100 results about "Magnetic particle imaging" patented technology

The present invention relates to an arrangement and a method for influencing and/or detecting magnetic particles in a region of action, in particular for monitoring of intra-cerebral or intra-cranial bleeding using Magnetic Particle Imaging (MPI). A common coupling unit per coil of a coil array is provided for coupling all signals for generating the magnetic fields to the set of common coils. Further, the same coils are used for acquiring detection signals. In this way a small scanner can be built that can be left permanently or can be provided periodically to the patient, in particular for bleeding monitoring.

A calibration method for an MPI (=magnetic particle imaging) apparatus for conducting an MPI experiment, wherein the calibration method comprises m calibration MPI measurements with a calibration test piece and uses these measurements to create an image reconstruction matrix with which the signal contributions of N voxels within an investigation volume of the MPI apparatus are determined, wherein compressed sensing steps are applied in the calibration method with a transformation matrix that sparsifies the image construction matrix, and wherein only a number M<N of calibration MPI measurements for M voxels are carried out, from which the image reconstruction matrix is created and stored. This specifies an efficient method for determination of the system matrix for the MPI imaging method, which does not require much time to determine an MPI system function and nevertheless achieves a high degree of precision.

The present invention relates to a coil arrangement, in particular for use in a magnetic particle imaging apparatus (100), comprising a coil split into at least two coil segments, wherein the winding direction is inverted between at least one coil segment to another coil segment, and a capacitor coupled between at least two adjacent coil segments. Further, the present invention relates to such a magnetic particle imaging apparatus, in particular an apparatus (100) for influencing and/or detecting magnetic particles in a field of view (28), which apparatus comprises selection means and drive means (120) wherein at least one drive field coil and/or at least one selection field coil representing a selection field element is implemented by a coil arrangement as proposed according to the present invention.

The present invention relates to an MPI (Magnetic Particle Imaging) apparatus and a method for influencing and/or detecting magnetic particles in a field of view. Rather than moving the FFP (field free point) along a single, time-consuming high density trajectory it is proposed to use a number of low density trajectories with travelling phase, wherein each of said low density trajectories has the form of a closed curve differently located within the field of view.

The present invention relates to an apparatus (100) for influencing and/or detecting magnetic particles in a field of view (28), wherein the field of view (28) comprises at least one sub field of interest covering at least a portion of an object of interest containing magnetic particles. The apparatus (100) applying the known principle of Magnetic Particle Imaging (MPI) comprises selection means for generating a magnetic selection field (50) having the known field pattern showing a field free point (FFP), drive means for changing the position in space of the FFP by means of a magnetic drive field, receiving means for acquiring detection signals depending on the magnetization of the magnetic particles within the field of view (28), a control unit (150) for controlling a signal receiving unit (140) comprised in the receiving means for acquiring a set of high resolution detection signals and a set of low resolution detection signals, wherein the set of high resolution detection signals depends on the magnetization of at least one subfield of interest and the set of low resolution detection signals depends on the magnetization of at least one adjacent subfield being arranged adjacent to the at least one subfield of interest, and a reconstruction unit (152) for reconstructing a particle distribution quantity depending on the set of high resolution detection signals and the set of low resolution detection signals. The present invention further relates to a corresponding method as well as to a computer program.

The present invention relates to an apparatus (100) for determining at least one electromagnetic quantity characterizing an electromagnetic property of an object, in particular a human body, wherein said object contains magnetic particles. The apparatus (100) applying the known principle of Magnetic Particle Imaging (MPI) comprises selection means for generating a magnetic selection field (50) having the known field pattern showing a field free point (FFP), drive means for changing the position in space of the FFP by means of a magnetic drive field, receiving means for acquiring detection signals depending on the magnetization of the magnetic particles within a field of view (28) and a reconstruction unit (152) for reconstructing a particle distribution quantity depending on the detection signals. The apparatus (100) further comprises a control unit (150) for controlling the receiving means for acquiring a first set of detection signals corresponding to a first drive field frequency and a second set of detection signals corresponding to a second drive field frequency, with both drive field frequencies differing from each other. The control unit (15) further controls the reconstruction unit (152) for reconstructing a first particle distribution quantity depending on the first set of detection signals and a second particle distribution quantity depending on the second set of detection signals. The apparatus (100) further comprises a determination unit (160) for determining the electromagnetic quantity depending on the first and second particle distribution quantity. The present invention further relates to a corresponding method as well as to a computer program.

A system for inspecting a pipe weld from within a pipe through use of magnetic particle imaging “MPI” includes an apparatus having a head unit that carries a wire wheel brush for cleaning an inspection area along an inner diameter of a pipe weld, and an MPI medium dispenser for spraying an MPI medium upon the inspection area, both controlled by an operator. The head unit also includes a video inspection device controlled by the operator and used for viewing at least portions of the inspection area after being sprayed with the MPI medium and when under the influence of a magnetic field to determine if the weld has any defects. The head unit is connected to a drive unit. The drive unit includes a frame having a longitudinal axis and mounted on a set of drive wheels, and a set of support wheels spaced axially from the drive wheels. A linear drive motor mounted to the frame and coupled to the drive wheels moves the head unit linearly along an interior of the pipe between weld inspection areas to allow the operator to locate and inspect the welds from within the pipe.

In Magnetic Particle Imaging (MPI) the reconstruction requires the knowledge of a so called system function. This function describes the relation between spatial position and frequency response and is currently measured once for a scanner set-up and a tracer material. For reasonable resolutions and fields of view the system function becomes quite large, resulting in large acquisition times to obtain reasonable signal-to-noise. However, the system function has a number of properties which can be used to improve signal-to-noise. According to the present invention use is made of the spatial symmetry and/or identical responses at different frequencies for this purpose.

The present invention relates to an arrangement (10) for influencing and/or detecting magnetic particles (100) in a region of action (300), which comprises selection means (210) for generating a magnetic selection field (211) having a pattern in space of its magnetic field strength such that a first sub-zone (301) having a low magnetic field strength and a second sub-zone (302) having a higher magnetic field strength are formed in the region of action (300). The arrangement further comprises drive means (220) for changing the position in space of the two sub-zones (301, 302) in the region of action (300) by means of a magnetic drive field (221) so that the magnetization of the magnetic material changes locally. The arrangement further comprises receiving means (230) for acquiring detection signals, which detection signals depend on the magnetization in the region of action (300), which magnetization is influenced by the change in the position in space of the first and second sub-zone (301, 302). Control means (76) are further introduced for controlling the selection means (210) to individually set the gradient strength of at least one of the static magnetic gradient fields (211) in a desired direction.

The invention belongs to the field of magnetic particle imaging, particularly relates to a magnetic particle imaging system based on magnetic field-free line scanning and is intended to solve the problem that a magnetic particle imaging system has unsatisfactory sensitivity and resolution. The magnetic particle imaging system based on magnetic field-free line scanning comprises a magnet unit, an induction coil, an imaging table, and a control and imaging device; the magnet unit comprises two pairs of circular magnets in axial orthogonal arrangement and a tubular magnet; two circular magnets ineach pair of circular magnets are coaxial; the tubular magnet is arranged in an enclosure space of the two pairs of circular magnets, and the axis of the tubular magnet crosses through an orthogonalpoint of the axes of the two pairs of circular magnets and is perpendicular to a plane formed by the axes of the two pairs of circular magnets; the control and imaging device is used to control changes in magnetic fields of the magnets in the magnet unit according to set control instructions so that magnetic field-free line rotation and/or shift is achieved; magnetic particle imaging is performedon current signals generated in the induction coil according to an induction magnetic field. The magnetic particle imaging system has the advantages that magnetic particle positioning precision is improved and resolution is increased.

The invention belongs to the technical field of biomedical imaging, particularly relates to a magnetic particle imaging method, system and equipment based on harmonic orthogonal projection, and aims to solve the problem that an existing magnetic particle imaging method cannot realize rapid high-resolution imaging under the conditions of a high driving magnetic field and a low gradient magnetic field. The method comprises the following steps: acquiring a magnetic particle time domain signal; performing grid discretization on a composite scanning path of the scanning magnetic field; performing time-frequency domain transformation on the acquired magnetic particle time domain signal; projecting the instantaneous harmonic components to the corresponding discrete grids to obtain harmonic orthogonal projection images with different frequencies; constructing a small sample prior harmonic orthogonal projection image, and further constructing projection convolution kernels of different frequencies; and performing deconvolution on the harmonic orthogonal projection image by using the projection convolution kernel to obtain a spatial distribution image of the magnetic particles. According to the invention, the spatial resolution of magnetic particle imaging is improved, and spatial distribution rapid high-resolution imaging of magnetic particles under the condition of a strong excitation magnetic field is realized.

The present invention relates to a composition comprising a shell structure forming a cavity, wherein said shell structure comprises a drug and wherein said composition is associated with at least one contrast agent; wherein said shell structure is capable of releasing its contents into the exterior upon the application of an external stimulus and wherein said contrast agent comprises magnetic particles which are capable of being detected by Magnetic Particle Imaging (MPI), wherein at least more than 5% (w/w) of the magnetic particles comprised in said contrast agent have a magnetic moment of at least −18 m 2 A, 10 wherein said magnetic particles are preferably composed of Fe, Co, Ni, Zn or Mn or alloys thereof or oxides of any of these. The present invention further relates to the use of such a composition or a composition comprising a shell structure forming a cavity, wherein said shell structure comprises a drug and wherein said composition is associated with at least one contrast agent, wherein said contrast agent is capable of being detected by MPI and wherein said shell structure is capable of releasing its contents into the exterior upon the application of an external stimulus as a carrier for a controlled delivery of a drug, as well as to a method of data acquisition for the control of a drug delivery process comprising the detection or localization via MPI of such compositions. In a further aspect the present invention relates to such compositions for treating a pathological condition, wherein the treatment comprises the release of the drug by the application of a stimulus.

The invention provides a magnetic tracer material for use in magnetic particle imaging and a manufacturing method thereof. The magnetic tracer material comprises clusters of a plurality of magnetic particles that are clustered in a controlled way to form individual entities, for example, stabilized oil droplets, solid emulsion particles, liposomes, polymersomes or vesicles, or naturally occurring biological entities such as cells or viruses.

The invention belongs to the technical field of medical imaging detection, particularly relates to a three-dimensional magnetic particle imaging detection system and method and electronic equipment, and aims to solve the problems that a magnetic particle imaging detection device is closed in structure, large in size and poor in flexibility. The system comprises a permanent magnet assembly, a driving coil assembly, a receiving coil, a motor turntable and a processing circuit; the permanent magnet assembly is used for generating non-magnetic field lines in a detection space; the driving coil assembly is used for generating an oscillating magnetic field perpendicular to the non-magnetic-field lines. the receiving coil is used for receiving a magnetic response signal generated by the magnetic nanoparticles in the detection space; the motor turntable can rotate under the driving of the power device; the processing circuit comprises a band elimination filter circuit, an amplifier and an A/D module; the band elimination filter circuit is used for attenuating a fundamental frequency signal in the detection signal; the amplifier is used for carrying out low-noise amplification on the detection signal; and the A/D module is used for sampling the signal and converting the signal into a digital quantity. According to the magnetic particle imaging detection system structure is compact, the size is small, and open type detection can be achieved.

The invention belongs to the technical field of magnetic particle imaging, particularly relates to a whole-body-oriented three-dimensional magnetic particle imaging method, a system and an equipment, and aims to solve the problem that whole-body imaging cannot be performed simultaneously during magnetic particle imaging. According to the invention, a single group of magnetic particle imaging systems are coupled to form an array type magnetic particle imaging system, and the imaging view is enlarged from a local part to a whole body size. In the signal acquisition process, excitation and receiving coils of each group of magnets in the whole body magnetic particle imaging system are synchronized, denoising and filtering amplification are carried out on obtained electromagnetic induction signals, image reconstruction is carried out by utilizing a deconvolution or regularization method, reconstructed images in all imaging view fields are spliced, finally, a three-dimensional distribution image of the magnetic particles in the whole body is obtained, whole-body imaging of an observed object is achieved, and high examination and diagnosis accuracy is achieved.

The present invention relates to an apparatus and a corresponding method for non-invasive intracardiac electrocardiography (ECG) by use of a magnetic and electrically conducting interference device (210). An MPI-based ECG mapping technique is proposed, wherein an interference device (210), e.g. an electrically conducting rod containing soft magnetic material, is steered through the vessel system and the heart using magnetic fields generated by a magnetic particle imaging (MPI) system so that the ECG signals measured in parallel are influenced. Using appropriately adapted evaluation means (153) this influence of the interference device (210) on the ECG signals can be evaluated to gain spatially resolved information about the electrical heart activity.

An apparatus for magnetic particle imaging, the apparatus comprising: a sensing unit configured to detect linear sample signals, which represent the mixed electromagnetic fields, generated from magnetic particles in a sample; a driving unit configured to move the sensing unit in a direction of X-axis, Y-axis, or Z-axis; and a data processing unit configured to rearrange in a matrix linear sample signals detected by the sensing unit that is moved by the driving unit.

The invention discloses a fast magnetic particle imaging reconstruction method based on undersampling. The method comprises the steps of obtaining MPI undersampling voltage signals, obtaining full-sampling MPI images, conducting nonlinear normalization on the signals and the images, training a neural network and predicting magnetic particle concentration distribution. According to the method, the voltage signals are directly mapped to the image domain, reconstruction can be carried out within several milliseconds, wide evaluation on a large number of data sets shows that the method can reconstruct the full-sampling high-resolution MPI image from the under-sampling voltage signals, and the method has good anti-noise capacity and anti-artifact capacity; the method has good generalization ability, the reconstructed image quality is higher, the reconstruction speed is higher, the imaging potential of a magnetic particle imaging system is improved, and the problem that MPI equipment introduces a large amount of noise due to too long acquisition time is solved.

The invention discloses a magnetic particle imaging reconstruction method based on an attention. According to the method, the strong computing power of a neural network model is utilized to match acquired large data volume, and effective information in signals is extracted by fusing self-attention mechanism learning, so that signal information loss caused by downsampling or truncation is reduced; and end-to-end reconstruction from a one-dimensional frequency domain signal to a two-dimensional image is realized.