# US 12,000,914 B2 · Resistive electromagnet systems and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,000,914 B2 - Document ID: US12000914B2 - Status: Granted - Kind: B2 - Application number: 17/559,957 - Filed: 2021-12-22 - Published: 2022-04-14 - Granted: 2024-06-04 - Earliest claimed: 2018-05-16 - Assignees: ViewRay Systems, Inc. - Applicants: ViewRay Technologies, Inc. - Inventors: James F. Dempsey; Massimo Dal Forno; Shmaryu M. Shvartsman; David L. Rayner - Web page: https://patentgrep.com/patent/US12000914B2 ## CPC - G01R 33/381: using electromagnets - G01R 33/3873: using ferromagnetic bodies {; Passive shimming} - A61B 5/055: involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging - G01R 33/34053: {Solenoid coils; Toroidal coils} - G01R 33/3802: {Manufacture or installation of magnet assemblies; Additional hardware for transportation or installation of the magnet assembly or for providing mechanical support to components of the magnet assembly} - G01R 33/3804: {Additional hardware for cooling or heating of the magnet assembly, for housing a cooled or heated part of the magnet assembly or for temperature control of the magnet assembly} - G01R 33/3806: {Open magnet assemblies for improved access to the sample, e.g. C-type or U-type magnets} - G01R 33/389: Field stabilisation {, e.g. by field measurements and control means or indirectly by current stabilisation} - A61N 5/1049: {for verifying the position of the patient with respect to the radiation beam} - A61N 2005/1055: {using magnetic resonance imaging [MRI]} - G01R 33/4808: {Multimodal MR, e.g. MR combined with positron emission tomography [PET], MR combined with ultrasound or MR combined with computed tomography [CT]} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) ## Abstract A magnetic resonance imaging (MRI) system having a resistive, solenoidal electromagnet for whole-body MRI may include ferromagnetic material within an envelope of the electromagnet. The system can be configured to have a field strength of at least 0.05 Tesla and its main electromagnetic field can be generated by layers of conductors instead of bundles. Certain electromagnet designs may be fabricated using non-metallic formers, such as fiberglass, and can be constructed to form a rigid object with the layers of conductors by fixing all together with an epoxy. The electromagnet may be configured to have two separated halves, which may be held apart by a fixation structure such as carbon fiber. The power supply for certain electromagnets herein may have current fluctuations, at frequencies of 180 Hz or above, of at least one part per ten thousand without requiring an additional current filter. ## Claims ### Claim 1 A magnetic resonance imaging (MRI) system comprising: a resistive, solenoidal electromagnet for whole-body MRI having a field strength of at least 0.05 Tesla comprising: conductors for creating a main electromagnetic field of the electromagnet; wherein the main electromagnetic field is not generated by bundles of conductors. ### Claim 2 A magnetic resonance imaging (MRI) system comprising: a resistive, solenoidal electromagnet for whole-body MRI having a field strength of at least 0.05 Tesla comprising: conductors for creating a main electromagnetic field of the electromagnet; wherein the main electromagnetic field is generated by layers of conductors. ### Claim 3 (depends on 2) The system of claim 2, wherein the electromagnet has less than 10 layers of conductors. ### Claim 4 (depends on 2) The system of claim 2, further comprising ferromagnetic material within an envelope of the electromagnet. ### Claim 5 (depends on 2) The system of claim 2, wherein the electromagnet is configured for current flow in only one circumferential direction within the electromagnet. ### Claim 6 (depends on 2) The system of claim 2, wherein the electromagnet is configured to operate with a single supplied current. ### Claim 7 (depends on 2) The system of claim 2, wherein the electromagnet is gapped. ### Claim 8 (depends on 2) The system of claim 2, wherein the electromagnet utilizes non-metallic formers for supporting conductors. ### Claim 9 (depends on 2) The system of claim 2, wherein the electromagnet utilizes fiberglass formers for supporting conductors. ### Claim 10 (depends on 8) The system of claim 8, wherein the layers of conductors and non-metallic formers are constructed to form a rigid object. ### Claim 11 (depends on 10) The system of claim 10, wherein the layers of conductors and non-metallic formers are constructed to form a rigid object by fixing together with an epoxy. ### Claim 12 (depends on 10) The system of claim 10, wherein the rigid object includes at least a portion of the gradient coil. ### Claim 13 (depends on 2) The system of claim 2, wherein the conductors have a cross-sectional area greater than 0.5 centimeters squared. ### Claim 14 (depends on 13) The system of claim 13, wherein the conductors include at least two solenoidal layers of conductors separated by a non-metallic former. ### Claim 15 (depends on 2) The system of claim 2, wherein the layers of conductors comprise: a first layer comprising helically wrapped conductor having a first helical tilt; and a second layer, adjacent to the first layer, comprising helically wrapped conductor having a second helical tilt; wherein the second helical tilt is opposite to the first helical tilt. ### Claim 16 (depends on 2) The system of claim 2, wherein the layers of conductors comprise: a first layer comprising a wrapped conductor having first S-bends bending in a first direction; and a second layer, adjacent to the first layer, comprising a wrapped conductor having second S-bends bending in a second direction. ### Claim 17 (depends on 16) The system of claim 16, wherein the first S-bends and the second S-bends overlap and the second direction is opposite to the first direction. ### Claim 18 (depends on 2) The system of claim 2, wherein the layers of conductors comprise: at least one layer including a section where a conductor traverses in a direction parallel to an axis of the solenoidal electromagnet. ### Claim 19 (depends on 18) The system of claim 18, wherein the conductor traversing in the direction parallel to the axis of the solenoidal electromagnet has a cross-sectional area greater than 0.5 centimeters squared. ### Claim 20 (depends on 2) The system of claim 2, wherein the electromagnet has two halves and the two halves are held apart by a fixation structure. ### Claim 21 (depends on 20) The system of claim 20, wherein the fixation structure is substantially nonmetallic. ### Claim 22 (depends on 21) The system of claim 21, wherein the fixation structure comprises carbon fiber. ### Claim 23 (depends on 21) The system of claim 21, further comprising a radiation therapy device, wherein the system is configured such that the radiation therapy device is directed to treat through the fixation structure. ### Claim 24 A magnetic resonance imaging (MRI) system comprising: a resistive, solenoidal electromagnet for whole-body MRI having a field strength of at least 0.05 Tesla comprising: conductors for creating a main electromagnetic field of the electromagnet; wherein the main electromagnetic field is generated by conductors covering at least 50% of an envelope of the electromagnet. ### Claim 25 (depends on 24) The system of claim 24, wherein the conductors have a cross-sectional area greater than 0.5 centimeters squared.