Abstract: A magnetic particle imaging (MPI) device based on an asymmetric bilateral structure includes a fixed section and a movable section. The fixed section includes a pair of magnetic field generation coils, and the magnetic field generation coils are configured to generate a uniform and variable magnetic field and drive a field-free point (FFP) to move along a Z-axis direction. The movable section includes a permanent magnet, excitation coils and a reception coil. The permanent magnet is configured to cooperate with the magnetic field generation coils to generate the FFP. The excitation coils are configured to move the FFP on a two-dimensional plane and excite magnetic particles to generate a nonlinear response signal. The reception coil is configured to receive an MPI signal. The MPI device is simple in structure and convenient to operate, and can perform targeted local imaging or covered overall imaging on the target object.

Abstract: A dental appliance system comprises: a set of dental appliances for progressively closing a tooth gap between a group of posterior teeth and an intermediate tooth in a patient's dentition, wherein the intermediate tooth is adjacent to the tooth gap and between the tooth gap and a group of anterior teeth in the patient's dentition; and wherein the set of dental appliances comprises: a first plurality of dental appliances for implementing anchorage preparation for the group of posterior teeth and performing one or both of moving the intermediate tooth distally and treating the group of anterior teeth; and a second plurality of dental appliances for mesially moving the group of posterior teeth after the anchorage preparation for the group of posterior teeth has been implemented by the first plurality of dental appliances.

Abstract: An MPI device based on parallel scanning of multiple magnetic field free lines (FFLs) is provided. The MPI device includes a first coil, a second coil, an excitation coil, and a receiving coil; the first coil is configured to receive a first-frequency current and generate a plurality of FFLs; the second coil is configured to receive the first-frequency current and drive the FFLs to rotate under a joint action with the first coil; the excitation coil is configured to receive a second-frequency current and drive the FFLs to scan fast; the receiving coil receives a particle signal scanned by the FFLs at each time point; and the first coil, the second coil, the excitation coil and the receiving coil are provided in longitudinal symmetry along the center of the imaging field of view.

Abstract: A three-dimensional (3D) magnetic particle imaging (MPI) method and system without rotating a field-free line (FFL) are disclosed. In accordance with the method, an FFL is generated such that magnetic particles in a region far from the FFL enter a magnetic saturation state. Further, a non-uniform mixed-frequency excitation magnetic field parallel to the FFL is applied to generate intermodulation response signals. In addition, the intermodulation response signals are acquired, amplified and filtered. Moreover, the intermodulation response signals are transmitted to a digital signal processing unit and an image reconstruction unit, and an encoding matrix is constructed. Additionally, a one-dimensional (1D) concentration distribution of the magnetic particles is reconstructed based on the encoding matrix and an actually measured voltage signal. The FFL is driven for line-by-line scanning along a vertical plane of the FFL, thereby achieving 3D imaging.

Abstract: A system for reconstructing a magnetic particle image based on a pre-trained model aims to address the influence by point spread function and reduce the computational and time costs, which results in low reconstruction accuracy, or high acquisition time and computational costs for high-precision images. The system is implemented by: generating a simulation system matrix; pre-training a pre-constructed neural network model, and fine-tuning a pre-trained neural network model by performing a downstream task; and inputting real data corresponding to the downstream task into the pre-trained neural network model after fine-tuning, thereby playing an auxiliary role to acquire a high-quality reconstructed MPI image. The system fits the relationship between different harmonics, which helps enhance frequency-domain information.

Abstract: The present disclosure includes: transforming a time-domain voltage signal collected by an MPI system device to a frequency domain; calculating a square root of a square sum of a real part and an imaginary part at each frequency point of a frequency domain signal; arranging acquired amplitudes in a descending order, and acquiring a screening threshold by an amplitude ratio method; screening an amplitude through the screening threshold and constructing frequency domain signal data; acquiring a row vector of a system matrix corresponding to each frequency point of the data, so as to construct an update system matrix; and solving, based on the frequency domain signal array and the update system matrix, an inverse problem in a form of a least square based on an L2 constraint to obtain a three-dimensional magnetic particle concentration distribution result, so as to achieve a fast reconstruction of the MPI system.

Abstract: A system for reconstructing a magnetic particle image based on adaptive optimization of regularization terms includes: a MPI device for scanning an imaging object to acquire a voltage response signal; a signal processor for constructing a system matrix; and a control processor for reconstructing the magnetic particle image based on an arbitrarily selected regularization term, inputting the reconstructed magnetic particle image to a regularization-term adaptive optimization neural network model for enhancement processing, taking the enhanced magnetic particle image as a first image, and calculating a loss value between the first image and an initial image to acquire a final reconstructed magnetic particle image. The system adopts a neural network model-based automatic learning approach, instead of the approach of manually selecting regularization terms and adjusting parameters, to improve the reconstruction efficiency and quality of the magnetic particle image.

Abstract: An apparatus and a method for magnetic particle imaging and thermotherapy fusion based on field-free line inertial scanning comprises a magnetic body group, an induction coil, a living body bed, a control device, a display device, an image processing device and a cooling system. The magnetic body group comprises a long curved magnetic body pair and a cylindrical magnetic body. The control device is used to scan and image the target living body and perform thermotherapy on a preset area.

Abstract: A high-resolution handheld OCT imaging system related to the optical imaging field solves the issues of handheld OCT systems with low resolution and the inability to measure the skin's stratum corneum thickness accurately. Through adopting the visible wavelength band of supercontinuum laser as the light source, mainly applying reflectors instead of lenses in the OCT system, and replacing fiber propagation with optical propagation in free space in the interference optical paths, to significantly reduce dispersion loss in the axial resolution and improve the axial resolution of OCT systems. The filter, attenuator, grating, camera, and other components are separated from the handheld module through modular design to reduce the handheld terminal's size and weight and realize the system construction. The invention improves the axial resolution, obtains the thickness information of whole-body skin's stratum corneum, and provides technical approaches for skin diagnosis and related medicine development.

Abstract: Disclosed is a noise reduction device for heat dissipation fans, the noise reduction device being applied to a heat dissipation fan with an interference structure for rotor and stator blades, wherein the noise reduction device comprises a duct formed at an end portion of a through-flow area of the heat dissipation fan, the inner diameter D of the duct is determined by the size and the rotation speed of the heat dissipation fan, and the axial length L of the duct is determined by an acoustic cutoff condition of the heat dissipation fan.

Abstract: A second near-infrared window/first near-infrared window dual-mode fluorescence tomography system having a lighting module, an excitation module, a second near-infrared window collection module, a first near-infrared window collection module, a CT imaging module and a central control module. The central control module is configured to reconstruct second near-infrared window three-dimensional and tomographic images and first near-infrared window three-dimensional and tomographic images based on the white light images, the second near-infrared window fluorescent images, the first near-infrared window fluorescent images, and the CT images. The reconstructed three-dimensional space tumor signal has depth characteristics, which is closer to the real distribution of tumors, such that the reconstruction position is more accurate. The three-dimensional shape of the tumor is displayed intuitively and clearly at any angle with the usage of image display unit.

Abstract: A high-resolution handheld OCT imaging system related to the optical imaging field solves the issues of handheld OCT systems with low resolution and the inability to measure the skin's stratum corneum thickness accurately. Through adopting the visible wavelength band of supercontinuum laser as the light source, mainly applying reflectors instead of lenses in the OCT system, and replacing fiber propagation with optical propagation in free space in the interference optical paths, to significantly reduce dispersion loss in the axial resolution and improve the axial resolution of OCT systems. The filter, attenuator, grating, camera, and other components are separated from the handheld module through modular design to reduce the handheld terminal's size and weight and realize the system construction. The invention improves the axial resolution, obtains the thickness information of whole-body skin's stratum corneum, and provides technical approaches for skin diagnosis and related medicine development.

Abstract: A magnetic particle imaging (MPI) and fluorescence molecular tomography (FMT)-fused multimodal imaging system and method for a small animal are provided. The multimodal imaging system includes an image processing module, a display module, a control module, an object table, a gradient coil, a driving coil, a reception coil, a fluorescence camera, and a light source module, where the gradient coil includes a first rounded rectangular coil and a second rounded rectangular coil; the driving coil includes a third rounded rectangular coil, a fourth rounded rectangular coil, and a fifth rounded rectangular coil; and the reception coil is a circular coil.

Abstract: A fixation and registration calibration system for multimodal MPI is provided. The fixation and registration calibration system includes an upper limiting device connected to a lower limiting device by a hand screw and an adjustable position component, where the upper limiting device and the lower limiting device each are symmetrical about the adjustable position component; an auxiliary clamping device is fixed at an upper end of the upper limiting device; the upper limiting device, the lower limiting device, and the auxiliary clamping device are provided with magnetic particle calibration holes at different positions; and an MPI calibration sample is provided through the magnetic particle calibration holes to achieve spatial position registration calibration. The fixation and registration calibration system achieves fixation of the detected object for MPI, flexible spatial position calibration based on magnetic particles, and stable and reliable multimodal MPI.

Abstract: A human-scale closed-bore MPI device and method based on radial-Cartesian trajectory scanning are provided. The human-scale closed-bore MPI device includes: a gradient module configured to generate a static gradient magnetic field; a rotating scanning module configured to construct a rotating uniform alternating magnetic field; an excitation module configured to construct a uniform alternating magnetic field; an induction module configured to acquire a nonlinear magnetization response signal of magnetic particles; and a compensation module configured to compensate for a coupling signal between a first cylindrical coil and a second cylindrical coil.

Abstract: A structure, a method, and an electronic device for multi-coil handheld magnetic particle imaging (MPI) are provided. The structure for multi-coil handheld MPI includes a processing device, a control device, an imager, a gradient and scanning module, an excitation and correction module, and a detection module, where the gradient and scanning module includes a first circular coil pair and a second circular coil pair; the excitation and correction module includes a circular excitation and correction coil; and the detection module includes a circular detection coil. The structure for multi-coil handheld MPI focuses the imaging region in a specific part, improving the MPI accuracy, and features small volume, simple structure, and low power consumption.

Abstract: A handheld MPI system and method based on field free line (FFL) rotation is provided. The handheld MPI system includes: a gradient module configured to construct a gradient field with an FFL; a cooling module configured to cool the gradient module; an excitation module configured to excite magnetic particles in a region of the FFL; a detection module configured to receive an excitation response signal of the magnetic particles and counteract an excitation signal directly induced by a reception coil; a rotation module configured to control the gradient module and the cooling module to rotate around an axis of an excitation coil; a control and signal processing module configured to control each module to operate as needed, and process a received magnetic particle induction signal; and an image reconstruction module configured to reconstruct a magnetic particle distribution into a two-dimensional image.

Abstract: In a magnetic particle imaging reconstruction method based on a neural network constrained by a forward model, a system matrix is obtained through calibration, voltage data generated by a specimen is measured, collected data are transformed into a frequency-domain by Fourier transform, frequency features of data are screened by a signal-to-noise ratio threshold, a reconstruction network is built by a Pytorch to realize mapping from one-dimensional voltage data to a multi-dimensional magnetic particle concentration distribution, the system matrix is used as the forward model of magnetic particle imaging, and simulated voltage data is generated according to a reconstructed multi-dimensional magnetic particle concentration distribution, a difference between the simulated voltage data and input voltage data is calculated as a loss function for network parameter updating, a total variation regularization term is added to the loss function, and training parameters and regularization parameters are adjusted to achie

Abstract: An MPI reconstruction method, device, and system based on a RecNet model include obtaining a one-dimensional (1D) MPI signal on which imaging reconstruction is to be performed, taking the 1D MPI signal as an input signal, and inputting the input signal and a velocity signal of an FFP corresponding to the input signal into a trained magnetic particle reconstruction model RecNet for image reconstruction to obtain a two-dimensional (2D) MPI image, where the magnetic particle reconstruction model RecNet is constructed based on a domain conversion network and an improved UNet network. The MPI reconstruction method, device, and system obtain a high-quality and clear magnetic particle distribution image without obtaining the system matrix.

Abstract: An MPI reconstruction method, device, and system based on a RecNet model include obtaining a one-dimensional (1D) MPI signal on which imaging reconstruction is to be performed, taking the 1D MPI signal as an input signal, and inputting the input signal and a velocity signal of an FFP corresponding to the input signal into a trained magnetic particle reconstruction model RecNet for image reconstruction to obtain a two-dimensional (2D) MPI image, where the magnetic particle reconstruction model RecNet is constructed based on a domain conversion network and an improved UNet network. The MPI reconstruction method, device, and system obtain a high-quality and clear magnetic particle distribution image without obtaining the system matrix.