Dual nuclear magnetic resonance imaging device

Abstract

The invention relates to the technical field of dual nuclear magnetic resonance imaging, in particular to a dual nuclear magnetic resonance imaging device, which comprises an inner shell for limiting an examination space; the outer shell is detachably fixed to the inner shell, and a mounting space surrounding the inspection space is defined between the outer shell and the inner shell; the first coil array comprises a plurality of first coils, and the first coils are attached to and fixed to the outer surface of the inner shell; a second coil array including a plurality of second coils disposed on an outer peripheral side of the first coil array at a predetermined radial interval, the second coils having a different resonance frequency from the first coils; the supporting assemblies are arranged in the circumferential direction and supported by the inner shell, and each supporting assembly comprises a lifting component which can be detached from the corresponding supporting assembly and supports the corresponding second coil, and the lifting components can be selectively close to or away from the inner shell, so that the radial interval is adjusted.

Description

Technical Field

[0001] The present application relates to the technical field of dual-nuclear magnetic resonance imaging, and in particular to a dual-nuclear magnetic resonance imaging device. Background Art

[0002] Multi-nuclear MRI devices, capable of performing imaging examinations based on the magnetic resonance effects of multiple atomic nuclei, are gaining increasing attention within the magnetic resonance imaging industry. In particular, in order to facilitate the study of the performance of multi-nuclear MRI devices in various scenarios, it is crucial to ensure that the MRI devices being studied can be flexibly configured in various configurations and adapted to RF coils with various resonant frequencies. Summary of the Invention

[0003] In view of this, the present application proposes a dual-nuclear magnetic resonance imaging device and an assembly method of the device.

[0004] In a first aspect, a dual-nuclear magnetic resonance imaging apparatus is provided, comprising:

[0005] An inner housing defines an inspection space for accommodating a test object on its inner circumference, wherein the inspection space defines an axial direction, a radial direction, and a circumferential direction;

[0006] an outer shell, detachably fixed to the inner shell and defining an installation space surrounding the inspection space between the outer shell and the inner shell;

[0007] Arranged in the installation space are:

[0008] a first coil array, comprising a plurality of first coils arranged along the circumferential direction, wherein the first coils are attached to and fixed on the outer surface of the inner shell;

[0009] a second coil array comprising a plurality of second coils arranged along the circumferential direction and arranged at predetermined radial intervals on the outer circumference of the first coil array, the second coils having a different resonant frequency from the first coil;

[0010] A plurality of support assemblies are arranged along the circumferential direction and supported by the inner shell, wherein the support assemblies include a lifting member that can be detached from the support assemblies and supports the second coil, and the lifting member is configured to be able to selectively approach or move away from the inner shell to adjust the size of the radial interval.

[0011] In some possible implementations, the lifting member includes:

[0012] a crosspiece extending in a straight line along the axial direction;

[0013] a supporting ring fixed to both ends of the crosspiece and supporting the second coil;

[0014] The support ring defines a support curved surface extending in the circumferential direction and the axial direction, and the second coil extends on the support curved surface.

[0015] In some possible implementations, the support assembly includes:

[0016] a screw extending from the inner housing in the radial direction and passing through the crosspiece;

[0017] Two adjusting nuts are respectively screwed with the screw on opposite sides of the crossbar along the radial direction. By rotating and adjusting the positions of the two adjusting nuts relative to the screw, the position of the crossbar is changed, thereby adjusting the size of the radial interval.

[0018] In some possible implementations, the support assembly includes:

[0019] two guide pillars extending from the inner housing in the radial direction and respectively arranged on opposite sides of the screw in the axial direction;

[0020] The guide post penetrates the crosspiece to guide position adjustment of the lifting member and the second coil in the radial direction and restrict the lifting member and the second coil from rotating around the screw.

[0021] In some possible implementations, the end portion of the crosspiece has a groove recessed along the axial direction, and the groove penetrates the end portion along the circumferential direction;

[0022] A portion of the first section of the support ring is detachably inserted into the slot, and the remaining portion of the first section is located outside the slot in the axial direction and defines a step surface with the end portion that includes a first surface and a second surface that intersect with each other, and the second coil is abutted against the first surface and the second surface.

[0023] In some possible implementations, the two guide pillars are arranged on the inner circumference of the first coil and are disposed close to the first coil.

[0024] In some possible embodiments, the top end of the guide post contacts or is adjacent to the inner surface of the outer shell, and the top end of the screw rod is lower than the top end of the guide post, so that when one of the adjusting nuts is at the top end of the screw rod, the cross piece is below the top end of the guide post.

[0025] In some possible implementations, the inner housing is configured to support the object to be measured, and a mounting bracket for mounting a power splitter and a preamplifier is integrally formed at a rear end portion of the inner housing along the axial direction, and a rear end portion of the mounting bracket has a plate seat;

[0026] Also includes:

[0027] a cable outlet box connected to a side of the panel base opposite to the inner housing in the axial direction and formed to be larger than a size of the connecting member;

[0028] a cable connected to the power splitter and the preamplifier via the outlet box;

[0029] The outer shell comprises:

[0030] a barrel, which is an integrally formed member and has a first end and a second end that are opposite to each other in the axial direction and open, wherein the first end is fixed to the outer lip of the inner shell;

[0031] an upper rear cover detachably fixed to the barrel and closing an upper half of the second end;

[0032] a lower rear cover detachably fixed to the barrel and closing a lower half of the second end;

[0033] An opening surrounding the panel seat is defined between the upper rear cover and the lower rear cover, the lower rear cover supports the panel seat via the lower half of the opening, and the cable outlet box is located outside the opening.

[0034] In some possible implementations, portions of any two adjacent lifting members overlap with each other, thereby causing portions of any two adjacent second coils to overlap with each other.

[0035] In a second aspect, a method for assembling the device according to the first aspect is provided, wherein the plurality of second coils include low-position coils and high-position coils alternately arranged along the circumferential direction, and each high-position coil is located on the outer circumference of two adjacent low-position coils. The assembly method includes:

[0036] Before the outer shell and the plurality of lifting members are mounted on the inner shell, the plurality of first coils are mounted on the inner shell, and the plurality of second coils are mounted on the plurality of lifting members respectively;

[0037] Each of the lifting members, i.e., the first lifting members, on which the low-position coils are mounted, is respectively placed on the corresponding screw rod, and the height of one of the first lifting members, i.e., the reference lifting member, is adjusted so that the radial spacing between the low-position coil on the member and the corresponding first coil becomes a set value, and then the reference lifting member is fixed using the adjusting nut;

[0038] Each of the lifting members, i.e., the second lifting members, on which the high-position coils are mounted, is respectively mounted on the corresponding screw rod, and the height of a second lifting member, i.e., the second reference lifting member, adjacent to the reference lifting member, is adjusted so that the second reference lifting member contacts the reference lifting member radially inward, and then the second reference lifting member is fixed using the adjusting nut;

[0039] Adjusting the height of another first lifting member adjacent to the second reference lifting member so that the other first lifting member contacts the reference lifting member radially outward, and then fixing the other first lifting member using the adjusting nut;

[0040] This process is deduced by analogy until the plurality of lifting components are all fixed by corresponding adjusting nuts;

[0041] The outer housing is mounted to the inner housing.

[0042] According to the dual-nuclear magnetic resonance imaging device provided by the present application, the radial position of the second coil array configured therein can be easily adjusted, so that for various application scenarios, scientific researchers as operators can easily find the optimal radial spacing based on experimental tests, and therefore, the device is particularly suitable for the field of scientific research. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present application, and are not limitations to the present application.

[0044] Figure 1 Schematic diagram of the appearance of a dual-nuclear magnetic resonance imaging device provided in an embodiment of the present application.

[0045] Figure 2 yes Figure 1 The structure shown is a schematic diagram after the cylinder of the outer shell is removed.

[0046] Figure 3 yes Figure 1 A schematic diagram of the structure shown with the outer shell removed.

[0047] Figure 4 From another perspective Figure 3 Schematic diagram of .

[0048] Figure 5 yes Figure 4 An enlarged view of a portion of the .

[0049] Figure 6 From another perspective Figure 1 Schematic diagram of .

[0050] Figure 7 Schematic diagram of the distribution of the first coil array and the second coil array.

[0051] Figure 8 This is a flow chart of the assembly method of the dual-nuclear magnetic resonance imaging device provided in an embodiment of the present application.

[0052] Figure 9 Schematic diagram of the circuit connection of the dual nuclear magnetic resonance coil assembly provided in an embodiment of the present application.

[0053] Figure 10 Schematic diagram of circuit connections of a dual nuclear magnetic resonance coil assembly provided in another embodiment of the present application.

[0054] Description of reference numerals:

[0055] 100-Dual MRI apparatus, 200-Assembly method of dual MRI apparatus;

[0056] 50-Dual MRI coil assembly;

[0057] F1-axial direction, F2-radial direction, F3-circumferential direction;

[0058] SP1-check space, SP2-install space;

[0059] dd-radial spacing;

[0060] 1- first coil;

[0061] 2-second coil, 2U-high coil, 2D-low coil;

[0062] 3-shell;

[0063] 4-inner shell, 4a-mounting bracket, 4a1-plate base;

[0064] 5- outer shell;

[0065] 6-Support assembly;

[0066] 7- lifting member;

[0067] 8- crossbar, 8a- slot, 8b- second side;

[0068] 9-support ring, 9a-first section, 9b-support curved surface, 9c-second surface;

[0069] 10-screw;

[0070] 11-adjusting nut;

[0071] 12-guide pillar;

[0072] 13- support;

[0073] 14-basal part;

[0074] 15- subject carrying part;

[0075] 16-first coil array, 17-second coil array;

[0076] 18-cylinder;

[0077] 19-upper rear cover;

[0078] 20-lower back cover

[0079] 21-power divider;

[0080] 22-outlet box;

[0081] 23-guard plate;

[0082] 24- switch selection circuit;

[0083] M1-first transistor, M2-second transistor;

[0084] P1-power input terminal, P2-power output terminal, P3-level output terminal. DETAILED DESCRIPTION

[0085] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. It is understood that, in the absence of conflict, some technical means of the various embodiments described herein can be replaced or combined with each other.

[0086] In the description of this application, the terms "first," "second," etc., if used, are used solely to distinguish the objects being described and do not convey any order or technical meaning. Thus, an object defined as "first," "second," etc. may explicitly or implicitly include one or more of such objects. Furthermore, for example, the term "first element" alone does not imply the presence of a "second element," nor does the term "second element" alone imply the presence of a "first element." Furthermore, the terms "a" or "an," and the like, do not denote a limitation on quantity, but rather indicate the presence of at least one, and "plurality" means at least two.

[0087] In the description of this application, the terms "including" and "having" indicate the existence of the stated features, numbers, operations, elements and / or their combinations, but do not exclude the existence or addition of one or more other features, numbers, operations, elements and / or their combinations.

[0088] In the description of this application, if there are similar terms such as "configured to" or "constructed to", they can generally be interchanged with "having the ability to...", "designed to", "for" or "capable of", depending on the context.

[0089] In the description of this application, reference to "one embodiment" or "some embodiments" means that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in one or more embodiments of the application. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in other embodiments," etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized.

[0090] Figures 1 to 7 A specific embodiment of a dual-nuclear magnetic resonance imaging device 100 (hereinafter sometimes referred to as the device 100 ) of the present application is shown. The device 100 includes a support 13 , a shell 3 supported by the support 13 , and a first coil array 16 and a second coil array 17 installed in the shell 3 .

[0091] The housing 3 includes an inner housing 4 and an outer housing 5 detachably secured to the inner housing 4. A mounting space SP2 is formed between the inner and outer housings 4 and accommodates the first and second coil arrays 16 and 17, as well as electronic components such as a power divider 21 (described later) and a preamplifier (not shown). The inner and outer housings 4 and 5 can be molded structures made of plastic, with the inner housing 4 being a single, integral part and the outer housing 5 being comprised of multiple, separate components. This design allows the outer housing 5 to be easily secured to the inner housing 4 after the first and second coil arrays 16 and 17 are mounted on the inner housing 4.

[0092] The inner shell 4 defines an inspection space SP1 on its inner circumferential side for accommodating the object to be measured and surrounded by the aforementioned installation space SP2. The inspection space SP1 defines the axial direction F1, the radial direction F2 and the circumferential direction F3, and the inspection space SP1 has an opening portion that is open toward the front end side of the axial direction F1, and the rear end side of the inspection space SP1 toward the axial direction F1 is closed.

[0093] The support 13 has a base portion 14 for supporting the housing 3 and a subject support portion 15 for supporting the subject. Figure 1 In the embodiment, the subject support portion 15 is formed into a curved plate shape that conforms to the contours and dimensions of the human head, making it suitable for magnetic resonance imaging examinations of the human head. Furthermore, the subject support portion 15 is detachably secured to the base portion 14 via screws (not shown), allowing it to be replaced with a subject support portion 15 of a different configuration suitable for supporting other subjects (e.g., small animals).

[0094] The first coil array 16 comprises a plurality of rectangular first coils 1 arranged along the circumferential direction F3, with any two adjacent first coils 1 partially overlapping to provide decoupling. The first coils 1 are affixed to and secured to the outer surface of the inner housing 4, the surface facing away from the examination space SP1. This ensures that the first coils 1 are sufficiently close to the examination space SP1 and the subject. Furthermore, the two short sides of the rectangular first coils 1 extend along the circumferential direction F3, and the two long sides extend in the axial direction F1, which is perpendicular to the circumferential direction F3.

[0095] The second coil array 17 includes a plurality of circular second coils 2 arranged along a circumferential direction F3. The second coil array 17 is spaced apart from the first coil array 16 at predetermined radial intervals dd. Therefore, the second coils 2 are further away from the examination space SP1 and the subject than the first coils 1. Furthermore, the second coils 2 and the first coil 1 have different resonant frequencies. These resonant frequencies correspond to the Larmor frequencies of two different atomic nuclei, respectively. This allows magnetic resonance images of the subject to be acquired based on the magnetic resonance effects of the two nuclei.

[0096] In this embodiment, both the first coil 1 and the second coil 2 are integrated transceiver coils. On the one hand, the first coil array 16 can be used to transmit radio frequency signals corresponding to the Larmor frequency of the first type of atomic nuclei to generate a B1 field in the examination space SP1, thereby exciting the first type of atomic nuclei in the subject to generate magnetic resonance signals. The first coil array 16 then receives the magnetic resonance signals of the first type of atomic nuclei, and a magnetic resonance image of the subject is obtained based on the magnetic resonance effect of the first type of atomic nuclei. On the other hand, the second coil array 17 can be used to transmit radio frequency signals corresponding to the Larmor frequency of the second type of atomic nuclei to generate a B1 field of a different characteristic in the examination space SP1, thereby exciting the second type of atomic nuclei in the subject to generate magnetic resonance signals. The second coil array 17 then receives the magnetic resonance signals of the second type of atomic nuclei, and a magnetic resonance image of the subject is obtained based on the magnetic resonance effect of the second type of atomic nuclei. In some embodiments, the magnetic resonance images based on the first type of atomic nuclei and the magnetic resonance images based on the second type of atomic nuclei can be fused to obtain a higher-quality magnetic resonance fusion image.

[0097] The first atomic nucleus and the second atomic nucleus may be any two of a hydrogen nucleus, a phosphorus nucleus, a carbon nucleus, a sodium nucleus, and a fluorine nucleus, respectively.

[0098] Furthermore, in the axial direction F1, the dimensions of the rectangular first coil 1 unit can be the same as the dimensions of the circular second coil 2 unit. Furthermore, the second coil array 17 and the first coil array 16 can be separated by 20 mm in the radial direction F2. The diameter of the circular second coil 2 unit can be 150 mm, and the length and width of the rectangular first coil 1 can be 150 mm and 100 mm, respectively.

[0099] In this embodiment, the multiple second coils 2 comprising the second coil array 17 are positioned within the installation space SP2 via multiple support assemblies 6. The radial position of the second coils 2, i.e., the size of the aforementioned radial spacing dd, can be adjusted by manipulating the support assemblies 6. When the first coil array 16 and the second coil array 17 are separated by a radial spacing dd, coupling interference between the two coil arrays can be significantly reduced, facilitating high-quality extraction of magnetic resonance signals from the respective coil arrays. Generally speaking, a larger radial spacing dd reduces coupling interference between the two coil arrays. However, a larger radial spacing dd increases the distance between the outer-circumferential second coil array 17 and the examination space SP1 and the subject, resulting in reduced transmission efficiency and receiving sensitivity of the second coils 2. Therefore, it is necessary to find an optimal radial spacing dd that balances low coupling between the two coil arrays with the transmission efficiency and receiving sensitivity of each coil array, so as to easily obtain magnetic resonance images of the highest possible quality.

[0100] Furthermore, factors influencing MRI image quality include not only the radial spacing dd between the first coil array 16 and the second coil 2 units, but also the type of nuclei targeted by the coils (which determines their resonant frequency / operating frequency) and the subject's biological characteristics. For example, if the first coil array 16 is located on the inner circumference, even at the same position (i.e., the same second coil array 17 position), the second coil array 17 may exhibit excellent MRI performance for sodium nuclei. However, after tuning, the second coil array 17 may exhibit relatively poor MRI performance for phosphorus nuclei. However, by changing the radial position of the tuned second coil array 17 (moving it farther or closer), excellent MRI performance for phosphorus nuclei can be achieved. Furthermore, the proportion of nuclei within different subjects varies, so it is necessary to design the resonant frequencies of the first coil array 16 and the second coil array 17 accordingly for each subject.

[0101] Advantageously, the radial position of the second coil array 17 of the dual-nuclear magnetic resonance imaging device provided in the embodiment of the present application can be easily adjusted. Therefore, for the various application scenarios mentioned above, scientific researchers as operators can easily find the optimal radial spacing dd based on experimental tests, and therefore, the device is particularly suitable for the field of scientific research.

[0102] Specifically, a plurality of support assemblies 6 are arranged in the installation space SP2 along the circumferential direction F3 and are supported by the inner shell 4. Therefore, when the outer shell 5 is removed, the second coil 2 can still maintain its relative position with respect to the inspection space SP1, and therefore, the outer shell 5 can be installed after the support assembly 6 and the second coil 2 are installed to the inner shell 4. Since the first coil 1, the support assembly 6 and the second coil 2 are all arranged on the outer surface side of the inner shell 4, sufficient operating space can be provided for the assembler of the device 100 to install the first coil 1, the support assembly 6 and the second coil 2 before the outer shell 5 is installed to the inner shell 4. The support assembly 6 includes a lifting member 7 that can be detached from the support assembly 6 and supports the second coil 2. The lifting member 7 is configured to be able to selectively approach or move away from the inner shell 4, thereby adjusting the size of the aforementioned radial interval dd. In addition, since the lifting member 7 can be detached from the support assembly 6, it can be Figures 2 to 5 The lifting member 7 in the embodiment is replaced with a lifting member 7 of other configurations to carry coils of other configurations, for example, a third coil or a fourth coil different from the second coil 2 .

[0103] The lifting member 7 includes a crosspiece 8 and a support ring 9. The crosspiece 8 extends into a straight shape along the axial direction F1. In some embodiments, the crosspiece 8 can support a monopole coil. The support ring 9 is fixed to both ends of the crosspiece 8 and supports the second coil 2. The support ring 9 has a three-dimensional shape and defines a support curved surface 9b facing radially outward. The support curved surface 9b extends along the circumferential direction F3 and the axial direction F1. The second coil 2 extends on the support curved surface 9b, so that the second coil 2 has a non-planar three-dimensional shape. This helps to reduce the thickness of the installation space SP2 and the structural compactness of the lifting device 100, thereby avoiding the enlargement of the outer dimensions of the housing 3.

[0104] The support assembly 6 includes a screw 10 and two adjustment nuts 11. The screw 10 extends from the inner housing 4 in the radial direction F2 and extends through the crosspiece 8. The two adjustment nuts 11 engage with the screw 10 on opposite sides of the crosspiece 8 in the radial direction F2. By rotating and adjusting the positions of the two adjustment nuts 11 relative to the screw 10, the position of the crosspiece 8 (and the support ring 9) relative to the screw 10 can be changed, thereby adjusting the radial spacing dd described above. In addition, one of the two adjustment nuts 11 (the radially inner one) is obscured in the drawings due to size and viewing angle considerations and is therefore not shown.

[0105] The support assembly 6 also includes two guide posts 12. These two guide posts 12 extend from the inner housing 4 in the radial direction F2 and are positioned on opposite sides of the screw 10 in the axial direction F1. The guide posts 12 extend through the crosspiece 8, thereby guiding the position adjustment of the lifting member 7 and the second coil 2 in the radial direction F2 and restricting the lifting member 7 and the second coil 2 from rotating about the screw 10. In this embodiment, the guide posts 12 are plastic components integrally formed on the outer surface of the inner housing 4. The screw 10 is a metal component that is detachably secured to the outer surface of the inner housing 4 via screws (not shown). The cross-section of the guide posts 12 is formed into a flat shape extending in the axial direction F1.

[0106] The end of crosspiece 8 has a recessed slot 8a recessed along axial direction F1, extending through the end of crosspiece 8 along circumferential direction F3. A portion of first segment 9a of support ring 9 is detachably inserted into slot 8a. The remaining portion of first segment 9a lies outside slot 8a in axial direction F1 and defines a stepped surface with the end portion, comprising intersecting first and second surfaces 8b, 9c. (A portion of) second coil 2 abuts against first and second surfaces 8b, 9c. This design facilitates positioning the second coil 2 on support ring 9 and allows each second coil 2 to be configured with substantially uniform dimensions, thereby achieving excellent signal uniformity when second coil array 17 operates in transmit mode.

[0107] In some embodiments, the axial spacing between the two guide posts 12 can be increased so that the two guide posts 12 are positioned adjacent to the first coil 1 on the inner circumference of the first coil 1. This design allows the guide posts 12 to be used to locate the installation position of the first coil 1, and allows each first coil 1 to be easily configured to have substantially uniform dimensions, thereby achieving excellent signal uniformity when the first coil array 16 operates in transmit mode.

[0108] In this embodiment, the two guide posts 12 have the same height, and the top ends of the guide posts 12 contact or are adjacent to the inner surface of the outer shell 5. Through such a design, the guide posts 12 can provide good radial support for the outer shell 5 and the inner shell 4, preventing the inner shell 4 from moving relative to the outer shell 5 and causing the position of the internal coil to change. In particular, when the device 100 is used in a horizontal orientation with the axial direction F1, the inner shell 4 has a tendency to droop downward (corresponding to a radial direction F2) due to its own gravity and the gravity of the coil array and related electronic components. In other embodiments, the subject-bearing portion 15 of the support 13 is omitted, and the subject is directly supported by the inner shell 4. In this case, the tendency of the inner shell 4 to droop relative to the outer shell 5 is more prominent.

[0109] The top of the screw rod 10 is lower than the top of the guide post 12. Consequently, when one of the adjustment nuts 11 is at the top of the screw rod 10, the crosspiece 8 is below the top of the guide post 12. This allows researchers to adjust the second coil 2 to its maximum allowable height using the adjustment nut 11, without the crosspiece 8 exceeding the top of the guide post 12 and interfering with the installation of the outer shell 5. More importantly, this prevents mechanical damage to the second coil 2 caused by excessively high crosspiece 8. Furthermore, by setting the top of the screw rod 10 lower than the top of the guide post 12, interference with the installation of the outer shell 5 is avoided.

[0110] In this embodiment, any two adjacent lifting members 7 partially overlap with each other. More specifically, any two adjacent support rings 9 partially overlap with each other, thereby causing any two adjacent second coils 2 to partially overlap with each other for decoupling.

[0111] The rear end of the inner housing 4, along the axial direction F1, is integrally formed with a mounting bracket 4a for mounting the power splitter 21 and preamplifier. The rear end of the mounting bracket 4a has a panel seat 4a1. A cable outlet box 22, indicated by dashed lines, is connected to the panel seat 4a1 on the side opposite the inner housing 4 along the axial direction F1 and is larger than the connecting member. Cables, not shown, are connected to the power splitter 21 and preamplifier via the cable outlet box 22. The outer housing 5 comprises a barrel 18, an upper rear cover 19, and a lower rear cover 20. The barrel 18 is a one-piece molded component having a first end and a second end that are opposite and open to each other along the axial direction F1. The first end is fixed to the outer lip of the inner housing 4. The upper rear cover 19, also a one-piece molded component, is detachably fixed to the barrel 18 and closes the upper half of the second end. The lower rear cover 20, also a one-piece molded component, is detachably fixed to the barrel 18 and closes the lower half of the second end. An opening surrounding the panel seat 4a1 is defined between the upper rear cover 19 and the lower rear cover 20. The lower rear cover 20 supports the panel seat 4a1 through the lower half of the opening, and the cable outlet box 22 is located outside the opening. This design allows for easy assembly of the outer housing 5 to the inner housing 4, while ensuring the outer housing 5's support for the inner housing 4 and the coaxiality between the inner and outer housings 4, 5.

[0112] Also, see Figure 3 The shell 3 also includes an arc-shaped support plate fixed to the outer surface side of the bottom of the outer shell 5. The arc-shaped support plate helps to strengthen the structural strength of the shell 3, especially the outer shell 5 at the bottom part, because the weight of the shell 3 is applied to the support 13 through its bottom part.

[0113] The plurality of second coils 2 constituting the second coil array 17 include lower coils 2D and upper coils 2U alternately arranged along the circumferential direction F3 , with each upper coil 2U being located on the outer circumference of two adjacent lower coils 2D.

[0114] Now, see Figure 8 And combined with Figures 2 to 5 As shown, the embodiment of the present application further provides an assembly method 200 of the device 100, the method 200 comprising:

[0115] S801 , before the outer housing 5 and the plurality of lifting members 7 are mounted to the inner housing 4 , the plurality of first coils 1 are mounted to the inner housing 4 , and the plurality of second coils 2 are mounted to the plurality of lifting members 7 , respectively.

[0116] S802, each lifting member 7 (for the convenience of description, referred to as the first lifting member 7) equipped with a low-position coil 2D is respectively placed on the corresponding screw 10, and the height of one of the first lifting members 7 (for the convenience of description, referred to as the reference lifting member 7) is adjusted so that the radial spacing dd between the low-position coil 2D and the corresponding first coil 1 on it becomes the set value, and then the reference lifting member 7 is fixed using the adjusting nut 11.

[0117] S803, each lifting component 7 (for the convenience of description, called the second lifting component 7) installed with the high-position coil 2U is respectively put on the corresponding screw 10, and the height of a second lifting component 7 (for the convenience of description, called the second reference lifting component 7) adjacent to the reference lifting component 7 is adjusted so that the second reference lifting component 7 contacts the reference lifting component 7 radially inward, and then the second reference lifting component 7 is fixed using the adjusting nut 11.

[0118] S804: Adjust the height of another first lifting member 7 adjacent to the second reference lifting member 7 so that the other first lifting member 7 contacts the reference lifting member 7 radially outward, and then secure the other first lifting member 7 with the adjustment nut 11. Repeat this process until all the lifting members 7 are secured with the corresponding adjustment nuts 11.

[0119] S805 , installing the outer shell 5 to the inner shell 4 .

[0120] It can be understood that, through the method 200 , each second coil 2 can be easily positioned at a desired height, thereby simplifying the assembly operation of the device 100 .

[0121] Now go to Figure 9 , Figure 9 The figure shows the connection circuit between the two coil arrays and the power divider 21 in the device 100. The power divider 21 has at least one power input terminal P1, eight power output terminals P2, and one level output terminal P3. The eight power output terminals P2 can simultaneously output a first radio frequency signal at a first resonant frequency or a second radio frequency signal at a second resonant frequency, and the level output terminal P3 is configured to output a high-level signal in response to the power output terminal P2 outputting the first radio frequency signal, and to output a low-level signal in response to the power output terminal P2 outputting the second radio frequency signal. The level output terminal P3 outputs a high-level signal or a low-level signal according to the frequency of the radio frequency signal, which can be implemented using a latch circuit or a frequency selection circuit, which will not be described in detail here.

[0122] Since the power divider 21 can output radio frequency power signals of multiple frequencies (including at least the first resonant frequency and the second resonant frequency) as needed, it can be called a multi-frequency power divider 21. Figure 9The combination of the first coil array 16 , the second coil array 17 , the power divider 21 and the switch selection circuit 24 illustrated in FIG. 5 may be referred to as a dual nuclear magnetic resonance coil assembly 50 .

[0123] Furthermore, the switch selection circuit 24 is connected to the level output terminal P3 of the power divider 21 and is configured to connect the eight power output terminals P2 to the eight first coils 1 in response to a high-level signal, and to connect the eight power output terminals P2 to the eight second coils 2 in response to a low-level signal. In other words, the operating state of the switch selection circuit 24 is controlled by the level output terminal P3 of the power divider 21.

[0124] More specifically, the first resonance frequency corresponds to the Larmor frequency of sodium nuclei, and the second resonance frequency corresponds to the Larmor frequency of hydrogen nuclei.

[0125] The device 100 also includes an RF transmitter (not shown). The RF transmitter is located outside the housing 3 and electrically connected to the power input terminal P1 of the power divider 21, for example, via an RF power amplifier. When the device 100 is operating in the sodium nucleus transmission mode, the RF transmitter can provide a first RF signal at a first resonant frequency to the power input terminal of the power divider 21. In response to the first RF signal, the level output terminal P3 of the power divider 21 outputs a high-level signal, causing the switch selection circuit 24 to couple the eight power output terminals P2 of the power divider 21 to the eight first coils 1 of the first coil array 16. Furthermore, the power divider 21 divides the received first RF signal into eight equal-power paths, each of which is transmitted to the eight first coils 1 of the first coil array 16 via the eight power output terminals P2.

[0126] When the device 100 needs to operate in the hydrogen nucleus transmission mode, the RF transmitter provides a second RF signal of a second resonant frequency to the power input terminal P1 of the power divider 21. Under the action of the second RF signal, the level output terminal P3 of the power divider 21 outputs a high-level signal, thereby causing the switch selection circuit 24 to couple the eight power output terminals P2 of the power divider 21 to the eight second coils 2 of the second coil array 17. At the same time, the power divider 21 divides the received second RF signal into eight paths with equal power, and transmits them to the eight second coils 2 of the second coil array 17 via the eight power output terminals P2.

[0127] like Figure 9As shown, the switch selection circuit 24 includes 8 first transistors M1 and 8 second transistors M2. The 8 first transistors M1 have control terminals (gate terminals) all connected to the level output terminal P3, first current terminals connected to the 8 power output terminals P2, and second current terminals connected to the 8 first coils 1, respectively. The first current terminal and the second current terminal can be the source and drain of the transistor, respectively. The 8 second transistors M2 have control terminals (gate terminals) all connected to the level output terminal P3, first current terminals connected to the 8 power output terminals P2, and second current terminals connected to the 8 second coils 2, respectively. The first current terminal and the second current terminal can be the drain and source of the transistor, respectively. In this way, when the level output terminal P3 of the power divider 21 applies a high-level signal to the control terminals of the eight first transistors M1 and the eight second transistors M2, each first transistor M1 is turned on and each second transistor M2 is turned off, and the switch selection circuit 24 couples the power divider 21 to the first coil array 16 and decouples the power divider 21 from the second coil array 17; when the level output terminal P3 of the power divider 21 applies a low-level signal to the control terminals of the eight first transistors M1 and the eight second transistors M2, each first transistor M1 is turned off and each second transistor M2 is turned on, and the switch selection circuit 24 couples the power divider 21 to the second coil array 17 and decouples the power divider 21 from the first coil array 16.

[0128] As described above, in embodiments of the present application, the device's lifting member 7 can be replaced with a lifting member 7 of a different configuration to carry a third coil or a fourth coil different from the second coil 2, thereby forming a third coil array or a fourth coil array. Because the third coil has a third resonant frequency different from the second resonant frequency, and the fourth coil has a fourth resonant frequency different from the second resonant frequency, in order to adapt the device 100 to such third and fourth coil arrays without replacing electronic components such as the power divider 21, the embodiment of the present application further configures the power divider 21 such that the eight power output terminals P2 can simultaneously output a third RF signal having a third resonant frequency or a fourth RF signal having a fourth resonant frequency. Furthermore, the level output terminal P3 of the power divider 21 is configured to output a low-level signal in response to the power output terminal P2 outputting a third RF signal having a third resonant frequency, and to output a low-level signal in response to the power output terminal P2 outputting a fourth RF signal having a fourth resonant frequency.

[0129] In order to easily realize that the level output terminal P3 outputs a high-level signal in response to the RF signal of the first resonant frequency, and outputs a low-level signal in response to the RF signal of the second, third or fourth resonant frequency, the second resonant frequency, the third resonant frequency and the fourth resonant frequency can all be selected as frequencies higher than the first resonant frequency.

[0130] In some more specific embodiments, the frequency of the third RF signal, i.e., the third resonant frequency, corresponds to the Larmor frequency of fluorine nuclei, and the frequency of the fourth RF signal, i.e., the fourth resonant frequency, corresponds to the Larmor frequency of phosphorus nuclei. Therefore, when the second coil array 17 is replaced with the third coil array, the apparatus 100 can be used for dual-NMR imaging of sodium and fluorine nuclei; and when the second coil array 17 is replaced with the fourth coil array, the apparatus 100 can be used for dual-NMR imaging of sodium and phosphorus nuclei.

[0131] In some other embodiments, the resonant frequency of the second coil 2 can be adjusted to a value different from the second resonant frequency as needed. Specifically, the second coil 2 includes at least one adjustable capacitor. By adjusting the capacitance of the adjustable capacitor, the resonant frequency of the second coil 2 can be changed, such as to the aforementioned third resonant frequency or the aforementioned fourth resonant frequency. This design enables magnetic resonance imaging based on other atomic nuclei, such as fluorine nuclei and phosphorus nuclei, without replacing the second coil 2.

[0132] In other embodiments, the first coil 1 includes at least one adjustable capacitor. By adjusting the capacitance of the adjustable capacitor, the resonant frequency of the first coil 1 can be changed, enabling the first coil 1 to be used for magnetic resonance imaging of atomic nuclei other than sodium nuclei, such as by changing the resonant frequency of the first coil 1 to the aforementioned third resonant frequency or fourth resonant frequency. Furthermore, to achieve radio frequency isolation from the second coil 2, in such embodiments, the level output terminal P3 of the power divider 21 can be configured to output a low-level signal in response to the power output terminal P2 outputting either a third radio frequency signal at the third resonant frequency or a fourth radio frequency signal at the fourth resonant frequency.

[0133] In another possible embodiment, Figure 10As shown, the eight power output terminals P2 of the power divider 21 are respectively connected to the eight first coils 1 via their respective corresponding first parallel resonant circuits composed of capacitor C1 and inductor L1, and are respectively connected to the eight second coils 2 via their respective corresponding second parallel resonant circuits composed of capacitor C2 and inductor L2, wherein the first parallel resonant circuit resonates at the second resonant frequency and the second parallel resonant circuit resonates at the first resonant frequency. Therefore, when the power output terminal P2 of the power divider 21 outputs a first RF signal of a first resonant frequency, the first RF signal is blocked by the second parallel resonant circuit resonating at the first resonant frequency, and thus cannot be transmitted to the second coil 2, but can be transmitted to the first coil 1 via the first parallel resonant circuit that does not resonate at the first resonant frequency, that is, the power output terminal P2 is coupled to the first coil 1 but decoupled from the second coil 2; when the power output terminal P2 of the power divider 21 outputs a second RF signal of a second resonant frequency, the second RF signal is blocked by the first parallel resonant circuit resonating at the second resonant frequency, and thus cannot be transmitted to the first coil 1, but can be transmitted to the second coil 2 via the second parallel resonant circuit that does not resonate at the second resonant frequency, that is, the power output terminal P2 is coupled to the second coil 2 but decoupled from the first coil 1.

[0134] Although in the above discussion, the number of coils in the two coil arrays on the inner and outer sides is set to 8, it is understandable that the number of coils in these two coil arrays can also be designed to be other values, such as 4 or 16. Accordingly, the power divider 21 has at least a corresponding number of power output terminals P2, which will not be elaborated here.

Claims

1. A dual-nuclear magnetic resonance imaging device, characterized in that: include: An inner housing defines an inspection space for accommodating a test object on its inner circumference, wherein the inspection space defines an axial direction, a radial direction, and a circumferential direction; an outer shell, detachably fixed to the inner shell and defining an installation space surrounding the inspection space between the outer shell and the inner shell; It is characterized in that the installation space is provided with: a first coil array, comprising a plurality of first coils arranged along the circumferential direction, wherein the first coils are attached to and fixed on the outer surface of the inner shell; a second coil array comprising a plurality of second coils arranged along the circumferential direction and arranged at predetermined radial intervals on the outer circumference of the first coil array, the second coils having a different resonant frequency from the first coil; A plurality of support assemblies are arranged along the circumferential direction and supported by the inner shell, wherein the support assemblies include a lifting member that can be detached from the support assemblies and supports the second coil, and the lifting member is configured to be able to selectively approach or move away from the inner shell to adjust the size of the radial interval.

2. The device according to claim 1, characterized in that The lifting member comprises: a crosspiece extending in a straight line along the axial direction; a supporting ring fixed to both ends of the crosspiece and supporting the second coil; The support ring defines a support curved surface extending in the circumferential direction and the axial direction, and the second coil extends on the support curved surface.

3. The device according to claim 2, characterized in that The support assembly comprises: a screw extending from the inner housing in the radial direction and passing through the crosspiece; Two adjusting nuts are respectively screwed with the screw on opposite sides of the crossbar along the radial direction. By rotating and adjusting the positions of the two adjusting nuts relative to the screw, the position of the crossbar is changed, thereby adjusting the size of the radial interval.

4. The device according to claim 3, characterized in that The support assembly comprises: two guide pillars extending from the inner housing in the radial direction and respectively arranged on opposite sides of the screw in the axial direction; The guide post penetrates the crosspiece to guide position adjustment of the lifting member and the second coil in the radial direction and restrict the lifting member and the second coil from rotating around the screw.

5. The device according to claim 4, characterized in that The end portion of the crosspiece has a groove recessed along the axial direction, and the groove penetrates the end portion along the circumferential direction; A portion of the first section of the support ring is detachably inserted into the slot, and the remaining portion of the first section is located outside the slot in the axial direction and defines a step surface with the end portion that includes a first surface and a second surface that intersect with each other, and the second coil is abutted against the first surface and the second surface.

6. The device according to claim 4, characterized in that The two guide posts are arranged on the inner circumference side of the first coil and are arranged close to the first coil.

7. The device according to claim 4, characterized in that The top end of the guide post contacts or is adjacent to the inner surface of the outer shell, and the top end of the screw rod is lower than the top end of the guide post, so that when one of the adjusting nuts is at the top end of the screw rod, the cross piece is below the top end of the guide post.

8. The device according to claim 7, characterized in that The inner housing is configured to support the object to be measured, and a mounting bracket for mounting the power divider and the preamplifier is integrally formed at the rear end portion of the inner housing in the axial direction, and the rear end portion of the mounting bracket has a plate seat; Also includes: a cable outlet box connected to a side of the panel base opposite to the inner housing in the axial direction and formed to be larger than a size of the connecting member; a cable connected to the power splitter and the preamplifier via the outlet box; The outer shell comprises: a barrel, which is an integrally formed member and has a first end and a second end that are opposite to each other in the axial direction and open, wherein the first end is fixed to the outer lip of the inner shell; an upper rear cover detachably fixed to the barrel and closing an upper half of the second end; a lower rear cover detachably fixed to the barrel and closing a lower half of the second end; An opening surrounding the panel seat is defined between the upper rear cover and the lower rear cover, the lower rear cover supports the panel seat via the lower half of the opening, and the cable outlet box is located outside the opening.

9. The coil device according to claim 3, characterized in that Parts of any two adjacent lifting members overlap with each other, and thereby parts of any two adjacent second coils overlap with each other.

10. A method for assembling the device according to any one of claims 3 to 8, wherein the plurality of second coils comprise low-position coils and high-position coils alternately arranged along the circumferential direction, each high-position coil being located on the outer circumference of two adjacent low-position coils, characterized in that: The assembly method comprises: Before the outer shell and the plurality of lifting members are mounted on the inner shell, the plurality of first coils are mounted on the inner shell, and the plurality of second coils are mounted on the plurality of lifting members respectively; Each of the lifting members, i.e., the first lifting members, on which the low-position coils are mounted, is respectively placed on the corresponding screw rod, and the height of one of the first lifting members, i.e., the reference lifting member, is adjusted so that the radial spacing between the low-position coil on the member and the corresponding first coil becomes a set value, and then the reference lifting member is fixed using the adjusting nut; Each of the lifting members, i.e., the second lifting members, on which the high-position coils are mounted, is respectively mounted on the corresponding screw rod, and the height of a second lifting member, i.e., the second reference lifting member, adjacent to the reference lifting member, is adjusted so that the second reference lifting member contacts the reference lifting member radially inward, and then the second reference lifting member is fixed using the adjusting nut; Adjusting the height of another first lifting member adjacent to the second reference lifting member so that the other first lifting member contacts the reference lifting member radially outward, and then fixing the other first lifting member using the adjusting nut; This process is deduced by analogy until the plurality of lifting components are all fixed by corresponding adjusting nuts; The outer housing is mounted to the inner housing.

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