Focused ultrasound processing apparatus and method thereof

Abstract

A focused ultrasound processing apparatus and a method thereof are provided. In one general aspect, the focused ultrasound treatment apparatus includes: a focused ultrasound transducer configured to output a focused ultrasound signal to tissue; a cavitation sensor configured to detect a cavitation signal resulting from a cavitation phenomenon occurring within the tissue due to the focused ultrasound signal; and a processor configured to analyze the cavitation signal detected by the cavitation sensor, and adjust at least one of an output time or a frequency of the focused ultrasound signal based on a result of the analysis.

Description

Technical Field

[0001] The present invention relates to diagnostic and therapeutic techniques using ultrasound, and more particularly, to image scanning and therapeutic techniques using focused ultrasound (FUS). Background Art

[0002] Ultrasonic signals can be used to treat biological tissues, such as cancer, tumors, lesions, etc. Ultrasonic therapy is a method of treating lesions by outputting ultrasonic signals to the lesions in the human body. Compared with general surgical treatment or chemotherapy, ultrasonic therapy can cause less trauma to the patient and achieve non-invasive treatment. Examples of ultrasonic therapy include liver cancer, osteosarcoma, breast cancer, pancreatic cancer, kidney cancer, soft tissue tumors, pelvic tumors, etc.

[0003] Ultrasonic signals can be used to treat tissues, such as cancer, tumors, lesions, etc. Treatment using FUS signals mainly focuses on the developing thermal ablation technology, which uses thermal effects to thermally ablate tissues. However, thermal ablation can cause thermal damage to surrounding tissues and pain. Summary of the invention

[0004] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0005] The following description relates to a focused ultrasound treatment apparatus and method thereof, which can perform safer and more effective tissue ablation using focused ultrasound beyond the limitation of thermal effects by utilizing mechanical effects.

[0006] Furthermore, the following description relates to a focused ultrasound processing apparatus and method thereof, which achieve tissue ablation without causing a shock scattering effect when a mechanical effect is applied to focused ultrasound tissue ablation.

[0007] In one general aspect, a focused ultrasound processing device is provided, comprising: a focused ultrasound transducer configured to output a focused ultrasound signal to tissue; a cavitation sensor configured to detect a cavitation signal generated by a cavitation phenomenon occurring in the tissue due to the focused ultrasound signal; and a processor configured to analyze the cavitation signal detected by the cavitation sensor and adjust at least one of an output time or a frequency of the focused ultrasound signal based on the analysis result.

[0008] The processor may compare the cavitation detection value obtained by the cavitation sensor with a predetermined cavitation threshold value or a cavitation limit value, and based on the comparison result, adjust at least one of the output time or frequency of the focused ultrasound signal to reduce the cavitation value.

[0009] The processor may compare the cavitation detection value with a boiling cavitation limit value, and when the cavitation detection value is greater than or equal to the boiling cavitation limit value, adjust at least one of an output time or a frequency of the focused ultrasound signal to reduce the cavitation detection value.

[0010] The processor may compare the cavitation detection value obtained by the cavitation sensor with at least one of a boiling cavitation threshold, a non-thermal cavitation limit value, or a non-thermal cavitation threshold, and adjust at least one of an output time or a frequency of the focused ultrasound signal based on the comparison result.

[0011] The processor can control the output of the focused ultrasound signal by repeating multiple cycles, each cycle can include a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and the first frequency interval can be a thermal period for thermal effect, and the second frequency interval can be a boiling period for mechanical effect.

[0012] The first frequency interval may include fh and Ph frequencies for thermal effects, and the second frequency interval may include fm and Pm frequencies for mechanical effects.

[0013] The processor may check the cavitation detection value within the first frequency interval of the first cycle, and may perform control to reduce the number of first pulses in the first frequency interval of a second cycle after the first cycle and increase the number of second pulses in the second frequency interval of the second cycle when the cavitation detection value becomes equal to or exceeds the boiling cavitation limit value.

[0014] The processor can check the cavitation detection value within the first frequency interval of the first cycle and can perform control to: when the cavitation detection value becomes equal to or exceeds the boiling cavitation threshold, reduce the total output time of the second cycle; when the cavitation detection value falls between the boiling cavitation threshold and the non-thermal cavitation limit value, increase the number of first pulses in the first frequency interval of the second cycle and reduce the number of second pulses in the second frequency interval of the second cycle; when the cavitation detection value falls between the non-thermal cavitation limit value and the non-thermal cavitation threshold, maintain the number of first pulses in the first frequency interval of the second cycle and the number of second pulses in the second frequency interval of the second cycle; and when the cavitation detection value is less than or equal to the non-thermal cavitation threshold, reduce the number of first pulses in the first frequency interval of the second cycle and increase the number of second pulses in the second frequency interval of the second cycle.

[0015] When a focused ultrasound signal is output to the first region for the first time, the processor may check each of the cavitation detection value in the first frequency interval of the first cycle and the cavitation detection value in the second frequency interval of the first cycle, and may execute control to move to a new second region and output a focused ultrasound signal when the cavitation detection value in the first frequency interval is greater than or equal to a boiling cavitation threshold and the cavitation detection value in the second frequency interval is greater than or equal to a non-thermal cavitation threshold, and in other cases, the processor may execute control to output a focused ultrasound signal to the first region again.

[0016] When a focused ultrasound signal is output to the first region for the first time, the processor may check each of the cavitation detection value in the first frequency interval of the first cycle and the cavitation detection value in the second frequency interval of the first cycle, and may execute control to move to a new second region and output a focused ultrasound signal when the cavitation detection value in the first frequency interval or the cavitation detection value in the second frequency interval is greater than or equal to the non-thermal cavitation threshold, and in other cases, the processor may execute control to output a focused ultrasound signal to the first region again.

[0017] The focused ultrasound processing device may further include an input unit configured to receive tissue characteristics and treatment information, and the processor may determine a cavitation limit value, a cavitation threshold, and an output time and frequency of the focused ultrasound signal by reflecting the input tissue characteristics and treatment information.

[0018] The processor may determine a first frequency for maximizing a thermal effect of the focused ultrasound signal before heat generation and a second frequency for maximizing a mechanical effect of the focused ultrasound signal after heat generation.

[0019] The processor can control a focused ultrasonic signal having a determined first frequency to be output through the focused ultrasonic transducer, compare the cavitation detection value with at least one of a boiling cavitation limit value or a non-thermal cavitation limit value, and when the cavitation detection value is greater than or equal to the non-thermal cavitation limit value or the boiling cavitation limit value, perform control to adjust the frequency of the focused ultrasonic signal from the first frequency to a second frequency, and then output the adjusted focused ultrasonic signal having the second frequency through the focused ultrasonic transducer.

[0020] The focused ultrasonic processing device may also include an image transducer configured to output an image ultrasonic signal to the tissue and receive an ultrasonic echo signal reflected from the tissue, and the processor may generate an ultrasonic image signal by performing signal processing on the received ultrasonic echo signal, analyze the generated ultrasonic image signal, and adjust at least one of the output time or frequency of the focused ultrasonic signal based on the analysis result.

[0021] The processor may control the output of the focused ultrasound signal by repeating a plurality of cycles, each cycle may include a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, the first frequency interval may be a thermal period for thermal effect, and the second frequency interval may be a boiling period for mechanical effect, and the processor may check the image brightness value of the focal area in the first frequency interval of the first cycle by analyzing the image signal, and perform control to reduce the number of first pulses in the first frequency interval of the second cycle and increase the number of second pulses in the second frequency interval of the second cycle when the image brightness value of the focal area becomes equal to or exceeds a boiling cavitation image brightness limit value.

[0022] The processor may control the output of the focused ultrasound signal by repeating a plurality of cycles, each cycle may include a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, the first frequency interval may be a thermal period for thermal effect, and the second frequency interval may be a boiling period for mechanical effect, and the processor may check the image brightness value of the focal area in the first frequency interval of the first cycle by analyzing the image signal, and perform control to: reduce the total output time of the second cycle when the image brightness value of the focal area becomes equal to or exceeds the boiling cavitation image brightness value; and reduce the total output time of the second cycle when the image brightness value of the focal area falls below the boiling cavitation image brightness value. When the image brightness value of the focal area falls between the non-thermal cavitation image brightness limit value and the non-thermal cavitation image brightness threshold value, the number of first pulses in the first frequency interval of the second cycle and the number of second pulses in the second frequency interval of the second cycle are maintained; and when the image brightness value of the focal area is less than or equal to the non-thermal cavitation image brightness threshold value, the number of first pulses in the first frequency interval of the second cycle and the number of second pulses in the second frequency interval of the second cycle are reduced.

[0023] In another general aspect, a focused ultrasound processing method using a focused ultrasound processing device is provided, the method comprising: determining a first output condition including at least one of an output time or a frequency of a focused ultrasound signal; outputting a focused ultrasound signal through a focused ultrasound transducer based on the determined first output condition; detecting, by a cavitation sensor, a cavitation signal generated by a cavitation phenomenon occurring in tissue due to the output focused ultrasound signal; analyzing a cavitation detection value obtained by the cavitation sensor, and adjusting the output condition including at least one of an output time or a frequency of the focused ultrasound signal to a second output condition based on the analysis result; and outputting a focused ultrasound signal to the tissue through the focused ultrasound transducer based on the adjusted second output condition.

[0024] Adjusting the output condition to a second output condition may include: when a focused ultrasound signal is output based on the first output condition during a first cycle, checking a cavitation detection value in a first frequency interval of the first cycle; and when the cavitation detection value becomes equal to or exceeds a boiling cavitation limit value, reducing the number of first pulses in the first frequency interval and increasing the number of second pulses in the second frequency interval as a second output condition for the second cycle, each cycle may include a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and the first frequency interval may be a thermal period for thermal effects, and the second frequency interval may be a boiling period for mechanical effects.

[0025] Adjusting the output condition to the second output condition may include: when outputting the focused ultrasound signal based on the first output condition during the first cycle, checking the cavitation detection value in the first frequency interval of the first cycle; when the cavitation detection value becomes equal to or exceeds the boiling cavitation threshold, reducing the total output time of the second cycle as the second output condition of the second cycle; when the cavitation detection value falls between the boiling cavitation threshold and the non-thermal cavitation limit value, increasing the number of first pulses in the first frequency interval and reducing the number of second pulses in the second frequency interval as the second output condition of the second cycle; when the cavitation detection value falls between the non-thermal cavitation limit value and the non-thermal cavitation threshold, maintaining the number of first pulses in the first frequency interval and the number of second pulses in the second frequency interval as the second output condition of the second cycle; and when the cavitation detection value is less than or equal to the non-thermal cavitation threshold, reducing the number of first pulses in the first frequency interval and increasing the number of second pulses in the second frequency interval as the second output condition of the second cycle, each cycle may include a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and the first frequency interval may be a thermal period for thermal effect, and the second frequency interval may be a boiling period for mechanical effect.

[0026] Adjusting the output condition to a second output condition may include: when outputting a focused ultrasound signal targeting a first region for the first time, checking each of the cavitation detection value in the first frequency interval of the first cycle and the cavitation detection value in the second frequency interval of the first cycle; and performing control to move to a new second region and output the focused ultrasound signal when the cavitation detection value in the first frequency interval is greater than or equal to a boiling cavitation threshold and the cavitation detection value in the second frequency interval is greater than or equal to a non-thermal cavitation threshold, and in other cases, outputting the focused ultrasound signal to the first region again, each cycle may include a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and the first frequency interval may be a thermal period for thermal effect, and the second frequency interval may be a boiling period for mechanical effect.

[0027] Adjusting the output condition to a second output condition may include: when outputting a focused ultrasound signal targeting a first region for the first time, checking each of the cavitation detection value in the first frequency interval of the first cycle and the cavitation detection value in the second frequency interval of the first cycle; executing control to move to a new second region and output the focused ultrasound signal when the cavitation detection value in the first frequency interval or the cavitation detection value in the second frequency interval is greater than or equal to a non-thermal cavitation threshold, and in other cases, outputting the focused ultrasound signal to the first region again, each cycle may include a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and the first frequency interval may be a thermal period for thermal effect, and the second frequency interval may be a boiling period for mechanical effect.

[0028] Other features and aspects will be apparent from the following detailed description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a diagram showing a configuration of a focused ultrasonic processing apparatus according to an embodiment of the present invention;

[0030] Figure 2 is a flow chart showing a focused ultrasound processing method according to an embodiment of the present invention;

[0031] Figure 3 is a diagram showing a cavitation limit value and a cavitation threshold value to be compared with a cavitation detection value according to an embodiment of the present invention;

[0032] Figure 4 is a diagram showing a signal waveform for explaining an example of adjusting the output time of a focused ultrasound signal according to an embodiment of the present invention; and

[0033] Figure 5 : is a diagram showing in more detail a signal waveform for explaining an example of adjusting the output time of a focused ultrasound signal according to an embodiment of the present invention.

[0034] Throughout the drawings and detailed description, unless otherwise described, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. The relative sizes and depictions of these elements may be exaggerated for clarity, illustration, and convenience. DETAILED DESCRIPTION

[0035] The advantages and features of the present invention and the manner in which these advantages and features are achieved will become apparent with reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein, and these embodiments are provided so that the present disclosure will be thorough and complete, and these embodiments fully convey the scope of the present invention to those skilled in the art, and the present invention is limited only by the scope of the appended claims. Throughout the present disclosure, the same reference numerals refer to the same components.

[0036] In the following description of the embodiments of the present invention, if it is determined that the detailed description of the relevant known functions or configurations unnecessarily obscures the subject matter of the present invention, the detailed description thereof will be omitted herein. The terms described below are defined in light of the functions in the embodiments of the present invention, and these terms may vary according to the intentions or habits of the user or operator. Therefore, the definitions of the terms used herein should follow the context disclosed herein.

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be implemented in various forms, and the scope of the present invention is not limited to these embodiments. Embodiments of the present invention are provided to help those skilled in the art to explain and understand the present invention.

[0038] Figure 1 is a block diagram showing a configuration of a focused ultrasound apparatus according to an embodiment of the present invention.

[0039] The focused ultrasound processing device 1 according to the embodiment can mechanically ablate soft tissue using not only the thermal effect of the focused ultrasound signal but also the mechanical effect of the focused ultrasound signal. The technique called "focused ultrasound ablation of soft tissue" or "boiling histotripsy" is a method of artificially inducing acoustic cavitation using a significantly stronger pressure at the focus that is several tens of times greater than the sound pressure used in the focused ultrasound signal, thereby mechanically fragmenting the tissue.

[0040] However, according to the focused ultrasound tissue ablation technique, a shock scattering effect may occur, in which secondary microbubbles are simultaneously generated not only at the focus but also in the vicinity thereof. Although the focused ultrasound tissue ablation technique has the advantage of mechanically decomposing tissue, the accuracy is compromised due to the shock scattering effect, which makes it challenging to apply the technique when ablating tissue or tumors that are closely positioned with important organs and blood vessels. In the focused ultrasound tissue ablation technique, the focused ultrasound processing device 1 can fragment tissue without causing the shock scattering effect.

[0041] In the following, reference will be made to Figure 1 The configuration of the focused ultrasonic processing apparatus 1 having the aforementioned characteristics is described.

[0042] Reference Figure 1 The focused ultrasonic processing device 1 includes a focused ultrasonic pulse generator 10, a focused ultrasonic transducer 11, a diagnostic ultrasonic pulse generator 12, an image transducer 13, a processor 14, a cavitation sensor 15, an input unit 16, a storage unit 17 and an output unit 18.

[0043] The focused ultrasound pulse generator 10 generates a driving signal having a pulse shape with a pulse repetition frequency (PRF) and a duty cycle, and transmits the generated focused ultrasound signal to the focused ultrasound transducer 11 .

[0044] The focused ultrasound transducer 11 converts the electrical waveform as the driving signal received from the focused ultrasound pulse generator 10 into a focused ultrasound signal, and outputs the converted focused ultrasound signal to the tissue. At this time, due to the transfer of ultrasound energy in the tissue, a local tissue temperature rise occurs. The focused ultrasound signal may be high intensity focused ultrasound (HIFU).

[0045] The image transducer 13 outputs an image ultrasound signal into the tissue according to the electrical signal of the short pulse as the driving signal received from the diagnostic ultrasound pulse generator 12, and receives the ultrasound echo signal reflected from the tissue. The image transducer 13 receives the ultrasound echo signal until the next pulse is generated and sends it to the processor 14.

[0046] The focused ultrasonic processing apparatus 1 may have a structure in which the image transducer 13 is located at the center and the focused ultrasonic transducer 11 is arranged at the periphery. However, the structure of the image transducer 13 and the focused ultrasonic transducer 11 is not limited thereto and may be modified in various ways.

[0047] The focused ultrasound treatment apparatus 1 according to one embodiment may perform a therapeutic operation using focused ultrasound of the focused ultrasound transducer 11 while obtaining a diagnostic image using imaging ultrasound of the image transducer 13 .

[0048] Due to the focused ultrasound signal output from the focused ultrasound transducer 11, cavitation may occur within the tissue. Cavitation involves the formation, expansion, and subsequent collapse of small bubbles, which are driven by the interaction of negative and positive pressures caused by pressure fluctuations within the tissue when the ultrasound signal interacts with the tissue. The repeated process of bubble expansion and collapse leads to the destruction of cells within the tissue. The bubbles caused by cavitation can vibrate and collapse in response to the acoustic pressure fluctuations, thereby generating shock waves. The boiling tissue destruction technology can use these shock waves caused by cavitation to fragment the tissue.

[0049] The cavitation sensor 15 detects a cavitation signal generated by a cavitation phenomenon from the tissue.

[0050] According to boiling tissue destruction, a shock scattering effect may occur, in which secondary microbubbles are simultaneously generated not only at the focal point of the tissue but also near it. The bubble cloud caused by the unintended shock scattering effect may cause the shock propagation at points other than the focal position and cause damage to unintended tissue areas.

[0051] Therefore, the focused ultrasound processing device 1 according to the embodiment is intended to fragment the tissue without causing the shock scattering effect. For example, the processor 14 can analyze the cavitation detection signal detected by the cavitation sensor 15, and adjust at least one of the output time or frequency of the focused ultrasound signal based on the analysis result. By doing so, the shock scattering effect can be prevented. The processor 14 can accurately control the bubble dynamics, by adjusting at least one of the output time or frequency of the focused ultrasound signal through the analysis of the cavitation detection signal, thereby ensuring that there is no shock scattering effect.

[0052] More specifically, the processor 14 may compare the cavitation detection value obtained by the cavitation sensor 15 with the boiling cavitation limit value, and when the cavitation detection value is greater than or equal to the boiling cavitation limit value, adjust at least one of the output time or frequency of the focused ultrasonic signal to reduce the cavitation detection value. Figure 2 and Figure 5 The implementation method thereof is described.

[0053] The processor 14 can determine the operation according to the amplitude of the cavitation signal, including the first output and re-output of the focused ultrasound signal to the first area, the movement from the first area to the second area (the subsequent tissue area) and the output of the focused ultrasound signal, the stop of the output of the focused ultrasound signal, and the maintenance of the output time of the focused ultrasound signal. Figure 2 and Figure 4 The implementation method thereof is described.

[0054] The processor 14 may analyze the image ultrasound signal and adjust at least one of the output time or frequency of the focused ultrasound signal based on the analysis result. To this end, the processor 14 receives the ultrasound echo signal from the image transducer 13, and converts the received echo signal into a digital signal, and then performs image processing to create an ultrasound image signal. At this time, the processor 14 may analyze the generated ultrasound image signal and adjust at least one of the output time or frequency of the focused ultrasound signal based on the analysis result. Figure 2 and Figure 5 The implementation method thereof is described.

[0055] The output unit 18 outputs the ultrasonic image. The storage unit 17 stores necessary information for the processor 14 to perform signal analysis, or stores information analyzed by the processor 14.

[0056] Figure 2is a flow chart illustrating a focused ultrasound processing method according to an embodiment of the present invention.

[0057] Reference Figure 1 and Figure 2 In 210, the focused ultrasound treatment device 1 receives tissue characteristics and treatment information from a user. The tissue characteristics information may include tissue thickness information. The treatment information may include treatment depth and treatment range.

[0058] Subsequently, in 220, the focused ultrasound processing device 1 determines a first output condition by reflecting the tissue characteristics and the treatment information, and the first output condition includes at least one of the output time or frequency of the focused ultrasound signal. In addition, the focused ultrasound processing device 1 may set a boiling cavitation threshold, a boiling cavitation limit value, a non-thermal cavitation threshold value, a non-thermal cavitation limit value, etc. to determine the first output condition. Figure 3 Each of the aforementioned cavitation values ​​is described. The focused ultrasonic processing apparatus 1 may store the first output condition in the storage unit 17 .

[0059] Then, in 230 , the focused ultrasound processing apparatus 1 outputs a focused ultrasound signal to the tissue through the focused ultrasound transducer 11 based on the determined first output condition.

[0060] Subsequently, in 240 , the focused ultrasound processing apparatus 1 detects, through the cavitation sensor 15 , a cavitation signal generated due to the cavitation phenomenon occurring in the tissue due to the output focused ultrasound signal.

[0061] Subsequently, the focused ultrasonic processing apparatus 1 analyzes the cavitation detection signal detected by the cavitation sensor 15 , and adjusts an output condition including at least one of the output time or frequency of the focused ultrasonic signal to a second output condition based on the analysis result.

[0062] For example, in 250, the focused ultrasonic processing apparatus 1 checks whether the cavitation detection value obtained by the cavitation sensor 15 is greater than or equal to the boiling cavitation limit value by comparing the cavitation signal detected by the cavitation sensor 15 with the boiling cavitation limit value. If the cavitation detection value is equal to or exceeds the boiling cavitation limit value, then in 260, at least one of the output time or frequency of the focused ultrasonic signal is adjusted to the second output condition.

[0063] Then, in 270 , the focused ultrasound processing device 1 outputs a focused ultrasound signal to the tissue through the focused ultrasound transducer 11 based on the adjusted second output condition.

[0064] Next, an embodiment of adjusting the output time as an output condition will be described.

[0065] First, the focused ultrasound output period is composed of a plurality of cycles, each cycle including a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse. Here, the first frequency interval can be a thermal period for thermal effect, and the second frequency interval can be a boiling period for mechanical effect.

[0066] In operation 260 in which the output condition is adjusted to the second output condition, the focused ultrasonic processing device 1 compares the cavitation detection value detected by the cavitation sensor with a predetermined cavitation threshold value or a cavitation limit value. According to the comparison result, the focused ultrasonic processing device 1 can adjust at least one of the output time or frequency of the focused ultrasonic signal to reduce the cavitation detection value. This method can be classified into a method using a boiling condition and a method not using a boiling condition.

[0067] As an example of a method using boiling conditions, the focused ultrasonic processing device 1 compares the cavitation detection value with the boiling cavitation limit value. If the cavitation detection value is equal to or exceeds the boiling cavitation limit value, the focused ultrasonic processing device 1 may adjust at least one of the output time or frequency of the focused ultrasonic signal to reduce the cavitation detection value.

[0068] As an example of a method that does not use boiling conditions, the focused ultrasound processing device 1 may compare the cavitation detection value with at least one of a boiling cavitation threshold, a non-thermal cavitation limit value, or a non-thermal cavitation threshold value. Based on the comparison result, the focused ultrasound processing device 1 may adjust at least one of the output time or frequency of the focused ultrasound signal. Figure 5 The implementation method thereof is described.

[0069] Next, an embodiment in which the frequency is adjusted as an output condition will be described.

[0070] In operation 220 of determining the first output condition, the focused ultrasound processing apparatus 1 determines a first frequency for maximizing a thermal effect of the focused ultrasound signal before heat generation and a second frequency for maximizing a mechanical effect of the focused ultrasound signal after heat generation.

[0071] Subsequently, in operation 230 of outputting a focused ultrasound signal based on the first output condition, the focused ultrasound processing apparatus 1 outputs focused ultrasound of the first frequency to the tissue.

[0072] Thereafter, in operation 260 in which the output condition is adjusted to the second output condition, the focused ultrasound processing apparatus 1 compares the cavitation detection value with the boiling cavitation limit value and the non-thermal cavitation limit value. If the cavitation detection value is greater than or equal to at least one of the boiling cavitation limit value or the non-thermal cavitation limit value, the focused ultrasound processing apparatus 1 adjusts the frequency of the focused ultrasound signal from the first frequency to the second frequency.

[0073] Subsequently, in operation 270 of outputting a focused ultrasound signal based on the second output condition, the focused ultrasound processing apparatus 1 outputs the adjusted second frequency focused ultrasound to the tissue.

[0074] Next, an embodiment in which the focused ultrasound processing apparatus 1 determines a first frequency for maximizing the thermal effect of the focused ultrasound signal before heat is generated is described.

[0075] As the frequency increases, tissue exhibits an increasing absorption coefficient α(f).

[0076] α(f)=(α0f), where α0 represents the absorption coefficient at 1 MHz, and f represents the frequency in megahertz (MHz).

[0077] Depending on the treatment depth, there is a frequency at which the maximum absorption coefficient is observed.

[0078] The heat generation rate Q(z) is as follows:

[0079] Heat generation rate Q(z)=2(αf)I0exp(-2αfz).

[0080] Here, α represents the absorption coefficient, z represents the treatment depth, and f represents the frequency in MHz.

[0081] The differential of the heat generation rate Q(z) is as follows:

[0082]

[0083] The first frequency at which the derivative of the heat generation rate Q(z) becomes zero is a function of the absorption coefficient α and the treatment depth z.

[0084]

[0085] Hereinafter, an example in which the focused ultrasound processing apparatus 1 determines the second frequency for maximizing the mechanical effect of the focused ultrasound signal after heat generation is described.

[0086] The focused ultrasonic processing apparatus 1 may determine the second frequency f using the following mechanical index.

[0087] Wherein Pr represents rarefaction pressure, and f represents frequency.

[0088] On the other hand, the focused ultrasound processing device 1 not only detects the cavitation signal, but also performs additional analysis of the ultrasound image signal. Based on the analysis result of the image signal, the focused ultrasound processing device 1 can adjust at least one of the output time or frequency of the focused ultrasound signal. Figure 5 The implementation method thereof is described.

[0089] Figure 3is a graph showing a cavitation limit value and a cavitation threshold value to be compared with a cavitation detection value according to an embodiment of the present invention.

[0090] Reference Figure 3 , the focused ultrasonic processing device 1 may compare the cavitation detection value with each of the boiling cavitation limit value, the boiling cavitation threshold value, the non-thermal cavitation limit value, and the non-thermal cavitation threshold value.

[0091] The segments used for comparison with the cavitation detection values ​​are divided into the following segments: segment 1 greater than or equal to the boiling cavitation limit value, segment 2 between the boiling cavitation limit value and the boiling cavitation threshold value, segment 3 between the boiling cavitation threshold value and the non-thermal cavitation limit value, segment 4 between the non-thermal cavitation limit value and the non-thermal cavitation threshold value, and segment 5 less than or equal to the non-thermal cavitation threshold value.

[0092] The boiling cavitation limit, boiling cavitation threshold, non-thermal cavitation limit, and non-thermal cavitation threshold may be preset by reflecting input tissue characteristics and treatment information, and may be changed by the user.

[0093] Figure 4 : is a diagram showing a signal waveform for explaining an example of adjusting the output time of a focused ultrasound signal according to an embodiment of the present invention.

[0094] Reference Figure 1 and Figure 4 The focused ultrasound processing device 1 can determine operations according to the amplitude of the cavitation signal, including the first output and re-output of the focused ultrasound signal to the first area, the movement from the first area to the second area (the subsequent tissue area) and the output of the focused ultrasound signal, the stopping of the output of the focused ultrasound signal, and the maintenance of the output time of the focused ultrasound signal.

[0095] First, the focused ultrasound output period is composed of a plurality of cycles, each cycle including a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse. Here, the first frequency interval is a thermal period for thermal effect, and the second frequency interval is a boiling period for mechanical effect.

[0096] In an example using boiling conditions, if the cavitation detection value in the first frequency interval targeting the first region is greater than or equal to the boiling cavitation threshold and the cavitation detection value in the second frequency interval is greater than or equal to the non-thermal cavitation threshold, the focused ultrasonic processing device 1 moves to a new second region and outputs a focused ultrasonic signal.

[0097] In other cases, the focused ultrasound processing device 1 outputs the focused ultrasound signal to the first region for the first time, and then outputs the focused ultrasound signal to the first region again. This embodiment shows an example in which the boiling condition is used for tissue ablation.

[0098] In an example where the boiling condition is not used, if the cavitation detection value in the first frequency interval or the cavitation detection value in the second frequency interval targeting the first area is greater than or equal to the non-thermal cavitation threshold, the focused ultrasound processing device 1 moves to a new second area and outputs a focused ultrasound signal. In other cases, the focused ultrasound processing device 1 may output a focused ultrasound signal to the first area again. This example shows an example where the boiling condition is not used for tissue ablation.

[0099] Meanwhile, the focused ultrasound processing apparatus 1 may adjust the frequency or output time of the second cycle when performing re-output of the focused ultrasound signal to the first area during the second cycle after the initial output to the first area during the first cycle.

[0100] For example, the focused ultrasound processing device 1 may generate a focused ultrasound signal consisting of a combination of N first pulses for thermal effect and M second pulses for mechanical effect during the first cycle, and output the generated focused ultrasound signal. During the second cycle, the focused ultrasound processing device 1 may change the combination of N and M to adjust the focused ultrasound signal while maintaining the total number of pulses, and output the adjusted focused ultrasound signal. Further details in this regard will be described below with reference to Figure 5 Give a description.

[0101] Figure 5 : is a diagram showing in more detail a signal waveform for explaining an example of adjusting the output time of a focused ultrasound signal according to an embodiment of the present invention.

[0102] The focused ultrasound output period consists of a plurality of cycles, each cycle including a first frequency interval consisting of at least one first pulse 51 and a second frequency interval consisting of at least one second pulse 52. Here, the first frequency interval is a thermal period for thermal effect, and the second frequency interval is a boiling period for mechanical effect.

[0103] Reference Figure 1 and Figure 5 , the focused ultrasonic processing apparatus 1 outputs a focused ultrasonic signal by combining a first pulse for a thermal effect of the ultrasonic signal and a second pulse for a mechanical effect.

[0104] For example, the focused ultrasonic processing device 1 can generate N (N is a positive integer) first pulses 51 and M (M is a positive integer) second pulses 52 per cycle, form the N first pulses 51 and the M second pulses 52 into a single pulse, and then output a single pulse per cycle through the focused ultrasonic transducer.

[0105] The first pulse 51 may be a long burst pulse signal, and the second pulse 52 may be a short burst pulse signal. The first pulse 51 may include a frequency fh for thermal effect and a pulse length Ph frequency. The second pulse 52 may include a frequency fm for mechanical effect and a pulse length Pm frequency.

[0106] In this case, the focused ultrasonic processing apparatus 1 may combine various frequencies including a combination of fh≠fm and Ph≠Pm, fh=fm and Ph≠Pm, or fh≠fm and Ph=Pm.

[0107] The focused ultrasonic processing device 1 checks the cavitation detection value in the first frequency interval of the first cycle. Then, if the cavitation detection value is greater than or equal to the boiling cavitation limit value ( Figure 3 As shown in segment 1), the focused ultrasonic processing device 1 reduces the number of first pulses 51 in the first frequency interval and increases the number of second pulses 52 in the second frequency interval in the second period to generate and output a focused ultrasonic signal.

[0108] For example, if the cavitation detection value at the point where Na first pulses 51 among N first pulses are output in the first cycle is greater than or equal to the boiling cavitation limit value, the focused ultrasonic processing device 1 generates Na first pulses 51 by reducing the number of first pulses 51, and generates and outputs the remaining M+a second pulses 52. This method shows an example of utilizing the boiling condition.

[0109] As another example, an embodiment that does not utilize boiling conditions will be described.

[0110] If the cavitation detection value is greater than or equal to the boiling cavitation threshold ( Figure 3 2), the focused ultrasound processing device 1 outputs a focused ultrasound signal by reducing the total output time of the second cycle.

[0111] In contrast, when the cavitation detection value falls between the boiling cavitation threshold and the non-thermal cavitation limit ( Figure 3 3), the focused ultrasound processing device 1 outputs a focused ultrasound signal by increasing the number of first pulses 51 in the first frequency interval of the second period and reducing the number of second pulses 52 in the second frequency interval.

[0112] If the cavitation detection value falls between the non-thermal cavitation limit value and the non-thermal cavitation threshold value ( Figure 3 4), the focused ultrasonic processing device 1 outputs a focused ultrasonic signal while maintaining the number of first pulses 51 in the first frequency interval and the number of second pulses 52 in the second frequency interval of the second period.

[0113] If the cavitation detection value is less than or equal to the non-thermal cavitation threshold ( Figure 3 5), the focused ultrasound processing device 1 outputs a focused ultrasound signal by reducing the number of first pulses 51 in the first frequency interval of the second period and increasing the number of second pulses 52 in the second frequency interval.

[0114] Therefore, the focused ultrasound treatment device 1 can locally generate bubbles and control the size and duration of the bubbles to enhance the accuracy of treatment.

[0115] In addition, the focused ultrasound processing device 1 may also analyze the ultrasound image signal, and adjust the output time and frequency of the focused ultrasound signal based on the analysis result.

[0116] As an example using the boiling condition, the focused ultrasound processing device 1 checks the image brightness value of the focus area within the first frequency interval of the first cycle by analyzing the image signal during the first cycle. In this case, if the image brightness value of the focus area becomes equal to or exceeds the boiling cavitation image brightness threshold, the focused ultrasound processing device 1 outputs a focused ultrasound signal by reducing the number of first pulses 51 in the first frequency interval of the second cycle and increasing the number of second pulses 52 in the second frequency interval.

[0117] As an example of not using the boiling condition, the focused ultrasonic processing device 1 checks the image brightness value of the focus area within the first frequency interval of the first cycle by analyzing the image signal during the first cycle. In this case, if the image brightness value of the focus area becomes equal to or exceeds the boiling cavitation image brightness value, the focused ultrasonic processing device 1 outputs the focused ultrasonic signal by reducing the total output time of the second cycle.

[0118] In contrast, when the image brightness value of the focal area falls between the boiling cavitation image brightness value and the non-thermal cavitation image limit value, the focused ultrasonic processing device 1 outputs a focused ultrasonic signal by increasing the number of first pulses 51 in the first frequency interval of the second period and reducing the number of second pulses 52 in the second frequency interval.

[0119] In contrast, when the image brightness value of the focal area falls between the non-thermal cavitation image brightness value and the non-thermal cavitation image threshold, the focused ultrasonic processing device 1 outputs a focused ultrasonic signal while maintaining the number of first pulses 51 in the first frequency interval of the second period and the number of second pulses 52 in the second frequency interval.

[0120] In this case, if the image brightness value of the focal area is less than or equal to the non-thermal cavitation image brightness threshold, the focused ultrasound processing device 1 outputs a focused ultrasound signal by reducing the number of first pulses 51 in the first frequency interval of the second period and increasing the number of second pulses 52 in the second frequency interval.

[0121] According to exemplary embodiments of a focused ultrasound treatment apparatus and method thereof, by applying a mechanical effect, tissue ablation using focused ultrasound can be achieved more safely and effectively beyond the limitation of a thermal effect.

[0122] In addition, when the mechanical effect is applied to focused ultrasound tissue ablation, the pressure and intensity of the focused ultrasound signal can be reduced by adjusting the frequency or output time of the focused ultrasound signal using the cavitation signal and the ultrasound image signal, thereby achieving tissue ablation without causing the impact scattering effect. In addition, the accuracy of the treatment can be enhanced by locally generating bubbles and controlling the size and duration of the bubbles.

[0123] So far, the present invention has been described by focusing on exemplary embodiments. It will be appreciated by those skilled in the art that the present invention may be implemented in a modified form without departing from the basic features of the present invention. Therefore, the disclosed embodiments should be considered illustrative rather than definitive. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of their equivalents should be interpreted as included in the present invention.

Claims

1. A focused ultrasound processing device, comprising: a focused ultrasound transducer configured to output a focused ultrasound signal to tissue; a cavitation sensor configured to detect a cavitation signal generated by a cavitation phenomenon occurring in the tissue due to the focused ultrasound signal; as well as A processor is configured to analyze the cavitation signal detected by the cavitation sensor and adjust at least one of an output time or a frequency of the focused ultrasound signal based on an analysis result.

2. The focused ultrasound processing device according to claim 1, wherein: The processor is configured to compare the cavitation detection value obtained by the cavitation sensor with a predetermined cavitation threshold or cavitation limit value, and based on the comparison result, adjust at least one of the output time or frequency of the focused ultrasound signal to reduce the cavitation value.

3. The focused ultrasonic processing device according to claim 2, wherein: The processor is configured to compare the cavitation detection value with a boiling cavitation limit value, and when the cavitation detection value is greater than or equal to the boiling cavitation limit value, adjust at least one of an output time or a frequency of the focused ultrasound signal to reduce the cavitation detection value.

4. The focused ultrasonic processing device according to claim 2, wherein: The processor is configured to compare the cavitation detection value obtained by the cavitation sensor with at least one of a boiling cavitation threshold, a non-thermal cavitation limit value, or a non-thermal cavitation threshold, and adjust at least one of an output time or a frequency of the focused ultrasound signal based on the comparison result.

5. The focused ultrasonic processing device according to claim 1, wherein: The processor is configured to control the output of the focused ultrasound signal by repeating a plurality of cycles, each cycle comprising a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and the first frequency interval is a thermal period for a thermal effect, and the second frequency interval is a boiling period for a mechanical effect.

6. The focused ultrasonic processing device according to claim 5, wherein: The first frequency interval includes fh and Ph frequencies for thermal effects, and the second frequency interval includes fm and Pm frequencies for mechanical effects.

7. The focused ultrasonic processing device according to claim 5, wherein: The processor is configured to check a cavitation detection value within a first frequency interval of a first cycle, and to perform control to reduce the number of first pulses in the first frequency interval of a second cycle after the first cycle and to increase the number of second pulses in a second frequency interval of the second cycle when the cavitation detection value becomes equal to or exceeds the boiling cavitation limit value.

8. The focused ultrasonic processing device according to claim 5, wherein: The processor is configured to check a cavitation detection value within a first frequency interval of a first cycle, and to perform control to: When the cavitation detection value becomes equal to or exceeds the boiling cavitation threshold, reducing the total output time of the second cycle, When the cavitation detection value falls between the boiling cavitation threshold and the non-thermal cavitation limit value, increasing the number of first pulses in the first frequency interval of the second cycle and decreasing the number of second pulses in the second frequency interval of the second cycle, When the cavitation detection value falls between the non-thermal cavitation limit value and the non-thermal cavitation threshold value, maintaining the number of first pulses in the first frequency interval of the second cycle and the number of second pulses in the second frequency interval of the second cycle, and When the cavitation detection value is less than or equal to the non-thermal cavitation threshold, the number of first pulses in a first frequency interval of the second cycle is reduced and the number of second pulses in a second frequency interval of the second cycle is increased.

9. The focused ultrasonic processing device according to claim 5, wherein: The processor is configured to, when outputting the focused ultrasound signal to the first region for the first time, check each of a cavitation detection value in a first frequency interval of a first cycle and a cavitation detection value in a second frequency interval of the first cycle, and perform control to move to a new second region and output the focused ultrasound signal when the cavitation detection value in the first frequency interval is greater than or equal to a boiling cavitation threshold and the cavitation detection value in the second frequency interval is greater than or equal to a non-thermal cavitation threshold, and In other cases, the processor is configured to perform control to output the focused ultrasound signal to the first region again.

10. The focused ultrasonic processing device according to claim 5, wherein: The processor is configured to check each of a cavitation detection value in a first frequency interval of a first cycle and a cavitation detection value in a second frequency interval of the first cycle when the focused ultrasound signal is output to the first region for the first time, and is capable of performing control to move to a new second region and output the focused ultrasound signal when the cavitation detection value in the first frequency interval or the cavitation detection value in the second frequency interval is greater than or equal to a non-thermal cavitation threshold value, and In other cases, the processor is configured to perform control to output the focused ultrasound signal to the first region again.

11. The focused ultrasound processing device according to claim 1, further comprising: an input unit configured to receive tissue characteristic and treatment information, The processor is configured to determine a cavitation limit value, a cavitation threshold value, and an output time and frequency of the focused ultrasound signal by reflecting input tissue characteristics and treatment information.

12. The focused ultrasonic processing device according to claim 1, wherein: The processor is configured to determine a first frequency for maximizing a thermal effect of the focused ultrasound signal before heat generation and a second frequency for maximizing a mechanical effect of the focused ultrasound signal after heat generation.

13. The focused ultrasound processing device according to claim 12, wherein: The processor is configured to control a focused ultrasonic signal having a determined first frequency to be output through the focused ultrasonic transducer, compare a cavitation detection value with at least one of a boiling cavitation limit value or a non-thermal cavitation limit value, and when the cavitation detection value is greater than or equal to the non-thermal cavitation limit value or the boiling cavitation limit value, perform control to adjust the frequency of the focused ultrasonic signal from the first frequency to the second frequency, and then output the adjusted focused ultrasonic signal having the second frequency through the focused ultrasonic transducer.

14. The focused ultrasound processing device according to claim 1, further comprising: an image transducer configured to output an image ultrasound signal to tissue and receive an ultrasound echo signal reflected from the tissue, The processor is configured to generate an ultrasonic image signal by performing signal processing on the received ultrasonic echo signal, analyze the generated ultrasonic image signal, and adjust at least one of the output time or frequency of the focused ultrasonic signal based on the analysis result.

15. The focused ultrasound processing device according to claim 14, wherein: The processor is configured to control the output of the focused ultrasound signal by repeating a plurality of cycles, Each cycle comprises a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, The first frequency interval is a hot period for thermal effects, and the second frequency interval is a boiling period for mechanical effects, and The processor is configured to check an image brightness value of a focal area in a first frequency interval of a first cycle by analyzing the image signal, and to perform control to reduce the number of first pulses in a first frequency interval of a second cycle and increase the number of second pulses in a second frequency interval of the second cycle when the image brightness value of the focal area becomes equal to or exceeds a boiling cavitation image brightness limit value.

16. The focused ultrasound processing device according to claim 14, wherein: The processor is configured to control the output of the focused ultrasound signal by repeating a plurality of cycles, Each cycle comprises a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, The first frequency interval is a hot period for thermal effects, and the second frequency interval is a boiling period for mechanical effects, and The processor is configured to check the image brightness value of the focus area in the first frequency interval of the first cycle by analyzing the image signal, and perform control to: When the image brightness value of the focus area becomes equal to or exceeds the boiling cavitation image brightness value, reducing the total output time of the second cycle, When the image brightness value of the focal area falls between the boiling cavitation threshold and the non-thermal cavitation image brightness limit value, increasing the number of first pulses in the first frequency interval of the second cycle and decreasing the number of second pulses in the second frequency interval of the second cycle, When the image brightness value of the focal area falls between the non-thermal cavitation image brightness limit value and the non-thermal cavitation image brightness threshold value, maintaining the number of first pulses in the first frequency interval of the second cycle and the number of second pulses in the second frequency interval of the second cycle, and When the image brightness value of the focal area is less than or equal to the non-thermal cavitation image brightness threshold, the number of first pulses in the first frequency interval of the second cycle is reduced and the number of second pulses in the second frequency interval of the second cycle is increased.

17. A focused ultrasound treatment method using a focused ultrasound treatment device, the method comprising: determining a first output condition including at least one of an output time or a frequency of a focused ultrasound signal; Based on the determined first output condition, outputting a focused ultrasound signal through a focused ultrasound transducer; The cavitation sensor detects a cavitation signal generated by a cavitation phenomenon in the tissue due to the output focused ultrasound signal; analyzing a cavitation detection value obtained by the cavitation sensor, and adjusting an output condition including at least one of an output time or a frequency of a focused ultrasound signal to a second output condition based on the analysis result; as well as Based on the adjusted second output condition, the focused ultrasound signal is output to the tissue through the focused ultrasound transducer.

18. The focused ultrasound treatment method according to claim 17, wherein: Adjusting the output condition to the second output condition comprises: When the focused ultrasound signal is output based on the first output condition during a first period, checking a cavitation detection value in a first frequency interval of the first period; and When the cavitation detection value becomes equal to or exceeds the boiling cavitation limit value, reducing the number of first pulses in the first frequency interval and increasing the number of second pulses in the second frequency interval as the second output condition of the second cycle, Each cycle includes a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and The first frequency interval is a hot period for thermal effects, while the second frequency interval can be a boiling period for mechanical effects.

19. The focused ultrasound treatment method according to claim 17, wherein: Adjusting the output condition to the second output condition comprises: when the focused ultrasound signal is output based on the first output condition during a first cycle, checking a cavitation detection value in a first frequency interval of the first cycle; When the cavitation detection value becomes equal to or exceeds a boiling cavitation threshold, reducing the total output time of the second cycle as a second output condition of the second cycle; When the cavitation detection value falls between the boiling cavitation threshold and the non-thermal cavitation limit value, increasing the number of first pulses in the first frequency interval and decreasing the number of second pulses in the second frequency interval as a second output condition of the second period; When the cavitation detection value falls between the non-thermal cavitation limit value and the non-thermal cavitation threshold value, maintaining the number of first pulses in the first frequency interval and the number of second pulses in the second frequency interval as the second output condition of the second period; and When the cavitation detection value is less than or equal to the non-thermal cavitation threshold, reducing the number of first pulses in the first frequency interval and increasing the number of second pulses in the second frequency interval as a second output condition of the second period, Each cycle includes a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and The first frequency interval is a hot period for thermal effect, and the second frequency interval is a boiling period for mechanical effect.

20. The focused ultrasound treatment method according to claim 17, wherein: Adjusting the output condition to the second output condition comprises: When a focused ultrasound signal targeting a first area is output for the first time, checking each of a cavitation detection value in a first frequency interval of a first cycle and a cavitation detection value in a second frequency interval of the first cycle; and performing control to move to a new second region and output the focused ultrasound signal when the cavitation detection value in the first frequency interval is greater than or equal to a boiling cavitation threshold and the cavitation detection value in the second frequency interval is greater than or equal to a non-thermal cavitation threshold, and to output the focused ultrasound signal again to the first region in other cases, Each cycle includes a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and The first frequency interval is a hot period for thermal effect, and the second frequency interval is a boiling period for mechanical effect.

21. The focused ultrasound treatment method according to claim 17, wherein: Adjusting the output condition to the second output condition comprises: When a focused ultrasound signal targeting a first area is output for the first time, checking each of a cavitation detection value in a first frequency interval of a first cycle and a cavitation detection value in a second frequency interval of the first cycle; and performing control to move to a new second region and output the focused ultrasound signal when the cavitation detection value in the first frequency interval or the cavitation detection value in the second frequency interval is greater than or equal to a non-thermal cavitation threshold, and to output the focused ultrasound signal again to the first region in other cases, Each cycle includes a first frequency interval consisting of at least one first pulse and a second frequency interval consisting of at least one second pulse, and The first frequency interval is a hot period for thermal effect, and the second frequency interval is a boiling period for mechanical effect.

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