WO2024027338A1

WO2024027338A1 - Device and method for verifying passive cavitation imaging accuracy

Info

Publication number: WO2024027338A1
Application number: PCT/CN2023/099060
Authority: WO
Inventors: 徐韵薇; 王熙; 马林斌; 赵兵
Original assignee: 重庆融海超声医学工程研究中心有限公司
Priority date: 2022-08-01
Filing date: 2023-06-08
Publication date: 2024-02-08
Also published as: CN117531132A

Abstract

The present disclosure provides a device for verifying passive cavitation imaging accuracy. The device comprises a high-intensity focused ultrasonic (HIFU) transducer, a passive cavitation receiving array, and an imaging apparatus. The passive cavitation receiving array is arranged in a hole of the HIFU transducer. The device for verifying passive cavitation imaging accuracy is characterized in that the position of the passive cavitation receiving array in the hole can be changed. The HIFU transducer is used for outputting irradiation and generating a cavitation signal by excitation. The passive cavitation receiving array is used for acquiring a passive acoustic signal at a position offset by a preset distance from the center of the HIFU transducer. The imaging apparatus is used for extracting the cavitation signal from the passive acoustic signal, and performing passive beam synthesis on the cavitation signal to obtain a passive cavitation imaging result graph. The present disclosure further provides a method for verifying passive cavitation imaging accuracy. The present disclosure can verify the sensitivity and accuracy of passive cavitation imaging monitoring.

Description

Equipment and methods for verifying the accuracy of passive cavitation imaging

Technical field

The present disclosure relates to the field of ultrasound technology, and in particular to a device for verifying the accuracy of passive cavitation imaging and a method for verifying the accuracy of passive cavitation imaging.

Background technique

High Intensity Focused Ultrasound (HIFU, High Intensity Focused Ultrasound) is a new non-invasive tumor treatment technology. In order to avoid damaging the normal tissue around the tumor, it is particularly important to effectively monitor the degree of damage to the target tissue during HIFU treatment. During ultrasound image-guided high-intensity focused ultrasound treatment, doctors judge the treatment situation by observing the hyperechoic areas on the B-ultrasound monitoring map.

Current ultrasound-based monitoring solutions assume that the focus of treatment is within the imaging plane. However, in actual clinical applications, due to the complexity of the sound field and the inhomogeneity of the tissue, the actual focus of treatment is not within the imaging plane. Ultrasound imaging only presents an image on a plane corresponding to the direction of the array, rather than a three-dimensional area. Therefore, when the actual focus shifts, existing conventional ultrasound monitoring solutions will fail.

Solutions that can effectively monitor the degree of damage to target tissues during HIFU treatment are urgently needed.

Contents of the invention

Embodiments of the present disclosure provide a device for verifying the accuracy of passive cavitation imaging and a method for verifying the accuracy of passive cavitation imaging.

In a first aspect, embodiments of the present disclosure provide a device for verifying the accuracy of passive cavitation imaging, including a HIFU transducer, a passive cavitation receiving array, and an imaging device; the passive cavitation receiving array is disposed on the HIFU transducer. In the opening of the energizer, the position of the passive cavitation receiving array in the opening can be changed;

The HIFU transducer is used to output irradiation and excite to generate cavitation signals;

The passive cavitation receiving array is used to acquire passive acoustic signals at a position offset by a preset distance from the center of the HIFU transducer;

The imaging device is used to extract the cavitation signal from the passive acoustic signal; perform passive beam synthesis on the cavitation signal to obtain a passive cavitation imaging result map.

In some embodiments, the preset distance ranges from 0 to 20 mm.

In some embodiments, the device further includes:

An offset fine-tuning device is used to adjust the position of the passive cavitation receiving array in the opening, so that the passive cavitation receiving array is offset by the preset distance from the center of the HIFU transducer.

In some embodiments, the imaging device includes a filter;

The filter is used to filter the passive acoustic signal to obtain the cavitation signal.

In some embodiments, the imaging device performs passive beam synthesis on the cavitation signal to obtain a passive cavitation imaging result map, including:

The cavitation signal is passively beam synthesized using the robust minimum variance method to obtain the passive cavitation imaging result map.

In some embodiments, the robust minimum variance method can be expressed as the following formula:

Among them, the solution of the optimal weight vector is:

Among them, B represents the reconstructed image point, w represents the weight, x represents the signal acquired by the passive cavitation receiving array, M represents the total number of vibration sources of the passive cavitation receiving array, t represents time, τ represents the delay vector, R represents the covariance matrix, e represents the direction vector, and m is an integer.

In a second aspect, embodiments of the present disclosure provide a method for verifying the accuracy of passive cavitation imaging. The method includes:

The HIFU transducer outputs irradiation and excites to generate cavitation signals;

A passive cavitation receiving array is used to obtain passive acoustic signals, wherein the passive cavitation receiving array is located in the opening of the HIFU transducer, and the passive cavitation receiving array is offset from the center of the HIFU transducer by a preset distance;

extracting the cavitation signal from the passive acoustic signal;

Passive beam synthesis is performed on the cavitation signal to obtain a passive cavitation imaging result map.

In some embodiments, before utilizing the passive cavitation receiving array to acquire the passive acoustic signal, the method further includes:

Adjust the position of the passive cavitation receiving array in the opening so that the passive cavitation receiving array is offset by the preset distance from the center of the HIFU transducer.

In some embodiments, passive beam synthesis is performed on the cavitation signal to obtain a passive cavitation imaging result map, including:

In some embodiments, after performing passive beam synthesis on the cavitation signal to obtain a passive cavitation imaging result map, the method further includes:

Compare the passive cavitation imaging result picture with the B-ultrasound monitoring picture of the center position of the HIFU transducer.

The disclosed embodiments can produce two beneficial effects: First, in the verification stage, by comparing the passive cavitation imaging result chart with the B-ultrasound monitoring chart at the center of the HIFU transducer, the sensitivity and accuracy of the passive cavitation imaging monitoring can be verified. accuracy. For example, when the high echo area cannot be monitored on the B-ultrasound monitoring map due to the complexity of the sound field or the inhomogeneity of the tissue, and the passive cavitation receiving array is offset from the center of the HIFU transducer by a preset distance, the passive cavitation can be obtained. The sensitivity and accuracy of passive cavitation imaging monitoring can be proved by looking at the result chart of passive cavitation imaging. Second, during the use phase, when the B-ultrasound cannot monitor the high echo area, the passive cavitation receiving array offset from the center of the HIFU transducer by a preset distance is used to obtain the cavitation signal and generate a passive cavitation imaging result map, which can compensate for the In B-ultrasound monitoring, the defect of inaccurate monitoring when the focus of HIFU treatment is no longer on the focal plane is beneficial to improving the sensitivity and accuracy of monitoring the HIFU treatment process.

Description of drawings

Figure 1 is a block diagram of a device for verifying the accuracy of passive cavitation imaging in an embodiment of the present disclosure;

Figure 2 is a schematic cross-sectional view of a device for verifying the accuracy of passive cavitation imaging in an embodiment of the present disclosure;

Figure 3 is a schematic top view of a device for verifying the accuracy of passive cavitation imaging in an embodiment of the present disclosure;

Figure 4 is a flow chart of a passive cavitation imaging method in an embodiment of the present disclosure;

Figure 5 is a flow chart of some steps in another passive cavitation imaging method in an embodiment of the present disclosure;

Figure 6 is a schematic diagram of an embodiment of verifying the accuracy of passive cavitation imaging;

Figure 7 is a schematic diagram to verify the accuracy of passive cavitation imaging;

Figure 8 is a schematic diagram of passive cavitation imaging result images at different offset distances.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present disclosure, the device for verifying the accuracy of passive cavitation imaging and the method for verifying the accuracy of passive cavitation imaging provided by the present disclosure are described in detail below with reference to the accompanying drawings.

Example embodiments will be described more fully below with reference to the accompanying drawings, which may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully understand the scope of the disclosure to those skilled in the art.

The embodiments of the present disclosure and the features in the embodiments may be combined with each other without conflict.

As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The terminology used herein is used to describe particular embodiments only and is not intended to limit the disclosure. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms "comprising" and/or "made of" are used in this specification, the presence of stated features, integers, steps, operations, elements and/or components is specified but does not exclude the presence or Add one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Embodiments described herein may be described with reference to plan and/or cross-sectional illustrations, with the aid of idealized schematic illustrations of the present disclosure. Accordingly, example illustrations may be modified based on manufacturing techniques and/or tolerances. Therefore, the embodiments are not limited to those shown in the drawings but include modifications of configurations formed based on the manufacturing process. Accordingly, the regions illustrated in the figures are of a schematic nature and the shapes of the regions shown in the figures are illustrative of the specific shapes of regions of the element and are not intended to be limiting.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. It will also be understood that terms such as those defined in commonly used dictionaries should be construed to have meanings consistent with their meanings in the context of the relevant art and the present disclosure, and will not be construed as having idealized or excessive formal meanings, Unless expressly so limited herein.

During HIFU treatment, acoustic cavitation is a common physical phenomenon. Cavitation nuclei in tissues undergo growth, compression, expansion, and finally collapse. These processes will produce acoustic cavitation signals. Monitoring of cavitation phenomena can be used to reflect treatment progress. Many studies have proven that there is a significant correlation between cavitation signal level and treatment effect. Cavitation imaging can realize monitoring carrying two-dimensional position information, which is mainly divided into active cavitation imaging (ACI, Active Cavitation Imaging) monitoring and passive Cavitation imaging (PCI, Passive Cavitation Imaging) monitoring. Active cavitation imaging relies on emitting ultrasonic pulses to excite imaging to obtain cavitation maps for monitoring, which is still conventional ultrasonic monitoring. Therefore, in principle, it cannot solve the problem that B-ultrasound cannot monitor when the focus shifts. Passive cavitation imaging does not use directional emission of ultrasonic pulses, but passively receives the acoustic signals emitted by the cavitation phenomenon itself during treatment, and locates the cavitation source based on the received acoustic signals. This process does not require the cavitation source to be in the normal plane of the imaging probe. Upper (B-ultrasound imaging plane). Passive cavitation imaging analyzes the acoustic cavitation signals generated during HIFU treatment to obtain a cavitation activity map, thereby imaging and monitoring the treatment situation in the focal area. It is expected to make up for the existing clinical B-ultrasound monitoring when the focus is not on the imaging plane. Functional failure is a defect.

In some related technologies, ultrasound-based monitoring solutions mainly have two shortcomings: (1) During HIFU treatment irradiation, since the treatment sound intensity is much greater than the sound intensity of imaging ultrasound, the ultrasound image cannot be imaged normally, so The above ultrasound imaging protocols need to be performed before the start of HIFU irradiation or after resting. As a result, the above ultrasound protocols do not monitor the treatment status during HIFU irradiation. Therefore, they can only be used to observe the HIFU treatment results, but cannot actually monitor the HIFU treatment results. HIFU treatment Real-time monitoring is performed during the process; (2) The treatment results that occur within the two-dimensional plane of ultrasound imaging can only be monitored. When the HIFU focus deviates from the imaging plane due to the complexity of the sound field and the inhomogeneity of the tissue, based on the above Monitoring strategies for ultrasound imaging programs will be ineffective.

In some related technologies, the receiving array of passive cavitation signals is usually placed in the center of the HIFU transducer opening, which does not reflect the monitoring sensitivity advantage of passive cavitation imaging compared with B-ultrasound.

In view of this, in the first aspect, with reference to Figures 1, 2, and 3, embodiments of the present disclosure provide a device for verifying the accuracy of passive cavitation imaging, including a HIFU transducer 101, a passive cavitation receiving array 102, an imaging Device 103; the passive cavitation receiving array 102 is arranged in the opening of the HIFU transducer 101, and the position of the passive cavitation receiving array 102 in the opening can be changed; the HIFU transducer 101 is used to output irradiation and excite to generate cavitation. signal; the passive cavitation receiving array 102 is used to acquire the passive acoustic signal at a position offset from the center of the HIFU transducer 101 by a preset distance; the imaging device 103 is used to extract the cavitation signal from the passive acoustic signal, and conduct Passive beam synthesis is used to obtain the passive cavitation imaging result map.

In the embodiment of the present disclosure, the position of the passive cavitation receiving array 102 in the opening can be changed, which means that the passive cavitation receiving array 102 can move in the opening of the HIFU transducer 101 .

It should be noted that the shapes and positional relationships of the HIFU transducer 101 and the passive cavitation receiving array 102 in Figures 2 and 3 are only used as the shapes and positional relationships of the HIFU transducer 101 and the passive cavitation receiving array 102 in the embodiment of the present disclosure. Examples of positional relationships. The shapes and positional relationships of the HIFU transducer 101 and the passive cavitation receiving array 102 in the embodiment of the present disclosure are not limited to those shown in Figures 2 and 3.

The device for verifying the accuracy of passive cavitation imaging provided by the embodiment of the present disclosure has two advantages: first, in the verification stage, the passive cavitation imaging result image is compared with the B-ultrasound monitoring image at the center of the HIFU transducer 101; The sensitivity and accuracy of passive cavitation imaging monitoring can be verified. For example, when the high echo area cannot be monitored on the B-ultrasound monitoring map due to the complexity of the sound field or the inhomogeneity of the tissue, and the passive cavitation receiving array 102 is offset by a preset distance from the center of the HIFU transducer 101, it can be obtained The passive cavitation imaging result chart can prove the sensitivity and accuracy of passive cavitation imaging monitoring. Second, during the use phase, when the B-ultrasound cannot monitor the high echo area, the passive cavitation receiving array 102 offset from the center of the HIFU transducer 101 by a preset distance is used to obtain the cavitation signal and generate a passive cavitation imaging result map. It can make up for the defect of inaccurate monitoring when the focus of HIFU treatment is no longer on the focal plane in B-ultrasound monitoring, and is conducive to improving the sensitivity and accuracy of monitoring the HIFU treatment process.

The embodiment of the present disclosure does not specifically limit the range in which the passive cavitation receiving array 102 moves in the opening of the HIFU transducer 101 . In the embodiment of the present disclosure, the range of movement of the passive cavitation receiving array 102 in the opening of the HIFU transducer 101 can be represented by a value range offset by a preset distance from the center of the HIFU transducer 101 . The embodiment of the present disclosure does not place any special limitations on the value range of the preset range.

In some embodiments, the preset distance ranges from 0 to 20 mm. In some embodiments, the preset distance ranges from 0 to 10 mm.

It should be noted that in the embodiment of the present disclosure, the value range of the preset distance is 0 to 20 mm, which means that the distance range within which the passive cavitation receiving array 102 can be offset from the center of the HIFU transducer 101 is 0 to 20 mm. Preferably, the passive cavitation receiving array 102 can be offset from the center of the HIFU transducer 101 by a distance ranging from 0 to 10 mm.

The embodiment of the present disclosure does not specifically limit how to adjust the position of the passive cavitation receiving array 102 in the opening of the HIFU transducer 101.

In some embodiments, the device further includes: an offset fine-tuning device for adjusting the position of the passive cavitation receiving array in the opening, so that the passive cavitation receiving array is offset by the The preset distance from the center of the HIFU transducer.

The embodiments of the present disclosure do not specifically limit how the imaging device 103 extracts the cavitation signal from the passive acoustic signal.

In some embodiments, the imaging device 103 includes a filter; the filter is used to filter the passive acoustic signal to obtain a cavitation signal.

In some embodiments, a filter is used to filter the passive acoustic signal, filter out the fundamental frequency and higher harmonics in the passive acoustic signal that are not clearly related to the cavitation activity, and extract the remaining broadband signal as the cavitation signal. come out.

The embodiments of the present disclosure do not specifically limit how the imaging device 103 performs passive beam synthesis on the cavitation signal to obtain the passive cavitation imaging result map.

In some embodiments, the imaging device 103 performs passive beam synthesis on the cavitation signal to obtain the passive cavitation imaging result map, including: using a robust minimum variance method to perform passive beam synthesis on the cavitation signal to obtain the passive cavitation Imaging results graph.

Among them, the solution of the optimal weight vector is:

Among them, B(·) represents the reconstructed image point, w represents the weight, x represents the signal acquired by the passive cavitation receiving array, M represents the total number of vibration sources of the passive cavitation receiving array, t represents time, and τ represents the delay. time vector, R represents the covariance matrix, e represents the direction vector, and m is an integer.

In the second aspect, referring to Figure 4, embodiments of the present disclosure provide a method for verifying the accuracy of passive cavitation imaging, including:

S1. Use the HIFU transducer to output irradiation and excite to generate cavitation signals;

S2. Use a passive cavitation receiving array to acquire passive acoustic signals, wherein the passive cavitation receiving array is located in the opening of the HIFU transducer, and the passive cavitation receiving array is offset from the center of the HIFU transducer. Default distance;

S3. Extract the cavitation signal from the passive acoustic signal;

S4. Perform passive beam synthesis on the cavitation signal to obtain a passive cavitation imaging result map.

The embodiments of the present disclosure do not impose special limitations on the passive cavitation receiving array. For example, the passive cavitation receiving array can be a B-ultrasound probe. In some embodiments, the passive cavitation receiving array and the HIFU transducer are different components of the same device. The passive cavitation receiving array is disposed in the opening of the HIFU transducer, and the passive cavitation receiving array is installed in the HIFU transducer. The position in the transducer opening can be changed, that is, the passive cavitation receiving array can move in the HIFU transducer opening. In some implementations, the passive cavitation receiving array and the HIFU transducer are independent devices, and the passive cavitation receiving array can move in the opening of the HIFU transducer. The embodiments of the present disclosure do not impose special limitations on this.

It should be noted that since the passive cavitation receiving array passively receives passive acoustic signals and extracts cavitation signals during HIFU treatment, and the cavitation signals are emitted in all directions, the passive cavitation imaging monitoring is biased towards the focus of HIFU treatment. It has a certain immunity to migration; that is to say, even if the focus of the actual HIFU treatment is not within the imaging plane due to reasons such as the complexity of the sound field or the inhomogeneity of the tissue, the HIFU treatment process can be effectively monitored by passively receiving the cavitation signal. .

The method for verifying the accuracy of passive cavitation imaging provided by the embodiments of the present disclosure can produce two beneficial effects: First, during the verification stage, the passive cavitation imaging result image is compared with the B-ultrasound monitoring image at the center of the HIFU transducer. , which can verify the sensitivity and accuracy of passive cavitation imaging monitoring. For example, when the high echo area cannot be monitored on the B-ultrasound monitoring map due to the complexity of the sound field or the inhomogeneity of the tissue, and the passive cavitation receiving array is offset from the center of the HIFU transducer by a preset distance When the passive cavitation imaging result map can be obtained, the sensitivity and accuracy of controlled cavitation imaging monitoring can be proved. Second, during the use phase, when the B-ultrasound cannot monitor the high echo area, the passive cavitation receiving array offset from the center of the HIFU transducer by a preset distance is used to obtain the cavitation signal and generate a passive cavitation imaging result map, which can compensate for the In B-ultrasound monitoring, the defect of inaccurate monitoring when the focus of HIFU treatment is no longer on the focal plane is beneficial to improving the sensitivity and accuracy of monitoring the HIFU treatment process.

In some embodiments, referring to Figure 5, before utilizing the passive cavitation receiving array to acquire the passive acoustic signal, the method further includes:

S5. Adjust the position of the passive cavitation receiving array in the opening so that the passive cavitation receiving array is offset by the preset distance from the center of the HIFU transducer.

The embodiment of the present disclosure places no special limitations on how to adjust the position of the passive cavitation receiving array. In some embodiments, the offset distance of the passive cavitation receiving array can be fine-tuned by a slide knob that controls the offset.

In embodiments of the present disclosure, the position of the passive cavitation receiving array can be changed, so that cavitation signals at different locations can be acquired and passive cavitation imaging result maps at different locations can be generated. By combining the passive cavitation imaging result maps at different locations Comparing with the B-ultrasound monitoring images at the center of the HIFU transducer, in the verification phase, it can improve the reliability of verifying the sensitivity and accuracy of passive cavitation imaging monitoring; in the use phase, it can verify the sensitivity and accuracy of passive cavitation imaging monitoring at different locations. The imaging result chart is used to monitor the HIFU treatment process, which is beneficial to improving monitoring sensitivity and accuracy.

Embodiments of the present disclosure do not specifically limit the range in which the passive cavitation receiving array can move in the opening, that is, the value range of the preset distance.

The embodiments of the present disclosure do not place special limitations on how to extract cavitation signals from passive acoustic signals.

In some embodiments, extracting a cavitation signal from the passive acoustic signal includes filtering the passive acoustic signal to obtain the cavitation signal.

The embodiments of the present disclosure do not specifically limit how to perform passive beam synthesis on cavitation signals to obtain passive cavitation imaging result images.

In some embodiments, performing passive beam synthesis on the cavitation signal to obtain passive cavitation imaging includes: using a robust minimum variance method to perform passive beam synthesis on the cavitation signal to obtain the passive cavitation imaging result map. .

Among them, the solution of the optimal weight vector is:

In the embodiment of the present disclosure, the robust minimum variance method used for passive beam synthesis is based on diagonal loading parameters and sub-array averaging. It can handle general coherent echoes, has strong robustness to parameter mismatch, and is more suitable. in passive cavitation imaging.

In some embodiments, the passive cavitation imaging method provided by the embodiments of the present disclosure is applied in the verification stage to verify the sensitivity and accuracy of passive cavitation imaging monitoring.

Correspondingly, in some embodiments, referring to Figure 5, after performing passive beam synthesis on the cavitation signal to obtain the passive cavitation imaging result map, the method further includes:

S6. Compare the passive cavitation imaging result image with the B-ultrasound monitoring image of the center position of the HIFU transducer.

In the embodiment of the present disclosure, the sensitivity and accuracy of passive cavitation imaging monitoring can be verified by comparing the passive cavitation imaging result image with the B-ultrasound monitoring image at the center of the HIFU transducer. For example, when the high echo area cannot be monitored on the B-ultrasound monitoring map due to the complexity of the sound field or the inhomogeneity of the tissue, and the passive cavitation receiving array is offset from the center of the HIFU transducer by a preset distance, the passive cavitation can be obtained. The imaging result chart can prove the sensitivity and accuracy of controlled cavitation imaging monitoring.

In order to enable those skilled in the art to more clearly understand the technical solutions provided by the embodiments of the present disclosure, the technical solutions provided by the embodiments of the present disclosure are described in detail below through specific examples:

Example

In order to determine the accuracy of passive cavitation imaging monitoring, in this embodiment, the B-ultrasound probe (passive cavitation receiving array) is placed at a preset distance away from the center of the HIFU transducer to passively receive cavitation signals, and the B-ultrasound The offset distance of the probe can be fine-tuned through the slide knob that controls the offset. The fine-tuning range is from 0 to 10 mm from the center of the HIFU transducer. Robust minimum variance is then used to image the cavitation signals received at different offset positions. .

As shown in Figure 6, during the HIFU treatment process, the passive acoustic signal is passively acquired by the B-ultrasound probe, and a filter is used to filter out the fundamental frequency and high-order harmonics in the passive acoustic signal that are not clearly related to the cavitation activity, leaving the remaining The broadband signal is extracted as a cavitation signal. The extracted cavitation signal is then subjected to passive beam synthesis to obtain the passive cavitation imaging result map. Figure 7 is a schematic diagram of passive cavitation imaging in this embodiment. Since the received cavitation signal changes when the B-ultrasound probe is placed in different positions, the passive cavitation signals at different offset positions can be obtained by changing the offset distance between the B-ultrasound probe and the focus of the HIFU transducer. Finally, The sensitivity of passive cavitation imaging monitoring can be verified by comparing the passive cavitation imaging result images at different offset positions with the B-ultrasound monitoring image when the HIFU transducer is placed at the center position. If no high-echoic area can be monitored on the B-ultrasound when the B-ultrasound probe is offset, and passive cavitation imaging can obtain a passive cavitation imaging result map of the focal area, and there is damage after incising the tissue, it indicates passive cavitation. Imaging monitoring can make up for the defect of inaccurate monitoring when the focus is not in the focal plane in B-ultrasound monitoring. For example, as shown in Figure 8, when the B-ultrasound probe is placed 2mm or 7mm away from the center of the HIFU transducer, the received cavitation signal can be processed to obtain the passive cavitation imaging result map; and as the offset distance increases When the B-ultrasound probe is placed 2mm or 7mm away from the center of the HIFU transducer, the high-echoic area cannot be monitored on the B-ultrasound, so it can be proved that when the B-ultrasound probe is When monitoring is not available, passive cavitation imaging can be used to monitor the treatment process.

In this embodiment, when performing passive beam synthesis on the cavitation signals received by the array and determining whether cavitation occurs at the monitoring location, the passive beam synthesis method used is the robust minimum variance method.

The output of the beamformer that reconstructs the image points can be written as a weighted sum of delay measurements:

Among them, the solution of the optimal weight vector is:

The robust minimum variance beamforming method used is based on diagonal loading parameters and sub-array averaging. It can handle general coherent echoes, has strong robustness to parameter mismatch, and is more suitable for passive cavitation imaging.

This embodiment also provides an array offset fine-tuning device, the offset distance of the B-ultrasound probe is adjustable, and the fine-tuning range is from 0 to 10 mm from the center of the HIFU transducer.

Those of ordinary skill in the art can understand that all or some steps, systems, and functional modules/units in the devices disclosed above can be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may consist of several physical components. Components execute cooperatively. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor, or a microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit . Such software may be distributed on computer-readable media, which may include computer storage media (or non-transitory media) and communication media (or transitory media). As is known to those of ordinary skill in the art, the term computer storage media includes volatile and nonvolatile media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. removable, removable and non-removable media. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, Digital Versatile Disk (DVD) or other optical disk storage, magnetic cassettes, tapes, disk storage or other magnetic storage devices, or may Any other medium used to store desired information and that can be accessed by a computer. Additionally, it is known to those of ordinary skill in the art that communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media .

Example embodiments have been disclosed herein, and although specific terms are employed, they are used and should be interpreted in a general illustrative sense only and not for purpose of limitation. In some instances, it will be apparent to those skilled in the art that features, characteristics and/or elements described in connection with a particular embodiment may be used alone, or may be used in conjunction with other embodiments, unless expressly stated otherwise. Features and/or components used in combination. Accordingly, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the present disclosure as set forth in the appended claims.

Claims

An equipment for verifying the accuracy of passive cavitation imaging, including a high-intensity focused ultrasound (HIFU) transducer, a passive cavitation receiving array, and an imaging device; the passive cavitation receiving array is arranged on the opening of the HIFU transducer. hole, characterized in that the position of the passive cavitation receiving array in the opening can be changed;

The HIFU transducer is used to output irradiation and excite to generate cavitation signals;

The passive cavitation receiving array is used to acquire passive acoustic signals at a position offset by a preset distance from the center of the HIFU transducer;

The imaging device is used to extract the cavitation signal from the passive acoustic signal; perform passive beam synthesis on the cavitation signal to obtain a passive cavitation imaging result map.
The device according to claim 1, wherein the preset distance ranges from 0 to 20 mm.
The device of claim 1, further comprising:

An offset fine-tuning device is used to adjust the position of the passive cavitation receiving array in the opening, so that the passive cavitation receiving array is offset by the preset distance from the center of the HIFU transducer.
The device according to any one of claims 1 to 3, characterized in that the imaging device includes a filter;

The filter is used to filter the passive acoustic signal to obtain the cavitation signal.
The device according to any one of claims 1 to 3, characterized in that the imaging device performs passive beam synthesis on the cavitation signal to obtain a passive cavitation imaging result map, including:

The cavitation signal is passively beam synthesized using the robust minimum variance method to obtain the passive cavitation imaging result map.
The device according to claim 5, wherein the robust minimum variance method can be expressed as the following formula:

Among them, the solution of the optimal weight vector is:

Among them, B(·) represents the reconstructed image point, w represents the weight, x represents the signal acquired by the passive cavitation receiving array, M represents the total number of vibration sources of the passive cavitation receiving array, t represents time, and τ represents the delay. time vector, R represents the covariance matrix, e represents the direction vector, and m is an integer.
A method for verifying the accuracy of passive cavitation imaging, characterized in that the method includes:

The HIFU transducer outputs irradiation and excites to generate cavitation signals;

A passive cavitation receiving array is used to obtain passive acoustic signals, wherein the passive cavitation receiving array is located in the opening of the HIFU transducer, and the passive cavitation receiving array is offset from the center of the HIFU transducer by a preset distance;

extracting the cavitation signal from the passive acoustic signal;

Passive beam synthesis is performed on the cavitation signal to obtain a passive cavitation imaging result map.
The method according to claim 7, characterized in that before using the passive cavitation receiving array to acquire the passive acoustic signal, the method further includes:

Adjust the position of the passive cavitation receiving array in the opening so that the passive cavitation receiving array is offset by the preset distance from the center of the HIFU transducer.
The method according to claim 7 or 8, characterized in that, performing passive beam synthesis on the cavitation signal to obtain a passive cavitation imaging result map, including:

The cavitation signal is passively beam synthesized using the robust minimum variance method to obtain the passive cavitation imaging result map.
The method according to claim 7 or 8, characterized in that, after performing passive beam synthesis on the cavitation signal to obtain the passive cavitation imaging result map, the method further includes:

Compare the passive cavitation imaging result picture with the B-ultrasound monitoring picture of the center position of the HIFU transducer.