50 results about "Particle imaging" patented technology

The invention provides a dynamic self-adaptive range compensator imaging system, which belongs to the technical field of particle imaging equipment, and comprises a particle track detection module used for screening particles directly penetrating through a detector, reconstructing the track and direction of particle motion, and obtaining the energy and position information when particles are incident; the self-adaptive range compensation module is used for realizing dynamic self-adaptive compensation of the particle residual range by adjusting the effective thickness of the compensator so as to receive the particle signal and obtain the residual range corresponding to the residual energy when the particle penetrates out of the imaged object; wherein the effective thickness of the compensator refers to the thickness of the compensator in the particle incidence range along the particle incidence direction; and the image processing module is used for calculating and outputting an image according to the residual range of the imaged object under the conditions of different positions and angles. Through the dynamic compensator, (quasi) continuous range compensation is realized, the precision is improved, and a better detection effect is realized while the cost is reduced.

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.

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 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.

Disclosed is an imaging apparatus comprising: a segmented scintillator structure; and a photocathode structure optically coupled to the segmented scintillator structure, for conversion of high-energy particles with an arbitrary spatial distribution to a corresponding distribution of photoelectrons, emitted with a spread in energy ranging from 100 meV to 1 meV. Also disclosed is an imaging apparatus comprising: a segmented scintillator structure, and a photocathode structure optically coupled to the segmented scintillator structure, for conversion of high-energy particles with an arbitrary spatial distribution to a corresponding distribution of photoelectrons, emitted with an angular spread ranging from 10 degrees to 0.1 degrees. Also disclosed is a pressureless filling of capillary tubes and nano-molds using electroosmosis effect.

This invention provides a three-dimensional detection system for lubricating oil abrasive particles based on a phase-shifting micromirror, comprising: a light source system, a beam splitter, an abrasive particle imaging system, a phase modulation system, and a detection system; the light source system emits a parallel beam that is incident on the beam splitter; the beam splitter divides the parallel beam into two identical transmitted beams and reflected beams; the reflected beam passes through the abrasive particle imaging system and is incident on the oil abrasive particle detection area, generating a scattered beam that returns to the beam splitter along the original path; the transmitted beam is modulated by the phase modulation system to form a reference beam that returns to the beam splitter along the original path; the reference beam and the scattered beam interfere at the exit position of the beam splitter, forming an interference beam that is then incident on the detection system to obtain interference spectrum information; the amplitude and phase information of the cross-correlation term in the interference intensity expression are extracted from the interference spectrum information to construct a complex function of the interference beam signal, and then a Fourier transform is performed on the complex function to finally obtain a clear three-dimensional reconstructed image of lubricating oil abrasive particles.

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 application belongs to the field of magnetic particle imaging, and particularly relates to a rotating gradient magnetic particle imaging device and method based on cross-coil driving, aiming to solve the problems of difficulty in effective coding in the absence of a magnetic field region and low imaging sensitivity in magnetic particle imaging. The application comprises: superimposing the magnetic field generated by two pairs of mutually orthogonal cross-coil pairs and the uniform bias field through a magnetic field generation module to generate an imaging region magnetic field; changing the current direction of any one of the coil pairs in the cross-coil pair or changing the current type of the cross-coil pair to generate a rotating magnetic field under multiple rotating gradients through a gradient rotating module while the uniform bias field remains unchanged; obtaining scanning signals of each point in the imaging region under different magnetic fields through a scanning module; and generating the imaging result of the object to be measured based on the scanning signals under different magnetic fields through an imaging module. The application can realize high-sensitivity and reliable two-dimensional position coding MPI imaging without relying on the traditional magnetic field-free region.

The application discloses an aerodynamic lens sample injection device for single-particle imaging and belongs to the technical field of particle sample injection. The aerodynamic lens sample injection device comprises a gas removal device, a vacuum connection device and an aerodynamic lens. The gas removal device, the vacuum connection device and the aerodynamic lens are sequentially connected and communicated. The input end of the aerodynamic lens is used for receiving particles transmitted by the vacuum connection device, and the output end of the aerodynamic lens is used for conveying the focused particles to an experimental area. The output end of the aerodynamic lens is provided with an acceleration nozzle. The acceleration nozzle comprises a stepped nozzle and a converging capillary tube. The inner diameter of the stepped nozzle decreases in sequence along the particle conveying direction. One end of the converging capillary tube is a tapered port, and the other end is communicated with the inner cavity of the aerodynamic lens after penetrating through the stepped nozzle. Through cooperation between the above structures, the Brown motion of small particles is inhibited, the particle beam width is smaller, the gas flow is reduced, and the scattering of the gas background is reduced.

Described herein are methods and systems for imaging one or more particles flowing through a fluidic channel. The system includes a first light source optically coupled to a first beam resizing optical element, a second light source optically coupled to a second beam resizing optical element, and a data processing device for processing optical data from light scanners.

The present application belongs to the technical field of magnetic particle imaging, and particularly relates to an open magnetic particle imaging method and system based on magnetic field rotation coding, aiming to solve the problems of limited imaging resolution, insufficient imaging depth, excessive power consumption and the inability of MPS to image in the prior art single-sided MPI imaging. The present application: uses a bar-shaped permanent magnet or a coil to create a stable and controllable static magnetic field environment, drives the static magnetic field to rotate by means of a mechanical mechanism, changes the distribution form of the spatial static magnetic field and completes the coding operation, increases the number of independent equations to be solved, and then generates a system matrix, constructs a matrix equation capable of accurately solving the magnetic particle concentration distribution, solves the matrix equation, and successfully reconstructs the magnetic particle image of the target object. The present application is applied to a single-sided MPI device, effectively increases the imaging depth, improves the resolution and reduces the power consumption; and is applied to an MPS device, has imaging capability and expands the application range.

The present application belongs to the field of magnetic particle imaging, and particularly relates to a magnetic particle imaging image reconstruction method, system and device based on a max-min concave and total variation constraint, aiming to solve the problem of large error, poor precision and low quality of the MPI image reconstructed by the existing magnetic particle imaging image reconstruction method. The method comprises: acquiring a time domain voltage signal as an input signal; performing Fourier transform on the input signal and constructing a system matrix; based on the system matrix, constructing a mapping equation between the concentration of magnetic particle imaging and the input signal after Fourier transform as a first equation; combining isotropic total variation and max-min concave constraint to reconstruct the first equation to obtain a second equation; and iteratively solving the second equation by an alternating direction multiplier method with a mixed penalty function to obtain the concentration of magnetic particle imaging and perform image reconstruction. The present application reduces the error of the reconstructed MPI image, and improves the precision and quality of the reconstructed MPI image.

The application discloses an interference fringe pattern positioning method based on target detection. The application uses an interference particle imaging system to obtain an interference fringe pattern of a transparent spherical particle, divides the labeled interference fringe pattern into a training set, a verification set and a test set, obtains optimal weights after training for 200 epochs, takes the test set as input of a target detection network, obtains a prediction box containing normalized position information of the interference fringe pattern, and obtains a center point of the interference fringe pattern after coordinate extraction and inverse transformation. The application can realize high-precision positioning of the interference fringe pattern of the transparent spherical particle, and provides technical support for particle size measurement.

The application belongs to the field of magnetic particle imaging, and particularly relates to a magnetic particle imaging method and device based on multi-source noise monitoring and collaborative compensation, aiming to solve the problem that magnetic particle signals are easily interfered by multi-source noise. The method comprises the following steps: during excitation or gradient field operation, a main receiving signal is collected, and multi-path noise monitoring signals are synchronously collected through at least two noise monitoring coils; the multi-path noise monitoring signals are input into a background noise prediction model to obtain predicted background noise, wherein the background noise prediction model is trained based on signals collected by the main receiving coil and the noise monitoring coil under the no-load state of a magnetic particle imaging device; the predicted background noise is eliminated from the main receiving signal to obtain a purified magnetic particle response signal; and a reconstructed image is generated based on the purified magnetic particle response signal. The application can obtain a high signal-to-noise ratio MPI response signal online, and improve the imaging speed and long-term stability without changing the existing scanning architecture.

The forward model constrained neural network magnetic particle imaging reconstruction method disclosed by the application obtains a system matrix through calibration, measures voltage data generated by a sample; Fourier transforms the collected data into a frequency domain, uses a signal-to-noise ratio threshold to screen frequency characteristics of the data; uses a Pytorch reconstruction network to realize mapping from one-dimensional voltage data to multi-dimensional magnetic particle concentration distribution; uses the system matrix as a forward model of magnetic particle imaging, generates voltage simulation data from the reconstructed magnetic particle concentration distribution, calculates a difference between the voltage simulation data and input voltage data as a loss function to update network parameters; adds a regularization term in the loss function, and adjusts training parameters and regularization parameters to obtain optimal reconstruction effect. The application uses a forward model constrained neural network to perform magnetic particle imaging reconstruction, and further improves the reconstruction effect by adding a total variation regularization term in the loss function of the network.

A magnetic particle imaging device comprises a detection coil (3) for detecting changes in the magnetism of magnetic particles (1), a compensating coil (4) which has a common central axis (CA) with the detection coil (3) and is connected to the detection coil (3) with opposite polarity, a first winding frame (21) for holding the detection coil (3), and a second winding frame (22) for holding the compensating coil (4). The distance between the detection coil (3) and the compensating coil (4) in one direction of the central axis (CA) is made variable by increasing or decreasing a contact section of the first winding frame (21) and the second winding frame (22).

A pair of first measurement coils is disposed so as to sandwich magnetic particles. A pair of second measurement coils is disposed so as to sandwich magnetic particles and the pair of first measurement coils. A pair of alternate-current magnetic field application coils is disposed so as to sandwich magnetic particles, the pair of first measurement coils, and the pair of second measurement coils. A measurement device outputs a signal representing a difference between a signal measured by the pair of first measurement coils and a signal measured by the pair of second measurement coils.

The application relates to the technical field of magnetic particle imaging, and more particularly to an iron oxide nanoparticle and application of the iron oxide nanoparticle in magnetic particle imaging. The nanoparticle is an octahedral superparamagnetic ferroferric oxide nanoparticle, the nanoparticle is synthesized by adding a surfactant and controlling a reaction rate through a high-temperature thermal decomposition method, the surfactant includes oleic acid and oleylamine, the octahedral superparamagnetic ferroferric oxide nanoparticle is coated with an amphiphilic polymer, the amphiphilic polymer includes polymaleic anhydride-1-octadecenoic acid and polystyrene maleic anhydride copolymer, and the outer layer of the amphiphilic polymer includes biological membranes such as macrophage membranes, red blood cell membranes, neutrophil membranes and tumor cell membranes according to biological application requirements. The surface of the octahedral magnetic particle is a crystal face, the crystal face has low spin disorder and low anisotropy, so that the octahedral magnetic particle has the advantages of low coercivity and high initial magnetic susceptibility, and thus becomes a high-sensitivity magnetic particle imaging tracer.

The invention belongs to the technical field of gas compressor internal flow field test and optical measurement, and discloses a gas compressor blade integrated laser endoscopic PIV flow field measuring device which is suitable for full-field measurement of gas flow velocity fields in a gas compressor inlet / outlet, an interstage and a rotor channel in a narrow space with a high Mach number. The device is characterized by comprising an endoscopic probe, a gas compressor stator blade, an optical window, a gas compressor rotor blade, a target measurement area, a cartridge receiver, an imaging camera, a laser, a light guide arm and a hub, and the laser endoscopic probe is introduced into the stator blade by forming a small-size optical hole in the cartridge receiver; laser sheet light is projected to a blade channel through an optical window arranged on the outer surface of the blade, tracer particles are evenly scattered at an inlet of a gas compressor, and an imaging camera obtains a particle image in a target area; and non-contact, transient and full-field measurement of gas flow velocity fields of an inlet, an outlet and an interstage channel of the gas compressor rotor can be realized under the working conditions of high Mach number and limited space.

The present application belongs to the technical field of magnetic particle imaging, and particularly relates to a phase offset calibration method for the instantaneous position of a magnetic field-free point in magnetic particle imaging, aiming to solve the problem that the existing phase offset calibration method for the instantaneous position of a magnetic field-free point requires separate measurement or calculation for each device in the MPI device, resulting in a large workload, a long calibration process time and troublesome adjustment. The method comprises: collecting magnetic particle response signals and current intensity signals as input signals; based on the input signals, cyclically automatically modulating the phase of the instantaneous position of the magnetic field-free point in the imaging process of the MPI device; after the automatic phase modulation is completed, solving the optimal solution of the phase offset; and based on the optimal solution of the phase offset, again automatically modulating the phase of the instantaneous position of the magnetic field-free point in the MPI device to obtain the final instantaneous position and instantaneous speed after phase offset calibration. The present application does not require setting of hardware, greatly reduces the difficulty of phase modulation and facilitates personnel operation.

Superparamagnetic nanoparticle-based analytical method comprising providing a sample having analytes in a sample matrix, providing a point of care chip having analytical regions, each of which is a stationary phase having at least one or more sections, labeling each of the analytes with a superparamagnetic nanoparticle and immobilizing the labeled analytes in the stationary phase, providing an analytical device having a means for exciting the superparamagnetic nanoparticles in vitro and a means for sensing, receiving, and transmitting response of the excited superparamagnetic nanoparticles, placing the chip in the analytical device and exciting the superparamagnetic nanoparticles in vitro, sensing, receiving, and transmitting the response of the superparamagnetic nanoparticles, and analyzing the response and determining characteristic of the analytes, wherein the response of the superparamagnetic nanoparticles comprises harmonics. The present invention also provides the hybrid point of care chip and analyzer to be used in the analytical method.

A source emits a pulse to an object to generate a particle, and an imaging detector produces a light flash at an X / Y hit position of the particle. The detector outputs a waveform arising from the particle. An event-driven camera provides a signal from the detector that includes intensity and time-over-threshold signals related to the light flash, time-of-arrival information of the event, and the X and Y hit position of the particle. A photodiode determines a time origin of the pulse from the source. A timing circuit is coupled to the detector and to the photodiode, and determines time-of-flight (TOF) of the particle based on the waveform, and based on the time origin of the pulse. The 3D coordinates are generated based on the X / Y hit position synchronized with the TOF of the particle.

A magnetic particle imaging (MPI) measurement method includes generating a multi-dimensional image-domain system matrix A using an MPI-sequence with a field free line, using a multi-dimensional sinogram-based system matrixASinogram(t,r,z)∈ℝ[T,Nr,Nz],comprising the following steps:for each time point tc, c∈[1, T]:get a time slice matrix Ac=ASinogram(t=tc, r, z)∈[N<sub2>r< / sub2>,N<sub2>z< / sub2>],replicate the time slice matrix Ac Nr−1 times and copying these replications along a newly added 2nd offset-dimension, resulting in a time volume matrixAc′∈ℝ[Nr,Nr,Nz],rotate the time volume matrixAc′ by the FFL θc=θ(t=tc) at time point t=tc in its 1st and 2nd offset-dimensions, resulting in a rotated matrixAcθ cconcatenate the rotated matricesAcθ c of all time points along a time-dimension and vectorize the spatial dimensions (x, y, z), resulting in a constructed system matrix cSM∈[T,(N<sub2>r< / sub2>×N<sub2>r< / sub2>×N<sub2>z< / sub2>)], andperform a Fourier transformation on the constructed system matrix cSM on its time-dimension resulting in the multi-dimensional image-domain system matrix A.

The invention belongs to the technical field of medical imaging, and relates to a magnetic particle imaging method based on high-low double-frequency magnetic field modulation and multi-group harmonic fusion, which comprises the following steps: determining a magnetic particle imaging area, and dividing the magnetic particle imaging area into a first area and a second area according to the direction of a low-frequency sine scanning magnetic field; placing a magnetic nanoparticle sample of a unit volume in the first area, externally adding a high-low double-frequency magnetic field, extracting harmonic signals of each order in the first area, constructing a system matrix, and calculating a harmonic energy distribution weight matrix corresponding to the system matrix; placing the to-be-measured object in the second area, externally adding a high-low double-frequency magnetic field, extracting harmonic signals of each order in the second area, and obtaining a harmonic signal matrix of the to-be-measured object; and constructing an equation to be solved and carrying out inversion solution to obtain an image of magnetic nanoparticle concentration distribution. The implementation process is convenient and simple, and the application of magnetic particle imaging in biomedicine is expected to be further improved.

This invention relates to a miniature detection system based on magnetic particle imaging, belonging to the field of medical inflammatory imaging technology. This invention is a miniature and simple device for magnetic particle imaging for fingertip detection. It uses a microcontroller as the control terminal, a receiving coil that is closer to the imaging aperture, and low-diameter driving and receiving coils. By improving the signal-to-noise ratio and reducing background interference signals, it effectively improves experimental efficiency and the sensitivity of the detection system, and greatly enhances portability.

The present specification relates to the field of MPI imaging technology, and discloses an open three-dimensional magnetic particle imaging device and method based on a magnetic field free line. The device comprises: a signal detection module configured to provide an open scanning environment by installing a magnetic field free line generating unit composed of two circular permanent magnets arranged in a cross direction of the magnetic poles and a signal receiving unit in two coaxial cylindrical scanning devices symmetrically arranged above and below, emit an initial scanning signal and receive a magnetic particle response signal; an electric control module for controlling the position, intensity and motion trail of the initial scanning signal emitted by the signal detection module; an external signal compensation module for measuring a direct feedthrough signal; and a signal processing and image reconstruction module for processing the magnetic particle response signal and the direct feedthrough signal to obtain a reconstructed image. The present application does not need to consider a high-power power supply module, eliminates the filtering operation on the input current, does not need to consider the heating problem possibly caused by long-time power-on, and simplifies the system.

The invention relates to the field of magnetic particle imaging, in particular to an MPI system matrix rapid calibration method and system based on multistage wavelet transform and a double-branch attention network, and aims to solve the problem that an existing calibration-based system matrix acquisition method is time-consuming and complicated. The method comprises the following steps: acquiring a low-resolution system matrix according to a preset under-sampling grid; carrying out RGB coding on the system matrix according to rows to obtain an RGB image; the RGB image is input into a trained MWaveDAN network model, and a high-resolution RGB image is obtained; a high-resolution RGB image is decoded into a complex number form, and a complex number-based system matrix is obtained. According to the method, high-resolution acquisition of the system matrix in the MPI is effectively accelerated, and important support is provided for future development of the MPI technology.

This invention discloses a method for classifying the shape of ice crystal particles based on interferometric defocus images. The method involves preprocessing ice crystal particle images used to train a neural network, constructing a laser interferometric particle imaging system, and sequentially inputting the processed particle images into a DMD for interferometric imaging. A CCD located on the defocus plane receives the interferometric defocus images of the particles. The acquired interferometric defocus images are used to construct a convolutional network training set to train the classification network. New particle interferometric defocus images are then input into the classification network obtained in step 5 to achieve ice crystal particle shape classification. Compared with existing technologies, this invention achieves automatic particle shape classification; the method has the advantages of high speed and high reliability, providing a foundation for the application of laser interferometric imaging technology in the research and analysis of ice crystal particles.

The invention belongs to the field of magnetic particle imaging, particularly relates to a magnetic particle imaging method and device based on multi-source noise monitoring and cooperative compensation, and aims to solve the problem that magnetic particle signals are easily interfered by multi-source noise. The method comprises the following steps: during the excitation or gradient field working period, acquiring a main receiving signal, and synchronously acquiring multiple paths of noise monitoring signals through at least two noise monitoring coils; the multiple noise monitoring signals are input into a background noise prediction model, predicted background noise is obtained, and the background noise prediction model completes training based on signals collected by a main receiving coil and a noise monitoring coil in the no-load state of the magnetic particle imaging device; the predicted background noise is eliminated from the main receiving signal, and a purified magnetic particle response signal is obtained; and generating a reconstructed image based on the purified magnetic particle response signal. According to the invention, the MPI response signal with a high signal-to-noise ratio can be obtained online, and the imaging speed and long-term stability are improved on the premise of not changing the existing scanning architecture.

The application belongs to the field of magnetic particle imaging, and particularly relates to an MPI acceleration calibration method based on a system matrix super-resolution network, aiming to solve the problems of long calibration time and poor accuracy of reconstructed MPI images of the existing magnetic particle imaging system matrix reconstruction method. The method comprises the following steps: placing a unit MNP sample in the imaging field of view of a magnetic particle imaging device for sparse calibration scanning, and constructing a system matrix as a low-resolution system matrix; inputting the low-resolution system matrix into a system matrix super-resolution network model after pretreatment, to obtain a super-resolved system matrix row set; performing post-processing on the super-resolved system matrix row set to obtain a high-resolution system matrix; and combining the high-resolution system matrix to solve the magnetic particle concentration distribution of a target object to be imaged, and reconstruct an MPI image of the target object to be imaged. The application can greatly reduce the calibration time while accurately reconstructing the MPI image.