Magnetic nanoparticle imaging system based on combined driving of permanent magnet and electromagnet

Abstract

The invention relates to the field of magnetic particle imaging, in particular to a magnetic nanoparticle imaging system based on composite driving of a permanent magnet and an electromagnet, which comprises a magnet device, a first electric rotating table, a second electric rotating table, a third electric rotating table and a sample introduction device, and is characterized in that the first electric rotating table and the second electric rotating table are positioned on two sides of the magnet device; the third electric rotating table is located on one side of the second electric rotating table, the magnet device comprises permanent magnets and electromagnets, the permanent magnets comprise a focusing field permanent magnet and two selection field permanent magnets, and the two selection field permanent magnets are driven by the first electric rotating table and the second electric rotating table to rotate. The focusing field permanent magnet is driven by the third electric rotating table to rotate, the electromagnet part is located on the outer side of the permanent magnet part and does not rotate, and the sample injection device is located in a cavity of the permanent magnet part and does not rotate. According to the invention, a permanent magnet and electromagnet composite driving mode is adopted, so that the power consumption of the magnetic nanoparticle imaging system can be effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic nanoparticle imaging, and particularly relates to a magnetic nanoparticle imaging system based on composite driving of a permanent magnet and an electromagnet. Background Art

[0002] Magnetic Particle Imaging (MPI) is a new imaging technology that uses an external magnetic field to manipulate the position and movement of magnetic nanoparticles for imaging. Compared with traditional imaging technologies, MPI technology has extremely high spatial resolution and sensitivity, can image at the cellular and tissue levels, has the advantages of no radiation, long-term dynamic monitoring, and high biosafety. Imaging devices based on MPI technology can be widely used in the diagnosis and treatment of cardiovascular and cerebrovascular diseases, neuroscience research, drug delivery, cell tracking and other fields, and have important scientific and socioeconomic significance in the biomedical field.

[0003] Existing MPI systems use electromagnets to achieve the selection field and the focusing field, but have high power consumption. Therefore, there is an urgent need for an MPI system with low power consumption. Summary of the Invention

[0004] In view of this, the present invention aims to provide a magnetic nanoparticle imaging system based on composite driving of a permanent magnet and an electromagnet to solve the technical problem of high power consumption of existing MPI systems.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows: A magnetic nanoparticle imaging system based on composite driving of a permanent magnet and an electromagnet, comprising a magnet device, a first electric rotating table, a second electric rotating table, a third electric rotating table and a sample injection device; wherein, The magnet device includes a first bearing sleeve, a second bearing sleeve, a first rolling bearing, a second rolling bearing, a third rolling bearing, a first connecting member, a second connecting member, a first selection field permanent magnet, a second selection field permanent magnet, a focusing field permanent magnet, a coil sleeve and an electromagnet. The first bearing sleeve is connected to the second bearing sleeve. The inner ring of the first rolling bearing is connected to the first selection field permanent magnet through the first connecting member, and the outer ring of the first rolling bearing is connected to the first bearing sleeve. The inner ring of the second rolling bearing is connected to the second selection field permanent magnet through the second connecting member, and the outer ring of the second rolling bearing is connected to the second bearing sleeve; The electromagnet is connected to the first bearing sleeve, or the electromagnet is connected to the second bearing sleeve, or the electromagnet is simultaneously connected to the first bearing sleeve and the second bearing sleeve; The first electric rotating table and the second electric rotating table are located on both sides of the magnet device. The first electric rotating table is connected to the first cylindrical Halbach array permanent magnet through a first transition flange and is used to drive the first cylindrical Halbach array permanent magnet to rotate; the second electric rotating table is connected to the second cylindrical Halbach array permanent magnet through a second transition flange and is used to drive the second cylindrical Halbach array permanent magnet to rotate; The focusing field permanent magnet is located in the inner cavities of the first selection field permanent magnet and the second selection field permanent magnet. The third electric rotating table is located on one side of the second electric rotating table. One end of the focusing field permanent magnet is connected to the inner ring of the third rolling bearing through a third connecting piece, the outer ring of the third rolling bearing is connected to the first transition flange, and the other end of the focusing field permanent magnet is connected to the third electric rotating table through a third transition flange. The first selection field permanent magnet, the second selection field permanent magnet, and the focusing field permanent magnet are all cylindrical Halbach array permanent magnets; A first flange bearing is installed in the central through hole of the first electric rotating table, and a second flange bearing is installed in the central through hole of the third electric rotating table. The sampling device is located inside the focusing field permanent magnet and is respectively matched with the first flange bearing and the second flange bearing at both ends.

[0006] Further, the electromagnet includes a coil sleeve and a fingerprint coil wound around the coil sleeve.

[0007] Further, the magnetic nanoparticle imaging system based on the composite drive of the permanent magnet and the electromagnet further includes a magnet support frame, and the coil sleeve is supported on the magnet support frame.

[0008] Further, when the number of coil sleeves is one, the coil sleeve is connected to the first bearing sleeve or the second bearing sleeve. When the number of coil sleeves is two, the two coil sleeves are respectively connected to the first bearing sleeve and the second bearing sleeve.

[0009] Further, the magnetic nanoparticle imaging system based on the composite drive of the permanent magnet and the electromagnet further includes a first annular connecting frame and a second annular connecting frame. The first annular connecting frame and the first bearing sleeve and the second annular connecting frame and the second bearing sleeve are respectively connected through connecting rods, and the first annular connecting frame and the second annular connecting frame are both supported on the magnet support frame.

[0010] Further, the magnetic nanoparticle imaging system based on the composite drive of the permanent magnet and the electromagnet further includes a first electric rotating table support frame and a second electric rotating table support frame. The first electric rotating table is supported on the first electric rotating table support frame, and the second electric rotating table and the third electric rotating table are jointly supported on the second electric rotating table support frame.

[0011] Further, the sample injection device includes a shielding cylinder, an excitation coil, a receiving coil, a first sample injection cylinder, a second sample injection cylinder, and a support cylinder. The receiving coil is located inside the excitation coil. The excitation coil and the receiving coil are combined to form a combined body. The combined body is located inside the support cylinder, and the support cylinder is located inside the shielding cylinder. Both ends of the shielding cylinder are respectively connected to the first sample injection cylinder and the second sample injection cylinder.

[0012] Further, grooves for reducing eddy currents are axially formed on the wall of the shielding cylinder.

[0013] Further, the grooves are evenly distributed along the circumferential direction of the shielding cylinder.

[0014] Further, the support cylinder is of a hollow structure.

[0015] Compared with the prior art, the present invention can achieve the following beneficial effects: 1. The magnetic nanoparticle imaging system provided by the present invention adopts a composite driving mode of a permanent magnet and an electromagnet. The selection field and the focusing field are realized by the Halbach permanent magnets arranged in a cylindrical shape. Since the permanent magnet is a passive device, the power consumption of the magnetic nanoparticle imaging system can be effectively reduced.

[0016] 2. The electromagnet adopts a fingerprint coil to improve the uniformity of the magnetic field.

[0017] 3. The grooves formed on the outer wall of the shielding cylinder can block the formation path of eddy currents, reduce the eddy current loss, and do not affect the radio frequency shielding effect of the shielding cylinder, thereby reducing the heating temperature of the shielding cylinder. Description of the Drawings

[0018] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is a schematic structural diagram of a magnetic nanoparticle imaging system based on the composite driving of a permanent magnet and an electromagnet according to an embodiment of the present invention; Figure 2 is a front view structural diagram of a magnetic nanoparticle imaging system based on the composite driving of a permanent magnet and an electromagnet according to an embodiment of the present invention; Figure 3 is a cross-sectional structural diagram of a magnetic nanoparticle imaging system based on the composite driving of a permanent magnet and an electromagnet according to an embodiment of the present invention; Figure 4 is Figure 3 a partial enlarged structural diagram of

[0019] Description of the Reference Numerals: Magnet device 1, first bearing sleeve 101, second bearing sleeve 102, first rolling bearing 103, second rolling bearing 104, first connecting piece 105, second connecting piece 106, first selection field permanent magnet 107, second selection field permanent magnet 108, electromagnet 110, first coil sleeve 111, first drive coil 112, second coil sleeve 113, second drive coil 114, focusing field permanent magnet 115, third rolling bearing 116, third connecting piece 117, first electric rotating table 2, first transition flange 201, first flange bearing 202, second electric rotating table 3, second transition flange 301, second flange bearing 302, sample introduction device 4, shielding cylinder 401, excitation coil 402, receiving coil 403, first sample introduction cylinder 404, second sample introduction cylinder 405, support cylinder 406, magnet support frame 5, first magnet support 501, second magnet support 502, transverse support rod 503, first annular connecting frame 6, second annular connecting frame 7, connecting rod 8, first electric rotating table support 9, turntable base 901, I-shaped support 902, second electric rotating table support 10, third electric rotating table 11, third transition flange 12. Detailed implementation manners

[0020] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following further details the present invention in combination with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0021] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0022] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0023] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0024] The present invention will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0025] As Figures 1-4 shown, the magnetic nanoparticle imaging system based on the composite drive of a permanent magnet and an electromagnet provided by the embodiment of the present invention includes a magnet device 1, a first electric rotating table 2, a second electric rotating table 3, a third electric rotating table 11, and a sampling device 4. The first electric rotating table 2 and the second electric rotating table 3 are located on both sides of the magnet device 1. The magnet device 1 includes a permanent magnet part and an electromagnet part. The permanent magnet part is driven to rotate by the first electric rotating table 2 and the second electric rotating table 3. The permanent magnet part provides a static gradient field. The electromagnet part is located outside the permanent magnet part and does not rotate. The electromagnet part provides a drive field to shift the zero magnetic field line. The shifting range of the zero magnetic field line is the scanning range. The sampling device 4 is located in the cavity of the permanent magnet part and does not rotate. The sample enters the inside of the magnet device 1 through the sampling device 4.

[0026] The magnet device 1 includes a first bearing sleeve 101, a second bearing sleeve 102, a first rolling bearing 103, a second rolling bearing 104, a first connecting member 105, a second connecting member 106, a first selection field permanent magnet 107, a second selection field permanent magnet 108, an electromagnet 110, a focusing field permanent magnet 115, a third rolling bearing 116, and a third connecting member 117. The first bearing sleeve 101 is connected to the second bearing sleeve 102. The inner ring of the first rolling bearing 103 is connected to the first selection field permanent magnet 107 through the first connecting member 105. The outer ring of the first rolling bearing 103 is connected to the first bearing sleeve 101. The inner ring of the second rolling bearing 104 is connected to the second selection field permanent magnet 108 through the second connecting member 106. The outer ring of the second rolling bearing 104 is connected to the second bearing sleeve 102. The electromagnet 110 includes a first coil sleeve 111, a first drive coil 112, a second coil sleeve 113, and a second drive coil 114. The first coil sleeve 111 is connected to the first bearing sleeve 101. The first drive coil 112 is wound around the first coil sleeve 111. The second coil sleeve 113 is connected to the second bearing sleeve 102. The second drive coil 114 is wound around the second coil sleeve 113.

[0027] It should be noted that when only one coil sleeve is used for the electromagnet 110, it is connected to either the first bearing sleeve 101 or the second bearing sleeve 102.

[0028] The drive coil of the electromagnet 110 uses a fingerprint coil, which can improve the uniformity of the magnetic field. The fingerprint coil can be an integral solenoid coil, a saddle coil, or a Helmholtz coil. When the fingerprint coil is energized, it provides a drive field to shift the zero magnetic field line, and the shift range of the zero magnetic field line is the scanning range.

[0029] The first electric rotating table 2 is connected to the first selectable field permanent magnet 107 through the first transition flange 201 and is used to drive the first selectable field permanent magnet 107 to rotate.

[0030] The second electric rotating table 3 is connected to the second selectable field permanent magnet 108 through the second transition flange 301 and is used to drive the second selectable field permanent magnet 108 to rotate.

[0031] The present invention can drive the first selectable field permanent magnet 107 and the second selectable field permanent magnet 108 to rotate synchronously through the first electric rotating table 2 and the second electric rotating table 3, or can drive the first selectable field permanent magnet 107 and the second selectable field permanent magnet 108 to rotate asynchronously, or can also drive a cylindrical Halbach array permanent magnet to rotate alone while the other cylindrical Halbach array permanent magnet does not rotate.

[0032] The focusing field permanent magnet 115 is located in the inner cavities of the first selectable field permanent magnet 107 and the second selectable field permanent magnet 108. The third electric rotating table 11 is located on one side of the second electric rotating table 3. One end of the focusing field permanent magnet 115 is connected to the inner ring of the third rolling bearing 116 through the third connecting member 117, and the outer ring of the third rolling bearing 116 is connected to the first transition flange 201. The other end of the focusing field permanent magnet 115 is connected to the third electric rotating table 11 through the third transition flange 12. The third transition flange 12 passes through the central through hole of the second electric rotating table 3 and is connected to the inner cavity of the first transition flange 201 and then to the focusing field permanent magnet 115, and the third electric rotating table 11 drives the focusing field permanent magnet 115 to rotate.

[0033] The first selectable field permanent magnet 107 and the second selectable field permanent magnet 108 are used to realize the selectable field, and the focusing field permanent magnet 115 is used to realize the focusing field. The first selectable field permanent magnet 107, the second selectable field permanent magnet 108, and the focusing field permanent magnet 115 are all cylindrical Halbach array permanent magnets, making the distribution of the magnetic field relatively uniform in the annular path. When using cylindrical Halbach array permanent magnets, the change in the magnetic field intensity is relatively small, which is beneficial to improving the stability of the magnetic field.

[0034] The driving method of the present invention is a composite focusing drive combining an electromagnet and an array of permanent magnets, while the traditional driving method is a simple electromagnet focusing drive. The use of passive permanent magnets can achieve low power consumption of the magnetic nanoparticle imaging system.

[0035] The sample injection device 4 includes a shielding cylinder 401, an excitation coil 402, a receiving coil 403, a first sample injection cylinder 404, a second sample injection cylinder 405, and a support cylinder 406. The receiving coil 403 is located inside the cavity of the excitation coil 402. The excitation coil 402 is used to emit an excitation signal to stimulate the magnetization effect of the magnetic nanoparticles in the sample. The receiving coil 403 is used to receive the magnetic nanoparticle signal. After the excitation coil 402 and the receiving coil 403 are combined, they form a combined body, which is located inside the inner cavity of the support cylinder 406. The support cylinder 406 is located inside the inner cavity of the focusing field permanent magnet 115. Both ends of the shielding cylinder 401 are respectively connected to the first sample injection cylinder 404 and the second sample injection cylinder 405.

[0036] Axially extending grooves for reducing eddy currents are provided on the barrel wall of the shielding cylinder 401. To avoid eddy current concentration, the grooves are evenly distributed circumferentially along the shielding cylinder.

[0037] To increase the heat dissipation effect of the sample injection device 4, the support cylinder 406 adopts a hollow structure.

[0038] A first flange bearing 202 is installed in the central through hole of the first electric rotating table 2. The first sample injection cylinder 404 passes through the inner cavities of the third connecting member 117 and the first transition flange 201 and then cooperates with the first flange bearing 202 to prevent the sample injection device 4 from rotating with the first electric rotating table 2. Similarly, a second flange bearing 302 is installed in the central through hole of the third electric rotating table 11. The second sample injection cylinder 405 passes through the inner cavity of the third transition flange 12 and then cooperates with the second flange bearing 302.

[0039] Considering the rotation accuracy, the present invention adopts a direct drive method in which the motor rotating table is connected to the transition flange to drive the permanent magnet to rotate, which has the advantages of relatively simple manufacturing, high transmission precision, low noise, and convenient installation. At the same time, the transition flange can be made of aluminum alloy material, so the weight can be greatly reduced and the magnetic field will not be interfered.

[0040] The magnetic nanoparticle imaging system further includes a magnet support frame 5, a first annular connecting frame 6, and a second annular connecting frame 7. The first annular connecting frame 6 and the first bearing sleeve 101, and the second annular connecting frame 7 and the second bearing sleeve 102 are respectively connected by connecting rods 8. The connecting rods 8 are evenly distributed along the circumferences of the first annular connecting frame 6 and the second annular connecting frame 7, connecting the first annular connecting frame 6, the first bearing sleeve 101, the second annular connecting frame 7, and the second bearing sleeve 102 into a whole. The first annular connecting frame 6 and the first bearing sleeve 101 are distributed at both ends of the first coil sleeve 111, and the second annular connecting frame 7 and the second bearing sleeve 102 are distributed at both ends of the second coil sleeve 113. Both the first annular connecting frame 6 and the second annular connecting frame 7 are supported on the magnet support frame 5 below.

[0041] The magnet support frame 5 includes a first magnet support 501, a second magnet support 502, and a plurality of transverse support rods 503. The transverse support rods 503 are respectively connected between the first magnet support 501 and the second magnet support 502, playing a role in laterally supporting the first magnet support 501 and the second magnet support 502, and realizing the light weight of the magnet support frame 5 while ensuring the stability of the magnet support frame 5. The bottom surfaces of the first magnet support 501 and the second magnet support 502 are flat, and the top surfaces are arc surfaces that cooperate with the first annular connecting frame 6 and the second annular connecting frame 7. Weight reduction holes are provided at the middle positions of the first magnet support 501 and the second magnet support 502.

[0042] The magnetic nanoparticle imaging system further includes a first electric rotating table support 9 and a second electric rotating table support 10 with the same structure. The first electric rotating table 9 includes a turntable base 901 and an I-shaped support 902. The turntable base 901 is fixed on the I-shaped support 902, and the first electric rotating table 2 is installed in the turntable base 901. The second electric rotating table support 10 has two turntable bases fixed on the I-shaped support, and the second electric rotating table 3 and the third electric rotating table 11 are jointly supported in the two turntable bases.

[0043] The present invention will adopt double inner rolling bearings to cooperate with bearing sleeves to connect the Halbach array permanent magnets, ensuring that the two Halbach array permanent magnets are coaxial and generating the magnetic fields of the selection field and the focusing field. The two ends of the Halbach array permanent magnets are connected to the electric rotating table, and the Halbach array permanent magnets are supported by a support frame below, minimizing the weight of the entire magnetic nanoparticle imaging system; adopting a direct drive mode of the electric rotating table to achieve low-noise and high-precision rotational scanning motion of the magnetic nanoparticle imaging system.

[0044] It should be understood that the various forms of processes shown above can be used, with steps reordered, added or deleted. For example, the steps recited in the disclosure of the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is imposed herein.

[0045] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A magnetic nanoparticle imaging system based on a composite drive of a permanent magnet and an electromagnet, characterized in that: It includes a magnet device, a first electric rotating table, a second electric rotating table, a third electric rotating table and a sample injection device; wherein, The magnet device includes a first bearing sleeve, a second bearing sleeve, a first rolling bearing, a second rolling bearing, a third rolling bearing, a first connecting piece, a second connecting piece, a first selection field permanent magnet, a second selection field permanent magnet, a focusing field permanent magnet, a coil sleeve and an electromagnet. The first bearing sleeve is connected to the second bearing sleeve, the inner ring of the first rolling bearing is connected to the first selection field permanent magnet through the first connecting piece, the outer ring of the first rolling bearing is connected to the first bearing sleeve, the inner ring of the second rolling bearing is connected to the second selection field permanent magnet through the second connecting piece, and the outer ring of the second rolling bearing is connected to the second bearing sleeve; the electromagnet is connected to the first bearing sleeve, or the electromagnet is connected to the second bearing sleeve, or the electromagnet is connected to the first bearing sleeve and the second bearing sleeve at the same time; The first electric rotating platform and the second electric rotating platform are located on both sides of the magnet device, the first electric rotating platform is connected to the first cylindrical Halbach array permanent magnet through a first transition flange, and is used to drive the first cylindrical Halbach array permanent magnet to rotate; the second electric rotating platform is connected to the second cylindrical Halbach array permanent magnet through a second transition flange, and is used to drive the second cylindrical Halbach array permanent magnet to rotate; The focusing field permanent magnet is located in the inner cavity of the first selection field permanent magnet and the second selection field permanent magnet, the third electric rotating platform is located on one side of the second electric rotating platform, one end of the focusing field permanent magnet is connected to the inner ring of the third rolling bearing through a third connecting piece, the outer ring of the third rolling bearing is connected to the first transition flange, the other end of the focusing field permanent magnet is connected to the third electric rotating platform through a third transition flange, and the first selection field permanent magnet, the second selection field permanent magnet and the focusing field permanent magnet are all cylindrical Halbach array permanent magnets; A first flange bearing is installed in the central through hole of the first electric rotating table, and a second flange bearing is installed in the central through hole of the third electric rotating table. The injection device is located inside the focusing field permanent magnet and its two ends are respectively matched with the first flange bearing and the second flange bearing.

2. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 1, characterized in that: The electromagnet comprises a coil sleeve and a fingerprint coil wound on the coil sleeve.

3. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 2, characterized in that: It also includes a magnet support frame, on which the coil sleeve is supported.

4. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 3 is characterized in that: When the number of the coil sleeves is one, the coil sleeve is connected to the first bearing sleeve or the second bearing sleeve. When the number of the coil sleeves is two, the two coil sleeves are connected to the first bearing sleeve and the second bearing sleeve respectively.

5. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 4, characterized in that: It also includes a first annular connecting frame and a second annular connecting frame. The first annular connecting frame and the first bearing sleeve, as well as the second annular connecting frame and the second bearing sleeve are connected respectively by connecting rods. The first annular connecting frame and the second annular connecting frame are both supported on the magnet support frame.

6. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 1, characterized in that: It also includes a first electric rotating table bracket and a second electric rotating table bracket, the first electric rotating table is supported on the first electric rotating table bracket, and the second electric rotating table and the third electric rotating table are jointly supported on the second electric rotating table bracket.

7. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 1, characterized in that: The injection device includes a shielding tube, an excitation coil, a receiving coil, a first injection tube, a second injection tube and a supporting tube. The receiving coil is located inside the excitation coil. The excitation coil and the receiving coil are combined to form a combination. The combination is located inside the supporting tube. The supporting tube is located inside the shielding tube. Both ends of the shielding tube are respectively connected to the first injection tube and the second injection tube.

8. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 7, characterized in that: A groove for reducing eddy current is provided on the wall of the shielding cylinder along the axial direction.

9. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 8, characterized in that: The grooves are evenly distributed along the circumference of the shielding tube.

10. The magnetic nanoparticle imaging system based on the composite drive of permanent magnet and electromagnet according to claim 7, characterized in that: The supporting tube is a hollow structure.

Images