# US 2014/0194727 A1 · Composite rf shield and method of making same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0194727 A1 - Document ID: US20140194727A1 - Status: Published application - Kind: A1 - Application number: 13/737,458 - Filed: 2013-01-09 - Published: 2014-07-10 - Earliest claimed: 2013-01-09 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Eddy Benjamin Boskamp - Web page: https://patentgrep.com/patent/US20140194727A1 ## CPC - G01R 33/422: of the radio frequency field - A61B 5/0035: {adapted for acquisition of images from more than one imaging mode, e.g. combining MRI and optical tomography} - A61B 5/055: involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging - G01R 33/0052: {Manufacturing aspects; Manufacturing of single devices, i.e. of semiconductor magnetic sensor chips (devices based on galvano-magnetic effect or the like H10N50/85)} - G01R 33/0076: {Protection, e.g. with housings against stray fields} - G01R 33/025: Compensating stray fields {(G01R33/0017 takes precedence)} - G01R 33/481: {MR combined with positron emission tomography [PET] or single photon emission computed tomography [SPECT]} - G01T 1/1603: {with a combination of at least two different types of detectors} - A61B 2562/182: Electrical shielding, e.g. using a Faraday cage - H05K 9/0081: {Electromagnetic shielding materials, e.g. EMI, RFI shielding (H05K9/0003 takes precedence)} - Y10T 29/49016: Antenna or wave energy "plumbing" making - 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) - G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00) - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract An imaging apparatus comprises an RF coil former comprising an inner surface and an outer surface and a composite RF shield positioned adjacently to the outer surface of the RF coil former so as to be formed about the RF coil former. The MRI system also comprises an RF coil positioned on the inner surface of the RF coil former. The RF coil former comprises a generally cylindrical member having an indented portion indented in a radial direction inwardly from the outer surface, and the composite RF shield comprises a first shield material positioned about the outer surface of the RF coil former, a second shield material position about the indented portion of the RF coil former, and a conformal shield material positioned about the RF coil former that electrically couples the first shield material to the second shield material. ## Claims ### Claim 1 An imaging apparatus comprising: a magnetic resonance imaging (MRI) system comprising: a plurality of gradient coils positioned about a patient bore; an RF coil former comprising an inner surface and an outer surface; a composite RF shield positioned adjacently to the outer surface of the RF coil former so as to be formed about the RF coil former; and an RF coil positioned on the inner surface of the RF coil former and about the patient bore, with the RF coil coupled to a pulse generator to emit an RF pulse sequence and receive resulting MR signals from a subject of interest; wherein the RF coil former comprises a generally cylindrical member having an indented portion indented in a radial direction inwardly from the outer surface; and wherein the composite RF shield comprises: a first shield material positioned about the outer surface of the RF coil former; a second shield material position about the indented portion of the RF coil former; and a conformal shield material positioned about the RF coil former, the conformal shield material electrically coupling the first shield material to the second shield material. ### Claim 2 (depends on 1) The imaging apparatus of claim 1 wherein the first and second RF shield portions comprise the same material. ### Claim 3 (depends on 2) The imaging apparatus of claim 2 wherein the first shield material is coupled to the second shield material only through the conformal shield material. ### Claim 4 (depends on 1) The imaging apparatus of claim 1 wherein the first and second shield materials comprise a stainless steel mesh. ### Claim 5 (depends on 1) The imaging apparatus of claim 1 wherein the first and second shield materials comprise the same material. ### Claim 6 (depends on 5) The imaging apparatus of claim 5 wherein the conformal shield material comprises a material distinct from the material of the first and second shield materials. ### Claim 7 (depends on 6) The imaging apparatus of claim 6 wherein the material of the conformal shield material comprises one of copper and silver. ### Claim 8 (depends on 1) The imaging apparatus of claim 1 wherein the conformal shield material has a higher susceptibility to eddy current generation than the first and second shield materials. ### Claim 9 (depends on 1) The imaging apparatus of claim 1 wherein the conformal shield material comprises a plurality of portions spaced apart from one another via a slit. ### Claim 10 (depends on 9) The imaging apparatus of claim 9 further comprising a capacitor coupled between an adjacent portion pair of the plurality of portions, wherein the capacitor is configured to electrically couple the adjacent portion pair together when an alternating voltage at an RF frequency is induced therein. ### Claim 11 (depends on 10) The imaging apparatus of claim 10 further comprising: a dielectric material positioned to overlap each conformal shield material portion across the slit; and an electrically conductive material coupled to the dielectric material, the electrically conductive material forming a capacitance between each conformal shield material portion overlapping therewith. ### Claim 12 A PET-MRI apparatus comprising: a magnetic resonance imaging (MRI) system having a plurality of gradient coils positioned about a patient bore, an RF coil former having inner and outer surfaces, an RF shield formed about the outer surface of the RF coil former, and an RF coil positioned on the inner surface of the RF coil former, with the RF coil coupled to a pulse generator to emit an RF pulse sequence and receive resulting MR signals from a subject of interest; and a positron emission tomography (PET) system having a detector array positioned to encircle the bore, with the detector array being controlled to acquire PET emissions of the subject of interest; wherein the RF shield comprises: a first RF shield portion forming a raised portion; a second RF shield portion forming an indented portion, the indented portion being indented from the raised portion in the radial direction inwardly toward the patient bore; and a conformal shield portion coupling the first RF shield portion to the second RF shield portion. ### Claim 13 (depends on 12) The PET-MRI apparatus of claim 12 wherein the first and second RF shield portions comprise the same material; and wherein the conformal shield portion comprises a material distinct from the material of the first and second RF shield portions. ### Claim 14 (depends on 12) The PET-MRI apparatus of claim 12 wherein the first and second shield materials are positioned in the non-overlapping arrangement. ### Claim 15 (depends on 12) The PET-MRI apparatus of claim 12 wherein the conformal shield portion comprises a spray-on conductive material. ### Claim 16 (depends on 15) The PET-MRI apparatus of claim 15 wherein the spray-on conductive material comprises one of an electrically conductive paint and an electrically conductive polymer. ### Claim 17 A method of forming a composite RF shield comprising: positioning a first shield material about an outer surface of an RF coil former; positioning a second shield material about an indented portion of the RF coil former, the indented portion indented in a radial direction inwardly from the outer surface; and applying a conformal shield material about the RF coil former to electrically couple the first shield material to the second shield material. ### Claim 18 (depends on 17) The method of claim 17 wherein applying the conformal shield material comprises spraying one of an electrically conductive paint and an electrically conductive polymer to overlap a portion of the first shield material and a portion of the second shield material. ### Claim 19 (depends on 18) The RF coil assembly of claim 18 wherein applying the conformal shield material comprises applying a conformal shield material having a higher susceptibility to eddy current generation in a changing magnetic field than a susceptibility of the first and second shield materials to eddy current generation in the changing magnetic field. ### Claim 20 (depends on 19) The RF coil assembly of claim 19 further comprising: forming a gap in the conformal shield material to create a plurality of conformal shield portions; and capacitively coupling the plurality of conformal shield portions together.