CN115797493A - Magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling - Google Patents
Magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling Download PDFInfo
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Abstract
The invention belongs to the technical field of magnetic particle imaging, and particularly relates to a magnetic field free line magnetic particle imaging method, system and equipment based on one-dimensional system matrix sparse sampling, aiming at solving the problems of low correction efficiency of the existing magnetic particle imaging method based on a system matrix dense sampling, relatively complex post-processing model and low imaging efficiency of the magnetic particle imaging method based on the system matrix sparse sampling. The method comprises the following steps: setting an initial angle, a rotation angle sequence and an imaging view field size, and measuring a one-dimensional system matrix in the gradient direction of a magnetic field free line at the initial angle; establishing an observation vector sequence; constructing a linear equation set sequence and solving to obtain a one-dimensional projection reconstruction result sequence; and reconstructing a magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence. The invention greatly reduces the correction difficulty, does not need a post-processing model and improves the imaging efficiency.
Description
Technical Field
The invention belongs to the technical field of magnetic particle imaging, and particularly relates to a magnetic field free line magnetic particle imaging method, system and equipment based on one-dimensional system matrix sparse sampling.
Background
Magnetic particle imaging is a new generation of medical imaging modalities proposed by professor Gleich and Weizenecker. Based on the nonlinear magnetization response of the magnetic nanoparticles, the magnetic particle imaging can realize in-vivo noninvasive three-dimensional tomography of organisms, and a large number of preclinical experiments prove that the magnetic particle imaging has potential application to key clinical problems such as cardiovascular and cerebrovascular monitoring, magnetocaloric therapy, cell tracing and the like. Magnetic particle imaging can be divided into two imaging modes based on a magnetic field free point and a magnetic field free line according to the selected field shape, compared with the magnetic field free point, the magnetic field free line can detect signals of magnetic nanoparticles in a linear region at a time, the detection range is wider, the imaging sensitivity is higher, and the method is a hot research direction in recent years.
The reconstruction process from the detected magnetic nanoparticle signal to the particle concentration spatial distribution image is a key link of magnetic particle imaging, and the reconstruction methods commonly adopted in the technical field at present comprise: the X-space method and the system matrix method. Research shows that compared with an X-space method, the system matrix method can measure and model the imaging system more accurately and has higher reconstruction quality.
The turkish research group proposed and manufactured an open magnetic field free line magnetic particle imaging device in 2020 that employs a system matrix method for reconstruction. In correcting the system matrix, an imaging field size of 34 mm long by 18 mm wide was set and the particle response spectrum at each pixel point was measured using a 2 mm by 2 mm sample. The team rotates 60 angles in total by adopting a rotating magnetic field free line mode and taking 3 degrees as a stepping angle, a system matrix with the size of 17-by-9 is measured once at each rotating angle, and finally the system matrices at all the angles are combined into a system matrix for constructing a linear equation set in an imaging model. The method is a method for magnetic field free line magnetic particle imaging based on a system matrix method, which is generally adopted in the current technical field. The measurement mode belongs to intensive sampling and is relatively accurate, but the operation of the system matrix correction process is complicated and time-consuming, the stored data volume is large, the calculation complexity during reconstruction is high, and the measurement mode is difficult to be used for real-time imaging.
Aiming at the problem of high complexity of system matrix correction, a sparse sampling system matrix correction method based on technologies such as compressed sensing, data interpolation and deep learning super-resolution network is further provided, data post-processing is carried out through sparse sampling points in a two-dimensional or three-dimensional space according to a magnetic particle imaging principle, a densely sampled system matrix is recovered, and image reconstruction is carried out. However, the post-processing models of these methods are relatively complex, and especially deep learning-based methods require a large amount of data and are heavily dependent on hardware systems for data measurement, which is currently difficult to popularize.
Disclosure of Invention
In order to solve the above problems in the prior art, that is, to solve the problems of low correction efficiency of the existing magnetic particle imaging method based on the dense sampling system matrix, relatively complex post-processing model and low imaging efficiency of the existing magnetic particle imaging method based on the sparse sampling system matrix, the invention provides a magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling, which is applied to magnetic particle imaging equipment based on magnetic field free lines, and the method comprises the following steps:
step S100, setting an initial angle, a rotation angle sequence and an imaging view field size of the magnetic particle imaging equipment based on the magnetic field free lines, and measuring a one-dimensional system matrix A in the gradient direction of the magnetic field free lines under the initial angle;
step S200, placing a target object to be imaged in the imaging view of the magnetic particle imaging equipment based on the magnetic field free line, rotating the magnetic field free line or the target object to be imaged according to the rotation angle sequence set in the step S100, and establishing an observation vector sequence;
step S300, combining the system matrix A and the observation vector sequence, constructing a linear equation set sequence and solving to obtain a one-dimensional projection reconstruction result sequence;
and S400, reconstructing a magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence.
In some preferred embodiments, the initial angle is an angle of the magnetic particle imaging apparatus based on a free line of a magnetic field along a radial direction of the free line of the magnetic field.
In some preferred embodiments, the sequence of rotation angles is set by:
rotating the N angles in an equidistant or unequal interval mode by 180 degrees in the initial angle of 0 degrees, and ensuring that the motion range of the free line of the magnetic field can cover all imaging visual fields; where N represents a set number.
In some preferred embodiments, the dimension of the observation vector in the observation vector sequence is equal to the number of rows of the system matrix a.
In some preferred embodiments, the method of reconstructing the magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence is as follows:
and converting the one-dimensional projection reconstruction result sequence into Radon space to establish a sinogram, and reconstructing a magnetic particle image of the target object by using a back projection method.
In a second aspect of the present invention, a magnetic field free line magnetic particle imaging system based on one-dimensional system matrix sparse sampling is provided, the system comprising: the system comprises an initialization setting module, an observation vector sequence construction module, an equation set construction and solving module and an image reconstruction module;
the initialization setting module is configured to set an initial angle, a rotation angle sequence and an imaging field of view size of the magnetic particle imaging device based on the magnetic field free lines, and measure a one-dimensional system matrix A in the gradient direction of the magnetic field free lines at the initial angle;
the observation vector sequence building module is configured to place a target object to be imaged in the imaging view of the magnetic particle imaging equipment based on the magnetic field free line, and rotate the magnetic field free line or the target object to be imaged according to the rotation angle sequence set by the initialization setting module to build an observation vector sequence;
the system matrix A is configured to be a linear system of equations, the system matrix A is configured to be an observation vector sequence, and the system matrix A is configured to be an observation vector sequence;
the image reconstruction module is configured to reconstruct a magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence.
In a third aspect of the present invention, an electronic device is provided, including: at least one processor; and a memory communicatively coupled to at least one of the processors; wherein the memory stores instructions executable by the processor for execution by the processor to implement the method for magnetic field free line magnetic particle imaging based on one-dimensional system matrix sparse sampling described above.
In a fourth aspect of the present invention, a computer-readable storage medium is provided, which stores computer instructions for being executed by the computer to implement the above-mentioned method for magnetic field free line magnetic particle imaging based on one-dimensional system matrix sparse sampling.
The invention has the beneficial effects that:
the invention greatly reduces the correction difficulty, does not need a post-processing model and improves the imaging efficiency.
Aiming at the projection imaging characteristics, the method adopts one-dimensional sparse sampling and carries out reconstruction by a projection imaging method, thereby avoiding a complex intensive sampling process or a data post-processing process; a large-volume test sample can be used in one-dimensional sampling, and the sampling signal-to-noise ratio is higher; the reconstruction is carried out based on the one-dimensional system matrix, the calculation speed is high, the real-time imaging is facilitated, and the method is simple in flow and beneficial to popularization.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings.
FIG. 1 is a schematic flow chart of a magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a framework of a magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling according to an embodiment of the present invention;
FIG. 3 is a schematic diagram comparing a prior art sampling process with the present invention for one embodiment of the present invention;
FIG. 4 is an exemplary diagram of a one-dimensional system matrix measuring the gradient direction of the free lines of the magnetic field at an initial angle according to one embodiment of the present invention;
FIG. 5 is an exemplary illustration of a rotating magnetic field free line or rotating target object to be imaged in accordance with one embodiment of the invention;
FIG. 6 is a sinogram of an L-shaped target object to be imaged according to one embodiment of the present invention;
FIG. 7 is a schematic representation of the reconstruction of an L-shaped target object to be imaged using direct back-projection in accordance with one embodiment of the present invention;
FIG. 8 is a diagram illustrating the reconstruction of an L-shaped target object to be imaged using filtered backprojection in accordance with one embodiment of the present invention;
fig. 9 is a schematic structural diagram of a computer system suitable for implementing an electronic device according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
A magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling according to a first embodiment of the present invention is applied to a magnetic particle imaging apparatus based on a magnetic field free line, as shown in fig. 1, and the method includes:
step S100, setting an initial angle, a rotation angle sequence and an imaging view field size of the magnetic particle imaging equipment based on the magnetic field free lines, and measuring a one-dimensional system matrix A in the gradient direction of the magnetic field free lines under the initial angle;
step S200, placing a target object to be imaged in the imaging view of the magnetic particle imaging equipment based on the magnetic field free line, rotating the magnetic field free line or the target object to be imaged according to the rotation angle sequence set in the step S100, and establishing an observation vector sequence;
step S300, combining the system matrix A and the observation vector sequence, constructing a linear equation set sequence and solving to obtain a one-dimensional projection reconstruction result sequence;
and S400, reconstructing a magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence.
In order to more clearly describe the magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling, the following describes in detail the steps in an embodiment of the method in conjunction with the accompanying drawings.
Step S100, setting an initial angle, a rotation angle sequence and an imaging view field size of the magnetic particle imaging equipment based on the magnetic field free lines, and measuring a one-dimensional system matrix A in the gradient direction of the magnetic field free lines under the initial angle;
in this embodiment, an initial angle, a sequence of rotation angles, and an imaging field size along the magnetic particle imaging apparatus based on the magnetic field free line are set, and a one-dimensional system matrix a in the gradient direction of the magnetic field free line at the initial angle is measured and stored.
In the present invention, it is preferable to set the angle of the magnetic particle imaging apparatus based on the magnetic field free line in the radial direction of the magnetic field free line as an initial angle. The rotation angle sequence rotates N angles in an equidistant or unequal interval mode by 180 degrees in the initial angle of 0 degrees, so that the movement range of the free line of the magnetic field can cover all imaging visual fields; where N represents the set number, it is preferably set to be 9 or more in this embodiment, and may be set according to actual conditions in other embodiments. The range of the one-dimensional system matrix A is required to be not less than the length of an imaging field of view; elongated, large-volume samples are used in measuring the system matrix. The mode of measuring the one-dimensional system matrix is not unique, the essence of "one-dimensional" is that information along each column of the magnetic field free line radial direction can be measured, wherein "column" is the dimension of "one-dimensional", is not the dimension of "row", is not two-dimensional ", is not limited to the shape and position of the test phantom, and conforms to the essence of" one-dimensional system matrix ", for example, six examples in 4 in the figure, the one-dimensional system matrix described in step S100 can be measured.
Step S200, placing a target object to be imaged in the imaging view of the magnetic particle imaging equipment based on the magnetic field free line, rotating the magnetic field free line or the target object to be imaged according to the rotation angle sequence set in the step S100, and establishing an observation vector sequence;
in the embodiment, the rotation process starts from 0 °, the free line of the magnetic field or the target object to be imaged (or referred to as the measured object) is rotated, and the observation vector sequence { b } is established 1 ,b 2 ,...,b N And d, wherein the dimension of an observation vector in the observation vector sequence is equal to the number of rows of the system matrix A.
Step S300, combining the system matrix A and the observation vector sequence, constructing a linear equation set sequence and solving to obtain a one-dimensional projection reconstruction result sequence;
in this embodiment, the mathematical description of the sequence of linear equations is:
when solving a linear equation set, the system matrix ill-condition is reduced by using a regularization method, in the invention, a truncated singular value decomposition algorithm is preferably used for solving the linear equation set sequence to obtain a one-dimensional projection reconstruction result sequence { x } 1 ,x 2 ,...,x N In other embodiments, the objective function may be established by a regularization method, and an iterative algorithm may be used to solve the objective function, or the linear equation set sequence may be solved by using an algebraic reconstruction technique such as SVD.
And S400, reconstructing a magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence.
In this embodiment, the one-dimensional projection reconstruction result sequence is converted into Radon space to establish a sinogram, and a back projection method is used to reconstruct a magnetic particle image of the target object.
In addition, to further verify the effectiveness of the method of the present invention, an imaging process of an "L" type skeleton (or simply called a phantom) is exemplified.
In the imaging process of the "L" type phantom, an open magnetic field free line magnetic particle imaging device is preferably adopted, which comprises four runway type gradient coils, two helmholtz type excitation coils and two helmholtz type receiving coils, and two-dimensional scanning imaging is performed by rotating a target object to be imaged. Specific references may be found in: top C, gungor A. Tomographic Field Free Line Imaging With open-side Scanner Configuration [ J ]. IEEE transactions on medical Imaging,2020, 39 (12): 4164-4173.
The middle plane of the upper and lower groups of gradient coils is set as an X-Y plane, the direction of a magnetic field on the X-Y plane is set as a Z-axis direction, and the geometric centers of the four gradient coils are set as coordinate origin points to establish a coordinate system. The selection field gradient is set to 1T/m, the excitation field uses a single frequency excitation, the frequency is 2500 hz, and the magnetic field strength is 30mT. Using a workstation to compile Libview control software to control two power amplifiers to supply power to a gradient coil and an exciting coil; rotating the measured object by using a rotating motor, wherein the step angle is set to be 3.6 degrees, the angle rotation sequence radially takes the free line of the magnetic field as 0 degree, and the equal angle is 3 degrees, and the clockwise step is N =60 degrees to 180 degrees; and (3) measuring a one-dimensional system matrix A of the gradient direction of the free line of the magnetic field by using a three-axis displacement table, wherein the sampling process is shown as (c) in figure 3.
The test phantom uses perimag particles, 3D prints an L-shaped framework, fills particle diluent as a target object to be imaged, and is placed on a rotary motor table to rotate, as shown in FIG. 5.
After the above setting is completed, the rotating motor is started according to a preset rotation angle sequence, and an observation vector sequence { b ] under each angle is measured 1 ,b 2 ,...,b N }. And after the measurement is finished, establishing a linear equation set sequence by using the system matrix A and the observation vector sequence.
Performing one-dimensional projection reconstruction on all linear equation sets by using a truncated singular value decomposition algorithm to obtain a result sequence { x 1 ,x 2 ,...,x N }. The truncated singular value decomposition algorithm achieves a certain regularization effect to suppress system noise interference by removing smaller singular values.
Will { x } 1 ,x 2 ,...,x N The sequence is converted to Radon space and a sinogram is built, as shown in figure 6, which is a sinogram of an "L" shaped phantom (i.e., the target object) used in the test.
After the sinogram is constructed, an image of an "L" type measured object (i.e., a target object) is reconstructed by using a direct back projection method, as shown in fig. 7, wherein (a) in fig. 7 is a standard reference of the "L" type measured object, and (b) in fig. 7 is a result of reconstruction by using the method proposed by the present patent.
The "Ram-Lak" filtered back projection method is used to reconstruct an "L" type measured object image, as shown in fig. 8, where (a) in fig. 8 is a standard reference of the "L" type measured object, and (b) in fig. 8 is a result reconstructed by using the method proposed by the present invention.
A magnetic field free line magnetic particle imaging system based on one-dimensional system matrix sparse sampling according to a second embodiment of the present invention, as shown in fig. 2, includes: the system comprises an initialization setting module 100, an observation vector sequence construction module 200, an equation set construction and solving module 300 and an image reconstruction module 400;
the initialization setting module 100 is configured to set an initial angle, a rotation angle sequence and an imaging field size of the magnetic particle imaging apparatus based on the magnetic field free lines, and measure a one-dimensional system matrix a in a gradient direction of the magnetic field free lines at the initial angle;
the observation vector sequence building module 200 is configured to place a target object to be imaged in the imaging field of view of the magnetic particle imaging device based on the magnetic field free line, and rotate the magnetic field free line or the target object to be imaged according to the rotation angle sequence set by the initialization setting module 100 to build an observation vector sequence;
the equation set constructing and solving module 300 is configured to combine the system matrix a and the observation vector sequence to construct a linear equation set sequence and solve the linear equation set sequence to obtain a one-dimensional projection reconstruction result sequence;
the image reconstruction module 400 is configured to reconstruct a magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence.
It can be clearly understood by those skilled in the art that, for convenience and simplicity of description, reference may be made to the corresponding process in the foregoing method embodiment for the specific working process and related description of the system described above, and details are not described herein again.
It should be noted that, the magnetic field free line magnetic particle imaging system based on one-dimensional system matrix sparse sampling provided in the foregoing embodiment is only illustrated by the division of the above functional modules, and in practical applications, the above functions may be allocated to different functional modules according to needs, that is, the modules or steps in the embodiment of the present invention are further decomposed or combined, for example, the modules in the foregoing embodiment may be combined into one module, or may be further split into multiple sub-modules, so as to complete all or part of the above described functions. Names of the modules and steps related in the embodiments of the present invention are only for distinguishing the modules or steps, and are not to be construed as unduly limiting the present invention.
An electronic device according to a third embodiment of the present invention includes at least one processor; and a memory communicatively coupled to at least one of the processors; wherein the memory stores instructions executable by the processor for execution by the processor to implement the method of claim for magnetic field free line magnetic particle imaging based on one-dimensional system matrix sparse sampling.
A computer readable storage medium of a fourth embodiment of the present invention stores computer instructions for being executed by the computer to implement the above-mentioned magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling.
It can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working processes and related descriptions of the electronic device and the computer-readable storage medium described above may refer to the corresponding processes in the foregoing method examples, and are not described herein again.
Reference is now made to FIG. 9, which is a block diagram illustrating a computer system suitable for use as a server in implementing embodiments of the present systems, methods, and apparatus. The server shown in fig. 9 is only an example, and should not bring any limitation to the functions and the use range of the embodiments of the present application.
As shown in fig. 9, the computer system includes a Central Processing Unit (CPU) 901 that can perform various appropriate actions and processes in accordance with a program stored in a Read Only Memory (ROM) 902 or a program loaded from a storage section 908 into a Random Access Memory (RAM) 903. In the RAM 903, various programs and data necessary for system operation are also stored. The CPU 901, ROM 902, and RAM 903 are connected to each other via a bus 904. An Input/Output (I/O) interface 905 is also connected to bus 904.
The following components are connected to the I/O interface 905: an input portion 906 including a keyboard, a mouse, and the like; an output portion 907 including a Cathode Ray Tube (CRT), a Liquid Crystal Display (LCD), and a speaker; a storage portion 908 including a hard disk and the like; and a communication section 909 including a Network interface card such as a LAN (Local Area Network) card, a modem, and the like. The communication section 909 performs communication processing via a network such as the internet. The drive 910 is also connected to the I/O interface 905 as necessary. A removable medium 911 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, or the like is mounted on the drive 910 as necessary so that a computer program read out therefrom is mounted into the storage section 908 as necessary.
In particular, the processes described above with reference to the flow diagrams may be implemented as computer software programs, according to embodiments of the present disclosure. For example, embodiments of the present disclosure include a computer program product comprising a computer program embodied on a computer readable medium, the computer program comprising program code for performing the method illustrated in the flow chart. In such an embodiment, the computer program may be downloaded and installed from a network via the communication section 909 and/or installed from the removable medium 911. The above-described functions defined in the method of the present application are executed when the computer program is executed by a Central Processing Unit (CPU) 901. It should be noted that the computer readable medium mentioned above in the present application may be a computer readable signal medium or a computer readable storage medium or any combination of the two. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples of the computer readable storage medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the present application, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. In this application, however, a computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to: wireless, wire, fiber optic cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations for aspects of the present application may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
The terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing or implying a particular order or sequence.
The terms "comprises," "comprising," or any other similar term are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Equivalent changes or substitutions of related technical features can be made by those skilled in the art without departing from the principle of the invention, and the technical scheme after the changes or substitutions can fall into the protection scope of the invention.
Claims (8)
1. A magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling is applied to magnetic particle imaging equipment based on magnetic field free lines, and is characterized by comprising the following steps:
step S100, setting an initial angle, a rotation angle sequence and an imaging view field size of the magnetic particle imaging equipment based on the magnetic field free line, and measuring a one-dimensional system matrix A in the gradient direction of the magnetic field free line under the initial angle;
step S200, placing a target object to be imaged in the imaging view of the magnetic particle imaging equipment based on the magnetic field free line, rotating the magnetic field free line or the target object to be imaged according to the rotation angle sequence set in the step S100, and establishing an observation vector sequence;
step S300, combining the system matrix A and the observation vector sequence, constructing a linear equation set sequence and solving to obtain a one-dimensional projection reconstruction result sequence;
and S400, reconstructing a magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence.
2. The method according to claim 1, wherein the initial angle is an angle of the magnetic field free line based magnetic particle imaging device along a radial direction of the magnetic field free line.
3. The magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling as claimed in claim 2, wherein the rotation angle sequence is set by:
rotating the N angles in an equidistant or unequal interval mode by 180 degrees in the initial angle of 0 degrees, and ensuring that the motion range of the free line of the magnetic field can cover all imaging visual fields; where N represents the set number.
4. The method according to claim 3, wherein the dimension of the observation vector in the observation vector sequence is equal to the number of rows of the system matrix A.
5. The magnetic field free line magnetic particle imaging method based on one-dimensional system matrix sparse sampling according to claim 1, wherein the magnetic particle image of the target object is reconstructed based on the one-dimensional projection reconstruction result sequence, and the method comprises:
and converting the one-dimensional projection reconstruction result sequence into Radon space to establish a sinogram, and reconstructing a magnetic particle image of the target object by using a back projection method.
6. A magnetic field free line magnetic particle imaging system based on one-dimensional system matrix sparse sampling is characterized by comprising: the system comprises an initialization setting module, an observation vector sequence construction module, an equation set construction and solving module and an image reconstruction module;
the initialization setting module is configured to set an initial angle, a rotation angle sequence and an imaging field of view size of the magnetic particle imaging device based on the magnetic field free lines, and measure a one-dimensional system matrix A in the gradient direction of the magnetic field free lines at the initial angle;
the observation vector sequence building module is configured to place a target object to be imaged in the imaging view of the magnetic particle imaging equipment based on the magnetic field free line, and rotate the magnetic field free line or the target object to be imaged according to the rotation angle sequence set by the initialization setting module to build an observation vector sequence;
the equation set constructing and solving module is configured to combine the system matrix A and the observation vector sequence to construct a linear equation set sequence and solve the linear equation set sequence to obtain a one-dimensional projection reconstruction result sequence;
the image reconstruction module is configured to reconstruct a magnetic particle image of the target object based on the one-dimensional projection reconstruction result sequence.
7. An electronic device, comprising:
at least one processor; and a memory communicatively coupled to at least one of the processors;
wherein the memory stores instructions executable by the processor for execution by the processor to implement the method of magnetic field free line magnetic particle imaging based on one-dimensional system matrix sparse sampling of any of claims 1-5.
8. A computer-readable storage medium storing computer instructions for execution by the computer to implement the method for magnetic field free line magnetic particle imaging based on one-dimensional system matrix sparse sampling according to any one of claims 1 to 5.
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160242721A1 (en) * | 2015-02-20 | 2016-08-25 | Kabushiki Kaisha Toshiba | Apparatus and method for fast iterative reconstruction in computed tomography |
| CN111183364A (en) * | 2017-08-16 | 2020-05-19 | 加利福尼亚大学董事会 | Pulsed magnetic particle imaging system and method |
| WO2021016473A1 (en) * | 2019-07-23 | 2021-01-28 | The Regents Of The University Of California | Strongly-interacting magnetic particle imaging |
| CN114209300A (en) * | 2021-12-14 | 2022-03-22 | 西安电子科技大学 | Pulse magnetic particle imaging method and system |
| CN114587328A (en) * | 2022-01-13 | 2022-06-07 | 西安电子科技大学 | Magnetic particle imaging method based on gradient field |
| CN115153490A (en) * | 2022-07-20 | 2022-10-11 | 北京航空航天大学 | Magnetic nanoparticle detection imaging device and method based on non-rotating field free line |
| US20230027988A1 (en) * | 2021-07-20 | 2023-01-26 | Institute Of Automation, Chinese Academy Of Sciences | Signal amplitude feature-based method for fast reconstructing a magnetic particle imaging and device |
-
2023
- 2023-02-03 CN CN202310054746.XA patent/CN115797493B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20160242721A1 (en) * | 2015-02-20 | 2016-08-25 | Kabushiki Kaisha Toshiba | Apparatus and method for fast iterative reconstruction in computed tomography |
| CN111183364A (en) * | 2017-08-16 | 2020-05-19 | 加利福尼亚大学董事会 | Pulsed magnetic particle imaging system and method |
| WO2021016473A1 (en) * | 2019-07-23 | 2021-01-28 | The Regents Of The University Of California | Strongly-interacting magnetic particle imaging |
| US20230027988A1 (en) * | 2021-07-20 | 2023-01-26 | Institute Of Automation, Chinese Academy Of Sciences | Signal amplitude feature-based method for fast reconstructing a magnetic particle imaging and device |
| CN114209300A (en) * | 2021-12-14 | 2022-03-22 | 西安电子科技大学 | Pulse magnetic particle imaging method and system |
| CN114587328A (en) * | 2022-01-13 | 2022-06-07 | 西安电子科技大学 | Magnetic particle imaging method based on gradient field |
| CN115153490A (en) * | 2022-07-20 | 2022-10-11 | 北京航空航天大学 | Magnetic nanoparticle detection imaging device and method based on non-rotating field free line |
Non-Patent Citations (1)
| Title |
|---|
| DAXIANG YAN等: "High-Resolution Reconstruction of FMT Based on Elastic Net Optimized by Relaxed ADMM" * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117100243A (en) * | 2023-10-23 | 2023-11-24 | 中国科学院自动化研究所 | Magnetic particle imaging system, method and equipment based on system matrix pixel compression |
| CN117100243B (en) * | 2023-10-23 | 2024-02-20 | 中国科学院自动化研究所 | Magnetic particle imaging system, method and equipment based on system matrix pixel compression |
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