Transmission device and transmission method

Abstract

Provided is a transmission device capable of, by using a simple configuration, transmitting a substance to be administered, while maintaining the super-polarization performance of the substance. This transmission device 4 is provided between: a polarization device 3; and an imaging device 2 that uses nuclear magnetic resonance. The transmission device is used when a substance super-polarized by the polarization device 3 is transferred to a location where the substance is used. The transmission device 4 comprises: a transmission tube 41 that forms a transmission path through which the substance is transmitted; a magnet 42 that generates a magnetic field in the transmission path; and a yoke 43 that is disposed so as to constitute a magnetic circuit with the magnet 42 and that has a relative permeability of 100 or greater.

Description

Transmission device and transmission method

[0001] The present invention relates to a delivery device and a delivery method for delivering, for example, hyperpolarized administered substances.

[0002] In order to improve the sensitivity of imaging using nuclear magnetic resonance, a conventional method has been proposed in which a substance (administered substance) is hyperpolarized using a polarization device, and the hyperpolarized substance (having hyperpolarizable ability) is administered into a living body to be imaged, thereby performing imaging.

[0003] The interiors of polarization devices and imaging devices (NMR and MRI devices) are in a strong magnetic field environment of several tesla, allowing the hyperpolarization of administered substances to be maintained to a certain extent during processing within the polarization device and imaging device. However, the hyperpolarization of administered substances is rapidly lost when passing through a low magnetic field region. Generally, the administration of administered substances into living bodies is performed on the imaging device side, so the path (transmission path) for transmitting the administered substance with hyperpolarization from the polarization device to the imaging device must be in a strong magnetic field environment.

[0004] To address this issue, a method of placing permanent magnets around the transmission path to generate a magnetic field in the transmission path has been proposed. As an example of a transmission device using permanent magnets, a transmission device employing a magnet-opposed structure, in which magnets are placed facing each other on both sides of the path, has been proposed (Non-Patent Document 1). However, the magnet-opposed structure has a problem in that the large leakage magnetic field can interfere with the imaging device. Furthermore, the magnet-opposed structure poses safety issues, such as the attraction of magnetic metals such as iron to the leakage magnetic field.

[0005] Also, a transmission device employing a simplified Halbach circuit structure has been proposed as a method for generating a stronger magnetic field in the transmission path (Non-Patent Document 2). However, to obtain the benefits of the simplified Halbach circuit structure, permanent magnets must be tightly arranged, which requires magnets of a special shape. In addition, the increased weight of the magnets requires a more complex and robust installation structure, which results in problems such as a complicated structure for the transmission device and increased manufacturing costs for the transmission device.

[0006] Hyperpolarized water through dissolution dynamic nuclear polarization with UV-generated radicals COMMUNICATIONS CHEMISTRY (2020)3:57 Arthur C. Pinon et al.A magnetic tunnel to shelter hyperpolarized fluidREVIEW OF SCIENTIFIC INSTRUMENTS 86, 024101(2015)Jonas Milani et al.

[0007] In view of the above-mentioned problems, an object of the present invention is to provide a transmission device and a transmission method that can transmit an administered substance while maintaining its hyperpolarizability with a simple configuration.

[0008] The present invention is characterized by a transmission device used to transfer hyperpolarized material to a location where the material is used, the transmission device and transmission method having a tubular member that forms a transmission path along which the material is transmitted, a magnet that generates a magnetic field in the transmission path, and a yoke member with a relative permeability of 100 or more that is arranged to form a magnetic circuit together with the magnet.

[0009] The present invention provides a transmission device and a transmission method that can transmit an administered substance while maintaining its hyperpolarizability with a simple configuration.

[0010] 1 is a schematic explanatory diagram showing the overall configuration of an imaging system; an end view illustrating the configuration of a transmission device of the present invention; a schematic explanatory diagram illustrating the flow of magnetic lines of force in a transmission device of the present invention; a lateral end view illustrating the configuration of a transmission device of the present invention; an end view illustrating an example of the configuration of a transmission device of a modified embodiment; an end view illustrating another example of the configuration of a transmission device of a modified embodiment; an end view illustrating another example of the configuration of a transmission device of a modified embodiment; an end view illustrating another example of the configuration of a transmission device of a modified embodiment; an end view illustrating another example of the configuration of a transmission device of a modified embodiment; a side view illustrating another example of the configuration of a transmission device of a modified embodiment; a side view illustrating another example of the configuration of a transmission device of a modified embodiment; a plan view illustrating another example of the configuration of a transmission device of a modified embodiment; a plan view illustrating another example of the configuration of a transmission device of a modified embodiment; an explanatory diagram illustrating another example of the configuration of a transmission device of a modified embodiment.

[0011] An embodiment of the present invention will now be described with reference to the drawings. Fig. 1 is a schematic diagram showing the overall configuration of an imaging system 1 according to a first embodiment of the present invention. The imaging system 1 includes an imaging device 2, a polarization device 3, and a transmission device 4.

[0012] The imaging device 2 is a device for converting information about the inside of a living body to be imaged into an image. For example, the imaging device 2 is a nuclear magnetic resonance (NMR) device or an MRI (magnetic resonance imaging) device that utilizes the NMR phenomenon.

[0013] An NMR device irradiates a radio-frequency signal onto an imaging target placed in a static magnetic field, then detects minute radio-frequency signals (nuclear magnetic resonance signals: NMR signals) emitted from the sample, and extracts molecular structure information contained in the nuclear magnetic resonance signals to analyze molecular structure. MRI devices used in medical settings are devices that use the magnetic resonance effect to capture tomographic images of an imaging target in real time. In other words, the imaging device 2 may also function as a detection device.

[0014] When capturing an image of the inside of a living body to be imaged using the imaging device 2, one method for improving the sensitivity of imaging is to hyperpolarize a liquid administered substance by using hyperpolarization, and then administer the hyperpolarized administered substance (having hyperpolarization ability) into the living body to be imaged.

[0015] The polarization device (hyperpolarization device) 3 is a device that hyperpolarizes the administered substance using hyperpolarization. Hyperpolarization is a technology that amplifies nuclear magnetic resonance signals by several tens to several tens of thousands of times, thereby increasing the sensitivity of the imaging device 2 that uses nuclear magnetic resonance to perform imaging. Types of hyperpolarization include rare gas polarization, in which a laser is irradiated onto the administered substance and rare gases such as 3He and 129Xe are used to polarize nuclear spins; parahydrogen polarization, in which parahydrogen is added through a chemical reaction to magnetize the target nuclei; and dynamic nuclear polarization (DNP), which uses double resonance between electron spins (free radicals) and nuclear spins.

[0016] For example, if the imaging device 2 is an MRI device, then in the polarization device 3 １３ Dynamic nuclear polarization is induced in C-labeled compounds (reagents), resulting in hyperpolarized １３ A C-labeled compound is administered to a living body as an imaging agent, １３ There is a method for metabolic imaging that observes the dynamics of C compounds.

[0017] An administered substance with hyperpolarizability is a liquid reagent with a polarization rate of 0.002% or more. Here, polarization rate refers to the ratio of the spin orientations of molecules in a substance. The polarization rate is expressed as 100% when all molecules in a substance have spins pointing either up or down, and as 0% when the number of molecules in a substance with equal numbers of spins pointing up and down. When used in imaging system 1, the polarization rate of the administered substance is preferably 1% or more, and more preferably 10% or more.

[0018] The transmission device 4 has a transmission path formed therein for transmitting the administered substance, and is a device for transmitting the hyperpolarizable administered substance from the polarization device 3 to the imaging device 2 or to the vicinity of the imaging device 2 (the location where the substance is administered to a living body). The imaging device 2 and the polarization device 3 are devices (strong magnetic field devices) that generate a strong magnetic field (3 tesla or more) and are arranged at a distance from each other to avoid being affected by each other's magnetic field (leakage magnetic field). For example, a position (safety line) where the magnetic field strength of the leakage magnetic field is 5 gauss or less is considered safe. Although the distance from each device to the safety line varies depending on the level of the leakage magnetic field, the imaging device 2 and the polarization device 3 are arranged at least 1 meter or more from each other, and may be arranged 2 meters or more, or even 3 meters or more apart. Furthermore, the imaging device 2 and the polarization device 3 may be arranged in separate rooms in a medical institution or the like, and it is conceivable that they may be arranged 10 to 100 meters or more apart.

[0019] In the imaging system 1 configured in this manner, the administered substance having hyperpolarizability can be quickly transmitted from the polarization device 3 to the imaging device 2 via the transmission device 4, and the administered substance can be administered into a living body to be imaged, thereby imaging the inside of the living body to be imaged. That is, the source of the transmission path (transmission device 4) is the polarization device 3, and the destination of the transmission path (transmission device 4) is an imaging device (detection device) 2 using magnetic resonance. Note that the destination of the transmission path (transmission device 4) can also be considered as the location where the administered substance having hyperpolarizability is used. The location where the administered substance having hyperpolarizability is used can be other than the imaging device (detection device) 2 using magnetic resonance. <Problems with the Prior Art>

[0020] As described above, it is preferable to maintain the hyperpolarizability of the administered substance as much as possible when transmitting the administered substance from the polarization device 3 to the imaging device 2. The hyperpolarizability of the administered substance can be maintained to a certain extent in a high magnetic field environment, but it rapidly decreases in a low magnetic field environment. In other words, the hyperpolarizability of the administered substance is lost when it passes through a low magnetic field region, resulting in a decrease in the final signal strength (a decrease in imaging sensitivity).

[0021] To address these issues, it is possible to construct a transmission device (strong magnetic field transmission device) with a strong magnetic field transmission path (magnet tunnel) to maintain the hyperpolarization ability of the administered substance. For example, a transmission device employing a simplified Halbach circuit structure has been proposed to construct a strong magnetic field transmission device. However, the simplified Halbach circuit has various problems, including the following:

[0022] First, to configure a simplified Halbach circuit, four magnets must be placed around the transmission path. In other words, a simplified Halbach circuit requires at least four magnets per cross section. Furthermore, in a simplified Halbach circuit, permanent magnets must be placed without gaps. Since gaps would occur with general-purpose magnets of a general shape, specialized magnets are required. Therefore, a transmission device that uses a simplified Halbach circuit faces the problem of increased cost per magnet and an increased number of magnets, which increases the manufacturing cost of configuring a strong magnetic field transmission path.

[0023] Furthermore, as described above, the simplified Halbach circuit requires a large number of magnets, which increases the weight and size of the magnets, resulting in a heavy and bulky configuration of the entire transmission device. This requires a robust structure to support the heavy configuration. In other words, a transmission device that uses a simplified Halbach circuit requires a more complex and robust installation structure due to the increased weight of the transmission path, resulting in increased manufacturing costs for the transmission device. Another problem is that a large and robust structure is less portable and less versatile.

[0024] Furthermore, the safety of equipment containing magnets is determined by the level of the leakage magnetic field, and if the leakage magnetic field emitted by the magnet itself is large, it can attract magnetic materials such as iron, making it extremely dangerous.While transmission devices that use simple Halbach circuits can generate strong magnetic fields, they cannot completely eliminate the leakage magnetic field, so there is still room for improvement in terms of safety.

[0025] As described above, transmission devices that use simple Halbach circuits have problems such as increased manufacturing costs for constructing a transmission path for a strong magnetic field, increased manufacturing costs due to the complexity and robustness of the installation structure, and safety issues. In response to these problems, the inventors have devised a new configuration for a transmission device, as described below, to solve the problems. <Configuration of the transmission device of the present invention>

[0026] Fig. 2 is a cross-sectional view illustrating the configuration of the transmission device 4 of the present invention. Fig. 3 is a schematic explanatory diagram illustrating the flow of magnetic lines of force in the transmission device 4 of the present invention. Fig. 4 is a cross-sectional view illustrating the configuration of the transmission device 4 of the present invention. Note that, for the sake of convenience, the support 44 is not shown in Fig. 4.

[0027] 2 and 3, the transmission device 4 includes a transmission tube 41, a magnet 42, a yoke 43, and a support 44. In this embodiment, the transmission device 4 extends linearly in the horizontal direction, and the axial direction of the transmission device 4 when viewed from the polarization device 3 toward the imaging device 2 (hereinafter sometimes simply referred to as the "axial direction") is defined as the front side (the polarization device 3 side) and the rear side (the imaging device 2 side) of the transmission device 4 as viewed from the polarization device 3 as the rear side, with the right side as viewed from the front side toward the rear side being the right side (the left side as viewed from the front side being the left side). Note that the above description is for convenience in defining the directions, and the transmission device 4 does not necessarily have to be linear or horizontal.

[0028] The transmission tube 41 is a cylindrical member (cylindrical member) with a circular or rectangular cross section. The internal space of the transmission tube 41 serves as a transmission path for transmitting the substance to be administered. In other words, the transmission tube 41 can also be said to be a path-forming member that forms the transmission path. The transmission tube 41 is made of a low-permeability material. A low-permeability material is one that has a relative magnetic permeability (μ / μ ０ ) is a material with a μ value of 1.1 or less. ０ is the magnetic permeability in a vacuum. For example, the material forming the transmission tube 41 can be a metal (such as copper or aluminum) with a relative magnetic permeability of 1.1 or less, a resin, or rubber. The material forming the transmission tube 41 is preferably made of a flexible material to ensure the flexibility of the transmission path.

[0029] The magnet 42 is a permanent magnet or an electromagnet. Examples of permanent magnets that can be used include neodymium magnets, samarium-cobalt magnets, and ferrite magnets. An electromagnet is a device that generates a magnetic field by passing a current through a coil formed from a conducting wire. Examples of electromagnets that can be used include electromagnets using normal conducting wires and superconducting magnets using superconducting wires. In this embodiment, the magnet 42 is a prismatic or cylindrical permanent magnet.

[0030] The magnet 42 is arranged so as to generate a magnetic field in the transmission path (the internal space of the transmission tube 41) (so that magnetic field lines generated from the magnet 42 pass through the transmission path.) For example, the magnet 42 is arranged so that an extension of an imaginary line connecting the north pole and south pole passes through the transmission path.

[0031] Furthermore, there may be one magnet 42 or multiple magnets 42. In this embodiment, two magnets 42 are arranged vertically in a certain cross section, one above the transmission tube 41 and the other below the transmission tube 41, and are arranged so that the opposing surfaces of the two magnets 42 sandwiching the transmission tube 41 have different polarities. That is, in a certain cross section, the two magnets 42 are arranged so as to sandwich the transmission tube 41 from above and below, with the north pole of one magnet 42 close to the transmission tube 41 and the south pole of the other magnet 42 close to the transmission tube 41.

[0032] Alternatively, instead of the above-described configuration, two magnets 42 may be arranged side by side in a certain cross section. In this case, the two magnets 42 can be arranged so as to sandwich the transmission tube 41 from the left and right.

[0033] Here, the distance between the upper and lower magnets 42, i.e., the distance a between the magnets on the same cross section (see FIG. 4), is preferably as small as possible from the perspective of increasing the magnetic field strength of the transmission path. For example, the distance a between the magnets on the same cross section can be 10 mm or less, preferably 8 mm or less, more preferably 5 mm or less, even more preferably 3 mm or less, and preferably 2 mm or less.

[0034] The size of the magnet 42 is not particularly limited, but may be, for example, 10 mm vertically (thickness from the north pole to the south pole), 10 mm horizontally, and 50 mm front-to-back. The longitudinal length of the transmission device 4 (the longitudinal length of the magnet 42) is approximately the same as the separation distance between the imaging device 2 and the polarization device 3. As described above, the separation distance between the imaging device 2 and the polarization device 3 is at least 1 m, so multiple magnets 42 must be arranged in the axial direction of the transmission path, as shown in FIG. 4 . The distance between adjacent magnets 42, i.e., the inter-magnet distance b in the longitudinal direction (axial direction of the transmission path), should also be as small as possible to enhance the magnetic field strength of the transmission path. For example, the inter-magnet distance b in the axial direction can be 10 mm or less, preferably 8 mm or less, more preferably 5 mm or less, even more preferably 3 mm or less, and preferably 2 mm or less.

[0035] Furthermore, when arranging multiple magnets 42 in the axial direction, it is preferable to displace the magnets 42 (so that their axial positions differ) from each other across the transmission tube 41, as shown in Figure 4, rather than aligning the positions (axial positions) of the magnets 42 that face each other across the transmission tube 41. In this way, the magnets 42 attract each other and become stable, and the axial distance b between the magnets can be reduced (for example, to about 2 mm).

[0036] 2 and 3, the yoke 43 is made of a material (high-permeability material) with a higher magnetic permeability than a low-permeability material. A high-permeability material is a material with a relative magnetic permeability of 100 or more. For example, the material that can be used to make the yoke 43 may be a general magnetic metal material such as soft iron or pure iron.

[0037] The yoke 43 is provided so that the magnetic field lines generated from the magnet 42 pass through the transmission path to form a loop-shaped magnetic circuit 45 connecting the north pole and south pole of the magnet 42. In other words, the yoke 43 functions as a magnetic circuit-forming member.

[0038] Specifically, the yoke 43 is provided in a loop shape so as to connect the north pole and south pole of the magnet 42. The yoke 43 may be composed of one or more plate-shaped members. For example, the yoke 43 may be formed from a single member, or may be formed from an appropriate combination of a flat plate-shaped member, a member with an L-shaped cross section (an L-shaped plate), a U-shaped member, or the like.

[0039] Furthermore, when multiple magnets 42 are provided, the number is not particularly limited, and each of the multiple magnets 42 is arranged on the magnetic circuit 45 and is arranged so that the arrangement of the north and south poles (the orientation of the magnets 42) is the same.

[0040] In this embodiment, the yoke 43 is formed to surround the magnet 42 and the transmission tube 41. Specifically, the yoke 43 in this embodiment is integrally formed in a rectangular cylindrical shape with a rectangular cross section, and the inner surface of the yoke 43 contacts the upper surface of the upper magnet 42 and the lower surface of the lower magnet 42. Furthermore, the yoke 43 in this embodiment tightly covers the outside of the magnet 42 and the transmission tube 41. Therefore, as shown in FIG. 3 , the magnetic field lines generated by the magnet 42 emerge upward from the north pole of the upper magnet 42 and then split into left and right along the top wall of the yoke 43. Each of the split magnetic field lines traces a U-shape along the top wall, side wall, and bottom wall of the yoke 43, which is made of a high-permeability material, before entering the south pole of the lower magnet 42. In other words, a loop is formed by the line connecting the north pole of the upper magnet 42 and the south pole of the lower magnet 42 and the portion of the yoke 43 outside of this line. This loop forms magnetic circuit 45, and because yoke 43 exists continuously between the north pole of magnet 42 arranged above and the south pole of magnet 42 arranged below, leakage magnetic field can also be reduced. Note that magnetic circuit 45 has been described as a loop because it has been explained in cross section, but in reality, magnet 42 and yoke 43 extend in the axial direction, so magnetic circuit 45 also has a cylindrical shape in three dimensions, with the loop being extended in the axial direction. Furthermore, if a through hole is formed in the side wall of yoke 43, magnetic circuit 45 will have a shape that bypasses the through hole (wound around the outside of the through hole).

[0041] Furthermore, the shortest distance d (see FIG. 2) between the side wall of the yoke 43 and the magnet 42 is at least greater than the distance a between the magnets on the same cross section. This prevents the magnetic field lines that leave the north pole of the magnet 42 placed below and head toward the south pole of the magnet 42 placed above from flowing to the side wall of the yoke 43. In other words, it is possible to prevent a decrease in the magnetic field strength (magnetic flux density) of the transmission path.

[0042] The support 44 is made of a low magnetic permeability material and is interposed between the transmission tube 41, the magnet 42, and the yoke 43 to maintain the relative positions of the transmission tube 41, the magnet 42, and the yoke 43 (supporting each component). In this embodiment, the support 44 is provided without any gaps between the transmission tube 41, the magnet 42, and the yoke 43. For example, the support 44 can be made of resin, wood, or the like.

[0043] In the transmission device 4 of the present invention, the above-described configuration allows the magnetic flux density in the transmission path (the internal space of the transmission tube 41) to be 10 mT (tesla) or more (a magnetic field environment of 10 mT or more). Here, the magnetic flux density in the transmission path refers to the magnetic flux density at the portion of the transmission path where the magnetic flux density is minimum. The same applies hereinafter to the magnetic flux density. For example, as in this embodiment ( FIG. 2 ), when magnets 42 with a thickness of 10 mm from north pole to south pole are arranged above and below the transmission path (transmission tube 41), the transmission path can be placed in a magnetic field environment of 350 mT or more. In addition, as shown in FIG. 4 , by arranging the magnets 42 facing each other across the transmission tube 41 with their axial positions offset, the transmission path can be placed in a magnetic field environment of 440 mT or more.

[0044] As described above, according to the present invention, by providing the yoke 43 for forming the loop-shaped magnetic circuit 45 connecting the north and south poles of the magnet 42, it is possible to place the transmission path in a magnetic field environment of at least 10 mT or greater, maintaining a strong magnetic field. This allows the administration of the substance while maintaining its hyperpolarization ability. This allows the administration of the substance hyperpolarized by the polarization device 3 to be transmitted to the imaging device 2 while maintaining its performance, thereby increasing the flexibility in the installation of the polarization device 3 and the imaging device 2. For example, the polarization device 3 and the imaging device 2 can be installed in separate rooms and connected by the transmission device 4. The administration substance hyperpolarized by the polarization device 3 is introduced into the transmission path and transmitted to the imaging device 2 located away from the polarization device 3 while remaining hyperpolarized. The hyperpolarized administration substance is then administered to a living body, and the imaging device 2 can capture the hyperpolarized substance with high imaging sensitivity, thereby obtaining clear images. Furthermore, the yoke 43 can be made of a common magnetic metal material, such as soft iron, which is smaller and less expensive than a magnet. This reduces the manufacturing cost of constructing a high-magnetic-field transmission path and avoids increasing the complexity and robustness of the installation structure. In other words, the administration substance can be transmitted while maintaining its hyperpolarization ability with a simple configuration. This provides a significant cost reduction effect, particularly when the polarization device 3 and the imaging device 2 must be installed separately due to facility restrictions. Furthermore, the use of a yoke 43 made of a magnetic metal material allows the path of magnetic force to be controlled, creating a strong magnetic field within the transmission tube 41, allowing the magnetic field generated by the magnet 42 to be efficiently applied to the administration substance within the transmission tube 41.

[0045] Furthermore, according to the present invention, since multiple magnets 42 are provided on the magnetic circuit 45, the magnetic field (magnetic flux density) in the transmission path can be further increased, and the hyperpolarization ability of the administered substance can be effectively maintained.

[0046] Furthermore, according to the present invention, the yoke 43 is constructed from one or more plate-shaped members, so that the yoke 43 can be constructed by combining members with highly versatile shapes, i.e., inexpensive materials, thereby reducing the manufacturing costs for constructing a high-magnetic field transmission path.

[0047] Furthermore, according to the present invention, the yoke 43 is formed so as to surround (cover) the magnet 42 and the transmission tube 41. Therefore, the yoke 43 exists continuously between the north pole of the magnet 42 arranged above and the south pole of the magnet 42 arranged below, thereby reducing the leakage magnetic field and further increasing the magnetic field (magnetic flux density) in the transmission path. <Configuration of the transmission device of the modified example>

[0048] FIG. 5 is an end view illustrating an example of the configuration of a transmission device 4 according to a modified embodiment. The configuration of the above-described embodiment may be partially modified, and as shown in FIG. 5 , the yoke 43 may be divided into multiple members (a first member 43a and a second member 43b). In this case, the multiple members (the first member 43a and the second member 43b) may be in contact with each other or may be spaced apart. In the example shown in FIG. 5 , the first member 43a and the second member 43b are spaced apart by a predetermined distance c in the vertical direction. When magnetic field lines pass between the first member 43a and the second member 43b, the magnetic field lines spread depending on the length of the distance c. The distance c is set to a distance that allows the magnetic circuit 45 to maintain a magnetic field environment of at least 10 mT along the transmission path, even if the magnetic field lines spread. For example, the separation distance c can be set to a distance shorter than three times the thickness of the yoke 43, preferably a distance shorter than twice the thickness of the yoke 43, and more preferably a distance shorter than the thickness of the yoke 43. Therefore, with the configuration shown in Fig. 5, a magnetic circuit having a loop-shaped cross section similar to the magnetic circuit 45 shown in Fig. 3 can be configured, and the same effects as those of the above embodiment can be obtained.

[0049] FIG. 6 is an end view illustrating another example of the configuration of the transmission device 4 according to the modified embodiment. As shown in FIG. 6 , the yoke 43 may be divided into multiple components (first and second components 43 a and 43 b), and the multiple components (first and second components 43 a and 43 b) may be fixed together with a fixing member 5. For example, flanges extending outward from opposing portions of the first and second components 43 a and 43 b may be formed, and the respective extensions of the first and second components 43 a and 43 b may be fixed together with the fixing member 5. The fixing member 5 is formed of a high-permeability material, for example, a material having a relative permeability similar to that of the yoke 43 (the same material as the yoke 43). The fixing member 5 may be, for example, a bolt 51 and a nut 50, but is not limited thereto. The configuration shown in FIG. 6 also allows for the formation of a magnetic circuit with a loop cross section similar to the magnetic circuit 45 shown in FIG. 3 , and provides the same effects as those of the above embodiment. Furthermore, the degree of freedom in the shape of the yoke 43 is increased, and the manufacturing cost of the yoke 43 can be reduced.

[0050] FIG. 7 is an end view illustrating another example of the configuration of the transmission device 4 according to a modified embodiment. As shown in FIG. 7 , the yoke 43 and the magnet 42 may be directly fixed by a fixing member 5. This eliminates the need for the support 44, reducing the manufacturing cost of constructing a high-magnetic-field transmission path. However, when the fixing member 5 is a bolt 51 and a nut 50 and the yoke 43 and the magnet 42 are fixed by the bolt 51 and the nut 50, it is preferable to position the bolt 51 and the nut 50 so that the axial direction of the bolt 51 is aligned with (or approximately aligned with) the direction connecting the south pole of the magnet 42. The configuration shown in FIG. 7 also allows for the construction of a magnetic circuit with a loop cross section similar to the magnetic circuit 45 shown in FIG. 3, and provides the same effects as the above embodiment.

[0051] FIG. 8A is an explanatory diagram illustrating another example of the configuration of the transmission device 4 according to a modified embodiment. FIG. 8B is an explanatory diagram illustrating another example of the configuration of the transmission device 4 according to a modified embodiment. As shown in FIGS. 8A and 8B , the magnet 42 may be arranged on only one of the top, bottom, left, and right sides as viewed from the transmission tube 41. In this case, in addition to the main yoke 43c formed to surround the magnet 42 and the transmission tube 41, a dense first auxiliary yoke 43d extending from the transmission tube 41 toward the main yoke 43c may be provided on the opposite side of the magnet 42 as viewed from the transmission tube 41. In this way, the magnetic field lines generated by the magnet 42 emerge upward from the north pole of the magnet 42, pass through the transmission path (transmission tube 41), pass through the inside of the first auxiliary yoke 43d, and reach the main yoke 43c. Therefore, the magnetic field lines can be efficiently guided to the main yoke 43c, efficiently forming a magnetic circuit 45 and maintaining a strong magnetic field in the transmission path. As shown in FIG. 8B , in addition to the main yoke 43c and first auxiliary yoke 43d, a dense second auxiliary yoke 43e can be provided between the transmission tube 41 and the magnet 42. The second auxiliary yoke 43e has a shape (conical or pyramidal) whose cross-sectional area decreases from the magnet 42 toward the center axis of the transmission tube 41 as it moves from the magnet 42 to the transmission tube 41. This allows the magnetic field lines generated by the magnet 42 to be concentrated toward the center of the transmission tube 41 along the shape of the second auxiliary yoke 43e, thereby maintaining a stronger magnetic field in the transmission path. As described above, the configurations shown in FIGS. 8A and 8B can also be used to form a magnetic circuit with a loop cross section similar to the magnetic circuit 45 shown in FIG. 3, achieving the same effects as the above embodiment. Furthermore, the number of magnets 42 can be reduced, thereby reducing the manufacturing cost of constructing a high-magnetic-field transmission path.

[0052] FIG. 9 is a side view illustrating another example of the configuration of a transmission device 4 according to a modified embodiment. FIG. 10 is a side view illustrating an example of the configuration of a transmission device 4 according to an embodiment that employs the embodiment of FIG. 9. Note that, for ease of explanation, the support 44 is omitted in FIGS. 9 and 10 . When the magnets 42 are arranged only on one of the top, bottom, left, and right sides of the transmission tube 41 as shown in FIG. 9 , a change section 6 that changes the direction of travel of the transmission path can be provided in the transmission device 4 as shown in FIG. 10 . The change section 6 shown in FIG. 10 bends the direction of travel of the transmission path in the vertical direction (the direction in which the south and north poles are aligned). In this case, the magnets 42 are arranged on the outside of the bend, and a yoke 43 is arranged on the inside of the bend. The yoke 43 has a shape that follows the bend of the transmission path. In other words, the magnetic circuit 45 is formed to follow the direction of travel of the transmission path. By adjusting the arrangement of the magnets 42 so that the gaps between the magnets 42 are located at the change section 6 (bend section), the magnets 42 can be general-purpose columnar magnets without requiring a special shape. On the other hand, the yoke 43 needs to be shaped to accommodate the bending, but since the yoke 43 is made of a common metal material such as soft iron and is easier to process than the magnet 42, the increase in manufacturing costs can be kept to a minimum and the degree of freedom in the transmission path can be increased.

[0053] 11A and 11B are plan views illustrating another example of the configuration of the transmission device 4 according to the modified embodiment. For ease of explanation, the yoke 43 and the support 44 are omitted from FIGS. 11A and 11B . As shown in FIGS. 11A and 11B , a transition section 6 that bends the direction of travel of the transmission path horizontally (perpendicular to the direction in which the south and north poles are aligned) can be provided in the transmission device 4. For example, the transition section 6 can be formed by placing a relay magnet (relay magnet) 42a between cylindrical magnets 42. For example, a relay magnet 42a with a circular (cylindrical) cross section, as shown in FIG. 11A , or a relay magnet 42a with a polygonal (prismatic) cross section, as shown in FIG. 11B , can be used. This arrangement minimizes increases in manufacturing costs and increases the flexibility of the transmission path. In particular, if a cylindrical relay magnet 42a is used, the distance between the relay magnet 42a and the adjacent magnets 42 can be kept constant regardless of the bending angle, so the bending angle can be freely set. Note that, although Fig. 11B shows an example of a triangular cross section, a sector-shaped cross section or various polygonal shapes may also be used.

[0054] FIG. 12 is an explanatory diagram illustrating another example of the configuration of the transmission device 4 according to a modified embodiment. As shown in FIG. 12 , the magnet 42 can be configured such that at least the magnet 42 at the axial end of the transmission path is an electromagnet 42c. As described above, the imaging device 2 and the polarization device 3 are strong magnetic field devices. If only permanent magnets were used as the magnets 42, it might be impossible to bring both longitudinal ends of the transmission device 4 close to the imaging device 2 and the polarization device 3. In this case, a large gap (zero magnetic field) would be created between the imaging device 2 and the polarization device 3 and the transmission device 4, respectively, and the hyperpolarization ability of the administered substance would be lost when passing through this gap. In contrast, the magnet 42 at the axial end of the transmission path can be configured as an electromagnet 42c. A current can be passed through the electromagnet 42c to generate a magnetic force only when the administered substance is being transmitted, and no current can be passed through the electromagnet 42c when the administered substance is not being transmitted, preventing the electromagnet 42c from generating a magnetic force. In this way, when the administered substance is not being transmitted, no magnetic force is generated at either end of the longitudinal direction of the transmission device 4, so that the device can be brought closer to the imaging device 2 and the polarization device 3, thereby effectively maintaining the hyperpolarization ability of the administered substance and increasing safety.

[0055] FIG. 13 is an explanatory diagram illustrating another example of the configuration of the transmission device 4 according to a modified embodiment. As shown in FIG. 13, the components other than the transmission tube 41 (the magnet 42, the yoke 43, and the support 44) may be divided into a first transmission device 4a and a second transmission device 4b midway along the traveling direction. In this case, the first transmission device 4a and the second transmission device 4b are disposed at a predetermined distance apart. However, because the gap between the first transmission device 4a and the second transmission device 4b is a low magnetic field (zero magnetic field) region, the separation distance between the first transmission device 4a and the second transmission device 4b can be set so that the transit time of the administered substance is within one second. In this way, the decrease in the hyperpolarization ability of the administered substance can be minimized.

[0056] The transmission device of the present invention corresponds to transmission device 4 in the above embodiment, and similarly, the imaging device corresponds to imaging device 2, the polarization device corresponds to polarization device 3, the cylindrical member corresponds to transmission tube 41, the magnet corresponds to magnet 42, the magnetic circuit forming member corresponds to yoke 43, the fixed member corresponds to fixed member 5, and the changing portion corresponds to changing portion 6, but the present invention is not limited to this embodiment and can be embodied in various other ways. Furthermore, the specific configurations and the like given in the above embodiment are merely examples and can be modified as appropriate depending on the actual product.

[0057] For example, in the above-described embodiment, the yoke 43 may have outer protrusions that protrude outward from the upper wall, side walls, and lower wall. In this case, the outer protrusions have little effect on the magnetic circuit 45, and therefore the same effect as in the above-described embodiment can be obtained.

[0058] In the above embodiment, the support 44 is provided without any gaps between the transmission tube 41, the magnet 42, and the yoke 43, but this is not a limitation. The support 44 does not contribute to the configuration of the magnetic circuit, and therefore may have any shape as long as it can function to support each component. For example, the support 44 may be provided only in a portion of the internal space of the yoke 43, or a portion of the support 44 may protrude outside the yoke 43.

[0059] The present invention can be used in industries that use imaging devices that utilize nuclear magnetic resonance to produce images of information about the inside of a living body as an imaging target.

[0060] REFERENCE SIGNS LIST 1...imaging system 2...imaging device 3...polarizing device 4...transmission device 41...transmission tube 42...magnet 43...yoke 44...support

Claims

1. 1. A transmission device for use in transporting hyperpolarized material to a point of use of said material, comprising: a cylindrical member that forms a transmission path through which the substance is transmitted; a magnet that generates a magnetic field in the transmission path; a yoke member having a relative magnetic permeability of 100 or more, which is arranged to form a magnetic circuit with the magnet. Transmission equipment.

2. a plurality of the magnets are provided in the magnetic circuit, The yoke member is characterized in that the magnetic field lines generated from the magnet pass through the transmission path to form a loop-shaped magnetic circuit connecting the north pole and south pole of the magnet. The transmission device according to claim 1 .

3. The yoke member is characterized in that it is composed of one or more plate-shaped members.

3. The transmission device according to claim 2.

4. The magnet further includes a fixing member having a relative magnetic permeability of 100 or more for fixing the magnet and the yoke member.

4. The transmission device according to claim 3.

5. The yoke member is formed so as to surround the magnet and the cylindrical member.

5. The transmission device according to claim 4.

6. The magnetic circuit further includes a changer that changes the direction of travel of the transmission path and causes the magnetic circuit to follow the direction of travel of the transmission path.

6. The transmission device according to claim 5.

7. At least the magnet at the end of the transmission path in the axial direction is an electromagnet. The transmission device according to any one of claims 1 to 6.

8. The magnetic field applied to the transmission path has a magnetic flux density of 10 mT or more. The transmission device according to any one of claims 1 to 6.

9. The magnetic field applied to at least the transmission path has a magnetic flux density of 100 mT or more. The transmission device according to any one of claims 1 to 6.

10. At least the source of the transmission path is a hyperpolarization device. The transmission device according to any one of claims 1 to 6.

11. At least the destination of the transmission path is a detection device or an imaging device using a magnetic resonance method. The transmission device according to any one of claims 1 to 6.

12. A transmission device is used that has a cylindrical member that forms a transmission path that can transmit a substance, a magnet that generates a magnetic field in the transmission path, and a yoke member that has a relative permeability of 100 or more and is arranged to form a magnetic circuit together with the magnet, The hyperpolarized material is introduced into the transmission path and transported to the point of use. Transmission method.