Chromatographic coding three-dimensional MPI imaging technology based on sensitivity space specificity

Abstract

The invention particularly relates to a tomographic coding three-dimensional MPI imaging technology based on sensitivity space specificity, which adopts a Halbach permanent magnet array to construct a zero magnetic field line type space selection gradient field, and solves the problem of low imaging space resolution caused by low gradient of the traditional zero magnetic field line type space selection field under the condition of large visual field. According to the invention, the multi-channel array receiving coil and the zero magnetic field line sensing are adopted to solve the problem of low magnetic particle imaging sensitivity under the condition of large visual field; three-dimensional imaging can be realized by adopting a sensitivity tomography coding method and zero magnetic field line two-dimensional scanning, and imaging time resolution is improved by low-dimensional scanning and high-dimensional imaging.

Description

Technical Field

[0001] This invention relates to the field of magnetic particle imaging technology, specifically to a sensitivity-spatial-specific tomographic coding three-dimensional MPI imaging technique. Background Technology

[0002] Among related technologies, magnetic particle imaging (MPI) utilizes the nonlinear response of magnetic nanoparticles in the free region of a high-gradient magnetic field to visualize the distribution and concentration of magnetic nanoparticles within biological organisms. Furthermore, the intensity of the magnetic particle signal is directly proportional to the concentration of the tracer, enabling quantitative imaging of its spatial distribution. Therefore, it possesses advantages such as high sensitivity and insensitivity to background tissue signals, making it a promising new imaging method for medical applications.

[0003] Traditional magnetic particle imaging techniques rely on spatially selected fields generated by static gradient magnetic fields for spatial encoding, primarily including two forms: zero-magnetic-field points and zero-magnetic-field lines. Zero-magnetic-field point selection uses permanent magnet pairs or Maxwell coils to generate a point-like zero-magnetic-field region. Then, electromagnetic drive coils in the X, Y, and Z directions drive the zero-magnetic-field point for three-dimensional spatial traversal scanning. Finally, the magnetic particle response signal is spatially mapped based on the three-dimensional scan trajectory to obtain the magnetic particle concentration distribution. However, the point-like zero-magnetic-field region results in a small magnetic particle response area, thus limiting imaging sensitivity, and the three-dimensional traversal scanning leads to low scanning efficiency. Zero-magnetic-field line selection uses multiple pairs of permanent magnets or Maxwell coils to generate a linear zero-magnetic-field region. Then, electromagnetic coils drive the zero-magnetic-field line to obtain parallel beam projection in a two-dimensional plane. Mechanically driven rotation of the zero-magnetic-field line acquires projection data from different angles, and finally, tomographic imaging is performed based on the projection data. The linear zero-magnetic-field region increases the magnetic particle response area; however, the multi-angle parallel beam projection tomographic scanning of the zero-magnetic-field line severely limits the temporal resolution of three-dimensional imaging. This shows that traditional magnetic particle imaging technology is limited in terms of sensitivity and three-dimensional imaging temporal resolution due to the spatial coding method.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides a sensitivity-spatial-specific tomographic coding three-dimensional MPI imaging method, which can effectively overcome the defects existing in the prior art.

[0006] Other features and advantages of the invention will become apparent from the following detailed description, or may be learned in part by practice of the invention.

[0007] According to a first aspect of the present invention, a sensitivity-spatial-specific tomographic coding three-dimensional MPI imaging method is provided, the method comprising: For a receiving coil sensing array arranged along the major axis of the zero magnetic field line (FFL), FFL projection X-space imaging is performed based on the voltage signal received by each receiving coil to obtain the corresponding reconstructed image; and the reconstructed images corresponding to each receiving coil are merged to obtain a merged image. The merged image is subjected to maximum value projection along the long axis to obtain the corresponding two-dimensional image, which is used to project the distribution of magnetic particles in three-dimensional space onto the two-dimensional image; Tomographic encoding was performed on multi-channel projection X-space imaging to obtain the one-dimensional magnetic particle concentration distribution of each pixel on the FFL. By combining one-dimensional magnetic particle concentration distribution and two-dimensional image, three-dimensional MPI image reconstruction is performed to obtain a three-dimensional MPI image.

[0008] In some exemplary embodiments, FFL projection X-space imaging is performed based on the voltage signals received by each receiving coil to obtain the corresponding reconstructed image, including:

[0009] in, The matrix represents the three-dimensional sensitivity matrix for magnetic particles; K represents a point. The impact function at the location; This indicates the position of the FFL at time t.

[0010] In some exemplary embodiments, tomographic encoding is performed on multi-channel projection X-space imaging to obtain the one-dimensional magnetic particle concentration distribution of each pixel on the FFL, including:

[0011] in, This represents the inverse of the one-dimensional sensitivity matrix in the y-direction of the multi-channel receiving coil.

[0012] In some exemplary embodiments, three-dimensional MPI image reconstruction is performed by combining one-dimensional magnetic particle concentration distribution and two-dimensional image to obtain a three-dimensional MPI image, including: A three-dimensional MPI image is obtained by filling the one-dimensional magnetic particle concentration distribution into a one-dimensional space perpendicular to the long axis of a two-dimensional image.

[0013] In some exemplary embodiments, a three-dimensional MPI image is reconstructed by combining a one-dimensional magnetic particle concentration distribution and a two-dimensional image, and the formula includes:

[0014] in, This represents a 3D MPI image.

[0015] In some exemplary embodiments, the method further includes: Data is acquired in parallel from each of the multi-channel receiving coils in the receiving coil sensor array.

[0016] In some exemplary embodiments, the method further includes: Determine whether each pixel in a two-dimensional image has a valid value.

[0017] In some exemplary embodiments, the method further includes: Multiple receiving coils are arranged along the long axis of the zero magnetic field line (FFL) to form a receiving coil sensing array; wherein, the receiving coils are arranged perpendicular to the long axis of the zero magnetic field line; or, the multi-channel receiving coils are arranged at an angle to the long axis of the leading magnetic field line.

[0018] In some exemplary embodiments, the receiving coil is in the form of a ring structure; or, the receiving coil is a saddle-shaped coil pair.

[0019] According to a second aspect of the present invention, a computer program product is provided, on which a computer program is stored, wherein when the computer program is executed by a processor, the above-described sensitivity-spatial-specific tomographic coded three-dimensional MPI imaging method is implemented.

[0020] According to a third aspect of the present invention, an electronic device is provided, comprising: Processor; and Memory for storing the executable instructions of the processor; The processor is configured to implement the above-described sensitivity-space-specific tomographic coded three-dimensional MPI imaging method by executing the executable instructions.

[0021] According to a fourth aspect of the present invention, a storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the above-described sensitivity-spatial-specific tomographic coded three-dimensional MPI imaging method.

[0022] The three-dimensional MPI imaging method based on sensitivity-space-specific tomographic coding provided by embodiments of the present invention effectively detects instantaneous changes in particles within the imaging space by acquiring data from multiple receiving coils arranged along the long axis of the zero magnetic field line and merging channel data, thus avoiding signal loss and improving the sensitivity of three-dimensional MPI imaging. Furthermore, based on sensitivity-space-specific tomographic coding of the zero magnetic field line, the present invention only requires a two-dimensional scan of the zero magnetic field line in the cross-section to achieve three-dimensional image reconstruction. This low-dimensional scanning and high-dimensional reconstruction simplifies the scanning method and improves the imaging temporal resolution. In addition, the present invention proposes a combined coding strategy: two-dimensional projection guides tomographic coding to achieve three-dimensional reconstruction, reducing the complexity of three-dimensional reconstruction and transforming the solution of the three-dimensional inverse problem into a one-dimensional inverse problem. This combined coding strategy simplifies the difficulty of three-dimensional imaging and improves the accuracy of three-dimensional imaging.

[0023] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0025] Figure 1 The diagram illustrates an exemplary embodiment of the present invention of a tomographically encoded three-dimensional MPI imaging method based on sensitivity spatial specificity; Figure 2 The schematic diagram illustrates a multi-channel receiving coil array according to an exemplary embodiment of the present invention; Figure 3 This schematic diagram illustrates a spatially specific distribution of multi-channel sensitivity on a zero magnetic field line, according to an exemplary embodiment of the present invention. Figure 4 This diagram illustrates the principle of a multi-channel FFL projection X-space image according to an exemplary embodiment of the present invention. Figure 5 The diagram illustrates a flowchart of a multi-channel FFL three-dimensional reconstruction method according to an exemplary embodiment of the present invention. Figure 6 This schematic diagram illustrates an exemplary embodiment of the present invention: a tilt-angle multi-channel receiving coil array. Figure 7 The schematic diagram illustrates a saddle-shaped multichannel receiving coil according to an exemplary embodiment of the present invention; Figure 8This schematic diagram illustrates the composition of an electronic device according to an exemplary embodiment of the present invention. Detailed Implementation

[0026] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the invention will be more comprehensive and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0027] Furthermore, the accompanying drawings are merely illustrative of the invention and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0028] In related technologies, traditional magnetic particle imaging techniques typically employ permanent magnet pairs or Maxwell coil pairs to generate a spatial gradient selective field. However, due to severe magnetic leakage in permanent magnet pairs and coil pairs, the resulting spatial selective field gradient is limited, leading to low spatial resolution. Furthermore, in traditional magnetic particle imaging techniques, a zero-magnetic-field point-type spatial selective field has only a single point-like magnetic particle response region, requiring only one receiving coil in a single dimension. Three-dimensional imaging requires a maximum of three receiving coils, resulting in low sensing sensitivity. While a zero-magnetic-field linear spatial selective field has a magnetic particle response region along a line, its tomographic beam scanning method limits the deployment of only one receiving channel, thus restricting sensing sensitivity. In addition, traditional zero-magnetic-field point-type magnetic particle imaging technology requires electromagnetic drive coils in the X, Y, and Z directions to drive the zero-magnetic-field point to perform a three-dimensional spatial traversal scan. Finally, the magnetic particle concentration distribution is obtained by spatially mapping the magnetic particle response signal based on the three-dimensional scan trajectory. The three-dimensional traversal scan results in low scanning efficiency. In traditional zero-magnetic-field line-type magnetic particle imaging technology, electromagnetic coils drive the zero-magnetic-field line to perform parallel beam projection in a two-dimensional plane. The mechanical drive rotates the zero-magnetic-field line to perform projection at different angles. Finally, tomographic imaging is performed based on the projection data. The complex tomographic scanning method severely restricts the temporal resolution of three-dimensional imaging.

[0029] To address the shortcomings and deficiencies of existing technologies, this exemplary embodiment provides a sensitivity-space-specific tomographic coding method for three-dimensional MPI imaging. It employs a Halbach permanent magnet array to construct a zero-magnetic-field linear spatially selected gradient field, solving the problem of low spatial resolution caused by the low gradient of traditional zero-magnetic-field linear spatially selected fields under large field-of-view conditions. The use of a multi-channel array receiving coil and zero-magnetic-field line sensing solves the problem of low sensitivity in magnetic particle imaging under large field-of-view conditions. Three-dimensional imaging can be achieved by using a sensitivity tomographic coding method and two-dimensional scanning with a zero-magnetic-field line, improving the temporal resolution of imaging through low-dimensional scanning and high-dimensional imaging. (Reference) Figure 1 As shown, the method may specifically include: Step S11: For the receiving coil sensing array arranged along the long axis of the zero magnetic field line FFL, perform FFL projection X-space imaging based on the voltage signal received by each receiving coil to obtain the corresponding reconstructed image; and merge the reconstructed images corresponding to each receiving coil to obtain the merged image. Step S12: Perform maximum value projection processing on the merged image along the long axis to obtain the corresponding two-dimensional image, which is used to project the distribution of magnetic particles in three-dimensional space onto the two-dimensional image. Step S13: Perform tomographic encoding on the multi-channel projection X-space imaging to obtain the one-dimensional magnetic particle concentration distribution of each pixel on the FFL. Step S14: Combine the one-dimensional magnetic particle concentration distribution and the two-dimensional image to reconstruct the three-dimensional MPI image and obtain the three-dimensional MPI image.

[0030] This invention employs a Halbach permanent magnet array to construct a zero-magnetic-field linear spatial selection gradient field, solving the problem of low imaging spatial resolution caused by the low gradient of traditional zero-magnetic-field linear spatial selection fields under large field-of-view conditions. This invention also employs a multi-channel array receiving coil and a zero-magnetic-field line sensor to solve the problem of low sensitivity in magnetic particle imaging under large field-of-view conditions. Furthermore, this invention achieves three-dimensional imaging by using a sensitivity tomography coding method and two-dimensional scanning with a zero-magnetic-field line, thus improving the imaging temporal resolution through low-dimensional scanning and high-dimensional imaging.

[0031] The following will describe in more detail each step of the sensitivity-space-specific tomographic coding 3D MPI imaging technique in this exemplary embodiment, with reference to the accompanying drawings and embodiments.

[0032] For example, Magnetic Particle Imaging (MPI) is a novel imaging technique that uses superparamagnetic iron oxide nanoparticles under an alternating magnetic field as tracers, utilizing their nonlinear magnetization properties to detect the spatiotemporal distribution of particle concentration. Magnetic nanoparticles exhibit distinct magnetization characteristics in a magnetic field environment, and their distribution can be obtained based on their nonlinear magnetization response. Based on the magnetization properties of magnetic nanoparticles in a magnetic field, when the external magnetic field strength... H When the field is zero (zero field region), the magnetic nanoparticles generate an alternating response signal in response to the applied sinusoidal excitation signal, which can be obtained by the receiving device; when the external magnetic field is non-zero, the particle magnetization intensity... M In a stable state, the receiving device will not respond. Placing the analyte containing magnetic nanoparticles in a magnetic field region will allow the receiver to transmit a response signal from the zero magnetic field region. S By obtaining the particle quantity at this point, changing the position of the zero magnetic field region can yield the particle concentration distribution within the imaging plane of the analyte, thereby obtaining a characteristic image of the analyte carrying magnetic nanoparticles.

[0033] For example, the above method includes: arranging multiple receiving coils along the long axis of the zero magnetic field line FFL to form a receiving coil sensing array; wherein the receiving coils are arranged perpendicular to the long axis of the zero magnetic field line; or, the multi-channel receiving coils are arranged at an angle to the long axis of the magnetic field line.

[0034] Specifically, a receiving coil sensor array can be pre-built. (Reference) Figure 2 As shown, this invention employs a linear array of receiving coils, with L receiving coils arranged along the FFL direction. The positions of the FFL and the L receiving coils are as follows: Figure 2 As shown, three-dimensional reconstruction is achieved by solving the spatially specific one-dimensional sensitivity matrix of multiple receiving coils.

[0035] For example, the receiving coil has a circular ring structure; or, the receiving coil is a saddle-shaped coil pair.

[0036] Specifically, different angles or types of receiving coils can be arranged in a zero-magnetic-field linear spatial selection field to create spatial specificity of sensitivity, such as tilting the angle of multi-channel receiving coils or using saddle-shaped multi-channel receiving coils.

[0037] refer to Figure 6 The tilted multi-channel receiving coil angle scheme shown has the receiving coil making an angle of θ with the zero magnetic field axis. , Tilted multi-channel receiving coils can provide more spatial sensitivity information. At the same time, the combination of tilted multi-channel receiving coils and existing multi-channel receiving coils can provide more condition numbers for linear problem solving, thereby improving the solution progress of magnetic particle concentration distribution.

[0038] Saddle-shaped multi-channel receiver coil solution, such as Figure 7 As shown, multiple saddle-shaped coil pairs are arranged along the long axis of the FFL, and the main receiving direction of the saddle-shaped coils is at a certain angle to the long axis of the FFL. , Multi-channel saddle-shaped receiving coils can also construct a sensitivity-specific spatial distribution using the FFL long-axis method. By rotating the saddle-shaped coil to bring it closer to the object being measured, detection sensitivity is increased while also providing a direction-specific sensitivity spatial distribution.

[0039] Specifically, the magnetization of a unit magnetic particle at spatial location p in MPI three-dimensional imaging is expressed as: Furthermore, the direction of magnetization is generally along the direction of the magnetic field, and magnetization can be represented as: (1) in, , .

[0040] Among them, magnetization vector The formula for differentiating with respect to time can include: (2) (3) (4) (5) Therefore, the derivative of the magnetization vector with respect to time can be expressed as: (6) Specifically, it can be defined as follows:

[0041] Correspondingly, we have:

[0042] Magnetization M is related to magnetic field strength. Since the magnetic field strength in the Y direction is uniform at any location within the imaging space, the magnetization is also uniform in the Y direction. Therefore, The spatial position of K is represented by a three-dimensional matrix, completely independent of the Y-direction, and also represented by a three-dimensional matrix according to the Y-direction. : (7) In an MPI device with a receiving coil, the physical model of the induced voltage... The corresponding formulas include: (8) (9) (10) in, The permeability of free space, The sensitivity of the receiving coil; This represents the magnetization component of the magnetic particles within the field of view. ; This represents the magnetic powder concentration distribution.

[0043] Will Represented by a matrix along the Y-axis: (11) (12) (13) Considering that the approximate MPI system is linear and spatially invariant, the received voltage of the coil can be expressed in convolution form: (14) In three-dimensional space, the sensitivity of a single receiving coil channel can be expressed as a matrix along the Y direction as follows: (15) Then we have: (16) Specifically, a multi-channel receiving coil was used in the Y-axis direction, and the spatially specific distribution of sensitivity on the zero magnetic field line is as follows: Figure 3 As shown. Furthermore, the receiving coils exhibit specific sensitivity distribution in three-dimensional space, thus the Y-axis spatial encoding can be achieved by utilizing the sensitivity distribution of multiple receiving coils along the Y-axis. Due to the different spatial distributions of the multiple receiving coils along the Y-axis, a highly spatially specific sensitivity distribution is generated in the Y-axis direction.

[0044] In step S11, for the receiving coil sensing array arranged along the long axis of the zero magnetic field line FFL, FFL projection X-space imaging is performed based on the voltage signal received by each receiving coil to obtain the corresponding reconstructed image; and the reconstructed images corresponding to each receiving coil are merged to obtain a merged image.

[0045] For example, the method further includes: acquiring data from each multi-channel receiving coil in the receiving coil sensing array in parallel.

[0046] Specifically, the FFL projection X-space reconstruction method is used for the XOZ plane. During multi-channel FFL projection X-space reconstruction, the reconstructed FFL projection X-space image of the receiving channel is obtained by normalizing the voltage signal received by a single receiving coil using the magnetic field derivative, including: (17) in, The matrix represents the three-dimensional sensitivity matrix for magnetic particles; K represents a point. The impact function at the location; This indicates the position of the FFL at time t.

[0047] After acquiring the reconstructed images corresponding to each receiving coil, multiple reconstructed images can be merged. (Reference) Figure 3 As shown, the multi-channel FFL projection X-space reconstruction can be expressed as: (18) The multi-channel parallel receiving scheme based on the zero magnetic field line arranges multiple receiving coils along the long axis of the zero magnetic field line. The parallel acquisition of data from the multi-channel receiving coils and the merging of channel data can effectively detect instantaneous changes of particles in the imaging space, avoid signal loss, and improve the sensitivity of 3D MPI imaging.

[0048] In step S12, the merged image is subjected to maximum value projection processing along the long axis to obtain the corresponding two-dimensional image, which is used to project the distribution of magnetic particles in three-dimensional space onto the two-dimensional image.

[0049] For example, the multi-channel FFL projection X-space imaging represented by formula (18) is projected along the Y direction using the maximum value to obtain a two-dimensional image. Then the distribution of magnetic particles in three-dimensional space has been projected onto In the image, such as Figure 4 As shown.

[0050] In some exemplary embodiments, the method further includes: determining whether each pixel in the two-dimensional image has a valid value.

[0051] Specifically, pixel thresholds can be pre-configured. After generating the 2D image, the pixel value of each pixel on the projection screen can be compared with the preset pixel threshold. If the pixel value is greater than the preset threshold, it can be determined that the pixel has a valid value.

[0052] Assumption Image at pixels If a valid value exists, it means that it is perpendicular to... Magnetic particles exist on the FFL line, and the precise spatial distribution of magnetic particles on the FFL line can be obtained through FFL tomography encoding. In step S13, tomographic encoding is performed on the multi-channel projection X-space imaging to obtain the one-dimensional magnetic particle concentration distribution of each pixel on the FFL.

[0053] For example, for the first channel, in pixel value at It can be represented as: (19) For pixels The value is only contributed by magnetic particles on the FFL line, and the spatial response of magnetic particles on the FFL line in three-dimensional space is approximately an impact function.

[0054] Therefore, in the above formula It can be represented as a point. The impact function at that point. Therefore, pixel value at It can be represented as: (20) Correspondingly, multi-channel can be represented as: (twenty one) The settlement process may include: (twenty two) (twenty three) (twenty four) (25) Indicates in The one-dimensional magnetic particle concentration distribution along the FFL line can be expressed as: (26) In step S14, a three-dimensional MPI image is reconstructed by combining the one-dimensional magnetic particle concentration distribution and the two-dimensional image to obtain a three-dimensional MPI image.

[0055] For example, define This represents the three-dimensional magnetic particle concentration distribution. According to... The result calculated using formula (26) It can be represented as: (27) Specifically, refer to Figure 5 As shown, multi-channel FFL projection X-space can guide the reconstruction of magnetic particle concentration distribution on the FFL, and can transform complex three-dimensional matrix solving into one-dimensional matrix solving, simplifying MPI three-dimensional reconstruction calculations and significantly improving imaging efficiency. The method provided in this invention employs a K=2 Halbach permanent magnet array to construct a field-free line (FFL) type spatially selected gradient field. Multiple receiving coils are arranged along the long axis of the FFL to form a receiving coil sensing array. The spatial specificity of the receiving sensing array's sensitivity is used to encode the space along the FFL. Based on the sensitivity tomography encoding of the array receiver and the two-dimensional scanning of the FFL, three-dimensional imaging of magnetic particles can be achieved.

[0056] The beneficial effects are as follows: 1) This invention differs from traditional FFL scanning, which involves multi-angle scanning of a two-dimensional plane through translation and rotation, and uses multi-tomographic reconstruction to achieve three-dimensional imaging, resulting in complex scanning and low temporal resolution. This invention is based on sensitivity-specific tomographic coding of zero magnetic field lines. Zero magnetic field lines only require two-dimensional scanning of the cross-section to achieve three-dimensional image reconstruction. Low-dimensional scanning and high-dimensional reconstruction simplify the scanning method and improve imaging temporal resolution.

[0057] 2) Traditional magnetic particle imaging technology is limited by the encoding method, which uses only one receiving coil in a single dimension, resulting in limited detection sensitivity. The novel tomographic encoding in this invention uses multi-channel receiving coils. By parallel acquisition and data merging of multiple receiving coils, it is possible to effectively detect instantaneous changes in particles in the imaging space, avoid signal loss, and improve the sensitivity of 3D MPI imaging.

[0058] 3) Traditional magnetic particle imaging technology relies on the selection of field gradient values ​​for 3D imaging spatial resolution. This invention proposes a combined coding strategy, which uses 2D projection-guided tomographic coding to achieve 3D reconstruction, reducing the complexity of 3D reconstruction and transforming the solution of the 3D inverse problem into the solution of the 1D inverse problem. This combined coding strategy simplifies the difficulty of 3D imaging and improves the accuracy of 3D imaging.

[0059] It should be noted that the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may, for example, be executed synchronously or asynchronously in multiple modules.

[0060] It should be noted that although several modules or units of the device for performing actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of the present invention, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0061] Figure 8 A schematic diagram of an electronic device suitable for implementing embodiments of the present invention is shown.

[0062] It should be noted that, Figure 8 The electronic device 1000 shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0063] like Figure 8 As shown, the electronic device 1000 includes a Central Processing Unit (CPU) 1001, which can perform various appropriate actions and processes based on programs stored in Read-Only Memory (ROM) 1002 or programs loaded from storage section 1008 into Random Access Memory (RAM) 1003. The RAM 1003 also stores various programs and data required for system operation. The CPU 1001, ROM 1002, and RAM 1003 are interconnected via a bus 1004. An Input / Output (I / O) interface 1005 is also connected to the bus 1004. Furthermore, the electronic device 1000 also includes an FPGA device and a System-on-a-Chip (SoC) device.

[0064] The following components are connected to I / O interface 1005: an input section 1006 including a keyboard, mouse, etc.; an output section 1007 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 1008 including a hard disk, etc.; and a communication section 1009 including a network interface card such as a LAN (Local Area Network) card, modem, etc. The communication section 1009 performs communication processing via a network such as the Internet. A drive 1010 is also connected to I / O interface 1005 as needed. Removable media 1011, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., are installed on drive 1010 as needed so that computer programs read from them can be installed into storage section 1008 as needed.

[0065] In particular, according to embodiments of the present invention, the processes described below with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a storage medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 1009, and / or installed from removable medium 1011. When the computer program is executed by central processing unit (CPU) 1001, it performs various functions defined in the system of this application.

[0066] Specifically, the aforementioned electronic devices can be intelligent electronic devices, such as computers, tablets, etc. These electronic devices can connect to and communicate with the sensor platform, execute the methods described above based on the received data, and output an estimate of the target's position.

[0067] It should be noted that the storage medium shown in the embodiments of the present invention can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. A computer-readable storage medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In the present invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, wherein computer-readable program code is carried. Such transmitted data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The computer-readable signal medium can also be any storage medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the storage medium can be transmitted using any suitable medium, including but not limited to wireless, wired, etc., or any suitable combination thereof.

[0068] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0069] The units described in the embodiments of the present invention can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0070] It should be noted that, as another aspect, this application also provides a storage medium, which may be included in an electronic device or may exist independently without being assembled into the electronic device. The aforementioned storage medium carries one or more programs, which, when executed by an electronic device, cause the electronic device to perform the methods described in the following embodiments. For example, the electronic device may perform... Figure 1 The steps of the method shown.

[0071] In one embodiment, this application provides a computer program product including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0072] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of the present invention, and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0073] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

[0074] It should be understood that the present invention is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A sensitivity-spatial-specific tomographic coding three-dimensional MPI imaging technique, characterized in that, The method includes: For a receiving coil sensing array arranged along the major axis of the zero magnetic field line (FFL), FFL projection X-space imaging is performed based on the voltage signal received by each receiving coil to obtain the corresponding reconstructed image; and the reconstructed images corresponding to each receiving coil are merged to obtain a merged image. The merged image is subjected to maximum value projection along the long axis to obtain the corresponding two-dimensional image, which is used to project the distribution of magnetic particles in three-dimensional space onto the two-dimensional image; Tomographic encoding was performed on multi-channel projection X-space imaging to obtain the one-dimensional magnetic particle concentration distribution of each pixel on the FFL. By combining one-dimensional magnetic particle concentration distribution and two-dimensional image, three-dimensional MPI image reconstruction is performed to obtain a three-dimensional MPI image.

2. The method according to claim 1, characterized in that, Based on the voltage signals received by each receiving coil, FFL projection X-space imaging is performed to obtain the corresponding reconstructed image, including: in, The matrix represents the three-dimensional sensitivity matrix for magnetic particles; K represents a point. The impact function at the location; This indicates the position of the FFL at time t.

3. The method according to claim 1, characterized in that, Tomographic encoding of multi-channel projected X-space imaging was performed to obtain the one-dimensional magnetic particle concentration distribution of each pixel on the FFL, including: in, This represents the inverse of the one-dimensional sensitivity matrix in the y-direction of the multi-channel receiving coil.

4. The method according to claim 1, characterized in that, By combining one-dimensional magnetic particle concentration distribution and two-dimensional images, three-dimensional MPI image reconstruction is performed to obtain a three-dimensional MPI image, including: A three-dimensional MPI image is obtained by filling the one-dimensional magnetic particle concentration distribution into a one-dimensional space perpendicular to the long axis of a two-dimensional image.

5. The method according to claim 1 or 4, characterized in that, Combining one-dimensional magnetic particle concentration distribution and two-dimensional images to reconstruct three-dimensional MPI images, the formula for obtaining three-dimensional MPI images includes: in, This represents a 3D MPI image.

6. The method according to claim 1, characterized in that, The method further includes: Data is acquired in parallel from each of the multi-channel receiving coils in the receiving coil sensor array.

7. The method according to claim 1, characterized in that, The method further includes: Determine whether each pixel in a two-dimensional image has a valid value.

8. The method according to claim 1, characterized in that, The method further includes: Multiple receiving coils are arranged along the long axis of the zero magnetic field line (FFL) to form a receiving coil sensing array; wherein, the receiving coils are arranged perpendicular to the long axis of the zero magnetic field line; or, the multi-channel receiving coils are arranged at an angle to the long axis of the leading magnetic field line.

9. The method according to claim 1 or 8, characterized in that, The receiving coil has a circular ring structure; or, the receiving coil is a saddle-shaped coil pair.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of sensitivity-space-specific tomographic coding three-dimensional MPI imaging technology as described in any one of claims 1 to 9.

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