阅读说明：本技术 Rf线圈 (RF coil ) 是由 Y·关 滨村良纪 于 2021-03-29 设计创作，主要内容包括：目的是提供一种具有良好的高频特性和挠性的RF线圈。有关实施方式的RF线圈具备形成RF线圈元件的3个以上的导电体。上述导电体在空间上相互平行。上述导电体沿着上述RF线圈元件的长度通过独立的多个距离及1个或多个电介质材料相互电气地分离。在上述导电体的每一个中,与上述长度的方向垂直的截面的形状相对于上述导电体各自的轴芯具有各向同性。(An object is to provide an RF coil having good high-frequency characteristics and flexibility. The RF coil according to the embodiment includes 3 or more conductors forming an RF coil element. The conductors are spatially parallel to each other. The conductors are electrically separated from each other by a plurality of independent distances and 1 or more dielectric materials along the length of the RF coil element. In each of the conductors, a shape of a cross section perpendicular to the longitudinal direction has isotropy with respect to an axial core of each of the conductors.)

1. An RF coil, characterized in that,

the RF coil device is provided with more than 3 conductors forming an RF coil element;

the conductors are spatially parallel to each other;

the conductors are electrically separated from each other by a plurality of independent distances and 1 or more dielectric materials along the length of the RF coil element;

in each of the conductors, a shape of a cross section perpendicular to the longitudinal direction has isotropy with respect to an axial core of each of the conductors.

2. The RF coil of claim 1,

the length, the plurality of independent distances, and the dielectric material of the RF coil elements are set such that the RF coil elements are configured to be B0 shimmed or B1 shimmed.

3. The RF coil of claim 1 or 2,

the length, the independent distances, and the 1 or more dielectric materials of the RF coil elements are set so that the RF coil elements are configured to be both B0 shimmed and B1 shimmed.

4. The RF coil of claim 1,

the 3 or more conductors are locally parallel to each other along at least a portion of the length.

5. The RF coil of claim 1,

the 3 or more conductors include a 1 st conductor, a 2 nd conductor, and a 3 rd conductor;

the RF coil further includes:

a 1 st shim circuit connected to the 1 st conductor; and

and a 2 nd shim circuit connected to the 2 nd conductor.

6. The RF coil of claim 1,

at least 1 of the 3 or more conductors has a non-connection end.

7. The RF coil of claim 1,

the above-mentioned 3 or more conductors function as 1 of a transmission coil, a reception coil, and a transmission/reception coil.

8. The RF coil of claim 1,

the RF coil element has flexibility.

9. The RF coil of claim 1,

the 3 or more conductors include a 1 st conductor, a 2 nd conductor, and a 3 rd conductor;

one end of the 1 st conductor is connected to one end of the 2 nd conductor;

the distributed capacitance along at least a portion of the length of the RF coil element is a sum of the distributed capacitance between the 1 st conductor and the 3 rd conductor along at least a portion of the length of the RF coil element and the distributed capacitance between the 2 nd conductor and the 3 rd conductor along at least a portion of the length of the RF coil element.

10. The RF coil of claim 1,

the above-mentioned 3 or more conductors are twisted.

11. The RF coil of claim 1,

one of the 3 or more conductors is formed of a braid, and the dielectric material covering the conductor other than the braid among the 3 or more conductors is surrounded.

12. The RF coil of claim 1,

2 conductors of the 3 or more conductors are formed by knitting;

one of the 2 conductors formed by the braid surrounds a dielectric material covering the conductor not formed by the braid among the 3 or more conductors;

the other of the 2 electrical conductors formed by the above braid surrounds the dielectric material covering the above one electrical conductor.

13. The RF coil of claim 1,

at least 2 of the 3 or more conductors are arranged as coaxial cables;

at least 1 of the 3 or more conductors is not disposed as the coaxial cable.

14. The RF coil of claim 1,

the 3 or more conductors have independent lengths;

the independent lengths, the independent distances, and the 1 or more dielectric materials of the 3 or more conductors are set so that the RF coil elements perform both B0 shimming and B1 shimming and function as a transmitting/receiving coil.

Technical Field

Embodiments disclosed in the specification and drawings relate to an RF coil.

Background

MRI is an image diagnostic method using a magnetic field and RF energy in order to create an internal image of a target (for example, a human patient) without using X-rays or other ionizing radiation. An MRI scanner generates a static magnetic field (B) for polarizing a target₀Field) of the main magnet. In addition, the RF pulse can generate other magnetic fields (B) as the pulse of RF energy is delivered through the target₁A field). MRI scanners may also use B for the purpose of improving the homogeneity of the static magnetic field₀In order to improve the homogeneity of the RF transmission field, B1 shimming is used for shimming coils.

Documents of the prior art

Patent document

Patent document 1: specification of U.S. Pat. No. 6980000

Patent document 2: specification of U.S. Pat. No. 9678180

Disclosure of Invention

Problems to be solved by the invention

One of the problems to be solved by the embodiments disclosed in the specification and the drawings is to provide an RF coil having excellent high-frequency characteristics and flexibility. However, the problems to be solved by the embodiments disclosed in the present specification and the drawings are not limited to the above problems. Problems corresponding to the respective effects of the respective configurations shown in the embodiments described below can be set as other problems.

Means for solving the problems

The RF coil according to the embodiment includes 3 or more conductors forming an RF coil element. The conductors are spatially parallel to each other. The conductors are electrically separated from each other by a plurality of independent distances and 1 or more dielectric materials along the length of the RF coil element. In each of the conductors, a shape of a cross section perpendicular to the longitudinal direction has isotropy with respect to an axial core of each of the conductors.

Drawings

Fig. 1A shows an exemplary embodiment of a medical imaging system.

FIG. 1B shows a cross-sectional model view of the exemplary embodiment of the MRI apparatus shown in FIG. 1A along line A-A.

Fig. 2A shows an exemplary embodiment of a radio frequency ("RF") coil.

Fig. 2B shows a cross-sectional view of the RF coil shown in fig. 2A along line a-a.

Fig. 2C shows 1 region of the capacitances of the RF coil of fig. 2A which overlap each other.

Fig. 2D illustrates connections between components of the RF coil of fig. 2A in other exemplary embodiments.

Fig. 3A shows an exemplary embodiment of an RF coil.

Fig. 3B shows a cross-sectional view of the RF coil shown in fig. 3A along line a-a.

Fig. 3C shows an exemplary embodiment of the circuitry of the RF coil.

Fig. 4A shows an exemplary embodiment of an RF coil.

Fig. 4B shows a cross-sectional view of the RF coil shown in fig. 4A along line a-a.

FIG. 4C illustrates a cross-sectional view of the RF coil shown in FIG. 4A along line A-A in accordance with another embodiment.

Fig. 5A shows an exemplary embodiment of an RF coil.

Fig. 5B shows a cross-sectional view of the RF coil shown in fig. 5A along line a-a.

Fig. 6 shows an exemplary embodiment of an RF coil.

Fig. 7A shows an exemplary embodiment of an RF coil.

Fig. 7B shows a cross-sectional view of the RF coil shown in fig. 7A along line a-a.

Fig. 8A shows an exemplary embodiment of an RF coil.

Fig. 8B shows a cross-sectional view of the RF coil shown in fig. 8A along line a-a.

Fig. 9A shows an exemplary embodiment of an RF coil.

Fig. 9B shows a cross-sectional view of the RF coil shown in fig. 9A along line a-a.

Fig. 9C shows a cross-sectional view of the RF coil of the other embodiment of fig. 9A along line a-a.

Fig. 9D shows a cross-sectional view of the RF coil of the other embodiment of fig. 9A along line a-a.

Fig. 10A shows an exemplary embodiment of an RF coil.

Fig. 10B shows a cross-sectional view of the RF coil shown in fig. 10A along line a-a.

Fig. 10C shows a cross-sectional view of the RF coil shown in fig. 10A along line B-B.

Fig. 11A shows an exemplary embodiment of an RF coil.

Fig. 11B shows a cross-sectional view of the RF coil shown in fig. 11A along line a-a.

Fig. 11C shows a cross-sectional view of the RF coil shown in fig. 11A along line B-B.

Fig. 12A shows an exemplary embodiment of an RF coil.

Fig. 12B shows a cross-sectional view of the RF coil shown in fig. 12A along line a-a.

Fig. 12C shows a cross-sectional view of the RF coil shown in fig. 12A along line B-B.

Fig. 13A shows an exemplary embodiment of an RF coil.

Fig. 13B shows a cross-sectional view of the RF coil shown in fig. 13A along line a-a.

Fig. 13C shows a cross-sectional view of the RF coil shown in fig. 13A along line B-B.

Fig. 14A shows an exemplary embodiment of an RF coil shape.

Fig. 14B shows an exemplary embodiment of an RF coil shape.

Fig. 14C shows an exemplary embodiment of an RF coil shape.

Fig. 14D shows an exemplary embodiment of an RF coil shape.

Fig. 14E shows an exemplary embodiment of an RF coil shape.

Fig. 14F shows an exemplary embodiment of an RF coil shape.

Fig. 14G shows an exemplary embodiment of an RF coil shape.

Fig. 14H shows an exemplary embodiment of an RF coil shape.

Fig. 14I shows an exemplary embodiment of the RF coil shape.

Fig. 15A shows an exemplary embodiment of an RF coil array.

Fig. 15B shows an exemplary embodiment of an RF coil array.

Fig. 15C shows an exemplary embodiment of an RF coil array.

Fig. 15D shows an exemplary embodiment of an RF coil array.

Figure 15E shows an exemplary embodiment of an RF coil array.

Fig. 15F shows an exemplary embodiment of an RF coil array.

Figure 15G shows an exemplary embodiment of an RF coil array.

Fig. 15H shows an exemplary embodiment of an RF coil array.

Fig. 16A shows an exemplary embodiment of an RF coil.

Fig. 16B shows the capacitance between the conductors shown in fig. 16A.

Fig. 17A shows an exemplary embodiment of an RF coil.

Fig. 17B shows capacitance between the conductors shown in fig. 17A.

Fig. 18A shows an exemplary embodiment of an RF coil.

Fig. 18B shows an exemplary embodiment of an RF coil.

Fig. 19A shows an exemplary embodiment of an RF coil.

Fig. 19B shows an exemplary embodiment of an RF coil.

Fig. 20 shows an exemplary embodiment of an RF coil.

Fig. 21A shows an exemplary embodiment of an RF coil.

Fig. 21B shows an exemplary implementation of the matching and decoupling circuit.

Fig. 22A shows an exemplary embodiment of an RF coil.

Fig. 22B shows an exemplary implementation of the matching and decoupling circuit.

Fig. 23 shows an exemplary embodiment of an RF coil.

Fig. 24 shows an exemplary embodiment of an RF coil.

Fig. 25 shows an exemplary embodiment of an RF coil.

Fig. 26A shows an exemplary embodiment of a cross-sectional view of an RF coil.

Figure 26B shows an exemplary embodiment of a cross-sectional view of an RF coil.

Fig. 26C shows an exemplary embodiment of a cross-sectional view of an RF coil.

Figure 26D shows an exemplary embodiment of a cross-sectional view of an RF coil.

Figure 26E shows an exemplary embodiment of a cross-sectional view of an RF coil.

Fig. 26F shows an exemplary embodiment of a cross-sectional view of an RF coil.

Figure 26G shows an exemplary embodiment of a cross-sectional view of an RF coil.

Fig. 26H shows an exemplary embodiment of a cross-sectional view of an RF coil.

Detailed Description

Embodiments are described in the following paragraphs. Other embodiments may include alternatives, equivalents, and modifications. Moreover, the described embodiments may incorporate new features, and certain features may not be necessary in certain embodiments of the devices, systems, methods described herein.

Fig. 1A shows an exemplary embodiment of a medical imaging system 10. The medical imaging system 10 includes at least 1 Magnetic Resonance Imaging (MRI) apparatus 100, 1 or more image generation apparatuses 110 each of which is a specifically configured computing apparatus (for example, a specifically configured desktop computer, a specifically configured notebook computer, and a specifically configured server), and a display apparatus 120.

The MRI apparatus 100 is configured to scan a region (e.g., a region, a volume, or a slice) of a target (e.g., a patient) by using a magnetic resonance imaging method and acquire scan data. The 1 or more image generating apparatuses 110 acquire scan data from the MRI apparatus 100 and generate an image of a target region based on the scan data. After the 1 or more image generation devices 110 generate the image, the 1 or more image generation devices 110 transmit the image to the display device 120 that displays the image.

FIG. 1B shows a cross-sectional model view along line A-A of the illustrative embodiment of the MRI apparatus 100 shown in FIG. 1A. The MRI apparatus 100 generates a static magnetic field (B)₀Magnetic field) 102. The main magnet 102 is hollow and cylindrical. The MRI apparatus 100 may include 1 or more RF whole-body coils 104, as well as the gradient magnetic field coil 103. The MRI apparatus 100 may house the gradient magnetic field coil 103 and the RF whole-body coil 104 (for example, on the inner periphery of the main magnet 102). In addition to the RF whole body coil 104 included in the MRI apparatus 100, 1 or more RF coils 130 (for example, one or more RF coils 130) may be usedPhased array coils, surface coils) are housed in other coil housing devices 105, or housings of felts, covers, shields placed on the patient, and the like. The MRI apparatus 100 or another computing apparatus having a particular configuration can function as a control apparatus for the RF coil 130.

The RF coil includes an RF transmit coil, an RF receive coil, and an RF transceiver coil. RF transmit coil generation to generate₀Magnetic field perpendicular B₁RF pulses of magnetic field. Rotating the macroscopic magnetization (net magnetization) so that it has a distance of B₀The reference of the magnetic field is far away, resulting in transverse magnetization precession. The RF transmission coil may be configured to have a Larmor frequency ω (Larmor frequency)_rMake B₁The magnetic field vibrates, resulting in precessing magnetization that generates a transverse magnetic field. Ralmo frequency omega_rDependent on the mass of a precessing system (e.g. nucleus of a substance constituting a target to be scanned) and B₀The strength of the magnetic field.

The RF receiving coil detects B via electromagnetic induction generating induced electromotive force (EMF)₁Precessional magnetization by the magnetic field. The detected induced EMF may also be used as scan data, or the scan data may be other data based on the detected induced EMF. The RF transmitting/receiving coil is a coil that combines the functions of an RF transmitting coil and an RF receiving coil.

The RF receiving coil, the RF transmitting coil, and the RF transmitting/receiving coil are resonant circuits (for example, LC resonant circuits) including tuned electric components. The tuned RF coil has a capacitance (C) (and sometimes an inductance (L) similar to the capacitance) where the resonance frequency of the RF coil coincides with a desired frequency (e.g., the frequency of nuclear magnetic resonance of spins of a substance constituting the tissue of the patient). At this resonance frequency, small external perturbations (small external perturbations) by the precessional magnetization produce a large response from the RF coil. The RF coil includes 3 or more conductors forming an RF coil element.

Fig. 2A shows an exemplary embodiment of an RF coil. The RF coil 230 includes 3 dielectric covered conductors 231A to C (e.g., covered conductors) constituting an RF coil element. Each of the dielectric covered conductors 231A to C includes a separate conductor (e.g., transmission line). In this way, the RF coil 230 includes 3 conductors 232A to C (collectively referred to as "conductors 232"), and the conductors 232 are arranged so as to be partially connected in parallel (or so that the distance between 2 closest portions of 2 conductors is constant or substantially constant over the length of the conductors 232) and so as to form a closed RF loop. That is, the conductive bodies 232 are spatially parallel to each other. For example, the electrical conductor 232 may also be a copper wire, 1 or more copper layers on the top or bottom surface of a flexible PCB substrate, 1 or more copper layers sandwiched by thin layers of Polyimide (Polyimide) or dielectric material, copper wiring, or other electrically conductive material. In the present embodiment and other embodiments described herein, at least some of the gauges (cross-sectional diameters) of the conductors 232 may be the same, or all of the gauges may be different from each other. In addition, conductor 232 may also be comprised of a plurality of smaller conductors (e.g., twisted wires).

In the present embodiment, each conductor 232 is covered (e.g., encased or wrapped) by a separate dielectric material 234A-C (collectively referred to as "dielectric material 234"). That is, the conductors 232 are electrically separated from each other by a plurality of independent distances and 1 or more dielectric materials along the length (longitudinal direction) of the RF coil element. At least some of the 1 st, 2 nd, and 3 rd dielectric materials 234A, 234B, 234C may also be the same dielectric material, or may all be different from each other. Fig. 2B shows a cross-sectional view of the RF coil 230 shown in fig. 2A along line a-a. As shown in fig. 2B, in each of the conductors, the shape of the cross section perpendicular to the longitudinal direction is isotropic with respect to the axial core of each of the conductors. That is, the RF coil element is formed of a structure having isotropy with respect to its own axial core. Therefore, the RF coil element having the conductor has flexibility capable of bending in any direction. In other words, the RF coil element is formed of a structure that can allow bending in any direction.

End of conductor 232 and B₀Shim circuits 241, B₁Shim circuit 242, matching and decouplingThe circuit 243, 1 or more of the at least 1 capacitor 244 are coupled (e.g., connected). For example, in the case where 3 or more conductors include the 1 st conductor, the 2 nd conductor, and the 3 rd conductor, the RF coil includes the 1 st shim circuit connected to the 1 st conductor and the 2 nd shim circuit connected to the 2 nd conductor. For example, in the 1 st shim circuit is B₀In the case of the shim circuit 241, the 2 nd shim circuit is B₁A shim circuit 242. The illustrative embodiment of the RF coil 230 has only a single break point capacitor 244. In this embodiment, the 1 st conductor 232A has (i) the 1 st terminal connected to the capacitor 244 and the matching and decoupling circuit 243 and (ii) the B terminal₁A 2 nd end to which a shim circuit 242 is connected. The 2 nd conductor 232B has (i) and (B)₀The 1 st end of the shim circuit 241 and (ii) to B₀A 2 nd end to which a shim circuit 241 is connected. The 3 rd conductor 232C has (i) and B₁A 1 st terminal to which the shim circuit 242 is connected and (ii) a 2 nd terminal to which the capacitor 244 and the matching and decoupling circuit 243 are connected.

The dielectric material 234 maintains the electrical separation of the electrical conductors 232 throughout the length of the RF coil 230, but the electrical conductors 232 have overlapping capacitances. For example, fig. 2C shows 1 region of the capacitances of the RF coil 230 of fig. 2A that overlap each other. Since the 1 st conductor 232A is separated from the 2 nd conductor 232B by the dielectric material and overlaps the 2 nd conductor 232B along the length of the RF coil 230 (for example, the circumference of the RF coil 230 or the outer circumference of the RF coil 230), the 1 st conductor 232A and the 2 nd conductor 232B generate capacitances overlapping each other in the overlapping region 239. The capacitance of the conductors 232 overlapping each other can function as 1 or more additional break-point capacitors along the length of the RF coil 230.

If the radius r is set_aLine A and radius r_bWhen the line B is parallel to each other and is separated from the line a by the distance D, the capacitance C between the line a and the line B can be described as follows.

[ numerical formula 1]

Here,. epsilon.is the dielectric constant, and L is the overlap length. At D>>r_aAnd r_bIn the case of (2), the following equation is used.

[ numerical formula 2]

The parameters of the RF coil 230, the 1 st conductor 232A, the 2 nd conductor 232B, and the dielectric material 234 may be selected by the configuration of the capacitors overlapping with the conductors 232 to tune the RF coil 230. The parameters include, for example, the size (e.g., diameter) of the RF coil 230, the shape of the RF coil 230, the distance between the conductors 232, the material constituting the conductors 232, the cross-sectional diameter (gauge) of the conductors 232, the length of the overlap of the conductors 232, the material constituting the dielectric material 234, the thickness of the dielectric material 234, and the capacitance of the capacitor 244.

The switching circuit (e.g. of the control device) being such that B₀Shim circuits 241, B₁The shim circuit 242 and the matching and decoupling circuit 243 may be used or may be effective by other methods. When it is effective (for example, when a current or a voltage is supplied to the RF coil 230), B₀The shim circuit 241 causes the RF coil 230 to generate B₀Variation in the magnetic field (variance) compensates the magnetic field. In case of being effective, B₁The shim circuit 242 causes the RF coil 230 to perform B₁And (4) shimming. Furthermore, some embodiments of the RF coil 230 and other RF coils described herein do not include B₀Shim circuit 241, B not provided₁Shim circuit 242, or B₀Shim circuits 241 or B₁None of the shim circuits 242 is provided.

Furthermore, some embodiments of the matching and decoupling circuitry 243 function the RF coil as 1 or more of an RF transmit coil, an RF receive coil, and an RF transmit/receive coil when effective. Furthermore, some embodiments of the RF coil 230 and other RF coils described herein are configured to function only as a transmitting coil, and some embodiments of the RF coil 230 and other RF coils described herein are configured to function only as a receiving coil. The matching and decoupling circuit 243 may be used for impedance matching or noise matching between the RF coil 230 and another circuit (for example, an amplifier such as a low noise amplifier). In addition, in an array of RF coils 230 (e.g., the array shown in fig. 15A-15H), matching and decoupling circuitry 243 decouples (e.g., reduces coupling due to mutual inductance) the RF coils 230 of the array.

Fig. 2D illustrates connections between components of the RF coil of fig. 2A in other exemplary embodiments. In this embodiment, one side of the capacitor 244 is connected to both the 1 st conductor 232A and the 2 nd conductor 232B, and the other side of the capacitor 244 is connected to only the 3 rd conductor 232C.

The RF coil may have another configuration as described in the embodiments below.

Fig. 3A shows an exemplary embodiment of an RF coil. Fig. 3B shows a cross-sectional view of the RF coil shown in fig. 3A along line a-a. The RF coil 330 (like the RF coil 23 of fig. 2A) forms a loop, but in fig. 3A, the opposite half of the capacitor 344 of the RF coil 330 is not illustrated.

This embodiment is similar to the embodiment shown in fig. 2A, but the dielectric covered conductors 331A-C are twisted (e.g., in a triple helix) or twisted by other means. Thus, the cross-sectional views of the RF coils 330 are different. In some embodiments of the RF coil shown in FIG. 3A, the dielectric covered conductors 331A-C are not twisted, but have a cross-sectional view similar or identical to the cross-sectional view shown in FIG. 3B.

The twist of the dielectric covered conductors 331A-C is also a parameter that can be adjusted for tuning the RF coil 330. The dielectric covered conductors 331A to C include conductors 332A to C and dielectric materials 334A to C, respectively. At least some of the dielectric materials 334A-C may be the same or all may be different. The conductors 332A to C are twisted, but the distance between 2 closest portions of any 2 of the conductors 332A to C may be constant or substantially constant over the length of the conductors 332A to C.

End portions of conductors 332A-C andB₀shim circuits 341, B₁1 or more of the shim circuit 342, the matching and decoupling circuit 343, the capacitor 344. In this embodiment, the 1 st conductor 332A has (i) a 1 st terminal connected to the capacitor 344 and the matching and decoupling circuit 343 and (ii) B₁A 2 nd end to which a shim circuit 342 is connected. The 2 nd conductor 332B has (i) and (B)₁A 1 st terminal to which the shim circuit 342 is connected and (ii) a 2 nd terminal to which the capacitor 344 and the matching and decoupling circuit 343 are connected. The 3 rd conductor 332C has (i) and B₀The 1 st end connected with the shimming circuit 341 and (ii) connected with B₀A 2 nd end to which a shim circuit 341 is connected.

Furthermore, in other embodiments of the RF coil 330, the structure of the capacitor 344 and the matching and decoupling circuit 343 may also be different, as indicated by block 349. Fig. 3C shows an exemplary embodiment of the circuitry of the RF coil. This circuit represents other implementations of the circuit shown in block 349. This embodiment is provided with a decoupling or tuning circuit 345 separate from the matching network 346 provided with matching circuits. In addition, this embodiment includes 2 capacitors 344A to B. Further, this embodiment of the circuit shown in block 349 may also be used with other embodiments of the RF coil 330 (e.g., other embodiments described herein).

In this embodiment and other embodiments described herein, B₀Shim circuits 341, B₁The shim circuit 342 and the matching and decoupling circuit 343 are combined with a control device (e.g., an MRI device, a specially configured computing device) that controls their operations.

Fig. 4A shows an exemplary embodiment of an RF coil, and fig. 4B shows a cross-sectional view of the RF coil shown in fig. 4A along line a-a. The RF coil 430 includes 2 dielectric covered conductors 431B to C and another conductor 432A not covered with a dielectric. The 2 dielectric covered conductors 431B to C and the other conductor 432A form an RF coil element. Each of the dielectric covered conductors 431B to C includes conductors 432B to C and dielectric materials 434B to C, respectively. The dielectric materials 434B to C may be the same or different from each other. Thus, the RF coil 430 includes 3 conductors 432A-C forming a closed RF loop.

One 1 of conductors 432B has a non-connected end 433B (e.g., floating end). The length of the conductor 432B having the non-connection terminal 433B can be adjusted, and this adjustment can be used for tuning the RF coil 430.

The other ends of the conductors 432A-C and B₀Shim circuit 441, B₁1 or more of the shim circuit 442, the matching and decoupling circuit 443, the capacitor 444. In this embodiment, the 1 st conductor 432A has (i) and (B)₁A 1 st terminal to which the shim circuit 442 is connected and (ii) a 2 nd terminal to which the capacitor 444 and the matching and decoupling circuit 443 are connected. The 2 nd conductor 432B has (i) a 1 st terminal connected to the capacitor 444 and the matching and decoupling circuit 443 and (ii) a non-connecting terminal 433B. The 3 rd conductor 432C has (i) and B₀The 1 st end of the shim circuit 441 and (ii) to B₀Shim circuit 441 and B₁A 2 nd end to which a shim circuit 442 is connected.

FIG. 4C illustrates a cross-sectional view of the RF coil shown in FIG. 4A along line A-A in accordance with another embodiment. In the present embodiment, the conductor 432 not covered with the dielectric is arranged at the same distance or substantially the same distance as the other 2 conductors 432.

Fig. 5A shows an exemplary embodiment of an RF coil, and fig. 5B shows a cross-sectional view of the RF coil shown in fig. 5A along line a-a. The RF coil 530 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 531A, a 2 nd dielectric covered conductor 531B, and a 3 rd dielectric covered conductor 531C (collectively referred to as "dielectric covered conductor 531") constituting the RF coil element. The dielectric covered conductor 531 is arranged in a biaxial (Twinax) configuration. For example, one conductor (conductor 532A) of the 3 or more conductors is formed by braiding a linear conductor such as a copper wire, an iron wire, or an aluminum wire into a mesh-like braid, and is surrounded by a dielectric material (2 nd dielectric-covered conductor 531B, 3 rd dielectric-covered conductor 531C) covering the conductors (conductor 532B, conductor 532C) of the 3 or more conductors in which no braid is formed. In this way, the 1 st dielectric covered conductor 531A includes the conductor 532A (for example, a braided fabric (braided fabric) formed of a braided fabric) surrounding the 2 nd dielectric covered conductor 531B and the 3 rd dielectric covered conductor 531C. The 2 nd dielectric covered conductor 531B and the 3 rd dielectric covered conductor 531C are provided with conductors 532B to C surrounded by dielectric materials 534B to C, respectively. At least some of the 1 st dielectric material 534A, the 2 nd dielectric material 534B, and the 3 rd dielectric material 534C may be the same dielectric material, or may be different. Thus, the RF coil 530 includes the conductors 532A to C forming a closed RF loop.

Ends of conductors 532A-C and B₀Shim circuits 541, B₁1 or more of the shim circuit 542, the matching and decoupling circuit 543, the capacitor 544 are connected. In this embodiment, the 1 st conductor 532A has (i) and (B)₀The 1 st end of the shimming circuit 541 is connected with (ii) and B₀A 2 nd end to which a shim circuit 541 is connected. The 2 nd conductor 532B has (i) and (B)₁A 1 st terminal to which the shim circuit 542 is connected and (ii) a 2 nd terminal to which the capacitor 544 and the matching and decoupling circuit 543 are connected. The 3 rd conductor 532C has (i) the 1 st terminal connected to the capacitor 544 and the matching and decoupling circuit 543 and (ii) the B terminal₁A shim circuit 542 is connected to the 2 nd terminal.

Fig. 6 shows an exemplary embodiment of an RF coil. As shown in fig. 5A, the RF coil 630 includes 3 dielectric covered conductors 631 including a 1 st dielectric covered conductor 631A, a 2 nd dielectric covered conductor 631B, and a 3 rd dielectric covered conductor 631C, which are arranged in a biaxial structure to constitute an RF coil element. Thus, the 1 st dielectric covered conductor 631A includes a conductor 632A surrounding the 2 nd dielectric covered conductor 631B and the 3 rd dielectric covered conductor 631C. That is, conductor 632A is composed of a knitted body, and surrounds 2 nd dielectric covered conductor 631B and 3 rd dielectric covered conductor 631C which cover 2 conductors (632B, 632C) not forming the knitted body, respectively. Further, the 2 nd dielectric covered conductor 631B and the 3 rd dielectric covered conductor 631C are provided with conductors 632B to C, respectively. However, 2 conductors 632B to C have non-contact ends 633B to C, respectively.

The other ends of conductors 632A-C are connected to B₀Shimming circuit 641, B₁1 or more of the shim circuit 642, the matching and decoupling circuit 643, and the capacitor 644. In this embodiment, the 1 st conductor 632A has (i) and (B)₀ShimmingTerminal 1 of circuit 641 and (ii) are connected to B₀Shimming circuit 641, B₁A shim circuit 642, a capacitor 644, and a matching and decoupling circuit 643 are connected at end 2. The 2 nd conductor 632B has (i) and (B)₁The 1 st end of the shim circuit 642 and (ii) the non-connection end 633B. Third conductor 632C has (i) a 1 st terminal connected to capacitor 644 and matching and decoupling circuit 643 and (ii) a non-connected terminal 633C.

Fig. 7A shows an exemplary embodiment of an RF coil, and fig. 7B shows a cross-sectional view of the RF coil shown in fig. 7A along line a-a. The RF coil 730 includes 3 dielectric covered conductors (collectively referred to as "dielectric covered conductors 731") including a 1 st dielectric covered conductor 731A, a 2 nd dielectric covered conductor 731B, and a 3 rd dielectric covered conductor 731C. The dielectric covered conductor 731 is arranged in a triaxial configuration (triaxial configuration) and constitutes an RF coil element. For example, 2 conductors (the 1 st conductor 732A and the 2 nd conductor 732B) out of 3 or more conductors are formed by braiding linear conductors such as copper wires, iron wires, or aluminum wires into a mesh-like braid. At this time, one conductor (2 nd conductor 732B) of the 2 conductors formed by the braid surrounds the dielectric material (3 rd dielectric material 734C) covering the conductor (3 rd conductor 732C) not formed by the braid of the 3 or more conductors. The other conductor (1 st conductor 732A) of the 2 conductors formed by the braid surrounds the dielectric material (2 nd dielectric material 734B) covering the one conductor (2 nd conductor 732B). In this way, the 1 st dielectric covered conductor 731A includes the 1 st conductor 732A surrounding the 2 nd dielectric covered conductor 731B and the 3 rd dielectric covered conductor 731C, and the 2 nd dielectric covered conductor 731B includes the 2 nd conductor 732B surrounding the 3 rd dielectric covered conductor 731C. Therefore, the RF coil 730 includes 3 conductors 732A to C forming a closed RF loop, and the 3 conductors 732A to C are directly surrounded by dielectric materials 734A to C, respectively. At least some of the 1 st, 2 nd, and 3 rd dielectric materials 734A, 734B, 734C may also be the same dielectric material or may all be different.

In this embodiment, the 2 nd conductor 732B has a non-connection end 733B, and the 3 rd conductor 732C has a non-connection end733C. The other ends of the conductors 732A-C are connected to B₀Shim circuit 741, B₁1 or more of the shim circuit 742, the matching and decoupling circuit 743, and the capacitor 744. In this embodiment, the 1 st conductor 732A has (i) and (B)₀The 1 st terminal to which the shim circuit 741, the capacitor 744, the matching and decoupling circuit 743 are connected and (ii) the connection with B₀Shim circuit 741 and B₁The 2 nd end to which the shim circuit 742 is connected. The 2 nd conductor 732B has (i) a 1 st end connected to the capacitor 744 and the matching and decoupling circuit 743 and (ii) a non-contact end 733B. The 3 rd conductor 732C has (i) and B₁The 1 st end to which the shim circuit 742 is connected, and (ii) the non-contact end 733C.

Fig. 8A shows an exemplary embodiment of an RF coil, and fig. 8B shows a cross-sectional view of the RF coil shown in fig. 8A along line a-a. The RF coil 830 includes 3 dielectric covered conductors (collectively referred to as "dielectric covered conductor 831") including a 1 st dielectric covered conductor 831A, a 2 nd dielectric covered conductor 831B, and a 3 rd dielectric covered conductor 831C, and configuring an RF coil element. The 2 nd dielectric covered conductor 831B and the 3 rd dielectric covered conductor 831C are arranged in a coaxial configuration. The 1 st dielectric covered conductor 831A includes a 1 st conductor 832A, and the 2 nd dielectric covered conductor 831B includes a 2 nd conductor 832B surrounding the 3 rd dielectric covered conductor 831C. The 3 rd dielectric covered conductor 831C includes a 3 rd conductor 832C. Therefore, the RF coil 830 includes 3 conductors 832A to C, and the 3 conductors 832A to C are directly surrounded by the dielectric materials 834A to C, respectively. At least some of the 1 st, 2 nd, and 3 rd dielectric materials 834A, 834B, 834C may be the same dielectric material or may all be different.

In the present embodiment, the 1 st conductor 832A has a non-connection end 833A, and the 3 rd conductor 832C has a non-connection end 833C. The other ends of conductors 832A-C are connected to B₀Shim circuits 841, B₁1 or more of the shim circuit 842, matching and decoupling circuit 843, and capacitor 844. In this embodiment, the 1 st conductor 832A has (i) a 1 st terminal connected to the capacitor 844 and the matching and decoupling circuit 843 and (ii) a non-connection terminal 833A. The 2 nd conductor 832B has (i) and B₀The 1 st terminal to which the shim circuit 841, capacitor 844, matching and decoupling circuit 843 are connected and (ii) the 1 st terminal to B₀Shim circuits 841 and B₁A shim circuit 842 connected to the 2 nd terminal. The 3 rd conductor 832C has (i) and B₁The 1 st end of the shim circuit 842 and (ii) the non-contact end 833C.

Some embodiments of the RF coil have more than 3 conductors. For example, fig. 9A shows an exemplary embodiment of an RF coil, and fig. 9B shows a cross-sectional view of the RF coil shown in fig. 9A along line a-a. The RF coil 930 includes 4 dielectric covered conductors (collectively referred to as "dielectric covered conductor 931") including a 1 st dielectric covered conductor 931A, a 2 nd dielectric covered conductor 931B, a 3 rd dielectric covered conductor 931C, and a 4 th dielectric covered conductor 931D, and constitutes an RF coil element. The 1 st dielectric covered conductor 931A includes a 1 st conductor 932A, the 2 nd dielectric covered conductor 931B includes a 2 nd conductor 932B, the 3 rd dielectric covered conductor 931C includes a 3 rd conductor 932C, and the 4 th dielectric covered conductor 931D includes a 4 th conductor 932D. Therefore, the RF coil 930 includes 4 conductors 932A to D, and the 4 conductors 932A to D are covered with the dielectric materials 934A to D, respectively. At least some of the 1 st dielectric material 934A, the 2 nd dielectric material 934B, the 3 rd dielectric material 934C, the 4 th dielectric material 934D may also be the same dielectric material, or may also all be different.

In this embodiment, one end of the 2 nd conductor 932B is connected to one end of the 4 th conductor 932D. The other ends of the conductors 932A-D and B₀Shim circuits 941, B₁1 or more of the shim circuit 942, matching and decoupling circuit 943, capacitor 944. In this embodiment, the 1 st conductor 932A has (i) and (B)₁A 1 st terminal to which the shim circuit 942 is connected, and (ii) a 2 nd terminal to which the capacitor 944, the matching and decoupling circuit 943 are connected. The 2 nd conductor 932B has (i) a 1 st end connected to the 2 nd end of the 4 th conductor 932D and (ii) a second end connected to B₀A shim circuit 941 is connected to the 2 nd terminal. The 3 rd conductor 932C has (i) a 1 st terminal connected to the capacitor 944 and the matching and decoupling circuit 943 and (ii) a terminal connected to B₁A 2 nd end to which a shim circuit 942 is connected. The 4 th conductor 932D has (i) and B₀The 1 st end to which the shim circuit 941 is connected and (ii) the 1 st end to the second end2 the 2 nd terminal connected to the 1 st terminal of the conductor 932B.

In the embodiment shown in fig. 9B, the dielectric covered conductors 931 are partially parallel. The dielectric covered conductors 931 are arranged in a line in the cross-sectional view.

Fig. 9C shows a cross-sectional view of the RF coil of the other embodiment of fig. 9A along line a-a. In this embodiment, the 4 dielectric covered conductors 931 are arranged so that the 1 st conductor 932A and the 4 th conductor 932D are closer to each other than the 1 st conductor 932A and the 4 th conductor 932D in fig. 9B. In addition, in the cross-sectional view, the dielectric covered conductor 931 is arranged to form a diamond shape.

The 4 electrical covered conductors 931A to D may also take other arrangements. For example, fig. 9D shows a cross-sectional view of the RF coil of the other embodiment of fig. 9A along line a-a. In the sectional view, the dielectric covered conductors 931 are arranged in such a manner that the 2 nd dielectric covered conductor 931B, the 3 rd dielectric covered conductor 931C, and the 4 th dielectric covered conductor 931D form a triangle. Further, the 2 nd dielectric covered conductor 931B is closest to the 1 st dielectric covered conductor 931A. Thus, in the cross-sectional view, the dielectric covered conductor 931 is arranged to form substantiallyThe shape of (2). Here, the 1 st dielectric covered conductor 931A is formedShaped rod, 2 nd dielectric covered conductor 931B, 3 rd dielectric covered conductor 931C, 4 th dielectric covered conductor 931DTriangular in shape.

Fig. 10A shows an exemplary embodiment of an RF coil, fig. 10B shows a cross-sectional view of the RF coil shown in fig. 10A taken along line a-a, and fig. 10C shows a cross-sectional view of the RF coil shown in fig. 10A taken along line B-B. The RF coil 1030 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 1031A, a 2 nd dielectric covered conductor 1031B, and a 3 rd dielectric covered conductor 1031C, and constitutes an RF coil. The 1 st dielectric covered conductor 1031A includes a 1 st conductor 1032A, the 2 nd dielectric covered conductor 1031B includes a 2 nd conductor 1032B, and the 3 rd dielectric covered conductor 1031C includes a 3 rd conductor 1032C. Therefore, RF coil 1030 includes 3 conductors 1032A to C, and 3 conductors 1032A to C are covered with dielectric materials 1034A to C, respectively. At least some of the 1 st, 2 nd, and 3 rd dielectric materials 1034A, 1034B, and 1034C may also be the same dielectric material, or may all be different.

In the present embodiment, the 2 nd conductor 1032B and the 3 rd conductor 1032C do not extend over the entire length (e.g., circumference, outer periphery) of the RF coil 1030 and do not overlap each other. In the present embodiment, the 2 nd electrical conductor 1032B and the 3 rd electrical conductor 1032C each extend over about half the length of the RF coil 1030. However, in some embodiments, 2 nd electrical conductor 1032B and 3 rd electrical conductor 1032C are not symmetrical, 1 of 2 nd electrical conductor 1032B and 3 rd electrical conductor 1032C extends more than half way through RF coil 1030, or at least 1 of 2 nd electrical conductor 1032B and 3 rd electrical conductor 1032C does not reach substantially half way through RF coil 1030. The lengths of the 2 nd conductor 1032B and the 3 rd conductor 1032C and the length of the overlap of the conductor and the 1 st conductor 1032A can be adjusted, and this adjustment can be used for tuning of the RF coil 1030.

In addition, the 2 nd conductor 1032B has a non-connection terminal 1033B and an end connected to the matching and decoupling circuit 1043 and the capacitor 1044. The 3 rd electrical conductor 1032C has a non-connecting terminal 1033C and ends for connection to the matching and decoupling circuit 1043 and capacitor 1044. The 1 st conductor 1032A has an input terminal connected to the first conductor B₀2 ends to which shim circuits 1041 are connected. Further, some embodiments are in addition to B₀A shim circuit 1041, which may be other than or in place of B₁A shimming circuit.

Fig. 11A shows an exemplary embodiment of an RF coil, fig. 11B shows a cross-sectional view of the RF coil shown in fig. 11A taken along line a-a, and fig. 11C shows a cross-sectional view of the RF coil shown in fig. 11A taken along line B-B. The RF coil 1130 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 1131A, a 2 nd dielectric covered conductor 1131B, and a 3 rd dielectric covered conductor 1131C. The 1 st dielectric covered conductor 1131A includes a 1 st conductor 1132A, the 2 nd dielectric covered conductor 1131B includes a 2 nd conductor 1132B, and the 3 rd dielectric covered conductor 1131C includes a 3 rd conductor 1132C. Therefore, the RF coil 1130 includes 3 conductors 1132A to 1132C, and the 3 conductors 1132A to C are covered with dielectric materials 1134A to C, respectively. At least some of the 1 st dielectric material 1134A, the 2 nd dielectric material 1134B, and the 3 rd dielectric material 1134C may also be the same dielectric material, or may also all be different.

In this embodiment, the 1 st dielectric covered conductor 1131A and the 2 nd dielectric covered conductor 1131B are coaxially arranged, and the 1 st dielectric covered conductor 1131A and the 3 rd dielectric covered conductor 1131C are coaxially arranged. In this example, the 2 nd conductor 1132B and the 3 rd conductor 1132C each extend only a part of the length of the RF coil 1130 and are located inside the 1 st dielectric covered conductor 1131A. The 2 nd conductor 1132B and the 3 rd conductor 1132C do not overlap each other. The 2 nd conductor 1132B has a non-connection end 1133B and an end connected to the matching and decoupling circuit 1143 and the capacitor 1144. The 3 rd conductor 1132C has a non-connection end 1133C and an end connected to the matching and decoupling circuit 1143 and the capacitor 1144. The 1 st conductor 1132A has an input terminal connected to the input terminal of the first conductor B₀The ends to which the shim circuits 1141 are connected. Further, some embodiments are in addition to B₀A shim circuit 1141, other than or in place of B₁A shimming circuit.

Fig. 12A shows an exemplary embodiment of an RF coil, fig. 12B shows a cross-sectional view of the RF coil shown in fig. 12A taken along line a-a, and fig. 12C shows a cross-sectional view of the RF coil shown in fig. 12A taken along line B-B. The RF coil 1230 includes 4 dielectric covered conductors including a 1 st dielectric covered conductor 1231A, a 2 nd dielectric covered conductor 1231B, a 3 rd dielectric covered conductor 1231C, and a 4 th dielectric covered conductor 1231D. The 1 st dielectric covered conductor 1231A and the 2 nd dielectric covered conductor 1231B are coaxially arranged, and the 3 rd dielectric covered conductor 1231C and the 4 th dielectric covered conductor 1231D are coaxially arranged. The 1 st dielectric covered conductor 1231A includes the 1 st conductor 1232A, the 2 nd dielectric covered conductor 1231B includes the 2 nd conductor 1232B, the 3 rd dielectric covered conductor 1231C includes the 3 rd conductor 1232C, and the 4 th dielectric covered conductor 1231D includes the 4 th conductor 1232D. The conductors 1232A to D are covered with dielectric materials 1234A to D, respectively. At least some of the 1 st, 2 nd, 3 rd, and 4 th dielectric materials 1234A, 1234B, 1234C, 1234D may also be the same dielectric material, or may all be different.

In the present embodiment, the 1 st conductor 1232A and the 2 nd conductor 1232B each extend over about half of the length of the RF coil 1230. The 3 rd conductor 1232C and the 4 th conductor 1232D extend over about half of the other length of the RF coil 1230. Both the 1 st conductor 1232A and the 2 nd conductor 1232B do not overlap with either the 3 rd conductor 1232C or the 4 th conductor 1232D along the length of the RF coil 1230. Further, both the 3 rd conductor 1232C and the 4 th conductor 1232D do not overlap with either the 1 st conductor 1232A or the 2 nd conductor 1232B along the length of the RF coil 1230.

The conductors 1232A to D have non-contact ends 1233A to D, respectively. The 1 st conductor 1232A has an end connected to the 1 st capacitor 1244A, and the 2 nd conductor 1232B has an end connected to the matching and decoupling circuit 1243 and the 2 nd capacitor 1244B. The 3 rd conductor 1232C has an end connected to the 1 st capacitor 1244A, and the 4 th conductor 1232D has an end connected to the matching and decoupling circuit 1243 and the 2 nd capacitor 1244B. In addition, according to the embodiment, the capacitance of the 1 st capacitor 1244A may be equal to the capacitance of the 2 nd capacitor 1244B, or the capacitance of the 1 st capacitor 1244A may be different from the capacitance of the 2 nd capacitor 1244B.

Fig. 13A shows an exemplary embodiment of an RF coil, fig. 13B shows a cross-sectional view of the RF coil shown in fig. 13A along line a-a, and fig. 13C shows a cross-sectional view of the RF coil shown in fig. 13A along line B-B. The RF coil 1330 includes 4 dielectric covered conductors including a 1 st dielectric covered conductor 1331A, a 2 nd dielectric covered conductor 1331B, a 3 rd dielectric covered conductor 1331C, and a 4 th dielectric covered conductor 1331D. The 1 st dielectric covered conductor 1331A includes a 1 st conductor 1332A, the 2 nd dielectric covered conductor 1331B includes a 2 nd conductor 1332B, the 3 rd dielectric covered conductor 1331C includes a 3 rd conductor 1332C, and the 4 th dielectric covered conductor 1331D includes a 4 th conductor 1332D. The conductors 1332A-D are covered with dielectric materials 1334A-D, respectively. At least some of the 1 st dielectric material 1334A, the 2 nd dielectric material 1334B, the 3 rd dielectric material 1334C, and the 4 th dielectric material 1334D may also be the same dielectric material, or may all be different.

In this embodiment, the 1 st conductor 1332A and the 2 nd conductor 1332B each extend over about half of the length of the RF coil 1330. Conductor 3C and conductor 4 1332D extend over about half the other length of RF coil 1330. Both 1 st conductor 1332A and 2 nd conductor 1332B do not overlap with either of 3 rd conductor 1332C and 4 th conductor 1332D along the length of RF coil 1330. Further, both conductor 3C and conductor 4D do not overlap with either conductor 1a and conductor 2B, 1332A and 1332B, along the length of RF coil 1330. However, in some embodiments, conductors 1, 1332A and 1332C are not symmetric, conductors 2, 1332B and 1332D are not symmetric, or at least 1 of conductors 1332A-D do not reach substantially half the length of RF coil 1330.

Conductors 1332A-D have non-connecting ends 1333A-D, respectively. The 1 st conductor 1332A has an end connected to the 1 st capacitor 1344A and the matching and decoupling circuit 1343, and the 2 nd conductor 1332B has an end connected to the 2 nd capacitor 1344B. The 3 rd conductor 1332C has an end connected to the 1 st capacitor 1344A and the matching and decoupling circuit 1343, and the 4 th conductor 1332D has an end connected to the 2 nd capacitor 1344B. In addition, according to the embodiment, the capacitance of the 1 st capacitor 1344A may be equal to the capacitance of the 2 nd capacitor 1344B, or the capacitance of the 1 st capacitor 1344A may be different from the capacitance of the 2 nd capacitor 1344B.

Some embodiments of the RF coil have a shape different from the shape of fig. 2A, 3A, 4A, 5A, 6, 7A, 8A, 9A, 10A, 11A, 12A, 13A. For example, fig. 14A to 14I show an exemplary embodiment of the shape of the RF coil 1430. As shown in fig. 14A to 14I, the shape of the RF coil 1430 is, for example, 1 shape of a butterfly shape, a rectangle, a solenoid shape, a square, an ellipse, a parallelogram, a trapezoid, a polygon, or a circle. The shape of the RF coil can be selected similarly to other parameters, and is configured for a specific application (for example, an RF transmission coil, an RF reception coil, and an RF transmission/reception coil).

Further, the plurality of RF coils may be configured as an RF coil array. Fig. 15A to 15H show an exemplary embodiment of an RF coil array. As represented by the exemplary embodiment of fig. 15A, some RF coil arrays are provided with non-overlapping RF coils 1530. As shown in fig. 15B to 15H, some of the RF coil arrays include RF coils 1530 that are overlapped with various overlapping amounts and arrangements. The shimming circuits, matching and decoupling circuits, control methods used for operating the RF coil array may be constructed according to different applications. For example, the shimming circuitry, matching and decoupling circuitry, and control methods may also be configured based on 1 or more of parameters of the MRI apparatus, the scan pattern, the anatomy of the patient or object being scanned, the material (e.g., tissue) being scanned, the position and orientation of the RF coil 1530 within the RF coil array, including the position and orientation of the RF coil array when deployed around the object being scanned (e.g., the patient).

Fig. 16A shows an exemplary embodiment of an RF coil, and fig. 16B shows capacitances between the conductors shown in fig. 16A. The RF coil 1630 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 1631A, a 2 nd dielectric covered conductor 1631B, and a 3 rd dielectric covered conductor 1631C. The 1 st dielectric covered conductor 1631A includes a 1 st conductor 1632A, the 2 nd dielectric covered conductor 1631B includes a 2 nd conductor 1632B, and the 3 rd dielectric covered conductor 1631C includes a 3 rd conductor 1632C. One end of the capacitor 1644 is connected to both of the 1 st conductor 1632A and the 2 nd conductor 1632B, and the other end of the capacitor 1644 is connected to the 3 rd conductor 1632C.

In fig. 16A, the 1 st conductor 1632A, the 2 nd conductor 1632B and the 3 rd conductor 1632C have non-connection ends 1633A to C, respectively. In some embodiments, however, at least 1 of non-connected ends 1633A-C is connected to 1 or more other circuits (e.g.,matching and decoupling circuit, B₀Shim circuit, B₁A shim circuit). Similarly, at least 1 of the ends of the 1 st conductor 1632A, the 2 nd conductor 1632B, and the 3 rd conductor 1632C connected to the capacitor 1644 may be connected to 1 or more other circuits.

The distributed capacitance between the 1 st 1632A and 3 rd 1632C conductors is C_AC. Further, the distributed capacitance between the 2 nd conductor 1632B and the 3 rd conductor 1632C is C_BC. Therefore, the total distributed capacitance C_TIs C_T＝C_AC+C_BC. Since 2 conductors are connected to one end of the capacitor 1644 and 1 conductor is connected to the other end of the capacitor 1644, the present embodiment of the RF coil 1630 has a wider tuning range or a higher Q value than the other embodiments. This can also be applied to an RF coil having more than 3 conductors as in the embodiment of the RF coil shown in fig. 17A.

Fig. 17A shows an exemplary embodiment of an RF coil, and fig. 17B shows capacitances between the conductors shown in fig. 17A. The RF coil 1730 includes 4 dielectric covered conductors including a 1 st dielectric covered conductor 1731A, a 2 nd dielectric covered conductor 1731B, a 3 rd dielectric covered conductor 1731C, and a 4 th dielectric covered conductor 1731D. The 1 st dielectric covered conductor 1731A includes a 1 st conductor 1732A, the 2 nd dielectric covered conductor 1731B includes a 2 nd conductor 1732B, the 3 rd dielectric covered conductor 1731C includes a 3 rd conductor 1732C, and the 4 th dielectric covered conductor 1731D includes a 4 th conductor 1732D. In addition, the conductors 1732A to D have non-connection ends 1733A to D, respectively.

One end of capacitor 1744 is connected to both of 1 st conductor 1732A and 2 nd conductor 1732B, and the other end of capacitor 1744 is connected to both of 3 rd conductor 1732C and 4 th conductor 1732D.

In FIG. 17A, conductors 1732A-D have non-connecting ends 1733A-D, respectively, but in some embodiments at least 1 of non-connecting ends 1733A-D is connected to 1 or more other circuits (e.g., matching and decoupling circuits, B)₀Shim circuit, B₁A shim circuit). Similarly, the 1 st conductor 1732A and the 2 nd conductor 1732 connected to the capacitor 1744B. At least 1 of the end portions of the 3 rd and 4 th conductors 1732C and 1732D may be connected to 1 or more other circuits.

The distributed capacitance between the 1 st conductor 1732A and the 3 rd conductor 1732C is C_AC. In addition, the distributed capacitance between the 1 st conductor 1732A and the 4 th conductor 1732D is C_AD. In addition, the distributed capacitance between the 2 nd conductor 1732B and the 3 rd conductor 1732C is C_BC. The distributed capacitance between the 2 nd conductor 1732B and the 4 th conductor 1732D is C_BD. Therefore, the total distributed capacitance C_TIs C_T＝C_AC+C_AD+C_BC+C_BD。

As an addition, table 1 shows parameters from an exemplary embodiment of the RF coil.

[ Table 1]

One side of the capacitor is connected to 2 out of 3 conductors (e.g., as shown in fig. 2D), and the other side of the capacitor is connected to only 1 out of 3 conductors.

One side of the capacitor is connected to only 1 of the 3 conductors and the other side of the capacitor is connected to only 1 of the 3 conductors (e.g., as shown in fig. 2A).

Some of the electrical conductors are formed from a plurality of smaller electrical conductors, the cross-sectional diameter being the diameter of the combination of the plurality of smaller electrical conductors.

As described above, the length and overlap of the conductors can be adjusted for tuning the RF coil, for example, as shown in fig. 18A, 18B, 19A, and 19B.

Fig. 18A shows an exemplary embodiment of an RF coil. The RF coil 1830 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 1831A, a 2 nd dielectric covered conductor 1831B, and a 3 rd dielectric covered conductor 1831C. First dielectric covered conductor 1831A includes first conductor 1832A, second dielectric covered conductor 1831B includes second conductor 1832B, and third dielectric covered conductor 1831C includes third conductor 1832C. One end of the capacitor 1844 is connected to both of the 1 st conductor 1832A and the 2 nd conductor 1832B, and the other end of the capacitor 1844 is connected to the 3 rd conductor 1832C. Conductors 1832A to C have non-connection ends 1833A to C, respectively.

In the present embodiment, the conductors 1832A to C extend less than the conductors 1632A to C in fig. 16A with respect to the length (e.g., circumference or outer periphery) of the RF coil 1830. Further, the overlap of conductors 1832A-C along the length of RF coil 1830 is smaller than the overlap of conductors 1632A-C of fig. 16A.

In fig. 18A, electrical conductors 1832A-C have non-contact ends 1833A-C, respectively, but in some embodiments at least 1 of non-contact ends 1833A-C is coupled to 1 or more other circuits (e.g., matching and decoupling circuits, B)₀Shim circuit, B₁A shim circuit). Similarly, at least 1 of the ends of the 1 st conductor 1832A, the 2 nd conductor 1832B and the 3 rd conductor 1832C connected to the capacitor 1844 may be connected to 1 or more other circuits.

Fig. 18B shows an exemplary embodiment of an RF coil. The RF coil 1830 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 1831A, a 2 nd dielectric covered conductor 1831B, and a 3 rd dielectric covered conductor 1831C. First dielectric covered conductor 1831A includes first conductor 1832A, second dielectric covered conductor 1831B includes second conductor 1832B, and third dielectric covered conductor 1831C includes third conductor 1832C.

Second conductor 1832B has non-contact end 1833B. The other ends of conductors 1832A-C and B₀Shim circuits 1841, B₁1 or more of the shim circuit 1842, the matching and decoupling circuit 1843, and the capacitor 1844. In this embodiment, the 1 st conductor 1832A has (i) and (B)₀The 1 st end of the shim circuit 1841 and (ii) connected with B₀Shim circuits 1841 and B₁A 2 nd end to which the shim circuit 1842 is connected. Second conductor 1832B has (i) a 1 st end connected to capacitor 1844 and matching and decoupling circuit 1843 and (ii) a non-contact end 1833B. The 3 rd conductor 1832C has (i) and B₁The 1 st end of the shim circuit 1842 connection and (ii) matching and decoupling with the capacitor 1844Coupling circuit 1843 is connected to terminal 2.

In this embodiment, the 2 nd conductive body 1832B having the non-contact end 1833B extends by a shorter amount with respect to the length of the RF coil 1830 than the conductive body 432 having the non-contact end 433 of fig. 4A.

Fig. 19A shows an exemplary embodiment of an RF coil. The RF coil 1930 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 1931A, a 2 nd dielectric covered conductor 1931B, and a 3 rd dielectric covered conductor 1931C. The 1 st dielectric covered conductor 1931A includes a 1 st conductor 1932A, the 2 nd dielectric covered conductor 1931B includes a 2 nd conductor 1932B, and the 3 rd dielectric covered conductor 1931C includes a 3 rd conductor 1932C.

The 2 nd conductor 1932B and the 3 rd conductor 1932C have non-connection terminals 1933B to 193c, respectively. The 2 nd conductor 1932B and the 3 rd conductor 1932C are connected to the capacitor 1944 at their respective ends. In addition, the end of the 1 st conductor 1932A is coupled to 1 or more other circuits (e.g., matching and decoupling circuits, B)₀Shim circuit, B₁Shim circuits) (not shown in fig. 19A) are connected. Likewise, at least 1 of the ends of the 2 nd and 3 rd conductors 1932B, 1932C connected to the capacitor 1944 may also be connected to 1 or more other circuits.

In contrast to the RF coil 1030 of fig. 10A, in this embodiment, the 2 nd and 3 rd electrical conductors 1932B, 1932C are not symmetrical or substantially symmetrical. Instead, the 2 nd conductor 1932B is substantially shorter than the 3 rd conductor 1932C, and the 3 rd conductor 1932C extends over more than half of the length of the RF coil 1930. Further, the overlap amount of the 3 rd conductor 1932C and the 1 st conductor 1932A along the length of the RF coil 1930 is larger than the overlap amount of the 2 nd conductor 1932B and the 1 st conductor 1932A.

Fig. 19B shows an exemplary embodiment of an RF coil. The RF coil 1930 includes 4 dielectric covered conductors including a 1 st dielectric covered conductor 1931A, a 2 nd dielectric covered conductor 1931B, a 3 rd dielectric covered conductor 1931C, and a 4 th dielectric covered conductor 1931D. The 1 st dielectric covered conductor 1931A includes a 1 st conductor 1932A, the 2 nd dielectric covered conductor 1931B includes a 2 nd conductor 1932B, the 3 rd dielectric covered conductor 1931C includes a 3 rd conductor 1932C, and the 4 th dielectric covered conductor 1931D includes a 4 th conductor 1932D.

The conductors 1932A to D have non-contact ends 1933A to D, respectively. The 1 st conductor 1932A and the 3 rd conductor 1932C have respective ends connected to the 1 st capacitor 1944A. The 2 nd conductor 1932B and the 4 th conductor 1932D have respective ends connected to the 2 nd capacitor 1944B. In addition, at least 1 of the ends of the 1 st conductor 1932A and the 3 rd conductor 1932C that are connected to the 1 st capacitor 1944A may also be connected to 1 or more other circuits (e.g., matching and decoupling circuits, B)₀Shim circuit, B₁Shim circuits) (not shown in fig. 19B) are connected. Further, at least 1 of the end portions of the 2 nd conductor 1932B and the 4 th conductor 1932D connected to the 2 nd capacitor 1944B may be connected to 1 or more other circuits.

In contrast to RF coil 1330 of fig. 13A, in fig. 19B, conductors 1932A and 1932C 1 and 1932C 3 are not symmetrical or substantially symmetrical, and conductors 1932B and 1932D 4 are not symmetrical or substantially symmetrical. Further, the amount of overlap of the 1 st conductor 1932A and the 2 nd conductor 1932B along the length of the RF coil 1930 is greater than the amount of overlap of the 3 rd conductor 1932C and the 4 th conductor 1932D.

Fig. 20 shows an exemplary embodiment of an RF coil. The RF coil 2030 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 2031A, a 2 nd dielectric covered conductor 2031B, and a 3 rd dielectric covered conductor 2031C. The 1 st dielectric covered conductor 2031A includes a 1 st conductor 2032A, the 2 nd dielectric covered conductor 2031B includes a 2 nd conductor 2032B, and the 3 rd dielectric covered conductor 2031C includes a 3 rd conductor 2032C. Ends of conductors 2032A-C and B₀Shim circuit 2041, B₁1 or more of the shim circuit 2042, the transmit/receive circuit 2048, and the capacitor 2044 are connected. The matching and decoupling circuit may be implemented, and the transmission/reception circuit 2048 may be provided with a circuit for supplying voltage or current to make the RF coil 2030 function as 1 of the transmission coil, the reception coil, or the transmission/reception coil. In addition, the switching circuit 2049 switches B₀Shim circuit 2041, B₁The shim circuit 2042 and the transmission/reception circuit 2048 are started and stopped.

Fig. 21 shows an exemplary embodiment of an RF coil. The RF coil 2130 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 2131A, a 2 nd dielectric covered conductor 2131B, and a 3 rd dielectric covered conductor 2131C. The 1 st dielectric covered conductor 2131A includes a 1 st conductor 2132A, the 2 nd dielectric covered conductor 2131B includes a 2 nd conductor 2132B, and the 3 rd dielectric covered conductor 2131C includes a 3 rd conductor 2132C. Respective ends of conductors 2132A-C and B₀Shim circuits 2141, B₁1 or more of the shim circuits 2142, the 1 st capacitor 2144A, the 2 nd capacitor 2144 are connected. In the present embodiment, the matching and decoupling circuit 2143 is connected to the RF coil 2130 via 2 capacitors 2144A to B so as to form 1 capacitor for each connection to the RF coil 2130. The present embodiment of the connection between the RF coil 2130 and the matching and decoupling circuit 2143 can be applied to other RF coils such as the RF coils shown in fig. 3A, 4A, 5A, 6, 7A, 8A, 9A, 10A, 11A, 12A, 13A, 16A, 17A, 18A, and 18B, for example.

Fig. 21B shows an exemplary implementation of the matching and decoupling circuit. In this embodiment, the matching and decoupling circuit 2143 includes a 1 st capacitor 2144A and a 2 nd capacitor 2144B. Some implementations of the matching and decoupling circuit 2143 are provided with only 1 of the 1 st capacitor 2144A and the 2 nd capacitor 2144B. Also, at least 1 of the 1 st capacitor 2144A and the 2 nd capacitor 2144B may also be a tuning capacitor.

Fig. 22A shows an exemplary embodiment of an RF coil. The RF coil 2230 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 2231A, a 2 nd dielectric covered conductor 2231B, and a 3 rd dielectric covered conductor 2231C. The 1 st dielectric covered conductor 2231A includes a 1 st conductor 2232A, the 2 nd dielectric covered conductor 2231B includes a 2 nd conductor 2232B, and the 3 rd dielectric covered conductor 2231C includes a 3 rd conductor 2232C. Ends of conductors 2232A-C and B₀Shimming circuit 2241 and B₁1 of the shim circuit 2242, the matching and decoupling circuit 2243, and the capacitor 2244 are connected. In the present embodiment, among 1 connection of the matching and decoupling circuit 2243 to the RF coil 2230, the matching and decoupling circuit 2243 and the RF coil are connected2230 has a capacitor 2244 therebetween. The present embodiment of the connection between the RF coil 2230 and the matching and decoupling circuit 2243 can be used for other RF coils such as the RF coils shown in fig. 3A, 4A, 5A, 6, 7A, 8A, 9A, 10A, 11A, 12A, 13A, 16A, 17A, 18A, and 18B, for example.

Fig. 22B shows an exemplary implementation of the matching and decoupling circuit. In the present embodiment, the matching and decoupling circuit 2243 includes a capacitor 2244. The capacitor 2244 may be a tuning capacitor.

Fig. 23 shows an exemplary embodiment of an RF coil. RF coil 2330 includes 3 conductors including 1 st conductor 2332A, 2 nd conductor 2332B and 3 rd conductor 2332C. The 2 nd conductor 2332B is a member of the 1 st dielectric covered conductor 2331B, and the 3 rd conductor 2332C is a member of the 2 nd dielectric covered conductor 2331C. End portions of conductors 2332A-C and B₀Shim circuit 2341, B₁1 or more of shim circuit 2342, matching and decoupling circuit 2343, and capacitor 2344 are connected. Unlike the embodiment of the RF coil of fig. 4A, this embodiment does not have a non-connection terminal.

Fig. 24 shows an exemplary embodiment of an RF coil. The RF coil 2430 includes 3 dielectric covered conductors including a 1 st dielectric covered conductor 2431A, a 2 nd dielectric covered conductor 2431B, and a 3 rd dielectric covered conductor 2431C. The dielectric covered conductors 2431A to C are arranged in a concentric triaxial configuration. In this way, the 1 st dielectric covered conductor 2431A includes the 1 st conductor 2432A surrounding the 2 nd dielectric covered conductor 2431B and the 3 rd dielectric covered conductor 2431C, and the 2 nd dielectric covered conductor 2431B includes the 2 nd conductor 2432B surrounding the 3 rd dielectric covered conductor 2431C. Thus, the 3 conductors 2432A-C are each directly surrounded by a separate dielectric material. Ends of conductors 2432A-C and B₀Shim circuit 2441, B₁1 or more of the shim circuit 2442, the matching and decoupling circuit 2443, and the capacitor 2444 are connected. Unlike the embodiment of the RF coil of fig. 7A, this embodiment does not have a non-connection end.

Fig. 25 shows an exemplary embodiment of an RF coil. The RF coil 2530 includes a bag3 dielectric covered conductors including a 1 st dielectric covered conductor 2531A, a 2 nd dielectric covered conductor 2531B and a 3 rd dielectric covered conductor 2531C. The 2 nd dielectric covered conductor 2531B and the 3 rd dielectric covered conductor 2531C are arranged in a concentric axis configuration. The 1 st dielectric covered conductor 2531A includes a 1 st conductor 2532A, and the 2 nd dielectric covered conductor 2531B includes a 2 nd conductor 2532B surrounding the 3 rd dielectric covered conductor 2531C. The 3 rd dielectric covered conductor 2531C includes a 3 rd conductor 2532C. The ends of conductors 2532A-C are connected to B₀Shim circuits 2541, B₁1 or more of the shim circuit 2542, the matching and decoupling circuit 2543, the capacitor 2544. Unlike the embodiment of the RF coil of fig. 8A, this embodiment does not have a non-connection end.

Fig. 26A to 26H show exemplary embodiments of cross-sectional views of the RF coil. As shown in fig. 26A to 26H, a plurality of conductors are surrounded by the same case of dielectric material. This may serve to maintain the distance between the electrical conductors at a desired distance.

Fig. 26A shows a cross-sectional view of dielectric covered conductor set 2631 including 3 conductors 2632A to C surrounded by dielectric material 2634. In the cross-sectional view of the present embodiment, the 3 conductors 2632A-C form a regular triangle or substantially regular triangle.

Fig. 26B shows a cross-sectional view of dielectric-covered conductor set 2631 including 3 conductors 2632A to C surrounded by dielectric material 2634. In the cross-sectional view of this embodiment, 3 conductors 2632A to C are arranged in a line, and the 2 nd conductor 2632B is closer to the 1 st conductor 2632A than the 3 rd conductor 2632C. In the present cross-sectional view, the dielectric material 2634 has a substantially stadium shape (i.e., a rectangle with a circular arc (discordant) or an elongated ellipse (obround)).

Fig. 26C is a cross-sectional view of dielectric covered conductor set 2631 including 3 conductors 2632A to C surrounded by dielectric material 2634. In the cross-sectional view of this embodiment, the 3 conductors 2632A-C form isosceles triangles or points that are substantially isosceles triangles.

Fig. 26D shows a cross-sectional view of dielectric-covered conductor set 2631 including 2 conductors 2632A to B surrounded by dielectric material 2634. In the cross-sectional view of this embodiment, the dielectric material 2634 is substantially stadium shaped.

Fig. 26E shows a cross-sectional view of dielectric-covered conductor set 2631 including 4 conductors 2632A to D surrounded by dielectric material 2634. In the cross-sectional view of this embodiment, 4 conductors 2632A-D are aligned in a row, and the 4 conductors 2632A-D are equally or substantially equally spaced. In this cross-sectional view, the dielectric material 2634 has a substantially stadium shape.

Fig. 26F shows a cross-sectional view of dielectric-covered conductor set 2631 including 4 conductors 2632A to D surrounded by dielectric material 2634. In the cross-sectional view of this embodiment, 4 conductors 2632A-D form diamond-shaped dots. In this cross-sectional view, the dielectric material 2634 is substantially diamond-shaped.

Fig. 26G shows a cross-sectional view of dielectric-covered conductor set 2631 including 4 conductors 2632A to D surrounded by dielectric material 2634. In the cross-sectional view of the present embodiment, 4 conductors 2632A-D are arranged to form a substantially rectangular shapeAnd (4) shape. Here, 3 of the conductors 2632B-D form triangular dots. In the cross-sectional view, the dielectric material 2634 is substantially the sameAnd (4) shape.

Fig. 26H shows a cross-sectional view of dielectric-covered conductor set 2631 including 4 conductors 2632A to D surrounded by dielectric material 2634. In the cross-sectional view of this embodiment, 3 conductors 2632A to C form diamond-shaped dots, and 1 conductor 2632D is located between 2 conductors 2632B to C on the base of the triangle. In the cross-sectional view, the dielectric material 2634 has a substantially triangular shape.

Here, the conjunction "or" generally means an inclusive "or". Where an exclusive or is expressly indicated or where an exclusive or must be implied depending on the context, "or" means an exclusive or.

According to the RF coil of the above-described embodiment, the RF coil element is constituted by 3 or more thin flexible conductors, and these conductors are arranged in close contact with each other. Further, according to the RF coil, the electric conductors are electrically separated by the dielectric material disposed between the electric conductors, thereby forming a wide range of distributed capacitance. As a result, the RF coil can be manufactured with more flexibility, light weight, low cost, and easier adjustment.

According to at least 1 embodiment and the like described above, an RF coil having excellent high-frequency characteristics and flexibility can be provided.

Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments may be implemented in other various forms, and various omissions, substitutions, changes, and combinations of the embodiments may be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Description of the reference symbols

10 medical imaging system

100 MRI apparatus

102 main magnet

103 gradient magnetic field coil

104 RF whole body coil

105 coil housing device

110 image generating device

120 display device

130. 230, 330, 430, 530, 630, 730, 830, 930, 1030, 1130, 1230, 1330, 1430, 1530, 1630, 1730, 1830, 1930, 2030, 2130, 2230, 2330, 2430, 2530 RF coils

239 area

241、341、441、541、641、741、841、941、1041、1141、1841、2041、2141、2241、2341、2441、2541 B₀Shimming circuit

242、342、442、542、642、742、842、942、1042、1142、1842、2042、2142、2242、2342、2442、2542 B₁Shimming circuit

243. 343, 443, 543, 643, 743, 843, 943, 1043, 1143, 1243, 1343, 1843, 2143, 2243, 2343, 2443, 2543 matching and decoupling circuits

244. 344, 444, 544, 644, 744, 844, 944, 1044, 1144, 1644, 1744, 1844, 1944, 2044, 2244, 2344, 2444, 2544 capacitors

345 tuning circuit

346 matching network

349 block

2048 transmitting/receiving circuit

2049 switching circuit

2631 dielectric covered conductor set

2634 dielectric material