MRI RF shielding jacket

• US 10,078,122 B2
• Filed: 02/16/2015
• Issued: 09/18/2018
• Est. Priority Date: 03/09/2014
• Status: Active Grant

• Current Assignee: Aspect Imaging Ltd.
• Original Assignee: Aspect Imaging Ltd.
• Inventors: Rapoport, Uri
• Primary Examiner(s): Arana, Louis
• Application Number:
  US14/623,051
• Publication Number:
  US 20150253401A1
• Time in Patent Office: 1,310 Days
• Field of Search: None
• CPC Class Codes: A61B 2560/04 Constructional details of apparatus
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: 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
• CPC Class Codes: G01R 33/422 of the radio frequency field
• CPC Class Codes: G01R 33/48 NMR imaging systems
• CPC Class Codes: Y10T 29/49016 Antenna or wave energy "plumbing" making

Abstract

A jacket for radio frequency (RF) shielding a Magnetic Resonance Device (MRD) from external environment electromagnetic interference during its operation, which allows for homogenized imaging conditions. The RF shielding jacket is sized and shaped like an envelope to accommodate the MRD, with at least a portion of the RF shielding jacket including an electromagnetic interference shield. The RF shielding jacket is also combined with passive temperature insulating properties.

Claims

1. An RF shielding jacket (RFSJ), useful for shielding a magnetic resonance device (MRD) having external dimensions A [m]², and length L₀ [m], from electromagnetic interference (EMI), comprising:

an envelope sized and shaped to accommodate said MRD, wherein at least a portion of said RFSJ comprising an EMI shield; and

a conduit having a first aperture to a bore of said MRD and a second aperture to an environment external to the RFSJ wherein the conduit has a length to width ratio that prevents radio frequency waves to flow between the bore of said MRD and the environment external to the RFSJ.

2. The RFSJ according to claim 1, wherein at least a portion of said RFSJ comprises means for shielding at least a portion of said MRD from a selected from a group consisting of:

magnetism, electromagnetic interference, physical damage and any combination thereof.

3. The RFSJ according to claim 1, wherein said conduit is configured to attenuate the passage of frequencies selected from a group consisting of:

0 to about 1000 MHz, 0 to about 500 MHz, 0 to about 200 MHz and any combination thereof.

4. The RFSJ according to claim 1, wherein said RFSJ comprises an EMI shield configured to attenuate the passage of frequencies selected from a group consisting of:

0 to about 1000 MHz, 0 to about 500 MHz, 0 to about 200 MHz and any combination thereof.

5. The RFSJ according to claim 1, configured for an MRD positioned in an atmospheric pressure system and temperature changing environment, having at least one first temperature T₁ [°

C.] and a Q [kj] amount of heat applied to the MRD, in which said RFSJ;

a. at least one second temperature T₂ [°

C.] in an inner portion of said RFSJ;

b. a specific mass, m [kg]; and

,

c. specific heat capacity, C_p [kj/kg];

wherein the following formula is being held true;

Q=C_pmdT;

where dT=T₁−

T₂,

wherein for each applied Q, dT2 is in the range of 0°

C.-0.2°

C.;

where dT2=T₂+dT.

6. The RFSJ according to claim 1, wherein at least a portion of said RFSJ comprising n layers.

7. The RFSJ according to claim 6, wherein at least 2 of said n layers comprising a substantially different specific heat capacity C_p for each layer;

where each of said layers has at least one first temperature H₁ [°

C.] measured on the outer side of said layer, and at least one first temperature H₂ [°

C.], measured on its inner side towards said MRD, having a dH₁- . . . dHn, where dT of RFSJ equals H₁-H_n.

8. The RFSJ according to claim 6, wherein at least one layer comprising an electrical isolating material.

9. The RFSJ according to claim 6, wherein at least one layer closes a conductive circle around said MRD.

10. The RFSJ according to claim 1, wherein at least a portion of RFSJ comprises a material selected from a group consisting of:

thermo insulating material, sealing material, foam material, fire retardant materials, at least partially transparent material and any combination thereof.

11. The RFSJ according to claim 1, wherein at least a portion comprises an active thermos regulating system.

12. The RFSJ according to claim 1, wherein said RFSJ is connected to a component selected from a group consisting of:

a CPU, an alarm system, at least one indicator, at least one sensor, and any combination thereof.

13. The RFSJ according to claim 1, configured for an MRD to be positioned in an atmospheric pressure, temperature changing environment, having at least one first temperature T₁ [°

C.] and at least one second temperature T₂ [°

C.], in which said RFSJ;

a. thermal conductivity, k [W/m °

C.];

b. thickness, s [m]; and

,

c. conductive heat transfer, q [W];

wherein the following formula is being held true;

q=kAdT/s,

where dT equals T₂−

T₁ and q<

<

0.01 W.

14. The RFSJ according to claim 1, comprising at least n layers, wherein at least 2 of said n layers comprising a substantially different conductive heat transfer value q for each layer;

where each of said layers has at least one first temperature H₁ [°

C.] measured on the outer side of said layer, and at least one first temperature H₂ [°

C.], measured on its inner side towards said MRD, having a dH₁ . . . dHn, where dT of said RFSJ equals H₁−

Hn.

15. The RFSJ according to claim 1, in an MRD being positioned in an atmospheric pressure and a temperature changing environment having at least one first temperature T₁ [°

C.] and at least one second temperature T₂ [°

C.], a RFSJ for said MRD, wherein said RFSJ is characterized by a thermal expansion coefficient substantially different than 0.

16. The RFSJ according to claim 1, comprising at least n layers, wherein at least 2 of said n layers comprising a substantially different thermal expansion coefficient for each layer;

where each of said layers has at least one first temperature H₁ [°

C.] measured on the outer side of said layer, and at least one first temperature H₂ [°

C.], measured on its inner side towards said MRD, having a dH₁ . . . dHn, where dT of said RFSJ equals H₁−

Hn.

17. The RFSJ according to claim 16, in which:

a. length L_{0, Jacket} [m] fitted by means of size and shape to said L_{0, MRD}; and

b. linear thermal expansion coefficient α

_L [°

C.<sup>−

1</sup>] substantially different than 0;

wherein if dT substantially different than 0;

said length L_{0, Jacket} will be varied to L_{1, Jacket}, such that the following formula is being held true for any change in temperature, dT;

18. The RFSJ according to claim 16, in which:

a. volume V_{0 Jacket} [m]; and

,

b. volumetric thermal expansion coefficient α

_V [°

C.<sup>−

1</sup>] substantially different than 0;

wherein if dT substantially different than 0;

said volume V_{0, Jacket} will be varied to V_{1, Jacket}, such that the following formula is being held true for any change in temperature, dT;

19. The RFSJ according to claim 16, in which:

a. area A_{0, Jacket} [m²]; and

,

b. area thermal expansion coefficient α

_A [°

C.<sup>−

1</sup>] substantially different than 0;

wherein if dT substantially different than 0;

said length A_{0, Jacket} will be varied to A_{1, Jacket}, such that the following formula is being held true for any change in temperature, dT;