultrasonic vibrators 28 arranged along the concave surface 4 in the vibrator housing 12 and fixed to the vibrator housing 12. The HIFU vibrator unit 10 does not necessarily have a physical concave surface 4. In this case, the plurality of ultrasonic vibrators 28 can be fixed to the vibrator housing 12 in a manner arranged along a假想 concave surface 4. The concave surface 4 of the vibrator housing 12 can also be the same shape as the side surface of a cone. Here, the so-called cone refers to a three-dimensional shape formed by a set of straight lines extending from a point in space to the bottom surface. Also, the concave surface 4 of the vibrator housing 12 can have a shape that expands into a dome shape on the upper side. Each ultrasonic vibrator 28 is fixed to the vibrator housing 12 in such a way that when each ultrasonic vibrator 28 emits ultrasonic waves, the intensity of the ultrasonic waves is enhanced at the focal point F below the vibrator housing 12. The HIFU drive circuit 14 causes each ultrasonic vibrator 28 included in the HIFU vibrator unit 10 to generate ultrasonic waves in response to the control of the controller 22. Also, the HIFU drive circuit 14 adjusts the intensity of the ultrasonic waves generated by each ultrasonic vibrator 28 in response to the control of the controller 22. The ultrasonic probe 16 is fixed to the vibrator housing 12 in such a way that ultrasonic waves are transmitted and received at a position below the vibrator housing 12 and above the focal point F. In this embodiment, the ultrasonic probe 16 penetrates the apex portion of the vibrator housing 12 in the vertical direction, and the transceiver portion 2 for transmitting and receiving ultrasonic waves faces downward. The transceiver circuit 18 and the imaging operation unit 20 can also use a general ultrasonic imaging device. The imaging operation unit 20 may be composed of a processor that controls the transceiver circuit 18 by executing a program. The transceiver circuit 18 performs the following processing in response to the control of the imaging operation unit 20. That is, the transceiver circuit 18 causes the ultrasonic probe 16 to transmit ultrasonic waves, and scans with the beam (ultrasonic beam) caused by the transmitted ultrasonic waves. The ultrasonic beam is scanned on an observation surface that includes the central axis 3 extending vertically along the apex of the oscillator housing 12. The transceiver circuit 18 causes the ultrasonic probe 16 to receive the reflected ultrasonic waves from the direction toward which the ultrasonic beam is directed, and obtains a reception signal based on the reflected ultrasonic waves received from each direction toward which the ultrasonic beam is directed from the ultrasonic probe 16. The transceiver circuit 18 outputs each reception signal to the imaging operation unit 20. The imaging operation unit 20 generates ultrasonic data based on each reception signal output from the transceiver circuit 18. The ultrasonic data may be irradiation area data indicating an area generated by the non-linear component of the biological tissue of the patient or B-mode image data indicating a B-mode image (tomographic image) obtained for the biological tissue of the patient. The drive device 26 moves the HIFU oscillator unit 10 and the ultrasonic probe 16 in response to the control of the controller 22, and adjusts their positions. Further, the drive device 26 can also rotate the ultrasonic probe 16 around the central axis 3 in response to the control of the controller 22, and rotate the observation surface of the ultrasonic probe 16 around the central axis 3. Before the therapeutic ultrasonic wave is irradiated from the HIFU oscillator unit 10 to the patient, the following positioning process can be performed. The HIFU drive circuit 14 causes each ultrasonic oscillator 28 to transmit ultrasonic waves with an intensity smaller than that during treatment. The drive device 26 sets the rotation angle position of the ultrasonic probe 16 in such a manner that the ultrasonic probe 16 scans with an ultrasonic beam on the observation surface at a specified rotation angle position. The imaging operation unit 20 scans the ultrasonic probe 16 with an ultrasonic beam on the observation surface, obtains B-mode image data as ultrasonic data, and outputs it to the controller 22. The controller 22 causes the B-mode image to be displayed on the display device 24. The user, as the operator, refers to the B-mode image displayed on the display device 24, and confirms the difference between the position (focus) where the ultrasonic wave transmitted from the HIFU oscillator unit 10 is enhanced and the position of the affected part. When the difference between the position of the user at the focus F and the position of the affected part is not within the allowable range, the positions or postures of the ultrasonic probe 16 and the HIFU oscillator unit 10 are changed. After the user confirms that the position of the focus F coincides with the position of the affected part or the difference between the position of the focus F and the position of the affected part is within the allowable range, an operation for treatment is performed on the controller 22. In response to the operation by the user, the controller 22 controls the HIFU drive circuit 14. In response to the control by the controller 22, the HIFU drive circuit 14 causes each ultrasonic oscillator 28 to transmit therapeutic ultrasonic waves having the intensity required for treatment. Thereby, biological tissue is burned at the focus F to perform treatment. The HIFU irradiation device 100 performs irradiation area display processing for displaying an image (irradiation area image) showing the irradiation area of the therapeutic ultrasonic wave on the display device 24 while irradiating the therapeutic ultrasonic wave to the patient. The irradiation area image is the image indicated by the irradiation area data. The irradiation area image can be displayed side by side with the B-mode image or can be displayed overlapping the B-mode image. Here, the process of displaying the two images overlapping can be a process of "synthesizing image data so as to see one image through the other image to generate new image data and displaying an image based on this new image data". FIG. 2 conceptually illustrates the transmission timing of the therapeutic ultrasonic wave 38 transmitted from the HIFU oscillator unit 10 and the HIFU / imaging hybrid wave 36 transmitted from the HIFU oscillator unit 10 and the ultrasonic probe 16 when performing the irradiation area display processing. The therapeutic ultrasonic wave 38 is composed of a therapeutic ultrasonic wave pulse 44 including a trigger pulse 40 and a heating burst wave 42 that follows the trigger pulse 40. The therapeutic ultrasonic wave pulse 44 is repeatedly transmitted from the HIFU oscillator unit 10 as time passes. An irradiation stop period 48 is provided between adjacent therapeutic ultrasonic wave pulses 44 on the time axis, and during the irradiation stop period 48, the therapeutic ultrasonic wave 38 stops being transmitted. The amplitude of the heating burst wave 42 can be smaller than the amplitude of the trigger pulse 40. The time length T1 of the trigger pulse 40 can be shorter than the time length T3 of the heating burst wave 42. If the therapeutic ultrasonic wave pulse 44 is transmitted from the HIFU oscillator unit 10, biological tissue can be burned at the focus F. Bubbles are generated from the biological tissue at the same time as the trigger pulse 40 is irradiated to the biological tissue, and the state in which bubbles are generated is maintained by the irradiation of the heating burst wave 42. During the irradiation stop period 48, an HIFU / imaging hybrid wave 36 is transmitted from the HIFU oscillator unit 10 and the ultrasonic probe 16. The HIFU / imaging hybrid wave 36 includes, at time intervals of time τ0, a first imaging pulse 46-1, a second imaging pulse 46-2, and a third imaging pulse 46-3 transmitted from the ultrasonic probe 16. The phase of the second imaging pulse 46-2 is delayed by only 120° relative to the first imaging pulse 46-1. The phase of the third imaging pulse 46-3 is delayed by only 120° relative to the second imaging pulse 46-2. In the following description, any one of the first imaging pulse 46-1 to the third imaging pulse 46-3 that is not specified is sometimes referred to as the imaging pulse 46. The HIFU / imaging hybrid wave 36 further includes a first interleaved pulse 50-1 and a second interleaved pulse 50-2 transmitted from the HIFU oscillator unit 10. In the following description, either the first interleaved pulse 50-1 or the second interleaved pulse 50-2 that is not specified is sometimes referred to as the interleaved pulse 50. The first interleaved pulse 50-1 is transmitted at a time point between the two time points at which the first imaging pulse 46-1 and the second imaging pulse 46-2 are transmitted, and the second interleaved pulse 50-2 is transmitted at a time point between the two time points at which the second imaging pulse 46-2 and the third imaging pulse 46-3 are transmitted. Specifically, the first interleaved pulse 50-1 is transmitted at time τ1 after the first imaging pulse 46-1 is transmitted, and the second imaging pulse 46-2 is transmitted at time τ2 after the first interleaved pulse 50-1 is transmitted. Also, the second interleaved pulse 50-2 is transmitted at time τ1 after the second imaging pulse 46-2 is transmitted, and the third imaging pulse 46-3 is transmitted at time τ2 after the second interleaved pulse 50-2 is transmitted. The time τ1 is shorter than the time τ2. That is, the first interleaved pulse 50-1 is transmitted at a time point earlier than the midpoint between the time point at which the first imaging pulse 46-1 is transmitted and the time point at which the second imaging pulse 46-2 is transmitted. Here, the midpoint refers to the time point corresponding to the midpoint between two points on the time axis. Also, the second interleaved pulse 50-2 is transmitted at a time point earlier than the midpoint between the time point at which the second imaging pulse 46-2 is transmitted and the time point at which the third imaging pulse 46-3 is transmitted. The times τ1 and τ2 can be determined by the manner in which the HIFU / imaging hybrid wave 36 acts in biological tissue. The first interleaved pulse 50-1 reaches the affected area after the reflected ultrasonic wave generated based on the first imaging pulse 46-1 is received by the ultrasonic probe 16, causing the bubbles generated in the affected area to vibrate. The second imaging pulse 46-2 reaches the affected area after the multiple reflection waves generated in the biological tissue by the first interleaved pulse 50-1 have sufficiently attenuated. The second interleaved pulse 50-2 reaches the affected area after the reflected ultrasonic wave generated based on the second imaging pulse 46-2 is received by the ultrasonic probe 16, causing the bubbles generated in the affected area to vibrate. The third imaging pulse 46-3 reaches the affected area after the multiple reflection waves generated in the biological tissue by the second interleaved pulse 50-2 have sufficiently attenuated. Each interleaved pulse 50 may be composed of one ultrasonic pulse or may be composed of a plurality of ultrasonic pulses connected on the time axis. The right lower part of FIG. 3 respectively shows the time points of the ultrasonic pulses in the case where the interleaved pulse 50 is composed of one ultrasonic pulse, three ultrasonic pulses, and ten ultrasonic pulses in sequence from above. In the example shown in FIG. 2, the time from the transmission of the first imaging pulse 46-1 to the transmission of the first interleaved pulse 50-1 is equal to the time from the transmission of the second imaging pulse 46-2 to the transmission of the second interleaved pulse 50-2, but these times may also be different. Each imaging pulse 46 reflects within the biological tissue. When the imaging pulse 46 reflects around the bubbles generated by the therapeutic ultrasonic pulse 44, non-linear components such as higher harmonics are generated. Therefore, the reflected ultrasonic wave reflected from the biological tissue contains, in addition to the fundamental wave, non-linear components caused by the bubbles. Generally, the more bubbles are generated, the greater the intensity of the generated non-linear components becomes. Now returning to FIG. 1, the processing of the reflected ultrasonic wave for each imaging pulse 46 received by the HIFU irradiation device 100 will be described. The ultrasonic probe 16 receives the first reflected ultrasonic wave to the third reflected ultrasonic wave for the first imaging pulse 46-1 to the third imaging pulse 46-3, and outputs the first received signal to the third received signal to the transceiver circuit 18 respectively. The transceiver circuit 18 performs amplification, etc. on the first received signal to the third received signal, and outputs it to the imaging operation unit 20. The imaging operation unit 20 sums up the first received signal to the third received signal, and generates a non-linear signal that sums up the non-linear components included in each of the first received signal to the third received signal. Through the phase relationship of the first imaging pulse 46-1 to the third imaging pulse 46-3, the fundamental wave component is suppressed in the signal obtained by summing up the first received signal to the third received signal. The imaging operation unit 20 generates non-linear signals for the first reflected ultrasonic wave to the third reflected ultrasonic wave in each direction towards which the ultrasonic beam is directed, and generates irradiation area data based on the non-linear signals generated for each direction. The irradiation area data is image data representing an irradiation area image of an area where bubbles are generated in the area scanned by the ultrasonic beam. Moreover, the imaging operation unit 20 generates a B-mode image based on one of the first reflected ultrasonic wave to the third reflected ultrasonic wave. For example, the imaging operation unit 20 generates pixel data for B-mode images in each direction based on the second reflected ultrasonic wave in each direction towards which the ultrasonic beam is directed, and generates B-mode image data based on the pixel data obtained for each direction. In addition, the reflected ultrasonic wave that forms the basis of the B-mode image data may be the first reflected ultrasonic wave or the third reflected ultrasonic wave. The imaging operation unit 20 outputs the irradiation area data and the B-mode image data to the controller 22. The controller 22 causes an image (B-mode irradiation area image) in which the irradiation area image is superimposed on the B-mode image to be displayed on the display device 24 based on the irradiation area data and the B-mode image data. The imaging operation unit 20 outputs the irradiation area data and the B-mode image data to the controller 22 in the form of a frame time interval (the reciprocal of the frame rate). The controller 22 sequentially causes the B-mode irradiation area image to be displayed on the display device 24 as time passes. In addition, the controller 22 may display the irradiation area image and the B-mode image individually without superimposing these images. For example, the controller 22 may cause the irradiation area image and the B-mode image to be displayed side by side on the display device 24 in a comparable manner. FIG. 4 shows experimental results. The upper left and lower left of FIG. 4 show a B-mode image and an irradiation area image, respectively, for the case of using a conventional basic imaging ultrasonic wave. The basic imaging ultrasonic wave is obtained by eliminating the first interleaved pulse 50-1 and the second interleaved pulse 50-2 from the HIFU / imaging hybrid wave 36. In the transmission of the basic imaging ultrasonic wave, the first interleaved pulse 50-1 is not transmitted after the first imaging pulse 46-1 is transmitted, and the second imaging pulse 46-2 is transmitted after a time τ0 has elapsed. Next, the second interleaved pulse 50-2 is not transmitted after the second imaging pulse 46-2 is transmitted, and the third imaging pulse 46-3 is transmitted after a time τ0 has elapsed. In each figure, the horizontal axis represents the width (mm), and the vertical axis represents the depth (mm). Each image shows an image of the bubble 60. The upper right and lower right of FIG. 4 respectively show the B-mode image and the irradiation area image of this embodiment using the HIFU / imaging hybrid wave 36. As the interleaved pulse 50, one composed of 3 ultrasonic pulses connected on the time axis is used. The horizontal axis in each figure represents the width (mm), and the vertical axis represents the depth (mm). Each image shows an image of bubbles 60. It can be understood from the lower left figure and the lower right figure that, compared with the case of using the basic imaging ultrasonic wave, the case of using the HIFU / imaging hybrid wave 36 clearly shows the bubbles 60 generated in the irradiation area. FIG. 5 shows the bubble-to-tissue contrast (hereinafter referred to as contrast) of the irradiation area image. The contrast in the case of using the HIFU / imaging hybrid wave 36 is about 9 dB greater than the contrast in the case of the basic imaging ultrasonic wave without using the interleaved pulse 50. The experimental conditions are as follows. The period T0 from the transmission of the previous trigger pulse 40 to the transmission of the next trigger pulse 40 is 50 msec. The time length T1 of the trigger pulse 40 is 0.1 msec. The time T2 from the end of the transmission of the trigger pulse 40 to the start of the transmission of the heating burst wave 42 is 3 msec. The time length T3 of the heating burst wave 42 is 43.9 msec. The time T4 from the end of the transmission of the heating burst wave 42 to the start of the transmission of the HIFU / imaging hybrid wave 36 is 1 msec. The time τ1 in the HIFU / imaging hybrid wave 36 is 120 μsec, and the time τ2 is 280 μsec. The irradiation stop period T5 is 3 msec. FIG. 6 shows the contrast in the case of different structures of the HIFU / imaging hybrid wave 36. From the left, the first to the third show the contrast in the case where the interleaved pulse 50 is composed of 10 high-intensity ultrasonic pulses, the case where it is composed of 3 high-intensity ultrasonic pulses, and the case where it is composed of 1 high-intensity pulse in sequence. From the left, the fourth to the sixth show the contrast in the case where the interleaved pulse 50 is composed of 10 medium-intensity ultrasonic pulses, the case where it is composed of 3 medium-intensity ultrasonic pulses, and the case where it is composed of 1 medium-intensity pulse in sequence. Here, the so-called high-intensity ultrasonic pulse means an ultrasonic pulse with the same amplitude as the trigger pulse 40, and the so-called medium-intensity ultrasonic pulse means an ultrasonic pulse with the same amplitude as the heating burst wave 42. The contrast in the case of using the basic imaging ultrasonic wave is shown on the far right. As shown in FIG. 6, the greater the amplitude of the interleaved pulse 50, the greater the tendency for the contrast to become larger, and the more the number of ultrasonic pulses constituting the interleaved pulse 50, the greater the tendency for the contrast to become larger. Thus, in the HIFU irradiation device 100 related to the present embodiment, by transmitting the HIFU / imaging hybrid wave 36, the first interleaved pulse 50-1 can be transmitted between the transmission of the first imaging pulse 46-1 and the transmission of the second imaging pulse 46-2. By transmitting the first interleaved pulse 50-1 to the affected part, the bubbles generated in the affected part by the therapeutic ultrasonic wave 38 will vibrate, and the non-linear component generated by the second imaging pulse 46-2 will increase. Further, the second interleaved pulse 50-2 is transmitted between the transmission of the second imaging pulse 46-2 and the transmission of the third imaging pulse 46-3. By transmitting the second interleaved pulse 50-2 to the affected part, the bubbles generated in the affected part by the therapeutic ultrasonic wave 38 will vibrate, and the non-linear component generated by the third imaging pulse 46-3 will increase. Thereby, the magnitude of the non-linear signal will become larger, the bubbles shown in the image of the irradiation area will be emphasized, and it becomes easier for the user to confirm that the therapeutic ultrasonic wave 38 is irradiated to the affected part. In the above content, the process of transmitting the interleaved pulse 50 at a time point between two time points of transmitting two adjacent imaging pulses 46 on the time axis is illustrated. The interleaved pulse 50 can also be transmitted between the transmission of the therapeutic ultrasonic pulse 44 and the transmission of the first imaging pulse 46. Moreover, in the above content, the process of transmitting the imaging pulse 46 for generating ultrasonic data three times is illustrated. The imaging pulse 46 can also be transmitted two times or four times or more. In the case of transmitting the imaging ultrasonic wave M times (M is an integer of 2 or more), the phase difference between adjacent imaging pulses 46 on the time axis is defined as 360° / M. Alternatively, regardless of the transmission order, the phases of the M imaging pulses 46 can be set in such a way that the phase is θ + i ∙ 360° / M (θ is an arbitrary phase, and i is an integer from 0 to M−1). The imaging operation unit 20 sums up the first received signal to the M-th received signal, and generates a non-linear signal that sums up the non-linear components included in each of the first received signal to the M-th received signal. Further, the imaging operation unit 20 generates a B-mode image based on one of the first reflected ultrasonic wave to the M-th reflected ultrasonic wave. In the above content, an embodiment in which the pulse including the trigger pulse 40 and the heating burst wave 42 following the trigger pulse 40 is used as the therapeutic ultrasonic pulse 44 is illustrated. The therapeutic ultrasonic pulse 44 can also use a pulse including only the trigger pulse 40 and not including the heating burst wave 42. FIG. 7 conceptually illustrates the transmission timing of the therapeutic ultrasonic pulse 44 not including the heating burst wave 42 and the HIFU / imaging hybrid wave 36. When the irradiation stop period T5 has elapsed after the transmission of the previous trigger pulse 40 ends, the next trigger pulse 40 is transmitted. During the irradiation stop period T5, the HIFU / imaging hybrid wave 36 is transmitted when the time T4 has elapsed after the transmission of the trigger pulse 40 ends. FIG. 8 shows the contrast in the case of using a therapeutic ultrasonic pulse 44 that does not include a heating burst wave 42. On the left, the contrast in the case of using an HIFU / imaging hybrid wave 36 composed of 3 high-intensity ultrasonic pulses by using an interleaved pulse 50 is shown. On the right, the contrast in the case of using a basic imaging ultrasonic wave is shown. The contrast in the case of using the HIFU / imaging hybrid wave 36 is approximately 6 dB greater than the contrast in the case of using the basic imaging ultrasonic wave. Even when the therapeutic ultrasonic pulse 44 does not include the heating burst wave 42, similar to the case where the therapeutic ultrasonic pulse 44 includes the heating burst wave 42, the contrast in the case of using the HIFU / imaging hybrid wave 36 tends to be greater than the contrast in the case of using the basic imaging ultrasonic wave. As described above, the HIFU irradiation device 100 is an ultrasonic treatment device including an HIFU oscillator unit 10 including a therapeutic ultrasonic oscillator 28, an ultrasonic probe 16, and a control unit 30 that controls the ultrasonic oscillator 28 and the ultrasonic probe 16. The control unit 30 is composed of an HIFU drive circuit 14, a transceiver circuit 18, an imaging operation unit 20, and a controller 22. The control unit 30 executes a therapeutic ultrasonic wave transmission process, an auxiliary ultrasonic wave transmission process, and an irradiation area image generation process. The therapeutic ultrasonic wave transmission process is a process of causing the ultrasonic oscillator 28 to transmit a therapeutic ultrasonic wave 38. The irradiation area image generation process is a process executed after the therapeutic ultrasonic wave 38 is transmitted. The irradiation area image generation process is the following process: causing the ultrasonic probe 16 to transmit a plurality of imaging pulses 46 as a plurality of ultrasonic waves at different time points, reflecting on biological tissue, and adding and summing (synthesizing) the first received signal to the Mth received signal (a plurality of received signals) based on the first reflected ultrasonic wave to the Mth reflected ultrasonic wave (a plurality of reflected ultrasonic waves) received by the ultrasonic probe 16, thereby generating irradiation area data based on the non-linear components of the respective received signals. Moreover, the auxiliary ultrasonic wave transmission process includes a process of "causing the ultrasonic oscillator 28 to transmit an interleaved pulse 50 as an auxiliary ultrasonic wave at a time point between two time points adjacent on the time axis among the plurality of imaging pulses 46". Moreover, the auxiliary ultrasonic wave transmission process may include a process of "causing the ultrasonic oscillator 28 to transmit an interleaved pulse 50 as an auxiliary ultrasonic wave at a time point earlier than the plurality of imaging pulses 46 after the therapeutic ultrasonic wave 38 is transmitted". The control unit 30 executes a B-mode image generation process of "generating B-mode image data of biological tissue by using any one of the plurality of received signals". The control unit 30 executes a display process of "displaying an irradiation area image based on irradiation area data and a B-mode image based on B-mode image data on the display device 24". The control unit 30 can also cause the irradiation area image and the B-mode image to be overlapped and displayed on the display device 24. According to such a configuration and process, while irradiating the biological tissue with the therapeutic ultrasonic wave 38, the area irradiated with the therapeutic ultrasonic wave 38 is displayed on the irradiation area image. Thereby, it becomes easy for the user to confirm that the therapeutic ultrasonic wave 38 is irradiated to the affected part. Further, by transmitting the alternating pulses 50, the non-linear component generated by the imaging pulse 46 is increased. Thereby, the magnitude of the non-linear signal becomes large, and the bubbles shown in the irradiation area image are emphasized, and it becomes easy for the user to confirm that the therapeutic ultrasonic wave 38 is irradiated to the affected part. [Structure of the present invention] Structure 1: An ultrasonic treatment device, comprising: a therapeutic ultrasonic oscillator, an ultrasonic probe, and a control unit for controlling the ultrasonic oscillator and the ultrasonic probe; wherein the control unit executes: a therapeutic ultrasonic wave transmission process for causing the ultrasonic oscillator to transmit a therapeutic ultrasonic wave; an auxiliary ultrasonic wave transmission process for causing the ultrasonic oscillator to transmit an auxiliary ultrasonic wave; and an irradiation area image generation process for causing the ultrasonic probe to transmit a plurality of ultrasonic waves at different time points and different phases after the therapeutic ultrasonic wave is transmitted, reflecting on the biological tissue, and synthesizing a plurality of received signals based on the plurality of reflected ultrasonic waves received by the ultrasonic probe, thereby generating irradiation area data based on the non-linear components of the respective received signals; wherein the auxiliary ultrasonic wave transmission process includes: a process of causing the ultrasonic oscillator to transmit the auxiliary ultrasonic wave at a time point between two time points at which two adjacent ones among the plurality of ultrasonic waves are transmitted on the time axis. Structure 2: The ultrasonic treatment device according to Structure 1, wherein the auxiliary ultrasonic wave transmission process includes: a process of causing the ultrasonic oscillator to transmit the auxiliary ultrasonic wave at a time point earlier than the intermediate time point between two time points at which two adjacent ones among the plurality of ultrasonic waves are transmitted on the time axis. Structure 3: The ultrasonic treatment device according to Structure 1 or Structure 2, wherein the auxiliary ultrasonic wave transmission process includes: a process of causing the ultrasonic oscillator to transmit the auxiliary ultrasonic wave at a time point earlier than the time points of the plurality of ultrasonic waves after the therapeutic ultrasonic wave is transmitted. Structure 4: The ultrasonic treatment device according to any one of Structures 1 to 3, wherein the plurality of received signals are signals of M channels of ultrasonic waves sequentially transmitted from the ultrasonic probe with a phase difference of 360° / M, based on the plurality of reflected ultrasonic waves received by the ultrasonic probe. Structure 5: An ultrasonic treatment device as described in any one of Structures 1 to 4, wherein the control unit performs: a B-mode image generation process of generating B-mode image data of the biological tissue using any one of the plurality of received signals. Structure 6: An ultrasonic treatment device as described in Structure 5, wherein the control unit causes an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data to be displayed on a display device. Structure 7: An ultrasonic treatment device as described in Structure 5, wherein the control unit causes an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data to be overlapped and displayed on the display device. 2: Transceiver unit 3: Central axis 4: Concave surface 10: HIFU oscillator unit 12: Oscillator housing 14: HIFU drive circuit 16: Ultrasonic probe 18: Transceiver circuit 20: Imaging operation unit 22: Controller 24: Display device 26: Drive device 28: Ultrasonic oscillator 30: Control unit 36: HIFU / imaging hybrid wave 38: Therapeutic ultrasonic wave 40: Trigger pulse 42: Heating burst wave 44: Therapeutic ultrasonic pulse 46-1: First imaging pulse 46-2: Second imaging pulse 46-3: Third imaging pulse 48: Irradiation stop period 50-1: First interleaved pulse (auxiliary ultrasonic wave) 50-2: Second interleaved pulse (auxiliary ultrasonic wave) 60: Bubble 100: HIFU irradiation device (ultrasonic treatment device). <Figure 1> is a diagram showing the structure of the HIFU irradiation device. <Figure 2> is a diagram conceptually showing the transmission timing of the therapeutic ultrasonic wave and the HIFU / imaging hybrid wave. <Figure 3> is a diagram showing the structure of the interleaved pulse. <Figure 4> is a diagram showing the B-mode image and the irradiation area image as experimental results. <Figure 5> is a diagram showing the experimental results of the contrast of the irradiation area image. <Figure 6> is a diagram showing the experimental results of the contrast of the irradiation area image. <Figure 7> is a diagram conceptually showing the transmission timing of the therapeutic ultrasonic pulse not including the heating burst wave and the HIFU / imaging hybrid wave. <Figure 8> is a diagram showing the experimental results of the contrast in the case of using the therapeutic ultrasonic pulse not including the heating burst wave. 2: Transceiver unit 3: Central axis 4: Concave surface 10: HIFU oscillator unit 12: Oscillator housing 14: HIFU drive circuit 16: Ultrasonic probe 18: Transceiving circuit 20: Imaging operation unit 22: Controller 24: Display device 26: Driving device 28: Ultrasonic oscillator 30: Control unit 100: HIFU irradiation device (ultrasonic treatment device)

Claims

1. An ultrasound therapy device comprising: a therapeutic ultrasound vibrator, an ultrasound probe, and a control unit for controlling the ultrasound vibrator and the ultrasound probe, wherein the control unit performs: therapeutic ultrasound transmission processing, causing the ultrasound vibrator to transmit therapeutic ultrasound; auxiliary ultrasound transmission processing, causing the ultrasound vibrator to transmit auxiliary ultrasound; and irradiation area image generation processing, causing the ultrasound probe to transmit multiple ultrasound waves at different times and phases after the therapeutic ultrasound is transmitted, and synthesizing an image based on the ultrasound waves by reflection from biological tissue. The probe receives multiple received signals of multiple reflected ultrasound waves, thereby generating irradiation area data based on the nonlinear components of each of the aforementioned received signals; wherein the aforementioned auxiliary ultrasound transmission process includes: among the multiple ultrasound waves that are the basis for the synthesis of the multiple aforementioned received signals in the aforementioned irradiation area image generation process, the aforementioned ultrasound vibrator transmits the aforementioned auxiliary ultrasound waves at a time point between two adjacent transmission points on the time axis, thereby increasing the contrast of the irradiation area image shown in the aforementioned irradiation area data.

2. The ultrasound therapy device as claimed in claim 1, wherein the aforementioned auxiliary ultrasound is composed of a single ultrasound pulse or a plurality of ultrasound pulses connected in time, and the aforementioned contrast is determined by at least one of the number and amplitude of the ultrasound pulses constituting the aforementioned auxiliary ultrasound.

3. The ultrasound therapy device as described in claim 1 or 2, wherein the aforementioned auxiliary ultrasound transmission process includes: transmitting the aforementioned auxiliary ultrasound at a time point earlier than the midpoint between the transmission times of the first imaging pulse and the second imaging pulse of two adjacent pulses in the time axis among the plurality of ultrasounds of the aforementioned synthetic object; after the reflected ultrasound generated according to the first imaging pulse is received by the aforementioned ultrasound probe, the aforementioned auxiliary ultrasound reaches the affected area in the aforementioned biological tissue; after the multiple reflected waves generated by the aforementioned auxiliary ultrasound in the aforementioned biological tissue are attenuated, the transmission sequence of the aforementioned first imaging pulse, the aforementioned auxiliary ultrasound, and the aforementioned second imaging pulse is determined in such a way that the second imaging pulse will reach the aforementioned affected area.

4. The ultrasound therapy apparatus as described in claim 1 or claim 2, wherein the aforementioned auxiliary ultrasound transmission process includes: a process of transmitting the aforementioned auxiliary ultrasound by the ultrasound vibrator at a time point earlier than the time point of the plurality of ultrasounds of the aforementioned synthetic object after the aforementioned therapeutic ultrasound has been transmitted.

5. The ultrasound therapy device as described in claim 1 or claim 2, wherein the plurality of the aforementioned received signals are sequentially transmitted from the aforementioned ultrasound probe as M channels of the aforementioned synthetic object based on a phase difference of 360° / M, and based on the signals of the plurality of aforementioned reflected ultrasound waves received by the aforementioned ultrasound probe.

6. The ultrasound therapy apparatus as described in claim 1 or claim 2, wherein the aforementioned control unit performs: B-mode image generation processing to generate B-mode image data of the aforementioned biological tissue using any one of the plurality of the aforementioned received signals.

7. The ultrasound therapy apparatus as claimed in claim 6, wherein the aforementioned control unit displays an irradiation area image based on the aforementioned irradiation area data and a B-mode image based on the aforementioned B-mode image data on a display device.

8. The ultrasound therapy device as claimed in claim 6, wherein the aforementioned control unit causes an irradiation area image based on the aforementioned irradiation area data and a B-mode image based on the aforementioned B-mode image data to be superimposed and displayed on a display device.

Images