A spirally arranged high frequency enhanced broadband focusing phased array transducer

Abstract

The present invention discloses a spirally arranged high-frequency enhanced broadband focused phased array transducer, the purpose of which is to provide a wide-band response and enhance the high-frequency energy conversion efficiency, and can simultaneously achieve efficient thermal ablation, blood-brain barrier disturbance and specific low-frequency neural regulation therapy, including a plurality of wide-band array elements and narrow-band array elements alternately arranged on a spherical shell according to a Fermat spiral with a divergence angle of 137.51°, wherein the narrow-band array element has a higher high-frequency energy conversion efficiency to enhance the thermal ablation treatment effect, the transducer is equipped with three signal sources, which can provide driving signals for three treatment frequencies respectively, and is also equipped with a control system, which can individually control the phase of each array element so that the transducer forms one or more focal points, and is also equipped with a driving circuit, which can individually drive each array element.

Description

Technical Field

[0001] The invention belongs to the technical field of power ultrasonic transducers, and in particular relates to a spirally arranged high-frequency enhanced broadband focused phased array transducer. Background Art

[0002] Focused ultrasound uses the biological effects it produces to intervene in brain diseases. It has become a non-invasive, non-interventional therapy and has been widely used in scientific research and clinical applications. In 1992, Foster's group first reported the use of high-intensity focused ultrasound (HIFU) technology to treat prostate cancer, pioneering the application of HIFU in the clinical field [Sanghvi et al., 1993 Proceedings IEEE Ultrasonics Symposium, 1993.pp.1207-1210vol.2]. With the change of the guidance method from ultrasound imaging to magnetic resonance imaging, magnetic resonance guided focused ultrasound (MRI guided focused ultrasound, MRgFUS) technology has achieved the intervention of brain diseases under the condition of intact skull.

[0003] Focused ultrasound of different frequencies can cause different biological effects in the brain and produce specific therapeutic effects. Continuous high-frequency focused ultrasound can form instantaneous high temperature in brain tissue, causing thermal coagulation necrosis of brain tissue at the focus, and ablating the lesion tissue. The frequency of high-frequency thermal ablation is usually higher than 650kHz, and is mainly used for the destruction of specific brain nuclei and tumor ablation. Pulsed or burst low-frequency focused ultrasound can form a stable cavitation effect in brain tissue, disturb the permeability of the blood-brain barrier, and allow large molecule drugs to pass through the blood-brain barrier to reach the lesion. The frequency of low-frequency perturbation of the blood-brain barrier is usually between 200-500kHz, and is mainly used for the delivery of viruses, genes, drugs, etc. Under the intervention of ultrasound of a specific frequency, certain brain regions can produce the effect of stimulating or inhibiting neurons, thereby achieving neural regulation. Specific brain regions only respond to ultrasound of a fixed frequency, and the frequency is mainly concentrated between 20-500kHz.

[0004] At present, the research and treatment of brain diseases mainly use one of the above methods for intervention, and single-frequency ultrasound is the mainstream intervention method [Hao-Li et al., IEEE Transactions on Biomedical Engineering, 2014.61(4):1350-1360]. However, in the treatment of certain diseases, multi-frequency composite intervention can optimize the treatment efficiency and improve the treatment effect. For example, in the treatment of Parkinson's disease with MRgFUS, high-frequency ablation of specific brain nuclei can suppress tremors, low-frequency drug delivery can delay dopamine loss, and specific low-frequency neural regulation has the potential to improve the treatment effect. For example, in the treatment of brain tumors with MRgFUS, high-frequency thermal ablation can destroy the main tumor tissue, and low-frequency tumor drug delivery can inhibit the growth of residual tumor tissue. Multi-frequency composite treatment is gradually showing more demand. At the same time, the lesion size and depth of different brain diseases are different, which will also affect the optimal treatment frequency. Adjusting the frequency according to the lesion situation can effectively improve the treatment effect. Therefore, a broadband response ultrasonic transducer has become one of the key factors in the MRgFUS composite brain disease treatment.

[0005] Focused ultrasound transducers mainly include single-element self-focusing transducers and multi-element phased array transducers. Large animals and clinical applications are mainly based on multi-element phased array transducers [Stavarache et al., World Neurosurgery, 2021.145:581-589.]. Phased array transducers are generally composed of multiple elements distributed on a shell of a specific shape in a certain arrangement, and the control system adjusts the moment when each element emits ultrasound so that the ultrasound emitted by all elements is focused on one point in space to form high energy. The shell of the phased array includes plane and spherical shapes, among which the plane shell is simple to assemble and the spherical shell has better focusing effect. The array element arrangement forms include concentric distribution of annular elements and uniform distribution of multi-element spherical surfaces. The first type is easy to assemble but can only focus on the central axis of the transducer, and the second type can focus in three-dimensional space but the assembly is complex and the control is cumbersome. Although the manufacturing process and control system of the multi-element spherical phased array transducer are complex, its treatment accuracy and electronic focus characteristics make it widely used.

[0006] With the development of science and technology, more and more treatment systems have adopted spherical phased array transducer solutions and proposed improvement methods. The elements of traditional phased arrays are periodic, that is, the elements are arranged according to a certain periodic pattern. This distribution is easy to assemble, but it is not conducive to sidelobe suppression and cannot achieve high-precision treatment. Random distribution of elements can suppress sidelobes and achieve high-precision treatment, but the density of randomly distributed elements is small, which can easily cause insufficient energy supply and is difficult to heat up quickly in high-frequency thermal ablation applications. At the same time, the randomness of element distribution is not conducive to the optimization of phased array performance. Spiral distribution of elements can effectively suppress sidelobes and increase element density, and its advantages are gradually reflected. According to the different spiral expressions, spiral distribution arrays mainly include Archimedean spiral arrays and Fermat spiral arrays. The Archimedean spiral array is characterized by a relatively simple manufacturing process but a low element density; the Fermat spiral array has a high element density and can well suppress sidelobes [Zeng Wei et al., Piezoelectrics and Acousto-Optics, 2021, (1): 149-156.].

[0007] There are two main methods to realize multi-frequency phased array transducers, namely, assembling multiple array elements of different frequencies on the same transducer [Lulu et al., Physics in Medicine and Biology, 2016. 61(24): p.8476-8501.] or impedance matching of single-frequency array elements [Hao-Li et al., IEEE Transactions on Biomedical Engineering, 2014. 61(4): 1350-1360] to increase the bandwidth. The first method has the advantages of relatively simple structure and high efficiency of acoustic energy conversion, but the disadvantages are limited frequency range and a large number of array elements; the second method has the advantage of each array element being able to continuously modulate frequency, but the disadvantage is low efficiency of acoustic energy conversion. High-frequency thermal ablation has high energy requirements, so transducers that can meet both wide frequency range and high output efficiency need to be improved.

[0008] In summary, phased array transducers that can provide multi-frequency composite treatments simultaneously and have high treatment power need to be further improved. Summary of the invention

[0009] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to provide a spirally arranged high-frequency enhanced broadband focused phased array transducer, which has the following characteristics: it can provide broadband focused ultrasound, enhance high-frequency energy, effectively suppress side lobes, has a high array element density, and can meet the needs of complex treatments including thermal ablation, blood-brain barrier disturbance and specific frequency neural regulation.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A spirally arranged high-frequency enhanced broadband focusing phased array transducer includes array elements and a spherical shell, wherein the array elements are distributed on the spherical shell, and the focus of ultrasound emitted by each array element is located at the center of the spherical shell. The array elements include broadband array elements and narrowband array elements, and the positions of the broadband array elements and the narrowband array elements on the spherical shell are determined based on the Fermat spiral arrangement formula, which is:

[0012]

[0013] Among them, n is the number of the array element, α is the divergence angle of the Fermat spiral, and x n is the position of each array element in polar coordinates, R n and α i are the radius and angle in polar coordinates respectively; R0 is the constant coefficient, N e is the number of array elements,

[0014] When n is an odd number, x n The array element at is a broadband array element; when n is an even number, x n The array element at is a narrow-band array element.

[0015] As mentioned above, the calculation formula of the constant coefficient R0 is:

[0016]

[0017] Among them, N e is the number of array elements; and D is the diameter of the opening disk of the spherical shell (3).

[0018] As described above, the spherical shell is a sandwich shell, an array element installation groove is provided on the inner spherical surface of the spherical shell, the array element is arranged in the array element installation groove, a lead wire reserved channel is provided in the interlayer of the spherical shell, and a lead wire reserved hole is provided on the outer spherical surface of the spherical shell, and the leads of each array element are led out through the lead wire reserved channel and the lead wire reserved hole in turn.

[0019] As mentioned above, the broadband array element comprises a broadband array element backing block, a broadband array element piezoelectric ceramic element and a broadband array element matching element which are sequentially connected along a direction toward the focal point;

[0020] The narrowband array element comprises a narrowband array element backing block, a narrowband array element piezoelectric ceramic element and a narrowband array element matching element which are sequentially connected along a direction toward a focus.

[0021] As described above, the acoustic impedance of the broadband array element piezoelectric ceramic component is greater than the acoustic impedance of the broadband array element backing block, and the acoustic impedance of the narrowband array element piezoelectric ceramic component is greater than the acoustic impedance of the narrowband array element backing block.

[0022] As mentioned above, the broadband array element frequency band covers the high frequency band of thermal ablation, the low frequency band of blood-brain barrier disturbance and the low frequency band of neural regulation.

[0023] The narrowband array element frequency band covers the high-frequency band of thermal ablation and the low-frequency band of blood-brain barrier disturbance.

[0024] The high-frequency band for thermal ablation is above 650kHz-1.5MHz, the low-frequency band for blood-brain barrier disturbance is 200kHz-500kHz, and the low-frequency band for neuromodulation is 20kHz-500kHz.

[0025] A spirally arranged high-frequency enhanced broadband focusing phased array transducer also includes a driving circuit, a control system, a first signal source, a second signal source and a third signal source.

[0026] The first signal source is used to provide a high-frequency signal for thermal ablation, the second signal source is used to provide a low-frequency signal for blood-brain barrier disturbance, and the third signal source is used to provide a low-frequency signal for neural regulation.

[0027] The control system is used to select the output signal of one of the first signal source, the second signal source and the third signal source and transmit it to the corresponding wide-band array element through the driving circuit, and is also used to select the output signal of one of the first signal source and the second signal source and transmit it to the corresponding narrow-band array element through the driving circuit.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] The present invention can achieve broadband ultrasonic response, high-frequency energy enhancement, effective side lobe suppression, and high array element distribution density. By adding matching elements to the array elements, the response bandwidth of the array elements is increased, and a wider range of frequency response is achieved. By changing the thickness and acoustic impedance of the matching elements, the array elements are divided into two groups with different bandwidths, among which the frequency band distribution of the narrowband array elements is concentrated in the high-frequency and part of the low-frequency areas, with higher energy conversion efficiency, so that the energy of the high-frequency part of the transducer is greater.

[0030] The array element arrangement of the present invention adopts a Fermat spiral arrangement with a divergence angle of 137.51°. Compared with the traditional periodic arrangement, the spiral arrangement can better suppress the side lobes; compared with the random arrangement, it can provide a higher array element density and thus obtain a higher focal energy; compared with the Archimedean spiral arrangement, a higher array element density can be obtained. In the Fermat spiral, different divergence angles will result in different arrangements. When the divergence angle is 137.51°, the obtained array element distribution density is the highest. The present invention adopts this divergence angle to obtain the maximum array element distribution density. The higher the array element distribution density, the higher the focal energy.

[0031] According to the properties of the matching elements, the wider the frequency response bandwidth, the lower the energy conversion efficiency, and the lower the focal energy obtained. In the intervention of focused ultrasound in the brain, low-frequency nerve regulation does not require too much acoustic energy, while thermal ablation requires higher energy. The narrow-band array element provided in the present invention increases the energy conversion efficiency of the high-frequency part to enhance the energy of the high-frequency part and improve the therapeutic effect of thermal ablation. Low-frequency nerve regulation can be completed by wide-band array elements.

[0032] The broadband array elements and the narrowband array elements are evenly distributed on the spherical shell in an alternating manner, so that ultrasound of different frequencies of the transducer can obtain better focusing quality.

[0033] All array elements in the phased array of the present invention can work independently, and array elements of different frequencies can form multiple focal points at the same time by controlling the phase, thereby performing thermal ablation, blood-brain barrier disturbance and neural regulation at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0035] In the figure: 1- broadband array element; 2- narrowband array element; 3- spherical housing; 4- driving circuit; 5- control system; 6- first signal source; 7- second signal source; 8- third signal source.

[0036] Figure 2a This is an oblique view of the present invention. Figure 2b It is a front view of the present invention.

[0037] In the figure: 1- broadband array element; 2- narrowband array element; 3- spherical shell; 16- natural focus.

[0038] Figure 3 It is a partial cross-sectional view of the present invention.

[0039] In the figure: 1- broadband array element; 2- narrowband array element; 3- spherical shell; 901- broadband array element backing block; 902- narrowband array element; 10- broadband array element piezoelectric ceramic element; 11- narrowband array element piezoelectric ceramic element; 12- broadband array element matching element; 13- narrowband array element matching element; 14- lead reserved channel; 15- lead reserved hole; 16- natural focus. DETAILED DESCRIPTION

[0040] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the implementation examples described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0041] Embodiment 1:

[0042] like Figure 1 , Figure 2a , Figure 2b , Figure 3 As shown, a spirally arranged high-frequency enhanced broadband focusing phased array transducer includes a spherical shell 3 and array elements arranged on the spherical shell 3, wherein the array elements include circular broadband array elements 1 and narrowband array elements 2. The focus of the ultrasonic waves emitted by each array element is located at the center of the spherical shell 3, and the spherical shell 3 provides a self-focusing base for the broadband array element 1 and the narrowband array element 2. The broadband array element 1 and the narrowband array element 2 are inlaid on the spherical shell 3.

[0043] like Figure 2a As shown, when the emission direction of each array element points to the natural focus 16. Compared with the phased array transducer with plane distribution, the phased array transducer with spherical distribution can obtain higher quality focusing.

[0044] like Figure 2b As shown, all hollow circles represent broadband array elements 1, solid circles represent narrowband array elements 2, and the outermost side is a spherical shell 3. The positions of the array elements on the spherical shell 3 are calculated by the Fermat spiral arrangement formula.

[0045] The Fermat spiral arrangement formula is:

[0046]

[0047] Where n is the number of the array element, α is the divergence angle of the Fermat spiral, that is, the angle between the line connecting two adjacent array elements and the origin of the spiral; x n is the position of each element in the Fermat spiral, expressed in polar coordinates; R n , α i x n The radius and angle in polar coordinates; R0 is a constant coefficient used to match the spiral size to the transducer aperture size when the number of array elements is fixed. The calculation formula for R0 is:

[0048]

[0049] Among them, N e is the number of array elements; D is the diameter of the opening disk of the spherical shell 3.

[0050] In this embodiment, the broadband array elements and the narrowband array elements are alternately distributed on the Fermat spiral, that is, when n is an odd number, x n The array element at is the broadband array element of the first group; when n is an even number, x nThe array element at the position is the narrowband array element of the second group. This alternating arrangement method makes the broadband array elements and the narrowband array elements evenly distributed on the spherical surface to obtain higher quality focusing. When calculating the array element distribution, the divergence angle used in the present invention is 137.51°. When other parameters remain unchanged, the array element distribution density under this divergence angle is the largest. The greater the array element distribution density, the greater the energy at the focus. The divergence angle α, the opening disk diameter D of the spherical shell 3 and the target array element number N are calculated. e Substituting into formula (2), the constant coefficient R0 can be calculated; then substituting the parameters into formula (1), the position of each array element center point can be calculated. The array element size is designed according to the position of these center points. Under the premise of ensuring that the array elements do not interfere with each other, the larger the array element size, the larger the effective emission area of ​​the phased array and the stronger the energy at the focus. In order to simplify the manufacturing process and the control system, all array elements use the same area. On the spherical shell 3, with the spiral site calculated above as the center and the array element diameter as the size, an array element installation groove for placing the array element is made. The array element is fixed in the array element installation groove with resin epoxy glue to complete the assembly.

[0051] like Figure 2b , Figure 3 As shown, the array elements of the transducer of the present invention are divided into broadband array element 1 and narrowband array element 2. The frequency band of broadband array element 1 can cover the high-frequency band of thermal ablation (higher than 650kHz, 650kHz-1.5MHz can be selected), the low-frequency band of blood-brain barrier disturbance (200kHz-500kHz) and the specific low-frequency band of neural regulation (20kHz-500kHz), and the frequency band of narrowband array element 2 only covers the high-frequency band of thermal ablation and the low-frequency band of blood-brain barrier disturbance. The broadband array element matching element 12 and the narrowband array element matching element 13 are made of lead zirconate titanate. Due to the material properties of the broadband array element matching element 12 and the narrowband array element matching element 13, the wider the bandwidth, the lower the energy conversion efficiency. The narrowband array element 2 is set to increase the energy of the high-frequency part of the transducer and enhance the therapeutic effect of thermal ablation.

[0052] like Figure 3 As shown, the broadband array element 1 and the narrowband array element 2 are assembled on the inner surface of the spherical shell 3. Each broadband array element 1 and narrowband array element 2 is a three-layer structure.

[0053] The broadband array element 1 comprises a broadband array element backing block 901, a broadband array element piezoelectric ceramic element 10 and a broadband array element matching element 12 which are sequentially connected along a direction toward the focus;

[0054] The narrowband array element 2 comprises a narrowband array element backing block 902 , a narrowband array element piezoelectric ceramic element 11 and a narrowband array element matching element 13 which are sequentially connected along a direction toward the focus.

[0055] The broadband array element backing block 901 and the narrowband array element backing block 902 are the bottom layer (far away from the natural focus 16). The broadband array element backing block 901 and the narrowband array element backing block 902 are a mixture of tungsten powder and insulating cement. The weight ratio of tungsten powder and insulating cement is between 1:1-8:1, and they are used to collect reverse propagating sound energy; the broadband array element piezoelectric ceramic element 10 and the narrowband array element piezoelectric ceramic element 11 are located in the middle layer for generating ultrasonic waves; the broadband array element matching element 12 and the narrowband array element matching element 13 are located in the outermost layer (closest to the natural focus 16) for increasing the frequency response bandwidth. The broadband array element piezoelectric ceramic element 10 is smaller than the acoustic impedance of the broadband array element backing block 901, and the acoustic impedance of the narrowband array element piezoelectric ceramic element 11 is smaller than the acoustic impedance of the narrowband array element backing block 902, and the difference is relatively large. The acoustic impedance difference formed between the two layers causes most of the ultrasonic waves to be reflected and transmitted from the front of the array element (i.e., the broadband array element matching element 12 and the narrowband array element matching element 13), thereby increasing the emission efficiency and improving the sound wave energy. The acoustic impedance of the broadband array element matching element 12 is smaller than the acoustic impedance of the broadband array element piezoelectric ceramic element 10, and the acoustic impedance of the narrowband array element matching element 13 is smaller than the acoustic impedance of the narrowband array element piezoelectric ceramic element 11. The acoustic impedance of the broadband array element matching element 12 is the square root of the product of the acoustic impedance of the broadband array element piezoelectric ceramic element 10 and the load acoustic impedance, and the acoustic impedance of the narrowband array element matching element 13 is the square root of the product of the acoustic impedance of the narrowband array element piezoelectric ceramic element 11 and the load acoustic impedance. The thickness of the broadband array element matching element 12 and the narrowband array element matching element 13 are different, and the acoustic impedance of the broadband array element matching element 12 and the narrowband array element matching element 13 are different. These two parameters are the main parameters affecting the frequency bandwidth. By changing the thickness and acoustic impedance, the frequency bandwidth of the emitted ultrasound wave can be increased to obtain a wider frequency response. The thickness and acoustic impedance of the broadband array element matching element 12 are adjusted so that the frequency bandwidth of the broadband array element can cover the high frequency band of thermal ablation (higher than 650kHz, 650kHz-1.5MHz can be selected), the low frequency band of blood-brain barrier disturbance (200kHz-500kHz) and the specific low frequency band of neural regulation (20kHz-500kHz), and the thickness and acoustic impedance of the narrowband array element matching element 13 are adjusted so that the frequency bandwidth of the narrowband array element can cover the high frequency band of thermal ablation (higher than 650kHz, 650kHz-1.5MHz can be selected) and the low frequency band of blood-brain barrier disturbance (200kHz-500kHz). Due to the material characteristics of the wideband array element matching component 12 and the narrowband array element matching component 13, the wider the response bandwidth, the lower the energy conversion efficiency of the transducer, and the lower the energy of the focus at the same output power.

[0056] The array elements in this embodiment are divided into two groups. The first group of array elements are broadband array elements. The frequency bandwidth of broadband array elements can cover the high-frequency band of thermal ablation (higher than 650kHz, 650kHz-1.5M can be selected), the low-frequency band of blood-brain barrier disturbance (200kHz-500kHz) and the specific low-frequency band of neural regulation (20kHz-500kHz); the second group of array elements are narrow-band array elements. The frequency bandwidth of narrow-band array elements only covers the high-frequency band of thermal ablation (higher than 650kHz, 650kHz-1.5MHz can be selected) and the low-frequency band of blood-brain barrier disturbance (200kHz-500kHz). The bandwidth of the second group of array elements is narrower than that of the first group of array elements, and the energy conversion efficiency is higher, which can increase the energy of the high-frequency part of the transducer and enhance the thermal ablation effect.

[0057] The driving wire of each array element is placed in the lead wire reserved channel 14 in the interlayer of the spherical shell 3, and the lead wire reserved channel 14 is connected to the lead wire reserved hole 15 set on the spherical shell 3. There are multiple lead wire reserved holes 15 on the back side of the spherical shell 3 (the side away from the natural focus 16). After the driving wires of each array element are merged in the lead wire reserved channel 14, they are led out of the spherical shell 3 through the lead wire reserved hole 15. The driving wires of each array element are respectively connected to the driving circuit 4, the driving circuit is connected to the control system 5, and the control system 5 is respectively connected to the first signal source 6, the second signal source 7 and the third signal source 8.

[0058] The present invention includes three signal sources, namely a first signal source 6, a second signal source 7 and a third signal source 8, which are used to provide high-frequency signals for thermal ablation, low-frequency signals for blood-brain barrier disturbance and low-frequency signals for neural regulation. The parameters set by the three signal sources include: emission mode, emission duration, emission frequency, etc. The signal frequency emitted by the signal source must be within the frequency response bandwidth of the array element.

[0059] The driving circuit 4 includes a plurality of driving units, each of which includes a series of components and circuits such as a power amplifier. Each driving unit is connected to an array element, and the driving circuit 4 is used to drive all array elements. The control system 5 is responsible for adjusting the phase of each array element through the driving circuit so that they form a thermal ablation focus, a blood-brain barrier disturbance focus, and a neural regulation focus in space respectively. The control system 5 is also responsible for selecting the output signal of one of the first signal source 6 (providing a high-frequency signal for thermal ablation), the second signal source 7 (a low-frequency signal for blood-brain barrier disturbance), and the third signal source 8 (a low-frequency signal for neural regulation) to be transmitted to the corresponding wide-band array element through the driving circuit 4, and is also responsible for selecting the output signal of one of the first signal source 6 (providing a high-frequency signal for thermal ablation) and the second signal source 7 (a low-frequency signal for blood-brain barrier disturbance) to be transmitted to the corresponding narrow-band array element through the driving circuit 4.

[0060] When the therapeutic targets of thermal ablation, blood-brain barrier disturbance, and neural regulation do not overlap, the present invention can simultaneously adjust the thermal ablation focus, blood-brain barrier disturbance focus, and neural regulation focus to the corresponding therapeutic targets, achieving multi-frequency simultaneous treatment and improving treatment efficiency and treatment effect.

[0061] In terms of frequency allocation of array elements, since thermal ablation therapy has a high demand for energy, sufficient array elements are first allocated to the high-frequency frequency band of thermal ablation, among which narrow-band array elements are preferentially allocated to provide high-frequency signals for thermal ablation. When the energy is insufficient, broadband array elements are allocated to provide high-frequency signals for thermal ablation to meet the energy required for thermal ablation, and the remaining array elements are allocated to blood-brain barrier perturbations and low-frequency neural regulation as needed.

[0062] The present invention needs to image the lesion and surrounding structures before use to plan a treatment plan, preferably magnetic resonance imaging. Except for the drive circuit 4, the control system 5, the first signal source 6, the second signal source 7, and the third signal source 8, the other components of the present invention are all non-magnetic designs that match the magnetic resonance imaging equipment, and all metal accessories used are non-magnetic copper materials. The drive circuit 4, the control system 5, the first signal source 6, the second signal source 7, and the third signal source 8 may contain magnetic accessories, which must be placed outside the magnetic field of the magnetic resonance imaging equipment during use, and the drive signal is conducted through a wire. Thus, the safety of the treated target, the operator and the present invention is guaranteed. If the present invention is used in conjunction with other imaging technologies, its non-magnetic design will not have additional effects on imaging.

[0063] Embodiment 2:

[0064] The parameters set in this embodiment are the preferred parameters of the present invention and are not limited to these parameters in practical applications. Figure 2b , let the total number of array elements be 256, that is, N e =256, divergence angle α = 137.51°. Let R0 = 0.5, the maximum spiral radius is about 124mm. The radius of the opening disk of the spherical shell 3 is set to 135mm, slightly larger than the maximum spiral radius. In order to avoid interference caused by the close spacing between adjacent array elements, the array element radius is set to 4.5mm. The front view of the obtained transducer is as follows Figure 2b As shown, the broadband array element 1 and the narrowband array element 2 are arranged alternately. By changing the thickness and acoustic impedance of the broadband array element matching element 12 and the narrowband array element matching element 13, the response bandwidth of the broadband array element 1 is 20-800kHz, and the response bandwidth of the narrowband array element 2 is 200-800kHz.

[0065] The frequency range commonly used for thermal ablation is higher than 650 kHz. In this embodiment, the frequency of thermal ablation is 650 kHz. Since the energy required for thermal ablation is relatively high, the frequency of all narrowband array elements 2 is set to 650 kHz through the first signal source 6 for thermal ablation.

[0066] The common frequency of blood-brain barrier perturbation is between 200-500kHz. In this embodiment, the frequency of blood-brain barrier perturbation is 250kHz. The common frequency range of neural regulation is 20kHz-500kHz. In this embodiment, the frequency of neural regulation is 100kHz. The broadband array element 1 is evenly divided into two parts. The first part of the broadband array elements is set to 250kHz through the second signal source 7 for blood-brain barrier perturbation; the second part of the broadband array elements is set to 100kHz through the third signal source 8 for neural regulation.

[0067] The emission mode of the first signal source 6 is set to continuous, and the total emission time is set to 1 minute; the emission mode of the second signal source 7 is set to a burst pulse with a pulse duration of 10 milliseconds, a repetition frequency of 1 Hz, and a total emission time of 5 minutes;

[0068] The emission mode of the third signal source 8 is set to a pulse form, the pulse duration is set to 0.36 milliseconds, the repetition frequency is set to 1 kHz, and the total emission time is set to 500 milliseconds.

[0069] Through the control system 5, the phases of the broadband array element 1 and the narrowband array element 2 are adjusted respectively, so that they form a thermal ablation focus, a blood-brain barrier disturbance focus and a neural regulation focus in space respectively. At the same time, the control system 5 is responsible for transmitting the signals of the first signal source 6, the second signal source 7, and the third signal source 8 to the corresponding array elements. The control system 5 is also responsible for controlling the output power of each array element and transmitting the corresponding power amplification factor instruction to the drive circuit 4. The drive circuit 4 includes a series of drive circuit elements such as a power amplifier, which is responsible for converting the signals generated by the first signal source 6, the second signal source 7, and the third signal source 8 and the control signal issued by the control system 5 into an electrical sequence to drive the corresponding array element. Through the control system 5 and the drive circuit 4, the output power of thermal ablation is set to 10W / cm 2 The blood-brain barrier perturbation output power is set to 1 W / cm 2 The output power of neural regulation is set to 3W / cm 2 .

[0070] The present invention needs to image the lesion and surrounding structures before use to plan a treatment plan, preferably magnetic resonance imaging. During use, the drive circuit 4, the control system 5, the first signal source 6, the second signal source 7, and the third signal source 8 need to be placed outside the magnetic field of the magnetic resonance imaging device to ensure the safety of the treated target, the operator, and the present invention.

[0071] The rest is the same as in Example 1.

[0072] It should be noted that the specific embodiments described in the present invention are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims.

Claims

1. A spirally arranged high-frequency enhanced broadband focusing phased array transducer, comprising array elements, It is characterized in that It also includes a spherical shell (3), each array element is distributed on the spherical shell (3), the focus of the ultrasonic wave emitted by each array element is located at the center of the spherical shell (3), the array elements include a broadband array element (1) and a narrowband array element (2), and the positions of the broadband array element (1) and the narrowband array element (2) on the spherical shell (3) are determined based on the Fermat spiral arrangement formula, which is: Among them, n is the number of the array element, α is the divergence angle of the Fermat spiral, and x n is the position of each array element in polar coordinates, R n and α i are the radius and angle in polar coordinates respectively; R 0 is a constant coefficient, N e is the number of array elements, When n is an odd number, x n The array element at is a broadband array element; when n is an even number, x n The array element at is a narrow-band array element.

2. According to claim 1, a spirally arranged high-frequency enhanced broadband focused phased array transducer, It is characterized in that The constant coefficient R 0 The calculation formula is: Among them, N e is the number of array elements; and D is the diameter of the opening disk of the spherical shell (3).

3. According to claim 1, a spirally arranged high-frequency enhanced broadband focused phased array transducer, It is characterized in that The spherical shell (3) is a sandwich shell, an array element installation groove is provided on the inner spherical surface of the spherical shell (3), the array element is arranged in the array element installation groove, a lead wire reserved channel (14) is provided in the sandwich of the spherical shell (3), and a lead wire reserved hole (15) is provided on the outer spherical surface of the spherical shell (3), and the lead wires of each array element are led out through the lead wire reserved channel (14) and the lead wire reserved hole (15) in sequence.

4. According to claim 1, a spirally arranged high-frequency enhanced broadband focused phased array transducer, It is characterized in that The broadband array element (1) comprises a broadband array element backing block (901), a broadband array element piezoelectric ceramic element (10) and a broadband array element matching element (12) which are sequentially connected along a direction toward the focal point; The narrowband array element (2) comprises a narrowband array element backing block (902), a narrowband array element piezoelectric ceramic element (11) and a narrowband array element matching element (13) which are sequentially connected along a direction toward the focal point.

5. According to claim 4, a spirally arranged high-frequency enhanced broadband focused phased array transducer, It is characterized in that The acoustic impedance of the broadband array element piezoelectric ceramic element (10) is greater than the acoustic impedance of the broadband array element backing block (901), and the acoustic impedance of the narrowband array element piezoelectric ceramic element (11) is greater than the acoustic impedance of the narrowband array element backing block (902).

6. According to claim 1, a spirally arranged high-frequency enhanced broadband focused phased array transducer, It is characterized in that The frequency band of the broadband array element (1) covers the high frequency band of thermal ablation, the low frequency band of blood-brain barrier disturbance and the low frequency band of neural regulation. The narrowband array element (2) has a frequency band covering the high frequency band of thermal ablation and the low frequency band of blood-brain barrier disturbance. The high-frequency band for thermal ablation is above 650kHz-1.5MHz, the low-frequency band for blood-brain barrier disturbance is 200kHz-500kHz, and the low-frequency band for neuromodulation is 20kHz-500kHz.

7. A spirally arranged high frequency enhanced broadband focused phased array transducer according to claim 6, It is characterized in that It also includes a driving circuit (4), a control system (5), a first signal source (6), a second signal source (7) and a third signal source (8), The first signal source (6) is used to provide a high-frequency signal for thermal ablation, the second signal source (7) is used to provide a low-frequency signal for blood-brain barrier disturbance, and the third signal source (8) is used to provide a low-frequency signal for neural regulation. The control system (5) is used for selecting an output signal of one of the first signal source (6), the second signal source (7) and the third signal source (8) and transmitting the output signal to the corresponding wideband array element through the driving circuit (4), and is also used for selecting an output signal of one of the first signal source (6) and the second signal source (7) and transmitting the output signal to the corresponding narrowband array element through the driving circuit (4).

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