128 results about "Magnetic particle imaging" patented technology

The invention belongs to the technical field of magnetic particle imaging, relates to a magnetic particle imaging reconstruction method based on a calibration magnetic field generation system matrix, and aims to solve the problems that a traditional magnetic particle imaging reconstruction method is poor in applicability in asymmetric bilateral structure magnetic particle imaging equipment (A-MPI) and cannot perform imaging in any region. The method comprises the following steps: performing grid division on an imaging area, calibrating magnetic field intensity, and obtaining magnetic field gradient distribution of each point; obtaining a theoretical system matrix according to a mathematical calculation mode; randomly moving the positions of the non-magnetic field points for scanning to obtain actually measured magnetic field gradient distribution and a system matrix, and constructing a data set; expanding the data set based on the simulation system; constructing a deep learning model, and inputting the extended data set and the measured data into the training deep learning model; and inputting a theoretical system matrix at any position, and obtaining an accurate system matrix by using the trained model. According to the invention, the system matrix at any position can be obtained under the A-MPI equipment, so that imaging at any position is realized.

The invention provides a magnetic particle imaging resolution improving method and system based on frequency domain information filtering, and relates to the technical field of magnetic particle imaging. Comprising the following steps: inputting original magnetic particle imaging data into a Transform model, and selectively filtering frequency domain information in the magnetic particle imaging data through a fusion frequency domain discrimination feedforward network module in an encoder to obtain the output of the encoder; inputting the output of the encoder into a bottleneck layer, aggregating global and local information through a multi-scale attention mechanism module, and then selectively filtering frequency domain information in the magnetic particle imaging data again to obtain the output of the bottleneck layer; inputting the output of the bottleneck layer into a decoder with the same structure as the bottleneck layer to obtain deep features; inputting the deep features into a convolutional layer to obtain a residual image; and calculating the sum of the original magnetic particle imaging data and the residual image to obtain a reconstructed image. According to the invention, the overall imaging resolution of the MPI image under the low-gradient field acquisition condition is improved.

The invention belongs to the field of magnetic particle imaging, particularly relates to a magnetic particle high-resolution reconstruction method based on fast feature fusion, and aims to solve the problems that an existing magnetic particle reconstruction method is slow in system matrix calibration, low in reconstructed magnetic particle image resolution, limited in signal-to-noise ratio and the like. The method comprises the following steps: collecting a system matrix generated by using a standard particle sample as a low-resolution system matrix; acquiring a voltage signal of the to-be-imaged phantom; inputting the low-resolution system matrix into the trained fast feature fusion Transform model to obtain a high-resolution system matrix; and based on the voltage signal, reconstructing the high-resolution system matrix to obtain a high-resolution MPI image. According to the method, the resolution of the MPI image is improved by carrying out rapid super-division on the system matrix, tedious and time-consuming calibration in system matrix reconstruction is avoided, in addition, resolution and signal-to-noise ratio improvement can be carried out on any system matrix, and a scanning mode related to the system matrix is not needed.

The invention belongs to the technical field of magnetic particle imaging, particularly relates to a magnetic particle imaging system and method based on a flexible receiving coil array, and aims to solve the problems that an existing rigid receiving coil is poor in biological surface adaptability and low in signal-to-noise ratio for micro geometric texture imaging. According to the structure, a receiving coil array adheres to the surface of an object to be measured, the receiving coil array and a compensation coil array are distributed on the two sides of a flexible substrate, the receiving coil array is used for receiving magnetic nanoparticle signals, and the partitioned small compensation coil array is used for conducting feed-through interference and electromagnetic interference compensation on a receiving coil; the reconstruction method comprises the following steps: sequentially carrying out Fourier transform on the collected receiving signals, extracting in-phase third harmonics and superposing to obtain processed signals, interpolating to construct a sinogram for Cartesian coordinate distribution, and reconstructing the three-dimensional particle concentration distribution of a measured object by a filtering back projection method. A flexible receiving coil array strategy is adopted, an adaptive reconstruction method is provided, and the imaging signal-to-noise ratio is improved.

The invention discloses a Brazilian splitting experiment device and method based on multiple heating modes, and belongs to the technical field of splitting experiments. Comprising a base, a Brazilian splitting clamp, a kettle body, a heating system, a heat transfer fluid injection hole, an axial pressure head, a temperature and pressure monitoring and heat transfer fluid outlet, a magnetic particle imaging system and a high-temperature early warning system, the temperature and pressure monitoring and heat-carrying fluid outlet is used for being connected with an external real-time observation system to conduct temperature and pressure monitoring and serves as an outlet of heat-carrying fluid at the same time. The magnetic particle imaging system is used for observing the distribution state of nano magnetic induction particles in the kettle body; the real-time high-temperature Brazilian splitting experiment can be carried out in multiple heating modes such as convection heating, conduction heating and supercritical fluid heating, the generation and expansion process of cracks in a sample can be monitored in real time, and the device is suitable for testing the strength and crack expansion of rocks under the thermal stress condition possibly encountered in actual engineering.

The invention belongs to the technical field of magnetic particle imaging, particularly relates to a stacked high-uniformity magnetic field free line magnetic particle imaging system and method, and aims to solve the problems that magnetic field free lines in an existing FFL-MPI are not uniform, imaging resolution is not uniform, and circumferential artifacts exist. The system comprises a laminated gradient coil unit composed of N groups of symmetrical coil pairs, each group comprising n layers of coils with increasing diameters, and a saddle-shaped driving scanning coil and a detection coil; through a reverse current mode of two adjacent layers of coils, the magnetic field amplitude is opposite to the current direction, the non-uniformity of the magnetic field is compensated, and a high-uniformity FFL gradient field is generated; the control system accurately collects and processes signals, the signals are fed back to the imaging unit after analog-to-digital conversion, amplification and filtering, and imaging is reconstructed through an imaging algorithm. According to the invention, the problems of non-uniform resolution and circumferential artifacts caused by non-uniform magnetic field are solved, and the imaging quality of FFL-MPI equipment is remarkably improved.

The invention belongs to the technical field of magnetic particle imaging, and relates to a magnetic particle imaging method based on mixed-frequency magnetic field excitation, which comprises the following steps: acquiring a dotted magnetic nanoparticle sample and a to-be-imaged object, respectively applying a mixed-frequency excitation magnetic field in an imaging mode to the dotted magnetic nanoparticle sample and the to-be-imaged object, acquiring a mixed frequency magnetic field excitation-based system matrix and a mixed frequency domain magnetization response frequency spectrum signal; and inputting the system matrix and the mixed frequency domain magnetization response frequency spectrum signal into a concentration spatial distribution inversion model to perform concentration spatial distribution inversion of the magnetic nanoparticles, obtaining the concentration spatial distribution of the magnetic nanoparticles in the object to be imaged, and performing magnetic particle concentration distribution imaging. According to the invention, real-time high-resolution magnetic particle imaging can be realized.

The invention discloses a magnetic particle imaging signal processing link and method based on adjustable external compensation, and the link is characterized in that a signal generator is respectively connected with the input ends of a first power amplifier and a second power amplifier through a first output end and a second output end, the output end of the first power amplifier is connected with the input end of a first capacitor, and the output end of the second power amplifier is connected with the input end of a second capacitor; the output end of the first capacitor is connected with the input end of the receiving excitation module, the output end of the second power amplifier is connected with the input end of the second capacitor, the output end of the second capacitor is connected with the input end of the compensation excitation module, and the output ends of the receiving excitation module and the compensation excitation module are connected with the input end of the low-noise amplifier. The output end of the low-noise amplifier is connected with the input end of the acquisition card, the output end of the acquisition card is connected with the input end of the central processing unit, and the output end of the central processing unit is connected with the input end of the signal generator. According to the invention, the sensitivity and the imaging quality of the MPI equipment are obviously improved.

The invention discloses a rock permeability testing system in a high-temperature and high-pressure environment and a using method thereof, and belongs to the technical field of geothermal development or coal in-situ gasification mining. The test system is composed of a stress loading system, a test kettle assembly and a magnetic particle imaging system. When in use, the stress loading system and the test kettle assembly provide conditions such as high temperature, high pressure, seepage fluid and the like for a test piece; and detecting the spatial distribution state of the nano magnetic induction particles added in the seepage fluid through a magnetic particle imaging system to observe the pore and crack distribution characteristics in the test piece or detecting the nano magnetic induction particles added in the pollutant solution to observe the pollutant migration condition. The test system is scientific in design, simple in structure and easy to operate and maintain, can monitor pore fracture distribution and pollutant migration conditions in the test piece in real time under high-temperature and high-pressure conditions, provides accurate dynamic observation data, and provides important technical support for reservoir assessment and optimization in a complex environment.

The invention belongs to the field of image reconstruction of magnetic particle imaging and multi-modal generative artificial intelligence models, particularly relates to a magnetic particle image reconstruction method and system based on a multi-modal diffusion model, and aims to solve the problem that there is no method capable of combining a generative model and a multi-modal imaging technology to realize accurate quantitative reconstruction of MPI. The method comprises the following steps: carrying out integral modeling and discretization operation on a first excitation signal to obtain discrete signals, fitting and superposing the discrete signals to obtain a first response signal, calculating a loss function, and training a model based on the loss function; processing the second time sequence signal by using the trained particle response model to obtain a second response signal; calculating based on the second response signal and the system matrix, gradually adding noise, and constraining to obtain a noise constrained image; and gradually denoising and recovering the noise constraint image in the last step to obtain a final reconstructed image. According to the invention, rapid and high-quality MPI image reconstruction becomes possible.

The invention relates to the technical field of biological medicine, in particular to a diagnosis and treatment integrated brain-targeted magnetic particle imaging tracer and a preparation method and application thereof. The preparation method comprises the following steps: loading tetrahydrocurcumin into glucan by adopting a nano-particle self-assembly technology to form glucan nano-particles loaded with tetrahydrocurcumin, synthesizing Fe3O4 nano-particles by adopting a chemical precipitation method, and embedding the Fe3O4 nano-particles on the glucan nano-particles to obtain the diagnosis and treatment integrated brain-targeted magnetic particle imaging tracer agent. The nano-particles are marked as THC (at) Dex-Fe3O4 nano-particles. The THC-Dex-Fe3O4 nanoparticles play a role in treating the Alzheimer's disease during brain imaging diagnosis, and the technical problems that magnetic particle imaging cannot be applied to diagnosis of the Alzheimer's disease and the Alzheimer's disease is difficult to treat are solved.

The invention belongs to the field of biomedical imaging, particularly relates to a multicolor magnetic particle imaging method and system based on magnetic field free line projection decoding, and aims to solve the problems of low imaging efficiency and quality caused by the absence of a relaxation-based multicolor imaging method by using a magnetic field free line in the prior art. The method comprises the following steps: respectively placing N kinds of magnetic nanoparticles in an imaging view center for scanning, and obtaining a time-frequency spectrum center spectral line by adopting time-frequency analysis; scanning an imaging object, acquiring a voltage response signal and performing time-frequency analysis to obtain a time-frequency spectrum; a linear equation set is constructed and solved, and all unknown quantities are obtained; discretely rotating the free line of the magnetic field by P angles, and obtaining the content distribution of N magnetic nanoparticles at each angle; and constructing a sinogram of the N magnetic nanoparticles, performing back projection reconstruction to obtain multicolor images, and superposing the multicolor images to obtain a reconstructed image. According to the invention, relaxation-based multicolor imaging is realized by using the free line of the magnetic field, and the imaging efficiency and quality are improved.

The invention provides an acid response magnetic particle imaging probe and a preparation method and application thereof.The preparation method comprises the steps that S1, a magnetic core, an iron precursor and long-chain alcohol diol are dispersed in a mixed solution of oleic acid, oleylamine, cyclohexane and octadecene, a reaction is conducted for 30-90 minutes under the inert atmosphere condition of 200-300 DEG C, a first non-polar solvent is used for washing, precipitation and centrifugation, and a first non-polar solvent is obtained; the oil-phase double-magnetic core-shell nanoparticles are obtained; s2, preparing water-phase aminated double-magnetic core-shell nanoparticles from the oil-phase double-magnetic core-shell nanoparticles and polymers with amino groups by adopting a film dispersion method or a nano coprecipitation method; s3, the aqueous-phase aminated double-magnetic core-shell nanoparticles and a compound with multiple aldehyde groups are subjected to an aldehyde-amine condensation reaction, a stable imine bond mediated nanometer assembly structure is formed, and the acid response magnetic particle imaging probe is obtained. The probe provided by the invention can respond to the change of the acid microenvironment, has high sensitivity, low background noise and a relatively strong imaging effect, and is suitable for dynamically monitoring diseases related to the acid microenvironment in real time.

The invention relates to the technical field of medical imaging, in particular to a narrowband-based multi-harmonic magnetic particle imaging method, which comprises the following steps of: determining a magnetic particle imaging area, and acquiring a first area and a second area according to the magnetic particle imaging area; placing a magnetic nanoparticle sample in the first area, externally applying a magnetic field, and extracting harmonic signals to construct a system matrix; placing a measured object in the second area and externally applying a magnetic field, and extracting harmonic signals to construct a harmonic signal matrix of the measured object; and according to the system matrix and the harmonic signal matrix of the measured object, constructing an equation to be solved and carrying out inversion solution to obtain an image of magnetic nanoparticle concentration distribution. Compared with a broadband imaging technology, the narrow-band imaging technology is adopted, the requirement for the bandwidth of a magnetic particle imaging system is lowered, and the problem of insufficient bandwidth under high-frequency excitation is solved.

The invention belongs to the field of magnetic particle imaging, particularly relates to a three-dimensional magnetic particle imaging enhancement method and system based on distillation structure contrast learning, and aims to solve the problems of anisotropic resolution and background noise interference caused by sparse scanning tracks in three-dimensional magnetic particle imaging. The method comprises the following steps: constructing a data set; building a two-dimensional isotropic teacher network model and a three-dimensional resolution improvement student network model; training a two-dimensional isotropic teacher network model and storing model parameters; the three-dimensional resolution improvement student network model obtains model parameters and then carries out training, an obtained three-dimensional training result is converted into two-dimensional training input data, and the two-dimensional training input data is input into the two-dimensional isotropic teacher network model to generate a supervision benchmark which is used for updating and optimizing the three-dimensional resolution improvement student network model; and after training, carrying out resolution improvement processing on the input three-dimensional magnetic particle imaging image. According to the method, the isotropic resolution of the three-dimensional magnetic particle image is improved, and background noise is effectively suppressed.

The invention belongs to the technical field of magnetic particle imaging, relates to a magnetic particle imaging reconstruction method based on multi-angle Cartesian scanning adaptive optimization, and aims to solve the problems of easy information redundancy, low resolution and insufficient response signal representation under the condition of low gradient in free point scanning in the existing imaging technology. The method comprises the following steps: setting magnetic field generation related parameters and a measurement mode of a rotating Cartesian angle scanning track of a magnetic field free point; constructing a system function harmonic diagram under each rotation angle; constructing a system matrix under each rotation angle, analyzing the system matrix under each angle and the weight and contribution of each frequency component in the system matrix, and determining an optimal system matrix; constructing an observation vector sequence; and reconstructing a magnetic particle image. According to the method, image reconstruction is carried out through the Cartesian scanning track of the free point of the rotating magnetic field and the weighted multi-angle system matrix, the system matrix and particle response representation under the low gradient are enriched, and the imaging resolution is improved.

The present application relates to the field of magnetic particle imaging, and particularly relates to a kind of fast calibration method and system of MPI system matrix based on multi-stage wavelet transform and double branch attention network, to solve the problem of time-consuming, complex of existing calibration-based system matrix acquisition method.The method of the present application comprises: obtaining a low-resolution system matrix according to a pre-set undersampling grid;The system matrix is encoded by row RGB to obtain an RGB image;The above-mentioned RGB image is input into the trained MWaveDAN network model to obtain a high-resolution RGB image;The high-resolution RGB image is decoded into complex form to obtain a complex-based system matrix.The present application effectively accelerates the high-resolution acquisition of system matrix in MPI, and provides important support for the future development of MPI technology.

A processor calculates a system function by a first deconvolution operation based on a set of a first detection signal obtained while a calibration sample is disposed in an examination region and a numerical model of a spatial distribution of magnetic particles included in the calibration sample. The processor obtains a spatial distribution of magnetic particles included in an examination sample by a second deconvolution operation based on a set of a second detection signal obtained while the examination sample is disposed in the examination region and the system function.

The invention relates to the technical field of magnetic particle imaging, in particular to a core-shell nanoprobe and a preparation method and application thereof.The core-shell nanoprobe comprises a magnetic core and a nanoshell which is located outside the magnetic core and has a magnetic shielding response function, and the structure of the nanoshell collapses under the tumor microenvironment condition; the saturation magnetization of the magnetic core is greater than or equal to 50 emu / g, and the coercive force is less than or equal to 5 Oe; the saturation magnetization of the nano shell is less than 50 emu / g, and the coercive force is more than 5 Oe. According to the core-shell nanoprobe, through a unique magnetic core-shell structure design and tumor microenvironment response characteristics, a magnetic shielding layer is formed by using a low-signal nano shell with a response magnetic shielding function, and background signal interference is inhibited. In a tumor microenvironment, the shell structure of the core-shell nanoprobe collapses, the magnetic core is exposed, and a high magnetic signal is released and generated, so that the imaging signal-to-noise ratio is remarkably improved. According to the invention, the bottleneck that the traditional MPI probe is lighted in the whole course can be broken through, the tumor specificity is lighted and positioned, and the problems that the external background of the tumor is high, the contrast ratio is poor, and tiny focuses are difficult to detect are solved.

The present invention belongs to the technical field of medical imaging detection, and particularly relates to a method for rapid calibration of a matrix of a magnetic particle imaging system, including: performing spatial discretization on an imaging region and setting magnetic particle imaging magnetic field configuration parameters; obtaining magnetic particle magnetization response spectrum information at different spatial positions of field-free points; obtaining magnetic particle magnetization response spectrum information at different magnetic particle spatial positions based on the principle of equivalent substitution; calculating and assembling to obtain a matrix of the magnetic particle imaging system. According to the symmetry of the magnetic particle imaging gradient magnetic field, the present invention uses the movement of the spatial position of the field-free point to replace the mechanical movement of the magnetic particle spatial position, realizes the rapid calibration of the matrix of the magnetic particle imaging system, and significantly shortens the calibration time.

The present invention belongs to the field of magnetic particle imaging, and specifically relates to a zero-inertia magnetic focusing ring magnetic particle imaging system and method without magnetic field lines, aiming to solve the problems of low magnetic field gradient, high complexity of magnetic field control, and limited imaging space. The present invention includes: the current of the gradient magnetic field coil group is generated by the magnetic field control and imaging module, output through the signal acquisition and output module, and amplified by the gradient power amplifier module. The current of the axial excitation magnetic field coil is generated by the magnetic field control and imaging module, output through the signal acquisition and output module, and amplified by the excitation power amplifier module. The signals received by the multi-axis detection coil are filtered and amplified by the signal processing unit, and then input to the imaging module by the magnetic field control and imaging module for algorithm reconstruction. The present invention not only significantly improves the magnetic field gradient and control accuracy, but also realizes the imaging space of the axial cross-section.

The invention discloses a magnetic particle imaging method based on multi-harmonic energy-full width at half maximum combined weighting, which comprises the following steps: acquiring point spread functions of a plurality of harmonic waves with different frequencies of magnetic nanoparticles, and constructing a corresponding system matrix; measuring a reference sample which does not contain the magnetic nanoparticles, and obtaining a plurality of noise matrixes corresponding to harmonic waves with different frequencies; measuring the sample to be measured, and obtaining magnetization response voltage vectors of a plurality of harmonic waves with different frequencies; respectively calculating an energy two-norm of a system matrix, an energy two-norm of a noise matrix and a full width at half maximum of a point spread function of the system matrix and the noise matrix; splicing the magnetization response voltage signals of each harmonic system matrix to form a total system matrix and a total measurement signal vector; calculating a weight factor of each harmonic wave and forming a weight matrix; and constructing a solution equation of the particle concentration distribution of the sample to be detected, and carrying out iterative solution on the solution equation to obtain a particle concentration distribution image of the sample to be detected. According to the invention, efficient utilization of multi-harmonic information is realized.

A magnetic particle imaging device is provided with: a detection coil (3) for detecting a magnetic change in magnetic particles (1); a compensation coil (4) having a central axis (CA) common to the detection coil (3) and connected to the detection coil (3) with opposite polarity; a first winding tube (21) that holds the detection coil (3); and a second winding tube (22) that holds the compensation coil (4). The distance in the direction of the central axis (CA) of the detection coil (3) and the compensation coil (4) can be changed by increasing or decreasing the contact portion of the first winding tube (21) and the second winding tube (22).

A magnet (100, 300, 400) for a magnetic particle imaging device is provided with a pair of first DC coils (10), a pair of second DC coils (20), and a pair of AC coils (30). The pair of first DC coils are disposed facing each other in a first direction (DR1). The pair of second DC coils are disposed facing each other in a second direction (DR2) perpendicular to the first direction or in a third direction (DR3) perpendicular to the first direction and the second direction. The pair of AC coils is disposed facing each other in a first direction or a second direction. Each of the pair of second DC coils has a pair of first linear portions (22). Each of the pair of first linear portions extends in the same direction as the direction in which the pair of AC coils are disposed facing each other.

The present invention belongs to the field of magnetic particle imaging, specifically to a generative reconstruction method for magnetic particle imaging based on physical priors. This method aims to address the issues of long matrix calibration time for magnetic particle imaging systems, reliance on model assumptions in mathematical modeling methods, and difficulty balancing acceleration performance and recovery accuracy in acceleration-based calibration methods, which in turn lead to low accuracy in reconstructed MPI images. The method comprises: constructing a system matrix containing physical priors; splitting the system matrix by column to obtain a set of system matrix columns as the original system matrix columns; inputting the original system matrix columns and various physical priors into a potential diffusion model based on physical priors for fine-tuning and training; inputting newly measured physical priors into the trained model to obtain generated system matrix columns, thereby forming a complete system matrix. The method then combines the measured signals to solve ill-conditioned equations and obtain an MPI image of the object to be measured. The present invention improves the accuracy of MPI image reconstruction while eliminating the need to calibrate the system matrix.

The present invention belongs to the field of magnetic particle imaging technology, and specifically relates to a magnetic particle imaging system and method based on a flexible receiving coil array, which aims to solve the problems of poor adaptability of current rigid receiving coils to biological surfaces and low signal-to-noise ratio for imaging tiny geometric textures. The present invention: Structurally, the receiving coil array is adhered to the surface of the object to be measured, and the compensation coil array is distributed on both sides of the flexible substrate. The receiving coil array is used to receive magnetic nanoparticle signals, and the block-type small compensation coil array is used to compensate for feedthrough interference and electromagnetic interference of the receiving coil; in terms of reconstruction method, the collected receiving signal is Fourier transformed in sequence, the in-phase third harmonic is extracted and superimposed to obtain the processed signal, interpolation is used to construct a sinusoidal diagram for the Cartesian coordinate distribution, and the filtered back projection method is used to reconstruct the three-dimensional particle concentration distribution of the object to be measured. The present invention adopts a flexible receiving coil array strategy and provides an adaptive reconstruction method, thereby improving the imaging signal-to-noise ratio.

The application discloses a kind of HPLC pipeline blockage detection system and method based on magnetic particle imaging, solve the problem that traditional indirect measurement mode relies on the experience and ability of instrument user, it is difficult to accurately identify the position and degree of blockage, low efficiency, easy to cause instrument damage.The HPLC pipeline blockage detection system and method based on magnetic particle imaging inject mobile phase containing magnetic nanoparticles into HPLC pipeline, open the flow pressure pump of HPLC to make liquid flow, then excite magnetic nanoparticles in the field-free point (FFP) of gradient field by alternating magnetic field, and use detection coil to induct the signal generated by magnetic nanoparticles, then transmit to data processing system, complete the detection of blockage position information in HPLC pipeline.The detection system and method realize real-time, non-destructive detection of HPLC pipeline blockage by the magnetic response characteristics of magnetic nanoparticles under the action of external magnetic field, can improve the accuracy and stability of analysis result, wide application range.

The invention belongs to the field of magnetic particle imaging, particularly relates to a magnetic particle imaging generative reconstruction method based on physical prior, and aims to solve the problems that a magnetic particle imaging system is long in matrix calibration time, depends on model hypothesis based on a mathematical modeling method, and is difficult to balance acceleration performance and recovery precision based on an acceleration calibration method. Therefore, the problem of low precision of the reconstructed MPI image is solved. The method comprises the following steps: constructing a system matrix containing physical prior; splitting the system matrix according to columns to obtain a group of system matrix columns as original system matrix columns; inputting the original system matrix array and each physical priori into a potential diffusion model based on the physical priori, and performing fine tuning and training; and inputting each newly measured physical priori into the trained model to obtain a generated system matrix array, forming a complete system matrix, and further combining a measurement signal to solve an ill-conditioned equation to obtain an MPI image of the to-be-measured object. According to the method, the MPI image reconstruction precision is improved, and a system matrix does not need to be calibrated.

The present invention belongs to the field of biomedical imaging technology, and specifically relates to a magnetic particle imaging method, system, and device based on harmonic orthogonal projection, which aims to solve the problem that the existing magnetic particle imaging method cannot achieve fast and high-resolution imaging under high driving magnetic field and low gradient magnetic field conditions. The method of the present invention includes: collecting magnetic particle time domain signals; grid discretizing the synthetic scanning path of the scanning magnetic field; transforming the collected magnetic particle time domain signals in the time-frequency domain; projecting the instantaneous harmonic components onto the corresponding discrete grid to obtain harmonic orthogonal projection images of different frequencies; constructing a small sample prior harmonic orthogonal projection image, and then constructing projection convolution kernels of different frequencies; using the projection convolution kernel to deconvolve the harmonic orthogonal projection image to obtain a spatial distribution image of magnetic particles. The present invention improves the spatial resolution of magnetic particle imaging and realizes fast and high-resolution imaging of the spatial distribution of magnetic particles under strong excitation magnetic field conditions.

The application relates to the field of magnetic particle imaging, in particular to a magnetic nanoparticle imaging system based on a permanent magnet and electromagnet composite driving mode, which comprises a magnet device, a first electric rotating table, a second electric rotating table, a third electric rotating table and a sample feeding device, the first electric rotating table and the second electric rotating table are located on the two sides of the magnet device, the third electric rotating table is located on one side of the second electric rotating table, the magnet device comprises a permanent magnet and an electromagnet, the permanent magnet comprises a focusing field permanent magnet and two selection field permanent magnets, the two selection field permanent magnets are driven to rotate through the first electric rotating table and the second electric rotating table, the focusing field permanent magnet is driven to rotate through the third electric rotating table, the electromagnet part is located outside the permanent magnet part and does not rotate, and the sample feeding device is located in the cavity of the permanent magnet part and does not rotate. The permanent magnet and the electromagnet composite driving mode can effectively reduce the power consumption of the magnetic nanoparticle imaging system.