Apparatus for generating field-free region, apparatus and method for nano magnetic particle image

Patent metadata

Field	Value
Publication number	US-11707202-B2
Application number	US-202117466898-A
Country	US
Kind code	B2
Filing date	Sep 3, 2021
Priority date	Sep 24, 2020
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

Disclosed herein is an apparatus for imaging nano magnetic particles using a 3D array of small magnets. A field-free region generation apparatus includes a hexahedral housing having an opening formed in the first surface thereof such that a measurement head is inserted into a spacing area, a pair of rectangular-shaped magnets installed respectively on two surfaces facing each other, among four surfaces perpendicular to the first surface of the housing, and a pair of magnet arrays installed respectively on the first surface of the housing and on another surface facing the first surface, each of the magnet arrays including multiple small magnets arranged along the edge of the opening.

First claim

What is claimed is:

1. An apparatus for generating a field-free region, comprising:
a hexahedral housing in which an opening, into which a measurement head is inserted, is formed in a first surface thereof;
a pair of rectangular-shaped magnets that are installed respectively on two surfaces facing each other, among four surfaces perpendicular to the first surface of the housing; and
a pair of magnet arrays that are installed respectively on the first surface of the housing and on another surface facing the first surface, each of the magnet arrays including multiple small magnets arranged along an edge of the opening,
wherein the measurement head in which a through hole for accommodating a sample is inserted in the direction perpendicular to the first surface.

2. The apparatus of claim 1 ,
wherein the multiple small magnets are arranged in a circular shape along the edge of the opening.

3. The apparatus of claim 1 ,
wherein the field-free region is a Field-Free Point (FFP) or a Field-Free Line (FFL).

4. The apparatus of claim 1 , further comprising:
a first driving unit for linearly moving or rotating the pair of rectangular-shaped magnets.

5. An apparatus for imaging nano magnetic particles, comprising:
a measurement head in which a through hole for accommodating a sample including the nano magnetic particles is formed and in which an excitation coil and a detection coil are installed;
a field-free region generation unit for forming a field-free region, in which there is a weak magnetic field or no magnetic field, in a spacing area between identical magnetic poles that face each other; and
a control unit for applying a signal to the excitation coil when the measurement head is placed within the spacing area of the field-free region generation unit, controlling the field-free region so as to move in the sample, and imaging 3D positional distribution of the nano magnetic particles included in the sample based on a detection signal output from the detection coil,
wherein the field-free region generation unit includes a pair of rectangular-shaped magnets and a pair of magnet arrays, in each of which multiple small magnets are arranged,
wherein the field-free region generation unit includes:
a hexahedral housing in which an opening, into which a measurement head is inserted, is formed in a first surface thereof,
the pair of rectangular-shaped magnets that are installed respectively on two surfaces facing each other, among four surfaces perpendicular to the first surface of the housing, and
the pair of magnet arrays that are installed respectively on the first surface of the housing and on another surface facing the first surface, each of the magnet arrays including the multiple small magnets arranged along an edge of the opening,

wherein the measurement head is inserted in the direction perpendicular to the first surface.

6. The apparatus of claim 5 ,
wherein the multiple small magnets are arranged in a circular shape along the edge of the opening.

7. The apparatus of claim 5 ,
wherein the field-free region is a Field-Free Point (FFP) or a Field-Free Line (FFL).

8. The apparatus of claim 5 , wherein the control unit is configured to:
generate a 2D image, which is 2D positional distribution of nano magnetic particles included in a cross section of the sample, based on the detection signal; and
generate a 3D image by synthesizing multiple 2D images corresponding to multiple cross sections that are parallel to each other.

9. The apparatus of claim 8 , further comprising:
a first driving unit for linearly moving or rotating the pair of rectangular-shaped magnets.

10. The apparatus of claim 9 , wherein the control unit is configured to:
repeatedly perform linear movement of the pair of rectangular-shaped magnets in one direction and rotation thereof so as to form a predetermined angle with the one direction by controlling the first driving unit, and
generate a sinogram using a signal output from the detection signal according to movement of the field-free region and generate the 2D image by performing inverse radon transform on the generated sinogram.

11. The apparatus of claim 10 , further comprising:
a second driving unit for moving the measurement head to the spacing area via the opening in the field-free region generation unit.

12. The apparatus of claim 11 ,
wherein the control unit repeats generation of the 2D image while moving the measurement head by a predetermined unit length in a direction perpendicular to the cross section of the sample.

13. A method performed by an apparatus for imaging nano magnetic particles, the apparatus including a processor and a memory operably coupled to the processor, wherein the memory stores program instructions to be executed by the processor, the method comprising:
applying, performed by the processor, a signal to an excitation coil installed in a measurement head that accommodates a sample including the nano magnetic particles; and
moving, performed by the processor, a field-free region, in which there is a weak magnetic field or no magnetic field and which is generated in a spacing area between identical magnetic poles facing each other, in a sample;
detecting, performed by the processor, a signal output from a detection coil of the measurement head; and
transforming, performed by the processor, a detection signal into a 3D image which is 3D positional distribution of the nano magnetic particles included in the sample,
wherein the field-free region is generated by a pair of rectangular-shaped magnets and a pair of magnet arrays, in each of which multiple small magnets are arranged,
wherein the pair of rectangular-shaped magnets is configured such that the rectangular-shaped magnets are installed respectively on two surfaces facing each other, among four surfaces perpendicular to a first surface of a hexahedral housing, in the first surface of which an opening, into which a measurement head is inserted, is formed in a first surface,
wherein the pair of magnet arrays is configured such that the magnet arrays are located respectively on the first surface of the housing and on another surface facing the first surface and such that the multiple small magnets are arranged along an edge of the opening, and
wherein the measurement head is inserted in the direction perpendicular to the first surface.

14. The method of claim 10 ,
wherein the multiple small magnets are arranged in a circular shape along the edge of the opening.

15. The method of claim 10 ,
wherein the field-free region is a Field-Free Point (FFP) or a Field-Free Line (FFL).

16. The method of claim 10 , wherein transforming the detection signal into the 3D image comprises:
generating a 2D image, which is 2D positional distribution of nano magnetic particles included in a cross section of the sample, based on the detection signal; and
generating a 3D image by synthesizing multiple 2D images corresponding to multiple cross sections that are parallel to each other.

17. The method of claim 16 , wherein generating the 2D image comprises;
generating a sinogram using a signal output from the detection signal according to movement of the field-free region while the pair of rectangular-shaped magnets is linearly moved in one direction or is rotated so as to form a predetermined angle with the one direction; and
generating the 2D image by performing inverse radon transform on the generated sinogram.

18. The method of claim 17 ,
wherein generating the 2D image is repeated while moving the measurement head by a pr

Assignees

• Electronics & Telecommunications Res Inst

Inventors

• Kim Jin-Sun
• Jong Jae-Chan
• Hong Hyo-Bong

Classifications

• A61B5/0515 Primary

  Magnetic particle imaging · CPC title

• A61K49/1818

  particles, e.g. uncoated or non-functionalised microparticles or nanoparticles · CPC title

• G01R33/481

  MR combined with positron emission tomography [PET] or single photon emission computed tomography [SPECT] · CPC title

• H01F1/0045

  Zero dimensional, e.g. nanoparticles, soft nanoparticles for medical/biological use (preparation of fullerenes in general C01B32/15) · CPC title

• B82Y25/00

  Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance · CPC title