Ultrasonic treatment device

Abstract

The purpose of the present invention is to make it easier, in treatment using an ultrasonic treatment device, to confirm that an affected part has been irradiated with treatment ultrasound. In a treatment ultrasound transmission process, an ultrasonic transducer (28) is caused to transmit treatment ultrasound (38). In an irradiation region image generation process, after the treatment ultrasound (38) has been transmitted, an ultrasonic probe (16) is caused to transmit a plurality of imaging pulses (46) at different timings and phases as a plurality of ultrasonic waves, and a plurality of reception signals based on a plurality of reflected ultrasound reflected by biological tissue and received by the ultrasonic probe (16) are added and summed to generate irradiation region data based on the non-linear component of each of the reception signals. In an auxiliary ultrasound transmission process, the ultrasonic transducer (28) is caused to transmit an interleave pulse (50) at a timing between two timings at which two imaging pulses (46), from among the plurality of imaging pulses (46), that are adjacent to each other on the time axis are transmitted.

Description

Ultrasonic therapy device

[0001] The present invention relates to an ultrasonic therapy device, and more particularly to a device including an ultrasonic transducer for therapy and an ultrasonic probe for generating images.

[0002] Treatment devices using high intensity focused ultrasound therapy are widely used. These ultrasound treatment devices are called HIFU irradiation devices or HIFU irradiation systems, and irradiate the treatment area with ultrasound to cause tissue necrosis.

[0003] Generally, a HIFU irradiation device includes multiple ultrasonic transducers arranged on a bowl-shaped surface. The multiple ultrasonic transducers are arranged so that ultrasonic waves emitted from each transducer are irradiated at a single point to form a focal point. During treatment, the focal point is aligned with the treatment area and ultrasonic waves are irradiated. To confirm the irradiation position, an ultrasound imaging device is used, which displays the focal point on an ultrasound image.

[0004] The following Patent Document 1 describes an ultrasonic treatment device that observes the position of a focal point using an ultrasonic imaging device that displays B-mode images (tomographic images). In this device, a therapeutic ultrasonic transducer emits ultrasonic waves at a low level that do not affect tissue, and an ultrasonic imaging probe transmits and receives ultrasonic waves to display a tomographic image. Since the acoustic properties of the subject's tissue change depending on the temperature of the tissue, the position of the focal point is indicated in the tomographic image by varying brightness.

[0005] Patent Document 2 describes, as a technology related to the present invention, a technology for visualizing echo components scattered by a microbubble contrast agent by clearly distinguishing them from components caused by nonlinear propagation of a transmission pulse.

[0006] Japanese Patent Application Laid-Open No. 8-71069 International Publication No. 2005 / 087109 Japanese Patent Application Laid-Open No. 2023-79320

[0007] Generally, when powerful therapeutic ultrasound is applied to an affected area of ​​biological tissue, bubbles (cavities) are generated at the irradiated area due to cavitation. In treatments using conventional HIFU irradiation devices, methods for confirming that therapeutic ultrasound has been applied to the affected area include observing the positions of bubbles generated by cavitation and observing the patient's biological tissue. Observation of the positions of bubbles is performed using harmonic imaging, in which ultrasound is transmitted from an ultrasound probe toward the affected area and harmonics generated around the bubbles are received by the ultrasound probe, as described in Patent Document 3, for example. Furthermore, observation of the patient's biological tissue is performed by acquiring B-mode images by transmitting and receiving ultrasound using the ultrasound probe.

[0008] In treatment using a HIFU irradiation device, for example, when the affected area is small, the therapeutic ultrasound is irradiated over a small area, and therefore, if the number of bubbles generated is small, it may be difficult to confirm that the therapeutic ultrasound has been irradiated to the affected area.

[0009] An object of the present invention is to make it easier to confirm that therapeutic ultrasound has been applied to an affected area during treatment using an ultrasonic treatment device.

[0010] The present invention comprises a therapeutic ultrasound transducer, an ultrasound probe, and a control unit that controls the ultrasound transducer and the ultrasound probe, wherein the control unit executes a therapeutic ultrasound transmission process that causes the ultrasound transducer to transmit therapeutic ultrasound, an auxiliary ultrasound transmission process that causes the ultrasound transducer to transmit auxiliary ultrasound, and an irradiation area image generation process that, after the therapeutic ultrasound has been transmitted, causes the ultrasound probe to transmit a plurality of ultrasound waves at different timings and different phases, and combines a plurality of reception signals based on a plurality of reflected ultrasound waves that are reflected by biological tissue and received by the ultrasound probe, thereby generating irradiation area data based on nonlinear components of each of the reception signals, wherein the auxiliary ultrasound transmission process includes a process that causes the ultrasound transducer to transmit the auxiliary ultrasound at a timing between two timings at which two of the plurality of ultrasound waves that are adjacent on the time axis are transmitted.

[0011] Preferably, the auxiliary ultrasonic wave transmission process includes a process of causing the ultrasonic transducer to transmit the auxiliary ultrasonic wave at a timing earlier than the midpoint between two timings at which two of the plurality of ultrasonic waves adjacent on the time axis are transmitted.

[0012] Preferably, the auxiliary ultrasound transmission process includes a process of causing the ultrasound transducer to transmit the auxiliary ultrasound at an earlier timing than the plurality of ultrasound waves after the therapeutic ultrasound has been transmitted.

[0013] Preferably, the plurality of received signals are signals based on a plurality of reflected ultrasonic waves received by the ultrasonic probe based on M types of ultrasonic waves sequentially transmitted from the ultrasonic probe with a phase difference of 360° / M.

[0014] Preferably, the control unit executes a B-mode image generation process for generating B-mode image data of the biological tissue using any one of the plurality of received signals.

[0015] Preferably, the control unit causes a display device to display an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data.

[0016] Preferably, the control unit causes the display device to display an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data in a superimposed manner.

[0017] According to the present invention, it is possible to easily confirm that the therapeutic ultrasound has been applied to the affected area.

[0018] 1 is a diagram showing the configuration of a HIFU irradiation device; 2 is a diagram conceptually showing the transmission timing of therapeutic ultrasound and HIFU / imaging hybrid waves; 3 is a diagram showing the configuration of an interleaved pulse; 4 is a diagram showing a B-mode image and an irradiation area image as experimental results; 5 is a diagram showing the experimental results of the contrast ratio of the irradiation area image; 6 is a diagram showing the experimental results of the contrast ratio of the irradiation area image; 7 is a diagram conceptually showing the transmission timing of therapeutic ultrasound pulses not including a heating burst and HIFU / imaging hybrid waves; 8 is a diagram showing the experimental results of the contrast ratio when a therapeutic ultrasound pulse not including a heating burst is used.

[0019] An embodiment of the present invention will be described with reference to the drawings. Identical components shown in multiple drawings are designated by the same reference numerals to simplify the description. Fig. 1 shows the configuration of a HIFU irradiation device 100 (ultrasonic treatment device) according to an embodiment of the present invention. The HIFU irradiation device 100 includes a HIFU transducer unit 10, a HIFU driver circuit 14, an ultrasound probe 16, a transmitter / receiver circuit 18, an imaging calculation unit 20, a controller 22, a display device 24, and a driver 26.

[0020] The controller 22 may be a personal computer, a tablet computer, etc. An operating device (not shown) is connected to the controller 22 so that the user can operate the HIFU irradiation device 100. The operating device may include a mouse, a touch panel integrated with the display device 24, a switch, a keyboard, etc.

[0021] The HIFU transducer unit 10 includes a transducer housing 12 having a concave surface 4 with an opening facing downward, and a plurality of ultrasound transducers 28 arranged along the concave surface 4 of the transducer housing 12 and fixed to the transducer housing 12. The HIFU transducer unit 10 does not necessarily have to have an actual concave surface 4. In this case, the plurality of ultrasound transducers 28 may be fixed to the transducer housing 12 so as to be arranged along a virtual concave surface 4.

[0022] The concave surface 4 of the transducer housing 12 may have a shape similar to the side surface of a pyramid. Here, a pyramid refers to a three-dimensional shape formed by a collection of straight lines extending from a point in space to a bottom surface. The concave surface 4 of the transducer housing 12 may also have a dome-like shape bulging upward. Each ultrasonic transducer 28 is fixed to the transducer housing 12 so that when each ultrasonic transducer 28 emits ultrasound, the intensity of the ultrasound is intensified at a focal point F below the transducer housing 12.

[0023] The HIFU drive circuit 14 causes each ultrasonic transducer 28 included in the HIFU transducer unit 10 to generate ultrasonic waves in accordance with the control of the controller 22. The HIFU drive circuit 14 also adjusts the intensity of the ultrasonic waves generated by each ultrasonic transducer 28 in accordance with the control of the controller 22.

[0024] The ultrasonic probe 16 is fixed to the transducer housing 12 so that ultrasonic waves are transmitted and received at a position below the transducer housing 12 and above the focal point F. In this embodiment, the ultrasonic probe 16 passes through the top of the transducer housing 12 in the vertical direction, and the transmitter / receiver unit 2 that transmits and receives ultrasonic waves faces downward.

[0025] A general ultrasound imaging device may be used for the transmission / reception circuitry 18 and the imaging calculation unit 20. The imaging calculation unit 20 may be configured by a processor that executes a program to control the transmission / reception circuitry 18. The transmission / reception circuitry 18 performs the following processing in accordance with the control of the imaging calculation unit 20. That is, the transmission / reception circuitry 18 causes the ultrasound probe 16 to transmit ultrasound waves and scan with a beam of the transmitted ultrasound waves (ultrasound beam). The ultrasound beam scans an observation plane including a central axis 3 extending vertically from the vertex of the transducer housing 12. The transmission / reception circuitry 18 causes the ultrasound probe 16 to receive reflected ultrasound waves arriving from the direction in which the ultrasound beam is directed, and acquires, from the ultrasound probe 16, received signals based on the reflected ultrasound waves received from each direction in which the ultrasound beam is directed. The transmission / reception circuitry 18 outputs each received signal to the imaging calculation unit 20.

[0026] The imaging calculation unit 20 generates ultrasound data based on each reception signal output from the transmission / reception circuit 18. The ultrasound data may be irradiation area data indicating an area in which a nonlinear component occurs in the patient's biological tissue, or B-mode image data indicating a B-mode image (tomographic image) acquired from the patient's biological tissue.

[0027] The driving device 26 moves and adjusts the positions of the HIFU transducer unit 10 and the ultrasonic probe 16 in accordance with the control of the controller 22. The driving device 26 may also rotate the ultrasonic probe 16 around the central axis 3 in accordance with the control of the controller 22, thereby rotating the observation surface of the ultrasonic probe 16 around the central axis 3.

[0028] Before the HIFU transducer unit 10 irradiates the patient with therapeutic ultrasound, the following positioning process is performed. The HIFU driver circuit 14 causes each ultrasound transducer 28 to transmit ultrasound waves with a lower intensity than that used during treatment. The driver 26 sets the rotational angle position of the ultrasound probe 16 so that the ultrasound probe 16 scans the observation plane at a predetermined rotational angle position with an ultrasound beam.

[0029] The imaging calculation unit 20 causes the ultrasonic probe 16 to scan the observation surface with an ultrasonic beam, acquires B-mode image data as ultrasonic data, and outputs it to the controller 22. The controller 22 displays the B-mode image on the display device 24. The user as a practitioner refers to the B-mode image displayed on the display device 24 and confirms the difference between the position (focus) where the ultrasonic waves transmitted from the HIFU transducer unit 10 are intensified and the position of the affected area.

[0030] If the difference between the position of the focal point F and the position of the affected area is not within an acceptable range, the user changes the position or posture of the ultrasound probe 16 and the HIFU transducer unit 10. After the user confirms that the position of the focal point F matches the position of the affected area or that the difference between the position of the focal point F and the position of the affected area is within an acceptable range, the user operates the controller 22 for treatment. The controller 22 controls the HIFU drive circuit 14 in response to the user's operation. The HIFU drive circuit 14 transmits therapeutic ultrasound having an intensity required for treatment to each ultrasound transducer 28 in response to the control of the controller 22. This cauterizes the living tissue at the focal point F, thereby performing treatment.

[0031] The HIFU irradiation device 100 performs irradiation area display processing to display an image (irradiation area image) showing the irradiation area irradiated with the therapeutic ultrasound on the display device 24 while irradiating the patient with therapeutic ultrasound. The irradiation area image is an image represented by irradiation area data. The irradiation area image may be displayed alongside the B-mode image or may be displayed superimposed on the B-mode image. Here, the processing to display two images superimposed may be processing to generate new image data by synthesizing image data so that one image can be seen through the other, and then display an image based on the new image data.

[0032] FIG. 2 conceptually illustrates the transmission timing of the therapeutic ultrasound 38 transmitted from the HIFU transducer unit 10 and the HIFU / imaging hybrid wave 36 transmitted from the HIFU transducer unit 10 and the ultrasound probe 16 when the irradiation area display process is executed.

[0033] The therapeutic ultrasound 38 is composed of a therapeutic ultrasound pulse 44 including a trigger pulse 40 and a heating burst 42 following the trigger pulse 40. The therapeutic ultrasound pulse 44 is repeatedly transmitted from the HIFU transducer unit 10 over time. An irradiation pause 48 is provided between adjacent therapeutic ultrasound pulses 44 on the time axis, and during the irradiation pause 48, transmission of the therapeutic ultrasound 38 is stopped. The amplitude of the heating burst 42 may be smaller than the amplitude of the trigger pulse 40. The time length T1 of the trigger pulse 40 may be shorter than the time length T3 of the heating burst 42.

[0034] When the therapeutic ultrasound pulse 44 is transmitted from the HIFU transducer unit 10, the biological tissue is cauterized at the focal point F. As the trigger pulse 40 is irradiated onto the biological tissue, bubbles are generated from the biological tissue, and the state in which the bubbles are generated is maintained by the irradiation of the heating burst 42.

[0035] During the irradiation pause period 48, the HIFU transducer unit 10 and the ultrasound probe 16 transmit a HIFU / imaging hybrid wave 36. The HIFU / imaging hybrid wave 36 includes a first imaging pulse 46-1, a second imaging pulse 46-2, and a third imaging pulse 46-3 transmitted from the ultrasound probe 16 at a time interval of time τ0. The second imaging pulse 46-2 is delayed in phase with respect to the first imaging pulse 46-1 by 120°. The third imaging pulse 46-3 is delayed in phase with respect to the second imaging pulse 46-2 by 120°. In the following description, any of the first imaging pulse 46-1 to the third imaging pulse 46-3 that is not specified may be referred to as an imaging pulse 46.

[0036] 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 transducer unit 10. In the following description, the first interleaved pulse 50-1 and the second interleaved pulse 50-2 that are not specified may be referred to as an interleaved pulse 50.

[0037] The first interleaved pulse 50-1 is transmitted at a timing between the two timings 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 timing between the two timings at which the second imaging pulse 46-2 and the third imaging pulse 46-3 are transmitted.

[0038] Specifically, the first interleaved pulse 50-1 is transmitted when time τ1 has elapsed since the first imaging pulse 46-1 was transmitted, the second interleaved pulse 50-2 is transmitted when time τ2 has elapsed since the first interleaved pulse 50-1 was transmitted, the second interleaved pulse 50-2 is transmitted when time τ1 has elapsed since the second imaging pulse 46-2 was transmitted, and the third interleaved pulse 50-3 is transmitted when time τ2 has elapsed since the second interleaved pulse 50-2 was transmitted.

[0039] Time τ1 is shorter than time τ2. That is, the first interleaved pulse 50-1 is transmitted at a timing earlier than the intermediate timing between the timing at which the first imaging pulse 46-1 is transmitted and the timing at which the second imaging pulse 46-2 is transmitted. Here, the intermediate timing refers to the timing corresponding to the midpoint between two points on the time axis. Also, the second interleaved pulse 50-2 is transmitted at a timing earlier than the intermediate timing between the timing at which the second imaging pulse 46-2 is transmitted and the timing at which the third imaging pulse 46-3 is transmitted.

[0040] The times τ1 and τ2 may be determined so that the HIFU / imaging hybrid wave 36 acts on the biological tissue as follows: The first interleaved pulse 50-1 reaches the affected area after the reflected ultrasound waves generated based on the first imaging pulse 46-1 are received by the ultrasound probe 16, and vibrates bubbles generated in the affected area. The second imaging pulse 46-2 reaches the affected area after the multiple reflected 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 ultrasound waves generated based on the second imaging pulse 46-2 are received by the ultrasound probe 16, and vibrates bubbles generated in the affected area. The third imaging pulse 46-3 reaches the affected area after the multiple reflected waves generated in the biological tissue by the second interleaved pulse 50-2 have sufficiently attenuated.

[0041] Each interleaved pulse 50 may be composed of one ultrasonic pulse or multiple ultrasonic pulses connected on the time axis. The lower right of Fig. 3 shows the timing of each ultrasonic pulse when the interleaved pulse 50 is composed of, from top to bottom, one ultrasonic pulse, three ultrasonic pulses, and ten ultrasonic pulses.

[0042] In the example shown in FIG. 2, the time from when the first imaging pulse 46-1 is transmitted to when the first interleaved pulse 50-1 is transmitted is equal to the time from when the second imaging pulse 46-2 is transmitted to when the second interleaved pulse 50-2 is transmitted, but these times may be different.

[0043] Each imaging pulse 46 is reflected within the biological tissue. When the imaging pulse 46 is reflected around the bubbles generated by the therapeutic ultrasonic pulse 44, nonlinear components such as harmonics are generated. Therefore, the reflected ultrasound waves from the biological tissue contain nonlinear components caused by the bubbles in addition to the fundamental wave. Generally, the greater the number of bubbles generated, the greater the intensity of the generated nonlinear components.

[0044] 1 , a description will be given of the process by which the HIFU irradiator 100 receives reflected ultrasound waves corresponding to each imaging pulse 46. The ultrasound probe 16 receives first to third reflected ultrasound waves corresponding to the first to third imaging pulses 46-1 to 46-3, and outputs first to third received signals, respectively, to the transmission / reception circuit 18. The transmission / reception circuit 18 amplifies the first to third received signals and outputs them to the imaging calculation unit 20.

[0045] The imaging calculation unit 20 adds up the first to third received signals and generates a nonlinear signal by adding up the nonlinear components contained in each of the first to third received signals. Due to the phase relationship between the first imaging pulse 46-1 to the third imaging pulse 46-3, the fundamental wave component is suppressed in the signal by adding up the first to third received signals. The imaging calculation unit 20 generates nonlinear signals for the first to third reflected ultrasonic waves arriving from each direction toward which the ultrasonic beam is directed, and generates irradiation area data based on the nonlinear signals generated for each direction. The irradiation area data is image data representing an irradiation area image that shows an area where bubbles have occurred within the area scanned by the ultrasonic beam.

[0046] The imaging calculation unit 20 also generates a B-mode image based on one of the first to third reflected ultrasound waves. For example, the imaging calculation unit 20 generates pixel data of a B-mode image in each direction based on the second reflected ultrasound wave arriving from each direction toward which the ultrasound beam is directed, and generates B-mode image data based on the pixel data acquired for each direction. Note that the reflected ultrasound wave that is the source of the B-mode image data may be the first reflected ultrasound wave or the third reflected ultrasound wave.

[0047] The imaging calculation unit 20 outputs the irradiation region data and the B-mode image data to the controller 22. The controller 22 causes the display device 24 to display an image in which the irradiation region image is superimposed on the B-mode image (B-mode irradiation region image) based on the irradiation region data and the B-mode image data.

[0048] The imaging calculation unit 20 outputs the irradiation area data and B-mode image data at frame time intervals (the reciprocal of the frame rate) to the controller 22. The controller 22 causes the display device 24 to display the B-mode irradiation area images sequentially over time.

[0049] The controller 22 may display the irradiation area image and the B-mode image separately without superimposing them. For example, the controller 22 may display the irradiation area image and the B-mode image side by side on the display device 24 so that they can be compared.

[0050] FIG. 4 shows the experimental results. The upper left and lower left of FIG. 4 show a B-mode image and an irradiation area image, respectively, when conventional fundamental imaging ultrasound was used. The fundamental imaging ultrasound is obtained by removing 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 fundamental imaging ultrasound, the second imaging pulse 46-2 is transmitted when a time τ0 has elapsed since the first imaging pulse 46-1 was transmitted without the first interleaved pulse 50-1 being transmitted. Furthermore, the third imaging pulse 46-3 is transmitted when a time τ0 has elapsed since the second imaging pulse 46-2 was transmitted without the second interleaved pulse 50-2 being transmitted. In each drawing, the horizontal axis represents width [mm], and the vertical axis represents depth [mm]. An image of a bubble 60 appears in each image.

[0051] The upper right and lower right of Figure 4 show a B-mode image and an image of the irradiation area, respectively, for this embodiment in which the HIFU / imaging hybrid wave 36 was used. The interleaved pulse 50 used consisted of three ultrasound pulses connected on the time axis. In each figure, the horizontal axis represents width [mm], and the vertical axis represents depth [mm]. Images of bubbles 60 appear in each image. As is clear from the lower left and lower right figures, bubbles 60 generated in the irradiation area are more clearly visible when the HIFU / imaging hybrid wave 36 is used than when the basic imaging ultrasound is used.

[0052] 5 shows the bubble-to-tissue contrast ratio (hereinafter referred to as the contrast ratio) of the irradiation area image. The contrast ratio when using the HIFU / imaging hybrid wave 36 is approximately 9 dB higher than the contrast ratio when using basic imaging ultrasound without the interleaved pulse 50. The experimental conditions were as follows: The period T0 from the transmission of the previous trigger pulse 40 to the transmission of the next trigger pulse 40 was 50 msec. The time length T1 of the trigger pulse 40 was 0.1 msec. The time T2 from the end of transmission of the trigger pulse 40 to the start of transmission of the heating burst 42 was 3 msec. The time length T3 of the heating burst 42 was 43.9 ms. The time T4 from the end of transmission of the heating burst 42 to the start of transmission of the HIFU / imaging hybrid wave 36 was 1 ms. The time τ1 for the HIFU / imaging hybrid wave 36 was 120 μsec, and the time τ2 was 280 μsec. The radiation pause period T5 is 3 msec.

[0053] 6 shows contrast ratios for different configurations of the HIFU / imaging hybrid wave 36. The first to third rows from the left show contrast ratios for the interleaved pulse 50 consisting of ten high-intensity ultrasound pulses, three high-intensity ultrasound pulses, and one high-intensity pulse, respectively. The fourth to sixth rows from the left show contrast ratios for the interleaved pulse 50 consisting of ten medium-intensity ultrasound pulses, three medium-intensity ultrasound pulses, and one medium-intensity pulse, respectively. Here, a high-intensity ultrasound pulse refers to an ultrasound pulse with the same amplitude as the trigger pulse 40, and a medium-intensity ultrasound pulse refers to an ultrasound pulse with the same amplitude as the heating burst 42. The rightmost row shows contrast ratios for the basic imaging ultrasound.

[0054] As shown in FIG. 6, the greater the amplitude of the interleaved pulse 50, the greater the contrast ratio tends to be, and the greater the number of ultrasonic pulses that make up the interleaved pulse 50, the greater the contrast ratio tends to be.

[0055] As described above, in the HIFU irradiation device 100 according to this embodiment, by transmitting the HIFU / imaging hybrid wave 36, the first interleaved pulse 50-1 is transmitted between the transmission of the first imaging pulse 46-1 and the transmission of the second imaging pulse 46-2. When the first interleaved pulse 50-1 is transmitted to the affected area, bubbles generated in the affected area by the therapeutic ultrasound 38 vibrate, increasing the nonlinear component generated by the second imaging pulse 46-2. Furthermore, 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. When the second interleaved pulse 50-2 is transmitted to the affected area, bubbles generated in the affected area by the therapeutic ultrasound 38 vibrate, increasing the nonlinear component generated by the third imaging pulse 46-3. This increases the magnitude of the nonlinear signal, emphasizing the bubbles shown in the irradiation area image and making it easier for the user to confirm that the therapeutic ultrasound 38 has been irradiated to the affected area.

[0056] In the above description, the interleaved pulse 50 is transmitted between the timings of two adjacent imaging pulses 46 on the time axis. The interleaved pulse 50 may be transmitted after the therapeutic ultrasound pulse 44 is transmitted and before the first imaging pulse 46 is transmitted.

[0057] In the above description, the imaging pulses 46 for generating ultrasound data are transmitted three times. The imaging pulses 46 may be transmitted two times or four or more times. When the imaging ultrasound waves are transmitted M times (M is an integer equal to or greater than two), the phase difference between adjacent imaging pulses 46 on the time axis is set to 360° / M. Alternatively, the phase of each imaging ultrasound wave may be set so that a phase of θ+i·360° / M (θ is an arbitrary phase, and i is an integer between 0 and M−1) is assigned to M imaging pulses 46, regardless of the transmission order.

[0058] The imaging calculation unit 20 adds up the first through Mth received signals and generates a nonlinear signal by adding up the nonlinear components contained in each of the first through Mth received signals. The imaging calculation unit 20 also generates a B-mode image based on one of the first through Mth reflected ultrasonic waves.

[0059] In the above, an embodiment has been shown in which a pulse including a trigger pulse 40 and a heating burst 42 following the trigger pulse 40 is used as the therapeutic ultrasound pulse 44. A pulse including only the trigger pulse 40, without the heating burst 42, may also be used as the therapeutic ultrasound pulse 44.

[0060] 7 conceptually illustrates the timing of transmission of a therapeutic ultrasound pulse 44 that does not include a heating burst 42 and a HIFU / imaging hybrid wave 36. The next trigger pulse 40 is transmitted when an irradiation pause period T5 has elapsed since the end of transmission of the previous trigger pulse 40. During the irradiation pause period T5, the HIFU / imaging hybrid wave 36 is transmitted when a time T4 has elapsed since the end of transmission of the trigger pulse 40.

[0061] 8 shows the contrast ratio when using a therapeutic ultrasound pulse 44 that does not include a heating burst 42. On the left side, the contrast ratio when using a HIFU / imaging hybrid wave 36 in which the interleaved pulse 50 is composed of three high-intensity ultrasound pulses is shown. On the right side, the contrast ratio when using fundamental imaging ultrasound is shown. The contrast ratio when using the HIFU / imaging hybrid wave 36 is approximately 6 dB higher than the contrast ratio when using fundamental imaging ultrasound. Even when the therapeutic ultrasound pulse 44 does not include a heating burst 42, the contrast ratio tends to be higher when using the HIFU / imaging hybrid wave 36 than when using fundamental imaging ultrasound, just as when the therapeutic ultrasound pulse 44 includes a heating burst 42.

[0062] As described above, the HIFU irradiation device 100 is an ultrasonic treatment device comprising the HIFU transducer unit 10 including the therapeutic ultrasonic transducer 28, the ultrasonic probe 16, and the control unit 30 that controls the ultrasonic transducer 28 and the ultrasonic probe 16. The control unit 30 is made up of the HIFU drive circuit 14, the transmission / reception circuit 18, the imaging calculation unit 20, and the controller 22.

[0063] The control unit 30 executes a therapeutic ultrasound transmission process, an auxiliary ultrasound transmission process, and an irradiation area image generation process. The therapeutic ultrasound transmission process is a process that causes the ultrasound transducer 28 to transmit therapeutic ultrasound 38. The irradiation area image generation process is a process that is executed after the therapeutic ultrasound 38 is transmitted. The irradiation area image generation process is a process that causes the ultrasound probe 16 to transmit a plurality of imaging pulses 46 as a plurality of ultrasound waves at different timings, and adds up (combines) first to Mth received signals (a plurality of received signals) based on first to Mth reflected ultrasound waves (a plurality of reflected ultrasound waves) that are reflected by biological tissue and received by the ultrasound probe 16, thereby generating irradiation area data based on the nonlinear components of each received signal.

[0064] The auxiliary ultrasound transmission process also includes a process of causing the ultrasound transducer 28 to transmit an interleaved pulse 50 as an auxiliary ultrasound wave at a timing between two timings at which two adjacent imaging pulses 46 on the time axis are transmitted.

[0065] In addition, the auxiliary ultrasound transmission process may include a process of causing the ultrasound transducer 28 to transmit an interleaved pulse 50 as an auxiliary ultrasound wave at an earlier timing than the multiple imaging pulses 46 after the therapeutic ultrasound wave 38 has been transmitted.

[0066] The control unit 30 executes a B-mode image generation process for generating B-mode image data of the living tissue using any one of the plurality of received signals.

[0067] The control unit 30 executes a display process to display an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data on the display device 24. The control unit 30 may display the irradiation area image and the B-mode image on the display device 24 in a superimposed manner.

[0068] With this configuration and processing, the therapeutic ultrasound 38 is irradiated onto the biological tissue, and the region irradiated with the therapeutic ultrasound 38 is displayed on the irradiation region image. This allows the user to easily confirm that the therapeutic ultrasound 38 has been irradiated onto the affected area. Furthermore, the transmission of the interleaved pulse 50 increases the nonlinear component generated by the imaging pulse 46. This increases the magnitude of the nonlinear signal, highlighting the bubbles displayed on the irradiation region image, allowing the user to easily confirm that the therapeutic ultrasound 38 has been irradiated onto the affected area.

[0069] [Configurations of the Invention] Configuration 1: An ultrasonic therapy device comprising: a therapeutic ultrasound transducer, an ultrasound probe, and a control unit that controls the ultrasound transducer and the ultrasound probe, wherein the control unit executes: a therapeutic ultrasound transmission process that causes the ultrasound transducer to transmit therapeutic ultrasound; an auxiliary ultrasound transmission process that causes the ultrasound transducer to transmit auxiliary ultrasound; and, after the therapeutic ultrasound has been transmitted, an irradiation area image generation process that causes the ultrasound probe to transmit multiple ultrasound waves at different timings and phases, and combines multiple received signals based on multiple reflected ultrasound waves reflected by biological tissue and received by the ultrasound probe, thereby generating irradiation area data based on nonlinear components of each received signal, wherein the auxiliary ultrasound transmission process includes a process of causing the ultrasound transducer to transmit the auxiliary ultrasound waves at a timing between two timings at which two of the multiple ultrasound waves adjacent on the time axis are transmitted. Configuration 2: An ultrasonic therapy device according to Configuration 1, wherein the auxiliary ultrasound transmission process includes a process of causing the ultrasound transducer to transmit the auxiliary ultrasound waves at a timing earlier than the midpoint between two timings at which two of the multiple ultrasound waves adjacent on the time axis are transmitted. Configuration 3: The ultrasonic therapy device according to configuration 1 or 2, wherein the auxiliary ultrasound transmission process includes a process of causing the ultrasound transducer to transmit the auxiliary ultrasound after the therapeutic ultrasound has been transmitted, at an earlier timing than the plurality of ultrasound waves.Configuration 4: The ultrasonic therapy device according to any one of configurations 1 to 3, wherein the plurality of received signals are signals based on the plurality of reflected ultrasound waves received by the ultrasound probe based on M different ultrasound waves sequentially transmitted from the ultrasound probe with a phase difference of 360° / M.Configuration 5: The ultrasonic therapy device according to any one of configurations 1 to 4, wherein the control unit executes a B-mode image generation process to generate B-mode image data of the biological tissue using any of the plurality of received signals.Configuration 6: The ultrasonic treatment device according to configuration 5, wherein the control unit causes a display device to display an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data.Configuration 7: The ultrasonic treatment device according to configuration 5, wherein the control unit causes the display device to display an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data in a superimposed manner.

[0070] 2 Transmitting and receiving unit, 3 Central axis, 4 Concave surface, 10 HIFU transducer unit, 14 HIFU drive circuit, 16 Ultrasonic probe, 18 Transmitting and receiving circuit, 20 Imaging calculation unit, 22 Controller, 24 Display device, 26 Drive device, 28 Ultrasonic transducer, 30 Control unit, 36 HIFU / imaging hybrid wave, 38 Therapeutic ultrasound, 40 Trigger pulse, 42 Heating burst, 44 Therapeutic ultrasound pulse, 46-1 First imaging pulse, 46-2 Second imaging pulse, 46-3 Third imaging pulse, 48 Irradiation pause period, 50-1 First interleaved pulse (auxiliary ultrasound), 50-2 Second interleaved pulse (auxiliary ultrasound), 60 Air bubble, 100 HIFU irradiation device (ultrasonic treatment device).

Claims

1. An ultrasonic treatment device comprising: a therapeutic ultrasonic transducer; an ultrasonic probe; and a control unit that controls the ultrasonic transducer and the ultrasonic probe, wherein the control unit executes: a therapeutic ultrasonic transmission process that causes the ultrasonic transducer to transmit therapeutic ultrasonic waves; an auxiliary ultrasonic transmission process that causes the ultrasonic transducer to transmit auxiliary ultrasonic waves; and, after the therapeutic ultrasonic waves have been transmitted, an irradiation area image generation process that causes the ultrasonic probe to transmit a plurality of ultrasonic waves at different timings and different phases, and combines a plurality of reception signals based on a plurality of reflected ultrasonic waves reflected by biological tissue and received by the ultrasonic probe, thereby generating irradiation area data based on nonlinear components of each of the reception signals, wherein the auxiliary ultrasonic transmission process includes a process that causes the ultrasonic transducer to transmit the auxiliary ultrasonic waves at a timing between two timings at which two of the plurality of ultrasonic waves adjacent on the time axis are transmitted.

2. An ultrasonic therapy device as described in claim 1, characterized in that the auxiliary ultrasonic transmission process includes a process of transmitting the auxiliary ultrasonic wave from the ultrasonic transducer at a timing earlier than the midpoint between two timings at which two of the multiple ultrasonic waves adjacent on the time axis are transmitted.

3. An ultrasonic therapy device as described in claim 1 or 2, characterized in that the auxiliary ultrasonic transmission process includes a process of transmitting the auxiliary ultrasonic wave from the ultrasonic transducer at an earlier timing than the plurality of ultrasonic waves after the therapeutic ultrasonic wave has been transmitted.

4. An ultrasonic therapy device as described in claim 1 or claim 2, characterized in that the multiple received signals are signals based on multiple reflected ultrasonic waves received by the ultrasonic probe based on M types of ultrasonic waves transmitted sequentially from the ultrasonic probe with a phase difference of 360° / M.

5. An ultrasonic therapy device as described in claim 1 or claim 2, characterized in that the control unit executes a B-mode image generation process to generate B-mode image data of the biological tissue using any one of the multiple received signals.

6. An ultrasonic treatment device as described in claim 5, characterized in that the control unit displays, on a display device, an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data.

7. An ultrasonic treatment device as described in claim 5, characterized in that the control unit causes the display device to display an irradiation area image based on the irradiation area data and a B-mode image based on the B-mode image data in a superimposed manner.

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