Magnetic particle imaging method, system and equipment based on harmonic orthogonal projection

Abstract

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.

Description

technical field [0001] The invention belongs to the technical field of biomedical imaging, and in particular relates to a magnetic particle imaging method, system and equipment based on harmonic orthogonal projection. Background technique [0002] Magnetic particles are nano-scale particles with superparamagnetic properties. In recent years, they have been widely studied and applied as a new type of medical imaging tracer in tumor detection, magnetic particle hyperthermia, targeted drug delivery and other issues. [0003] The basic process of the traditional magnetic particle imaging (MPI) method is: 1. Firstly, a high-strength static gradient magnetic field is used to construct a field-free region (FFR) in the imaging space. This region can be a field-free point (FFP), or Can be free of field lines (FFL). The magnetic particles in the FFR are in an unsaturated state, which can generate a magnetization response signal; 2. Applying a high-frequency driving magnetic field cau...

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Problems solved by technology

[0008] In order to solve the above-mentioned problems in the prior art, that is, in order to solve the problem that the existing magnetic particle imaging method cannot realize fast and high-resolution imaging under the conditions of high driving magnetic field and low gradient magnetic field, the present invention proposes a method based on harmonic The magnetic particle imaging method of orthogonal projection is applied to a magnetic particle imaging device, and the magnetic particle imaging device includes a permanent magnet pair, a scanning coil group, a sample moving bed, and an image reconstruction device; the scanning coil group includes two pairs of annular scanning coils pair, two cylindrical coils; the two annular scanning coils in the pair of annular scanning coils are coaxial and the axes are orthogonal; two cylindrical coils, one is an excitation coil and the other is a receiving coil, coaxially arranged on the two The enclosing space of the annular scanning coil pair; the magnetic particle imaging device takes the axis direction of the cylindrical coil as the x direction, and the longitudinal direction of the axis of the cylindrical coil as the z direction; the permanent magnet pair is arranged in the z direction between the pair of annular scan coils and the cylindrical coil; the method comprising:

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