US-20260126503-A1 - Field Synthesizer Devices with Shim Arrays for Control of Magnetic Fields

US20260126503A1US 20260126503 A1US20260126503 A1US 20260126503A1US-20260126503-A1

Abstract

Field synthesizer devices utilizing shim arrays for control of magnetic fields in accordance with embodiments of the invention are disclosed. In one embodiment, a field synthesizer device for local control of a magnetic field within a region of interest (“ROI”) is provided, comprising: a first array comprising a plurality of electromagnets; a second array comprising a plurality of electromagnets; at least one current controller configured to provide electric current to the plurality of electromagnets of the first and second arrays; a processor and a memory storing a program comprising instructions that, when executed by the processor, cause the field synthesizer device to: calculate shimming field data; calculate gradient field data; generate the shimming field and the at least one gradient field using the first and second arrays; and wherein the shimming field and the at least one gradient field combine for local control of a magnetic field within the ROI.

Inventors

GIL TRAVISH
Geoffrey Gao

Assignees

ViBo Health Inc.

Dates

Publication Date: 20260507
Application Date: 20251104

Claims (20)

1 . A field synthesizer device for local control of a magnetic field within a region of interest (“ROI”), the field synthesizer device comprising: a first array comprising a plurality of electromagnets; a second array comprising a plurality of electromagnets, wherein the second array is positioned opposite and parallel to the first array; at least one current controller configured to provide electric current to the plurality of electromagnets of the first array and to the plurality of electromagnets of the second array; a processor operatively connected to the at least one current controller; memory storing a program comprising instructions that, when executed by the processor, cause the field synthesizer device to: calculate shimming field data for generating a shimming field within a ROI; calculate gradient field data for generating at least one gradient field within the ROI; generate the shimming field, within the ROI, using the first and second arrays; and generate the at least one gradient field, within the ROI, using the first and second arrays; and wherein the shimming field and the at least one gradient field combine for local control of a magnetic field within the ROI.
2 . The field synthesizer device of claim 1 , wherein each electromagnet of the first array comprises an independently powered coil.
3 . The field synthesizer device of claim 2 , wherein each electromagnet of the second array comprises an independently powered coil.
4 . The field synthesizer device of claim 1 further comprising a primary magnet configured to generate a main field B 0.
5 . The field synthesizer device of claim 4 , wherein the first and second arrays are positioned laterally to the primary magnet.
6 . The field synthesizer device of claim 5 wherein the program comprises further instructions that, when executed by the processor, cause the field synthesizer device to: calculate anti-shimming field data for generating at least one anti-shimming field outside of the ROI; and generate the at least one anti-shimming field, outside of the ROI, using the first and second arrays.
7 . The field synthesizer device of claim 6 , wherein the shimming field and the at least one gradient field are generated parallel to the main field B 0 .
8 . The field synthesizer device of claim 7 , wherein the shimming field and the at least one gradient field produce a z-component that alters the main field B 0 .
9 . The field synthesizer device of claim 1 , wherein the shimming field data is calculated based on a pre-calculated shim field and a correction factor.
10 . The field synthesizer device of claim 1 , wherein the gradient field data is calculated based on a spatial filtering component and a pulse sequence component.
11 . The field synthesizer device of claim 1 , wherein the shimming field is generated by: selecting a first subset of electromagnets in the first array and a second subset of electromagnets in the second array; determining, using the shimming field data, a current level for each electromagnet in the first subsets of electromagnets; determining, using the shimming field data, a current level for each electromagnet in the second subsets of electromagnets; and applying the current levels to each electromagnet in the first and second subsets of electromagnets causing the first and second arrays to generate the shimming field.
12 . The field synthesizer device of claim 1 , wherein the at least one gradient field is generated by: selecting a first subset of electromagnets in the first array and a second subset of electromagnets in the second array; determining, using the gradient field data, a current level for each electromagnet in the first subsets of electromagnets; determining, using the gradient field data, a current level for each electromagnet in the second subsets of electromagnets; and applying the current level to each electromagnet in the first and second subsets of electromagnets causing the first and second arrays to generate the at least one gradient field.
13 . The field synthesizer device of claim 1 , wherein the plurality of electromagnets of the first array use the electric current to generate a first gradient field.
14 . The field synthesizer device of claim 13 , wherein the electric current is used to activate and set a polarity to NORTH for a first electromagnet of the plurality of electromagnets of the first array.
15 . The field synthesizer device of claim 14 , wherein the electric current is used to activate and set a polarity to SOUTH for a second electromagnet of the plurality of electromagnets of the first array.
16 . The field synthesizer device of claim 15 , wherein the plurality of electromagnets of the second array use the electric current to generate a second gradient field.
17 . The field synthesizer device of claim 16 , wherein the electric current is used to activate and set a polarity to SOUTH for a first electromagnet of the plurality of electromagnets of the second array.
18 . The field synthesizer device of claim 17 , wherein the electric current is used to activate and set a polarity to NORTH for a second electromagnet of the plurality of electromagnets of the second array.
19 . The field synthesizer device of claim 1 , wherein the plurality of electromagnets of the first and second arrays comprises a plurality of solenoids.
20 . The field synthesizer device of claim 19 , wherein each of the plurality of solenoids is wound around an iron core or other magnetic material.

Description

CROSS-REFERENCE TO RELATED APPLICATION The current application claims priority to U.S. Provisional Patent Application No. 63/715,808, filed on Nov. 4, 2024, the disclosure of which is incorporated herein by reference. FIELD OF THE INVENTION The present invention generally relates to magnetic fields and more specifically to field synthesizers having shim arrays for control of magnetic fields. BACKGROUND Magnets have been constructed for many applications ranging from audio speakers to MRI machines and generators. Magnets have been made from exotic materials, simple wire coils, wrapped foil (to lower inductance), super conducting cables, etched circuit board patterns, etc. A distinction may be made between permanent magnets formed from magnetized materials and electromagnets which require current to produce a field. Further, a distinction may be made between continuous (“DC”) magnets and pulsed magnets. Generally, magnetic resonance is a process by which a physical excitation (resonance) is set up via magnetism. This process was used to develop magnetic resonance imaging (“MRI”) and nuclear magnetic resonance (“NMR”) spectroscopy technology. An MRI may provide an anatomic image and magnetic resonance spectroscopy (“MRS”) may provide a tissue composition analysis related to underlying dynamic physiology. Typically, NMR describes a physical phenomenon in which nuclei in a strong constant magnetic field are perturbed by a weak oscillating magnetic field and respond by producing an electromagnetic signal with a frequency characteristic of the magnetic field at the nucleus. This process generally occurs near resonance, when the oscillation frequency matches the intrinsic frequency of the nuclei, which depends on the strength of the static magnetic field, the chemical environment, and the magnetic properties of the isotope involved. NMR spectroscopy may be used for various applications and NMR is also routinely used in advanced medical imaging techniques, such as in MRI. BRIEF DESCRIPTION OF THE DRAWINGS The various embodiments of the present field synthesizer devices comprising shim arrays (may also be referred to simply as “field synthesizer devices”) now will be discussed in detail with an emphasis on highlighting the advantageous features. These embodiments depict the novel and non-obvious field synthesizer devices shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures: FIG. 1 is a block diagram illustrating a system for field synthesizer devices in accordance with an embodiment of the invention; FIG. 2 is a block diagram illustrating a client device in accordance with an embodiment of the invention; FIG. 3 is a block diagram illustrating a field synthesizer device that includes shim arrays in accordance with an embodiment of the invention; FIG. 4 is a block diagram illustrating a server in accordance with an embodiment of the invention; FIG. 5 is a diagram illustrating a first array of electromagnets and a second array of electromagnets (may also be referred to as “field synthesizer arrays” (“FSA”) or “shim arrays”) (e.g., a “paired coil array”) in accordance with an embodiment of the invention; FIG. 6 is a diagram illustrating generating of a gradient at a region of interest (“ROI”) via magnetic fields using a paired coil array in accordance with an embodiment of the invention; FIG. 7A is a diagram illustrating a linear x-gradient generated by a paired coil array in accordance with an embodiment of the invention; FIG. 7B is a diagram illustrating a resulting magnetic field due to a superposition of a main field B0 and the x-gradient generated by a paired coil array in accordance with an embodiment of the invention; FIG. 8 is a block diagram illustrating another field synthesizer device that includes shim arrays in accordance with an embodiment of the invention; FIG. 9 is a diagram illustrating a ROI, sub-regions, and associated fields in accordance with an embodiment of the invention; FIG. 10 is a diagram illustrating field distribution as a function of one axis in accordance with an embodiment of the invention; FIG. 11 is a diagram illustrating various volumes in accordance with an embodiment of the invention; FIG. 12 is a diagram illustrating an ideal main field B0 and a ROI in accordance with an embodiment of the invention; FIG. 13 is a diagram illustrating a main field B0 and a ROI in accordance with an embodiment of the invention; FIG. 14 is a diagram illustrating a main field B0, ROI, a sub-volume, and correction fields in accordance with an embodiment of the invention; FIG. 15 is a diagram illustrating a main field B0, ROI, a sub-volume, and correction fields after application of shimming fields in accordance with an embodiment of the invention; FIG. 16 is a diagram illustrating a main field B0, ROI, a sub-volume, and correction fields after application of shimming fields and a gradient field in accordance with an embodiment of the inv