JP2021118916A5 - - Google Patents

Description

Mutual reference to related applications This application is a divisional application of Japanese Patent Application No. 2019-137259 submitted on July 25, 2019, and Japanese Patent Application No. 2019-137259 is a divisional application of Japanese Patent Application No. 2018-104096 submitted on May 30, 2018. It is an application, and Japanese Patent Application No. 2018-104096 is a divisional application of Japanese Patent Application No. 2015-557977, and Japanese Patent Application No. 2015-557977 is a domestic transition by the submission of a domestic document dated August 13, 2015. This is a Japanese application corresponding to International Application No. PCT / US2013 / 026006 filed on February 14 . The international application relates to Patent Document 2 filed on August 10, 2012, which claims the benefit of Patent Document 1 filed on August 10, 2011.

Statement on Federally Funded Research and Development This disclosure was not the subject of federal-sponsored research and development.

The present disclosure relates to the establishment of a magnetic field pattern through the application of an electric current; more specifically, the present disclosure relates to an accurate magnetic field in the context of a magnetic resonance imaging (MRI) scanner as well as for deriving information from an object. It relates to the establishment of magnetic field patterns through the application of current in the context of other systems, such as nuclear magnetic resonance spectroscopy, electron normal magnetic resonance imaging, and electron normal magnetic resonance spectroscopy, which also require the above establishment of patterns.

Magnetic resonance imaging (MRI) scanners and other similar devices establish a magnetic field to precisely manipulate the orientation of the magnetic moments that are essentially present within the object. The magnetic moments precisely oriented by these magnetic fields generate electrical signals in the scanner, which are then used to construct a detailed image of the internal composition of the object.

At a given point in time of imaging, within the volume of the scanner specifically designed for imaging, the total magnetic field established within the MRI scanner is typically generated by the scanner within the imaged volume designed. The sum of two or more very different magnetic field patterns. These patterns must be carefully designed and timed so that their net effect results in the desired magnetic moment orientation at a particular point in time. The magnetic field patterns considered important for MR image acquisition are extremely strong and uniform B0 fields; _B1 fields oscillating at radio frequencies; and their respective sizes in the _x , y, and z directions. The x-sloping field, the y-sloping field, and the z-sloping field, which change almost linearly, respectively. _Simming magnetic fields are also frequently used to improve the uniformity of the B0 field.

With the exception of the linear shimming magnetic field ( which can be generated by the same multiple structures that each generate an x-sloping field, a y-sloping field, and a z-sloping field) , each of the above magnetic field patterns is usually a scanner dedicated to that magnetic field pattern. Produced by one or two of the structures, each such structure is either a current configuration or a permanent magnet configuration. For resistant MRI scanners, the non-superconducting electrical configuration is usually involved in all generation of the desired magnetic field pattern.

MR imaging has been applied with great success in disease diagnosis. However, the extension of MRI to disease testing, including cancer testing, is unfortunately relatively limited. Two factors that significantly limit the use of MRI for examination are the relatively high costs commonly associated with MRI scanner construction and the discomfort normally associated with the typically small patient space found within MRI scanners.

One approach to making MRI scanners cheaper and more spacious, and therefore specifically oriented towards disease testing, is to combine multiple magnetic field patterns used in MRI with their respective currents. It will be generated at the same time using a configuration that carries the total. Since all vectors of the B0 field, the tilting field, and the _shimming field are oriented mainly in a single direction, or in the z direction by convention, in principle it is possible to sum the currents in these fields. Conceivable.

However, methods have been developed that appear to be extremely successful in generating multiple tilting and / or _shimming fields with the summed current configuration, especially the B0 field, through the tilting field through the total current configuration. And / or practical means for synthesizing with the shimming world have not yet been introduced. For example, FIG. 14 of Patent Document 3 of Gaphard et al. Can simultaneously establish different MRI magnetic field patterns and consists of a series of parallel coaxial loops connected by regularly spaced line segments oriented at right angles to the plane of the loop. It shows the electrical configuration. Since the current required for the _B0 field is about tens of thousands of amperes when the loop winding is not used, each loop in this structure that contributes to the hypothetical _B0 field can supply an extremely large current. Will have to have a good voltage source. Therefore, assuming at least four loops for a sufficiently uniform _B0 field, the structure has four voltage sources for extremely large currents to generate the _B0 field among its other magnetic field patterns. Will be needed.

FIG. 1 of Patent Document 4 of Watkins et al. Discloses an electrical configuration in which each loop is replaced with a separate loop segment having an independent voltage source , that is, a separate arc. It is clearly possible that the current patterns in each segmented loop and in the structure as a whole represent the sum of the current patterns associated with the different MRI field patterns. However, here, every segment used to contribute to the hypothetical _B0 field will require a voltage source capable of producing tens of thousands of amps. Again, assuming an assembly of at least four loops for the _B0 field, and further assuming that each segmented loop of Watkins et al.'S structure consists of at least four segments, this structure is the other magnetic field of it. If the _B0 field were generated simultaneously with the pattern, 16 power supplies with extremely high current would be required. Beyond its extremely impractical requirements, the extremely high supply and return currents associated with each of the at least 16 segments that contribute to the _B0 field can lead to wasted energy and even within the imager volume of the scanner. It can significantly distort the magnetic field.

US Provisional Patent Application No. 61 / 574,823 International Application No. PCT / US2012 / 050462 US Pat. No. 6,492,817 US Pat. No. 6,933,724

Establish a _B0 field with one or more other magnetic field patterns through the summed current configuration without the need for multiple voltage sources of extremely high current or without having to deal with the other problems described above. It is an object of the present disclosure to provide possible systems and methods.

This object is achieved in accordance with the present disclosure through embodiments with a conduction loop with a thick cross-sectional area and a single voltage source capable of generating extremely high currents. The antiparallel segments of the loop are brought very close to each other, which means that the loop is effectively "tightened" at one or more locations, and each pair of antiparallel segments is nearly zero in the scanner's imaging volume. It means that it contributes to the magnetic field of. The unpaired segments in this loop are shaped to collectively form a uniform _B0 field. The voltage source then obtains the redistribution of the current in this thick loop so that it simultaneously establishes the required tilt and / or _shimming fields in addition to its B0 field. Short the current from one point in this thick loop to another.

A better understanding of the disclosed systems and methods for the simultaneous establishment of the _B0 field and other magnetic field patterns using a single thick loop may be obtained by referring to the drawings below:

FIG. 1 is a single thick loop capable of generating a B0 field, an x-sloping field, a y-sloping field, and a z-sloping field, with a thick line of a single thick loop to which _a current shunt is attached. It is a schematic circuit diagram shown as. FIG. 2 is a schematic schematic showing an actual current pattern that may be associated with any one of the circular structures within the single thick loop of FIG. FIG. 3 shows what the schematic schematic embodiment represented by FIG. 1 may actually look like in an MRI scanner, and FIG. 3A is of FIG. 1 to prepare for conversion to a physical embodiment. Showing the changes made to the schematic schematic, FIG. 3B shows how the actual physical embodiment of FIG. 1 appears, and FIG. 3C shows the annular and tubular structures of the physical embodiment of FIG. 3B. Showing how they are connected to each other, FIG. 3D illustrates the use of nested within the tubular structure of the physical embodiment of FIG. 3B. FIG. 4 presents an alternative embodiment of FIG. ₁ that simultaneously generates a B0 field and other magnetic field patterns via a shared current configuration. FIG. 5 also presents an alternative embodiment of FIG. ₁ that simultaneously produces a B0 field and other magnetic field patterns via a shared current configuration. FIG. 6A shows that a single thin loop can be used to form the z-slope, and the attached current shunt allows this single thin loop to also establish an x-slope and a y-slope. A structure similar to FIG. 1 that is possible is shown. FIG. 6B shows how the acoustic vibration of the structure of FIG. 6A can be reduced. FIG. 6C also shows how the acoustic vibration of the structure of FIG. 6A can be reduced.

FIG. 1 is a schematic schematic showing a single thick conduction loop 100 represented by a thick black line that receives power from a single voltage source V _{HIGH I} capable of producing extremely high current I _polishing . be. The thick loop 100 is bent so that some segments 110 of the antiparallel current are paired in addition to the antiparallel current that would normally be expected to be attached to the voltage source V _{HIGH I.} Each such segment pair is understood to have a synthetic magnetic field that is approximately equal to zero in the volume of the scanner designated for imaging, for example, a given segment pair may have segments very close to each other. It can be achieved by placing, telescoping one segment into the other, or alternating the two segments with each other. Insulation and / or air gaps prevent the segments in the pair from forming direct physical contact with each other or conducting direct electrical conduction with each other. The 100 unpaired segments that form the four circular structures (partial loops) generate a _{B0 field} with current I polishing when the circular structures are properly sized and placed. Three current shunts 20 are connected to each of the four circular structures of 100. Each current shunt 20 receives power from the voltage source V so that proper activation of the current shunt 20 adds an _x -sloping field, a y-sloping field, and / or a z-sloping field to the B0 field generated by 100. The current is redistributed in the thick loop 100. The shunts are drawn with both solid and dashed lines throughout the drawings of the present application to help them visually distinguish from each other.

FIG. 2 is a schematic circuit diagram showing an actual current pattern that may be associated with any one of the circular structures within the thick loop 100 of FIG. Consistent with the axis shown in FIG. 2, the circular structure of FIG. 2 is understood to be parallel to the xy plane and centered on the z-axis. The shunt A40 transmits a current from a point 42 on the y-axis to a point 44 on the y-axis, a shunt B60 transmits a current from a point 62 on the x-axis to a point 64 on the x-axis, and the shunt C80 is shown in FIG. Current is transmitted from point 82 on one segment 110 of the vertical segment pair to point 84 on the other segment 110 of the vertical segment pair. Those skilled in the art recognize that the currents β, γ, and δ generated by the voltage source shown in FIG. 2 can contribute to the x-inclined, y-inclined, and z-inclined fields in the imager's imaging volume, respectively. Will do. Those skilled in the art further have Kirchhoff's junction law to easily solve the currents and voltages that need to be generated by the voltage source of FIG. 2 to achieve the currents β, γ, and δ shown in FIG. And will understand that the loop law can be used. The current emanating from the voltage source is shown directly in Figure 2, and the shunt voltage is as follows:
_VA = (2β) R _Α +2 (I _polarizing + δ + β) R _q
V _B = (2γ) R _B + 2 (-I _polarizing -δ + γ) R _q
VC = (δ _- β + γ) _RC +4 (I _polarizing + δ) R _q ,
Where R _q is the resistance of each quarter of the circular structure, RA is the total resistance associated with shunt _A , RB is the total resistance associated with shunt _B , and _RC is associated with shunt C. Total resistance to do.

FIG. 3 shows how the schematic embodiment of FIG. 1 may actually look physically in an MRI scanner. FIG. 3A is a preliminary view of FIG. 3B and shows the deleted vertical segment pair of FIG. The vertical segment pair of FIG. ₁ helps the embodiment to be better understood by more clearly and visually separating the paired segment 110 from the 100 unpaired segments that actually generate the B0 field. However, they are not required for the operation of this embodiment, and in fact, their currents may represent a waste of energy. FIG. 3B shows the actual physical manifestations of the schematic schematic of FIG. 1 where each circular structure has the same orientation as the circular structure of FIG. Those skilled in the art will appreciate that the counter-δ currents associated with the first two circular structures and the last two circular structures of FIG. It will be recognized that the parallel γ currents of the two intermediate loops coincide with the generation of the x-sloping and y-sloping fields, respectively.

Some practical notes regarding FIG. 3B can be made here. First, it can be seen that each β shunt and each γ shunt splits into two branches as it travels at right angles to the z-axis. The exact configuration associated with this branch can be shown to preserve the x and y gradient magnetic field patterns generated by the scanner. One of skill in the art will be able to confirm that the shunts associated with this disclosure are generally constructed so as not to distort the desired magnetic field pattern within the imaging volume of the scanner. Second, the thick loop of FIG. 3B may have to include a slot within it that prevents the formation of eddy currents. These slots should be designed so as not to affect the overall accuracy of the magnetic field pattern resulting from the loop. Third, a voltage source that drives a current in the shunt can be used to overcome the inductance of this thick loop, thus the magnetic field established by this thick loop is typically of MRI scanning. It turns out that it can be changed as quickly (ie, within about 1/2 ms) as it is needed for. Fourth, the associated voltage source V _{HIGH I} may need to be constructed specifically to handle the very high currents and very low resistance associated with this thick loop. This can be achieved, for example, by using a stack of rectifier controller units wired in parallel with each other, and by adopting isolated gate bipolar transistors (IGBTs), thyristors, or other semiconductor techniques.

FIG. 3C shows the means by which the circular structures of FIG. 3B are connected to each other by the tubular structure of FIG. 3B, which collectively correspond to the horizontal segment pair of FIG. Obviously, between the tubular structure and each circular structure of FIG. 3B is short, even if the vertical segment pair shown by FIG. 3A is removed, due only to the thickness of the conductor on which these structures are constructed. There will be a pair of reverse current segments.

FIG. 3D shows the use of telescoping to help ensure that the current corresponding to the horizontal segment pair of FIG. 1 totals near zero within the imager volume of the scanner. Those of skill in the art should be aware of how to achieve the highest possible current erasure, and the accuracy of this current erasure is the maximum threshold of corresponding magnetic field contamination allowed within the imager volume of the scanner. Can be specified with respect to (eg, among the options, ₁ part per million, 5 ppm, 10 ppm, or 50 ppm with respect to the size of the B0 field).

FIG. 4A shows a variant of the embodiment of FIG. 1 in which the shunt connects points between different circular structures as opposed to points within the same circular structure. FIG. 4B shows a variant of the embodiment of FIG. ₁ where the B0 field is generated by six semi-circular structures and one circular structure as opposed to four circular structures.

FIG. 5A is a variant of the embodiment of FIG. 1 showing that two separate shunts can be connected to the same point in a thick loop. FIG. 5B is a variant showing that a shunt can be connected to three or more points in a thick loop. FIG. 5C is a variant that one of ordinary skill in the art will recognize that thick loops make it particularly possible to generate _shimming boundaries in addition to B0 and tilt boundaries. FIG. 5D shows that two shunts can intersect at a node, and FIG. 5E further suggests that two shunts can intersect via a circle, polygon, or more complex structure.

FIG. 5F illustrates the _B0 field and other magnetic field patterns using the summed current structure without the actual use of either a thick loop or a voltage source capable of generating extremely large currents. It is a modification of the embodiment of FIG. 1 showing the method of FIG. In particular, the thick loop 100 of FIG. 1 is replaced with a thin loop carrying a current of only a few tens of amperes. Moreover, instead of the unpaired segments of the loops that each form a rigid circular structure, as in the case of FIG. 1, each unpaired segment is an extremely long, flexible segment that can be wound in parallel multiple times. The three thin circular structures at the top of FIG. 5F are assumed to represent the individual windings of one such long, flexible segment. The total number of amperes associated with each of the long, flexible segments wound is large enough for the unpaired segment of FIG. 5F to generate about the _{B0 boundary} associated with FIG. In addition, the shunts attached to each winding and the pair of vertical segments near the bottom of FIG. 5F show that the _x -inclined, y-inclined, and / or z-inclined boundaries occur at the same time as their B0 boundaries. to enable.

FIG. 6A is a modified form of FIG. 1 using a thin loop 100'that does not carry an extremely large current, as in FIG. 5F. However, the structure of FIG. 6A does not include the long, flexible segments and windings that the structure of FIG. 5F contains, so that the circuit of FIG. 6A does not generate the _B0 field at all. Not intended. Instead, FIG. 6A is intended to show an analog of FIG. 1, where the major thin loop 100'establishes a non-B ₀ field pattern and into its initial non-B ₀ field pattern. A shunt 20 attached to the main thin loop 100'is used to add in other magnetic field patterns. In the particular case of FIG. 6A, the major thin loop 100'can generate a z-inclination, and the shunt 20 connected to the loop 100' then has an x-inclination and / or y-inclination in the z-inclination. Should add a world.

As is well known to those of skill in the art, structures exposed to extremely strong magnetic fields and containing currents that change over time generally oscillate from Lorentz forces, thereby producing acoustic noise. The segment of the thick loop 100 with the changing current is generally related to the field emanating from the other segments of the thick loop 100 , only because the thick loop 100 can weigh as much as a few thousand kilograms. It can be expected that it will not be affected by Lorentz force. On the other hand, the thin loop _100'placed near the B0 field generation structure may be clearly susceptible to Lorentz force. One method for alleviating the problem is shown through FIG. 6B. In FIG. 6B, in a hollow circular tunnel 402 in which both the thin loop _100'and the structure 400 generating the B0 boundary have a circular cross section and are symmetrically formed in a part of the structure 400 generating the _B0 boundary. A part of the thin loop 100'is arranged symmetrically. Similarly, in FIG. 6C, both the thin loop _100'and the structure 500 generating the B0 boundary again have a circular cross section, but this time they are formed symmetrically in part of the thin loop 100'. A part of the structure 500 that generates the _B0 boundary is symmetrically arranged in the hollow circular tunnel 502. Part of a thin loop _100'placed within or surrounding a portion of a structure that produces a B0 boundary by one of ordinary skill in the art, due to the symmetry of the configurations shown in FIGS. 6B and 6C. The acoustic vibration of _100'can be reduced against the vibration that part of 100' would receive if that part of 100'was simply left adjacent to the structure generating the B0 field. Will understand that is possible. Such reduction in vibration is expected to be more pronounced if both part of the concentric thin loop _100'and part of the structure that produces the B0 field have a relatively large radius of curvature. Will be.

Those skilled in the art will appreciate that there are many other variants associated with this disclosure other than those presented through the figures above. In some embodiments, thick loops may be branched and recombined, or multiple thick loops may be placed together, but the overall structure of the current is described for the embodiment of FIG. Can still be equivalent to the one. Thick loops, in some embodiments, generate only part of the _B0 field required by the scanner, but can sometimes appear as shown in FIG. Each current shunt, in some embodiments, may have some variable resistance that can be used to help achieve the required current distribution within a thick loop in addition to its voltage source. Each current shunt may, in some embodiments, pick up currents from multiple points in a thick loop, return currents to multiple points in a thick loop, or both. Any given voltage source discussed above may apply in some embodiments, for example, in the case of a high current voltage source used to power the thick loops of a single thick loop scanner. As possible, it can be replaced with a group of voltage sources connected in series and / or in parallel. Obviously, the present disclosure can be used in systems other than MRI scanners that generate magnetic field patterns. Nuclear magnetic resonance spectroscopy, electron normal magnetic resonance spectroscopy, and electron normal magnetic resonance imaging are three examples of non-MRI methods to which the present disclosure can be applied.

Now that the systems and methods of this disclosure have been disclosed, one of ordinary skill in the art will appreciate that some or all of the benefits described in the following paragraphs may be possible. In the following paragraphs, the physical embodiment of the circuit depicted in FIG. 1 is referred to as a "thick loop scanner".

The first advantage of the thick loop scanner is that if the accuracy of the _B0 field pattern is particularly important in MRI, the partial loop of the thick loop scanner is resistant enough to electrically generate its _B0 field. It will be seen from the fact that it may be designed to have a position, diameter, and thickness that is equal to or nearly equal to the position, diameter, and thickness of a typical _B0 field generation winding in an MRI scanner. .. Assuming that the shunt path is set to be outside the volume surrounded by the thick loops, as in Figure 3B, in terms of size, the thick loop scanner will have a _B0 field. And B1 means that it is equivalent to an MRI scanner containing only _a field generation structure. The size of the radio frequency coil set can be made larger than usual due to the space freed in the thick loop scanner. A significantly increased sense of breadth can make disease testing more pleasing to the general population: imaging of obese individuals, imaging of individuals with claustrophobia, veterinary imaging, and interventional or interventional or It will also increase opportunities for imaging during surgical procedures.

A second advantageous feature of thick loop scanners is the relatively low expected manufacturing cost. Only one significant field generation structure other than the B _one -field generation structure may need to be manufactured for the scanner. In addition, thick loops will probably be assembled from the part, and therefore will be more cost effective to create compared to the structure formed by careful and repeated winding of the wire. Molded structures are also less susceptible to errors due to mechanical stresses in transportation than wound structures, which is why, for example, in the case of scanners with multiple windings, for donations to developing countries. It may be more economical to disassemble the thick loop scanner and reassemble it elsewhere than to get it. It is true that the current shunt is manufactured with a thick loop in a thick loop scanner and must be attached to that thick loop; however, like the thick loop itself, the current shunt is a relatively simple structure.

A third advantageous feature of the thick loop scanner is its ability to provide relatively quiet operation. In standard MRI, various structures are often placed within each other in the form of tightly fitted concentric cylinders; however, as explained above, thick loop scanners have a relatively large amount of free space. Is expected to have. Part of this increased space can be devoted to the placement of elongated vacuum tubes around the current shunt, which significantly reduces the noise transmission resulting from the Lorentz force acting on the shunt as the values of those currents change. Can be done. If the shunt were to have the arrangement shown in FIG. 3B, where the shunt is shown to be located outside the volume surrounded by the thick loop, the vacuum tube used to enclose the β and γ shunts would be It may simply consist of eight straight vacuum tubes and two circular vacuum rings. The tube is placed around any part of the thick loop itself, as the thick loop will probably weigh as much as 1,000 kg and therefore is less likely to vibrate significantly when its current changes. Wouldn't have to be.

Now that one of ordinary skill in the art has read and understood the disclosed systems and methods for the simultaneous establishment of the _B0 field and other magnetic field patterns, one of ordinary skill in the art has made possible by the above disclosures of other advantages, variants, and practices. Will recognize the morphology. Such advantages, variants, and embodiments should be considered as part of the scope and meaning of the appended claims and their legal equivalents.

Although specific embodiments have been described above, these embodiments do not limit the scope of the present disclosure even if only one embodiment is described for a particular feature. The examples of features provided in this disclosure are intended to be non-limiting, but exemplary, unless otherwise stated. The above description embraces such alternative, modified, and equivalent forms that should be apparent to those skilled in the art who have the benefit of the present disclosure.

The scope of this disclosure is any feature disclosed herein (explicitly or implicitly), whether or not it alleviates any or all of the problems addressed herein. Or a combination of features, or any generalization of them. Although the various advantages of the present disclosure have been described herein, the embodiments covered by the claims provide some, all, or no such advantages. I may not do it.

Claims (23)

A device for the generation of some or all of the uniform _B0 fields in the imaging volume and for the simultaneous generation of the required tilt and / or shimming fields, said device.
Main conduction loop and
A single voltage source capable of generating a polarization current, or a single effective voltage source capable of generating a polarization current,
With multiple current shunts,
Equipped with
A single effective voltage source capable of generating the polarization current consists of a group of voltage sources connected in series and / or in parallel, and further.
The single voltage source or single effective voltage source capable of generating a polarization current is connected in series with the main conduction loop.
The main conduction loop
With one or more erase segment pairs,
Two or more contribution segments and
Shaped to include
The two erase segments of each erase segment pair
It is a segment of the main conduction loop brought very close to each other so that the currents are antiparallel.
Both contribute to a magnetic field of almost zero within the imaging volume of the device,
Each of the contribution segments
An unpaired segment that is a segment other than the erased segment of the main conduction loop.
The contribution segments are grouped into multiple incomplete loops.
Each individual said incomplete loop
Consists of one or more of the contribution segments
Equivalent to a complete loop with one or more small gaps around it,
It is centered on a common axis,
The whole of the multiple incomplete loops
Shaped to collectively form part or all of the uniform B0 _field within the imaging volume of the device.
The two erase segments of each erase segment pair
By at least one intervening contribution segment, they are spaced apart along the overall length of the main conduction loop.
Not both are placed at each of the ends of the main conduction loop.
Each said current shunt comprises one or more shunt conductor segments and at least one shunt voltage source inserted within said one or more shunt conductor segments.
The one or more shunt conductor segments are separate from the main conductor loop.
The at least one shunt voltage source is separate and physically separate from the single voltage source or single effective voltage source capable of generating a polarization current.
Each said current shunt is configured to short the current from one or more points in the main conduction loop to one or more other points in the main conduction loop.
For each of the incomplete loops
Both sides of one small gap in the circumference of the incomplete loop are connected to the end of the shunt conductor segment.
For each of at least two incomplete loops out of the plurality of incomplete loops
The four positions on the circumference of the incomplete loop are connected to the end of the shunt conductor segment, and the four positions are spaced 90 ° in the azimuth direction within the coordinate system defined by the common axis. Have,
For all of the at least two of the incomplete loops
The hydrangea in each of the four positions is the same,
Thereby, the device is
Using the current from the single voltage source or single effective voltage source capable of generating a polarization current, for magnetic resonance imaging or spectroscopy, or for electron normal magnetic resonance imaging or spectroscopy. To generate part or all of the uniform B0 _field for
And,
Both to establish the required tilt and / or _shimming fields at the same time as part or all of the uniform B0 field through redistributing current within the main conduction loop through the shunt voltage source. The device that enables. The device of claim 1, wherein each of the incomplete loops comprises exactly one of the contribution segments. The device of claim 1, wherein all but one of the plurality of incomplete loops comprises more than one of the contribution segments. The device of claim 1, wherein each individual incomplete loop has either the vertical erase segment pair or the vertical portion of the erase segment pair beneath it. For each of the incomplete loops, four positions within the coordinate system defined by the common axis with an interval of 90 ° in the azimuth direction are connected to the end of the shunt conductor segment.
A first current shunt is coupled between the first and second positions of the four positions so that the first and second positions are on the incomplete loop. On opposite sides of the diameter of each other, and even
A second current shunt is coupled between the third and fourth positions of the four positions so that the third and fourth positions are on the incomplete loop. On opposite sides of the diameter of each other so that the lines on the third and fourth positions rotate 90 ° with respect to the lines on the first and second positions. The device according to claim 1, which is in a shunted state. A portion of the first current shunt between the first position and the second position is divided into two branches.
A portion of the second current shunt between the third position and the fourth position is also divided into two branches.
The device according to claim 5. Each of the incomplete loops
Formed in a circle,
And located on a plane perpendicular to the common axis,
The device according to claim 6. The device of claim 1, wherein at least one of the plurality of current shunts has a variable resistor. The device of claim 1, wherein at least one of the plurality of current shunts is placed in a vacuum tube. The plurality of current shunts are located outside the volume surrounded by the passage formed when each of the adjacent pairs of the imperfect loops is connected to the connecting volume.
Each of the connection volumes has a tunnel-like structure centered on the common axis, and each connection volume has two end faces, one inner surface, and one outer surface.
The two end faces are exactly aligned and adjacent to each of the opposite faces of the two adjacent imperfect loops connected to the connection volume.
The device according to claim 1, wherein the inner surface and the outer surface each have a minimum area. The device according to claim 1, wherein a single effective voltage source capable of generating the polarization current is formed from a plurality of rectifier controller units which are wired in parallel and employ an insulated gate bipolar transistor. The device of claim 1, wherein a single effective voltage source capable of generating the polarization current is formed from a plurality of rectifier controller units that are wired in parallel and employ thyristors. The device of claim 1, wherein any two adjacent contributing segments are spaced apart by an elimination segment belonging to two or three elimination segment pairs intervening along the entire length of the main conduction loop. The device of claim 1, wherein any two adjacent contributing segments are spaced apart by a single erasing segment intervening along the entire length of the main conduction loop. The device of claim 1, wherein the geometric centers of the contribution segments are all aligned on the common axis. The device of claim 1, wherein the geometric centers of the contribution segments are not all aligned on the common axis. The device of claim 1, wherein the magnetic field elimination of the two erase segments of the erase segment pair involves telescoping within one of the erase segments and the other erase segment. The device of claim 1, wherein the magnetic field elimination of the two erase segments of the erase segment pair involves twisting of the two erase segments. 1. Device. 19. The device of claim 19, wherein the specified maximum threshold of magnetic field contamination is a value between ₁ and 50 parts per million with respect to the magnitude of the uniform B0 field. The device of claim 1, wherein the main conduction loop is assembled from an article. A method for simultaneously generating a portion or all of a uniform _B0 field and a required tilt and / or shimming field within the imagery volume of a scanner, said method.
With the step of connecting a single voltage source capable of generating a polarization current in series with the main conduction loop, or a group of voltage sources connected in series and / or in parallel.
A step of shaping the main conduction loop to include one or more erase segment pairs and two or more contribution segments.
The two erase segments of each erase segment pair
A segment of said main conduction loop that has been brought very close to each other or effectively tightened together so that the currents are antiparallel.
Both contribute to a magnetic field of almost zero in the imaging volume of the scanner and
Each of the contribution segments
An unpaired segment that is a segment other than the erased segment of the main conduction loop.
A step of _{shaping the main conduction loop, wherein the contributing segment is shaped to collectively form part or all of the uniform B0} field within the imaging volume of the scanner.
A step of attaching a plurality of shunt voltage sources to the main conduction loop, wherein each shunt voltage source draws current from one or more points of the main conduction loop to one or more of the main conduction loops. With the step of installing multiple shunt voltage sources configured to short-circuit to other points,
Accordingly, the above method is:
The current from the single voltage source capable of generating a polarization current or the group of the voltage sources capable of generating a polarization current is used for magnetic resonance imaging or spectroscopy, or Generating part or all of the uniform B0 _field for electron normal magnetic resonance imaging or spectral copying,
as well as,
Both to establish the required tilt and / or _shimming fields at the same time as part or all of the uniform B0 field through redistributing current within the main conduction loop through the shunt voltage source. Is possible, how. 22. The method of claim 22, wherein the short circuit of current from one or more points of the main conduction loop to one or more other points of the main conduction loop is accompanied by a variable resistor.

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