Phased array modulation method and system of transcranial ultrasonic treatment system

Abstract

The invention discloses a phased array modulation method and system for a transcranial ultrasonic treatment system, and the method comprises the following steps: scanning a target object through CT, obtaining a CT data file, and reading the CT data file to obtain a CT value H of the target object; obtaining sound parameters of the target object based on the CT value H of the target object, and constructing a three-dimensional model of the target object; and determining emission parameters of each array element of the phased array through a time reversal method based on the set virtual point source and the three-dimensional model of the target object. Meanwhile, the phase and amplitude of each array element of the phased array are modulated, the phase and amplitude difference caused by different distances between each array element and a focusing target point can be compensated at the same time, the problems of focus distortion, offset and the like are avoided, ultrasonic waves emitted by each array element can reach the target point for accurate focusing at the same phase and the same amplitude, and the spatial resolution of the focusing point is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical ultrasound navigation, and in particular relates to a phased array modulation method and system for a transcranial ultrasound therapy system. Background Art

[0002] Low-intensity focused ultrasound is a type of ultrasound with a low emission frequency and dose. The energy delivered to tissue is generally less than 3W·cm -2 , it will not deposit too much energy at the target site, causing the target site to be overheated and causing thermal damage. Currently, low-intensity focused ultrasound has been proven to be applicable to fields such as particle manipulation and neuromodulation. As an ultrasound brain intervention technology, low-intensity ultrasound neuromodulation technology is an important means of treating neuropsychiatric diseases and conducting neuroscience research that has emerged in recent years. Through clinical trials, neuromodulation technology has been proven to be able to inhibit neurological diseases such as Parkinson's disease, depression, and epilepsy without drug side effects.

[0003] A key issue in the application of ultrasound brain intervention technology in the human brain is how to achieve transcranial focusing of ultrasound. The focal shift phenomenon caused by the irregular shape of the skull and the uneven distribution of sound speed and density is one of the problems that transcranial focused ultrasound needs to solve. Summary of the Invention

[0004] To solve the above problems, the purpose of the present invention is to provide a phased array modulation method and system for a transcranial ultrasound therapy system, which simultaneously modulates the phase and amplitude of each array element of the phased array, and can simultaneously compensate for the phase and amplitude differences caused by the different distances between each array element and the focusing target point, avoid focus distortion, offset and other problems, and ensure that the ultrasound waves emitted by each array element can reach the target point with the same phase and amplitude and be accurately focused, thereby improving the spatial resolution of the focusing point.

[0005] The technical solution provided by the present invention is: a phased array modulation method for a transcranial ultrasound therapy system, comprising the following steps:

[0006] Scanning the target object through CT to obtain a CT data file, and reading the CT data file to obtain a CT value H of the target object;

[0007] Acquiring acoustic parameters of the target object based on the CT value H of the target object and constructing a three-dimensional model of the target object;

[0008] Based on the set virtual point source and the three-dimensional model of the target object, the emission parameters of each element of the phased array are determined by the time reversal method.

[0009] Preferably, determining the transmission parameters of each element of the phased array by a time reversal method based on the set three-dimensional model of the virtual point source and the target object further includes:

[0010] A single-frequency point sound source is set at a set virtual point source position. After numerical simulation using the k-space pseudospectral method, the sound waves emitted by the virtual point source are received by each element of the set transducer array. The signal received by a reference element in the transducer array is selected as the reference signal. The reference signal is correlated with the signal received by any element to extract the control delay Δt of each element.

[0011] After the obtained control delay Δt of each array element is reversed according to the principle of first-come-first-served and last-come-last-served, the transmission is performed according to the obtained delay to achieve transcranial focusing;

[0012] Among them, the S of the reference array element is xx is the reference signal, denoted as S xx，ref , do the following related processing:

[0013] R ref.n (τ ref.n )=∫S xx，ref (t)S xx，n (t-τ ref.n )dt

[0014] R ref.ref (τ ref )=∫S xx，ref (t)S xx，ref (t-τ ref )dt

[0015] Where S xx，n Indicates the S received by the nth unit xx Time domain waveform, R ref.n Indicates S xx，n With S xx，ref The cross-correlation function between ref，n，max -τ ref，max is the delay of the nth array element relative to the reference array element.

[0016] Preferably, determining the transmission parameters of each element of the phased array by a time reversal method based on the set three-dimensional model of the virtual point source and the target object further includes:

[0017] When the amplitude of the transmitted signal of the reference array element n is B n When the amplitude of the transmitted signal of the pth array element is B p =B n / k p ; Among them, let the total number of array elements be m, and the amplitude A of the virtual source signal received by the nth array element n As a benchmark, 1≤n≤m, the amplitude of the virtual source signal received by the pth array element is A p , the ratio of p array elements is k p =A p / A n, 1≤p≤m, p≠n;

[0018] The ratio of the transmit signal amplitude of each array element is determined according to the above algorithm. When the transmit signal amplitude of a certain array element is changed, the amplitudes of other array elements are increased or decreased in the same proportion.

[0019] Preferably, obtaining the target object acoustic parameters based on the CT value H of the target object includes:

[0020]

[0021]

[0022]

[0023]

[0024] in: is the porosity of the skull, α water , ρ water 、c water Represent the attenuation coefficient, density, and sound speed of water, α bone , ρ bone 、c bone represent the attenuation coefficient, density, and speed of sound of cortical bone, respectively.

[0025] Preferably, acquiring the target object acoustic parameters based on the CT value H of the target object and constructing the three-dimensional model of the target object further includes:

[0026] Preprocess the acquired CT values, including denoising and contrast enhancement;

[0027] The density distribution of skull tissue is inferred based on the CT value H;

[0028] The pre-processed CT values ​​are used to construct a three-dimensional model of the skull through a three-dimensional reconstruction algorithm. The three-dimensional model reflects the external morphological characteristics of the skull and the detailed structural characteristics of its interior.

[0029] Preferably, the phased array transmit frequency range is 0.1-5 MHz, the center frequency is 2 MHz, the frequency range of a single array is narrow, and multiple different arrays are used to cover the frequency range; the array element material is piezoelectric ceramics and / or PVDF and / or piezoelectric crystals; the array element structure is a one-dimensional linear array or a two-dimensional surface array or a three-dimensional spherical array.

[0030] Preferably, after determining the transmission parameters of each element of the phased array by a time reversal method based on the set three-dimensional model of the virtual point source and the target object, the method further includes:

[0031] placing the phased array at a focal position a certain distance in front of a target object;

[0032] transmitting ultrasonic waves toward the target object based on the transmission parameters of each array element of the phased array;

[0033] The actual focal position of the ultrasound is obtained and compared with the set virtual point source position to verify the control effect.

[0034] Based on the same concept, the present invention also provides a phased array modulation system for a transcranial ultrasound therapy system, comprising:

[0035] a scanning unit, configured to scan a target object using CT, obtain a CT data file, and read the CT data file to obtain a CT value H of the target object;

[0036] a modeling unit, configured to obtain acoustic parameters of the target object based on the CT value H of the target object and construct a three-dimensional model of the target object;

[0037] The control unit is used to determine the emission parameters of each array element of the phased array through the time reversal method based on the set virtual point source and the three-dimensional model of the target object.

[0038] Based on the same concept, the present invention also provides an electronic device, comprising:

[0039] a memory for storing a processing program;

[0040] A processor, wherein when executing the processing program, the processor implements the phased array modulation method of the transcranial ultrasound therapy system described in any one of the above.

[0041] Based on the same concept, the present invention also provides a readable storage medium having a processing program stored thereon. When the processing program is executed by a processor, any one of the above-mentioned phased array modulation methods for a transcranial ultrasound therapy system is implemented.

[0042] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art:

[0043] The present invention simultaneously modulates the phase and amplitude of each array element of the phased array, which can simultaneously compensate for the phase and amplitude differences caused by the different distances between each array element and the focusing target point, avoid problems such as focus distortion and offset, and ensure that the ultrasonic waves emitted by each array element can reach the target point with the same phase and amplitude and be accurately focused, thereby improving the spatial resolution of the focusing point. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein:

[0045] Figure 1 The three-dimensional skull model reconstructed by the present invention;

[0046] Figure 2This is the sound velocity distribution diagram of the skull section of the present invention;

[0047] Figure 3 The array element structure that can be adopted by the present invention;

[0048] Figure 4 Schematic diagram of the phased array modulation method of the transcranial ultrasound therapy system of the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are greatly simplified and not to exact ratios, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0050] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0051] Since the main factors causing the focus shift of transcranial focusing are the shape of the skull and the non-uniform distribution of sound velocity, and when the focusing depth is large, the shear wave and sound attenuation have little effect on the control phase based on time reversal, in order to simplify the acoustic model, the present invention only considers the sound velocity, density, and shape of the skull during modeling and simulation, and ignores the influence of the attenuation term and shear wave on sound propagation.

[0052] First embodiment

[0053] See also Figure 4 This embodiment provides a phased array modulation method for a transcranial ultrasound therapy system, comprising the following steps:

[0054] Scanning the target object by spiral CT to obtain a CT data file in DICOM format, and reading the CT data file by Matlab to obtain a CT value H of the target object;

[0055] Acquiring acoustic parameters of the target object based on the CT value H of the target object and constructing a three-dimensional model of the target object;

[0056] Based on the set virtual point source and the three-dimensional model of the target object, the emission parameters of each element of the phased array are determined by the time reversal method.

[0057] The technical solution of this embodiment takes into account the individual differences in the skulls of different patients. The patient's skull CT data file is obtained by spiral CT scanning, and then a three-dimensional model of the skull is reconstructed based on the skull CT values ​​in the CT data file. Figure 1, is the reconstructed three-dimensional skull model, and then the transmission parameters of each element of the phased array are determined by the time reversal method. Figure 2 , is the sound velocity distribution diagram of the skull section.

[0058] Preferably, determining the transmission parameters of each element of the phased array by a time reversal method based on the set three-dimensional model of the virtual point source and the target object further includes:

[0059] A single-frequency point sound source with a center frequency of 2 MHz is set at the set virtual point source position. After numerical simulation using the k-space pseudospectral method, the sound waves emitted by the virtual point source are received by each array element of the set transducer array. The signal received by a reference array element in the transducer array is selected as the reference signal. The reference signal is correlated with the signal received by any array element to extract the control delay Δt of each array element.

[0060] After the obtained control delay Δt of each array element is reversed according to the principle of first-come-first-served and last-come-last-served, the transmission is performed according to the obtained delay to achieve transcranial focusing;

[0061] Among them, the S of the reference array element is xx is the reference signal, denoted as S xx，ref , do the following related processing:

[0062] R ref.n (τ ref.n )=∫S xx，ref (t)S xx，n (, -τ ref.n )dt

[0063] R ref.ref (τ ref )=∫S xx，ref (t)S xx，ref (t-τ ref )dt

[0064] Where S xx，n Indicates the S received by the nth unit xx Time domain waveform, R ref.n Indicates S xx，n With S xx，ref The cross-correlation function between ref，n，max -τ ref，max is the delay of the nth array element relative to the reference array element.

[0065] The technical solution of this embodiment modulates the phase of the phased array, which can compensate for the phase difference caused by the different distances between each array element and the focusing target point, avoid problems such as focus distortion and offset, and ensure that the ultrasonic waves emitted by each array element can reach the target point with the same phase and be accurately focused, thereby improving the spatial resolution of the focusing point.

[0066] Preferably, determining the transmission parameters of each element of the phased array by a time reversal method based on the set three-dimensional model of the virtual point source and the target object further includes:

[0067] When the amplitude of the transmitted signal of the reference array element n is B n When the amplitude of the transmitted signal of the pth array element is B p =B n / k p ; Wherein, the total number of array elements is m, the amplitude of the virtual source signal received by the nth array element is Ax as the reference, 1≤n≤m, the amplitude of the virtual source signal received by the pth array element is A p , the ratio of p array elements is k p =A p / A n , 1≤p≤m, p≠n;

[0068] The ratio of the transmit signal amplitude of each array element is determined according to the above algorithm. When the transmit signal amplitude of a certain array element is changed, the amplitudes of other array elements are increased or decreased in the same proportion.

[0069] The technical solution of this embodiment modulates the amplitude of the phased array to compensate for amplitude variations caused by the varying distances between each array element and the focal target, avoiding issues such as focal distortion and offset. This ensures that ultrasound waves emitted by each array element reach the target with the same amplitude and are precisely focused, improving the spatial resolution of the focal point. More preferably, both phase and amplitude are modulated simultaneously, ensuring that ultrasound waves emitted by more array elements are focused on the target with the same phase and amplitude, further preventing issues such as focal distortion and offset.

[0070] Preferably, obtaining the target object acoustic parameters based on the CT value H of the target object includes:

[0071]

[0072]

[0073]

[0074]

[0075] in: is the porosity of the skull, α water , ρ water 、c water Represent the attenuation coefficient, density, and sound speed of water, α bone , ρ bone 、c bone represent the attenuation coefficient, density, and speed of sound of cortical bone, respectively.

[0076] Preferably, acquiring the target object acoustic parameters based on the CT value H of the target object and constructing the three-dimensional model of the target object further includes:

[0077] Preprocess the acquired CT values, including denoising and contrast enhancement;

[0078] The density distribution of skull tissue is inferred based on the CT value H;

[0079] The pre-processed CT values ​​are used to construct a three-dimensional model of the skull through a three-dimensional reconstruction algorithm. The three-dimensional model reflects the external morphological characteristics of the skull and the detailed structural characteristics of its interior.

[0080] Preferably, the array elements of the phased array are distributed in 16*16; the phased array transmission frequency range is 0.1-5MHz, the center frequency is 2MHz, the frequency range of a single array is narrow, and multiple different arrays are used to cover the frequency range; the array element material is piezoelectric ceramics and / or PVDF and / or piezoelectric crystals; the array element structure is a one-dimensional linear array or a two-dimensional surface array or a three-dimensional spherical array.

[0081] See also Figure 3 , the array element structure can adopt one-dimensional linear array, two-dimensional surface array, three-dimensional spherical array, etc. Array element material: piezoelectric ceramics, PVDF, piezoelectric crystal and other transducer materials can be used.

[0082] Preferably, after determining the transmission parameters of each element of the phased array by a time reversal method based on the set three-dimensional model of the virtual point source and the target object, the method further includes:

[0083] Positioning the phased array at a position 2 mm from the target object;

[0084] transmitting ultrasonic waves toward the target object based on the transmission parameters of each array element of the phased array;

[0085] The actual focal position of the ultrasound is obtained and compared with the set virtual point source position to verify the control effect.

[0086] Based on the same concept, the present invention also provides a phased array modulation system for a transcranial ultrasound therapy system, comprising:

[0087] a scanning unit, configured to scan a target object using spiral CT, obtain a CT data file in DICOM format, and read the CT data file using Matlab to obtain a CT value H of the target object;

[0088] a modeling unit, configured to obtain acoustic parameters of the target object based on the CT value H of the target object and construct a three-dimensional model of the target object;

[0089] The control unit is used to determine the emission parameters of each array element of the phased array through the time reversal method based on the set virtual point source and the three-dimensional model of the target object.

[0090] The technical solution of this embodiment takes into account the individual differences in the skulls of different patients. The patient's skull CT data file is obtained through spiral CT scanning. Then, a three-dimensional model of the skull is reconstructed based on the skull CT values ​​in the CT data file. Then, the transmission parameters of each array element of the phased array are determined through the time reversal method.

[0091] Based on the same concept, the present invention also provides an electronic device, comprising: a memory for storing a processing program; and a processor for implementing any one of the above-mentioned phased array modulation methods for a transcranial ultrasound therapy system when executing the processing program.

[0092] Based on the same concept, the present invention also provides a readable storage medium having a processing program stored thereon. When the processing program is executed by a processor, the phased array modulation method of the transcranial ultrasound therapy system described in any one of the above is implemented.

[0093] If the phased array modulation method of the transcranial ultrasound therapy system is implemented in the form of program instructions and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this embodiment is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of software. The computer software is stored in a storage medium, including several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program code.

[0094] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the identification content specifically executed by the above-described system and device can refer to the corresponding process in the aforementioned method embodiment.

[0095] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, if these changes fall within the scope of the claims of the present invention and their equivalents, they still fall within the scope of protection of the present invention.

Claims

1. A phased array modulation method for a transcranial ultrasound therapy system, characterized in that: The steps include: Scanning the target object by CT to obtain a CT data file, and reading the CT data file to obtain a CT value H of the target object; Acquire the acoustic parameters of the target object based on the CT value H of the target object, and construct a three-dimensional model of the target object; Based on the set virtual point source and the three-dimensional model of the target object, the emission parameters of each element of the phased array are determined by the time reversal method.

2. The phased array modulation method of the transcranial ultrasound therapy system according to claim 1, characterized in that: Determining the emission parameters of each array element of the phased array by the time reversal method based on the set virtual point source and the three-dimensional model of the target object further includes: A single-frequency point sound source is set at the set virtual point source position. After numerical simulation of the k-space pseudo-spectral method, the sound wave emitted by the virtual point source is received by each array element of the set transducer array. The signal received by a reference array element in the transducer array is selected as the reference signal. The reference signal is correlated with the signal received by any array element to extract the control delay Δt of each array element. After the obtained control delay Δt of each array element is reversed according to the principle of first-come-first-served and last-come-last-served, it is transmitted according to the obtained delay to achieve transcranial focusing; Among them, the S of the reference array element is xx is the reference signal, denoted by S xx，ref , do the following related processing: R ref.n (τ ref.n )=∫S xx，ref (t)S xx，n (t-*τ ref.n )dt R ref.ref (τ ref )=∫S xx，ref (t)S xx，ref (t-τ ref )dt In the formula, S xx，n Indicates the S received by the nth unit xx Time domain waveform, R ref.n Indicates S xx，n With S xx，ref The cross-correlation function between ref，n，max -τ ref，max is the delay of the nth array element relative to the reference array element.

3. The phased array modulation method of the transcranial ultrasound therapy system according to claim 1 or 2, characterized in that: Determining the transmission parameters of each array element of the phased array by the time reversal method based on the set virtual point source and the three-dimensional model of the target object further includes: When the amplitude of the transmitted signal of the reference array element n is B n When the pth array element transmits a signal with an amplitude of B p =B n / k p ; Where, assuming the total number of array elements is m, the amplitude A of the virtual source signal received by the nth array element n As a benchmark, 1≤n≤m, the amplitude of the virtual source signal received by the pth array element is A p , the ratio of p elements is k p =A p / A n , 1≤p≤m, p≠n; The amplitude ratio of the transmitted signal of each array element is determined according to the above algorithm. When the amplitude of the transmitted signal of a certain array element is changed, the amplitudes of other array elements are increased or decreased in the same proportion.

4. The phased array modulation method of the transcranial ultrasound therapy system according to claim 1, characterized in that: Acquiring the acoustic parameters of the target object based on the CT value H of the target object includes: in: is the porosity of the skull, α water , water 、c water Respectively represent the attenuation coefficient, density, and sound speed of water, α bone , bone 、c bone Represent the attenuation coefficient, density, and speed of sound of cortical bone, respectively.

5. The phased array modulation method of the transcranial ultrasound therapy system according to claim 4, characterized in that: Acquiring the acoustic parameters of the target object based on the CT value H of the target object and constructing the three-dimensional model of the target object further includes: Preprocess the acquired CT values, including denoising and contrast enhancement; The density distribution of skull tissue is inferred based on the CT value H; The preprocessed CT values ​​are used to construct a three-dimensional model of the skull through a three-dimensional reconstruction algorithm, and the three-dimensional model reflects the external morphological characteristics of the skull and the detailed structural characteristics of its interior.

6. The phased array modulation method of the transcranial ultrasound therapy system according to claim 1, characterized in that: The phased array transmission frequency range is 0.1-5MHz. The frequency range of a single array is narrow, and multiple different arrays are used to cover this frequency range; the array element material is piezoelectric ceramics and / or PVDF and / or piezoelectric crystals; the array element structure is a one-dimensional linear array or a two-dimensional surface array or a three-dimensional spherical array.

7. The phased array modulation method of the transcranial ultrasound therapy system according to claim 1, characterized in that: After determining the emission parameters of each element of the phased array by the time reversal method based on the set virtual point source and the three-dimensional model of the target object, the method also includes: Disposing the phased array at a focal position a certain distance in front of a target object; transmitting ultrasonic waves to the target object based on the transmission parameters of each array element of the phased array; The actual focal position of the ultrasound is obtained and compared with the set virtual point source position to verify the regulation effect.

8. A phased array modulation system for a transcranial ultrasound therapy system, characterized in that: include: A scanning unit, used to scan the target object through CT, obtain a CT data file, and read the CT data file to obtain a CT value H of the target object; A modeling unit, used for acquiring acoustic parameters of the target object based on the CT value H of the target object, and constructing a three-dimensional model of the target object; The control unit is used to determine the emission parameters of each array element of the phased array through the time reversal method based on the set virtual point source and the three-dimensional model of the target object.

9. An electronic device, characterized in that: include: A memory, the memory being used to store a processing program; A processor, wherein when executing the processing program, the processor implements the phased array modulation method of the transcranial ultrasound therapy system as described in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: The readable storage medium stores a processing program, and when the processing program is executed by the processor, the phased array modulation method of the transcranial ultrasound therapy system according to any one of claims 1 to 7 is implemented.

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