Faraday cage for MR imaging with accessory equipment

Patent metadata

Field	Value
Publication number	US-9625545-B2
Application number	US-201414263077-A
Country	US
Kind code	B2
Filing date	Apr 28, 2014
Priority date	May 29, 2013
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A Faraday cage assembly for use with a Magnetic Resonance (MR) Imaging scanner is deployed inside the MR scanner room. The Faraday cage assembly is configured to accept accessory medical equipment which is desired to be attached to the patient during scanning. Accessory medical equipment can include patient monitoring systems, injector pumps, and intravenous (IV) poles with infusion pumps. Once the accessory medical equipment is placed inside the Faraday cage, radiofrequency (RF) interference emitted by the accessory medical equipment is contained within the cage and cannot significantly degrade MR image quality. The cage may permit non-MR compatible accessory equipment such as infusion pumps to be used without modification or reconfiguration during MR scanning.

First claim

What is claimed is:

1. An assembly for housing a patient's treatment or monitoring equipment during a patient's Magnetic Resonance (MR) exam, comprising:
a Faraday cage having an interior sized for receiving a patient's treatment or monitoring equipment, the Faraday cage having a door-opening into the interior and a door adapted to cover the door-opening.

2. The assembly of claim 1 , further comprising:
a slot opening and extending into at least one of (a) an outer side edge of the door and (b) an inner side edge of the door-opening, the slot providing an opening into the Faraday cage interior when the door is closed that is sized to receive lines extending between the patient and patient's treatment or monitoring equipment.

3. The assembly of claim 2 , wherein the slot is dimensioned to block RF signals below a predetermined frequency.

4. The assembly of claim 3 , wherein the predetermined frequency is higher than the Larmor frequency of an MR scanner used for the patient's MR exam.

5. The assembly of claim 3 , wherein the opening provided by the slot has a maximum opening width dimension of less than ¼ th the wavelength of radio frequency waves at the Larmor frequency of an MR scanner used for the patient's MR exam.

6. The assembly of claim 2 , further comprising a waveguide assembly mounted thereto and having a waveguide channel extending therethrough and sized to receive lines extending between the patient and patient's treatment or monitoring equipment, the waveguide channel communicating with the slot opening into the Faraday cage.

7. The assembly of claim 6 , wherein the waveguide assembly includes:
an elongated waveguide body having a longitudinal side opening into the waveguide channel for receiving the lines extending between the patient and patient's treatment or monitoring equipment therein; and
an elongated cap adapted to mount over the longitudinal side opening of the waveguide body.

8. The assembly of claim 6 , wherein the waveguide assembly is mounted within the Faraday cage.

9. The assembly of claim 6 , wherein the waveguide assembly is mounted to one of an inner surface and outer surface of the door.

10. The assembly of claim 6 , wherein the length of the waveguide body is longer than approximately ¼ th the wavelength of radio frequency waves at the Larmor frequency of an MR scanner used for the patient's MR exam.

11. The assembly of claim 6 , wherein the waveguide channel has a maximum cross-sectional width dimension of less than ¼ th the wavelength of radio frequency waves at the Larmor frequency of an MR scanner used for the patient's MR exam.

12. The assembly of claim 1 , wherein the Faraday cage interior is sized to receive an accessory equipment assembly including an IV pole, an IV bag holder, an IV bag, and an infusion pump.

13. The assembly of claim 12 , further comprising a ramp providing a slanted surface from a floor surface on which the assembly is situated to a bottom surface of the Faraday cage interior.

14. The assembly of claim 12 , further comprising rollers mounted on an underside surface of the Faraday cage.

15. The assembly of claim 1 , wherein the Faraday cage is adapted to be mounted to, seated on, or hung from an IV pole.

16. The assembly of claim 1 , further comprising a power supply, the power supply providing electrical outlets to the Faraday cage interior.

17. The assembly of claim 16 , wherein the power supply is contained within the Faraday cage interior.

18. The assembly of claim 16 , wherein the power supply includes and external power supply cord and RF filters that substantially limit RF interference from exiting the Faraday cage via the external power supply cord.

19. The assembly of claim 16 , wherein the power supply includes an internal battery providing power to the electrical outlets.

20. The assembly of claim 1 , wherein the door-opening comprises a door frame and the assembly further comprises a conductor mounted to one or more of the door and the door frame, providing electrical contact between the door and the door frame when the door is closed onto the door frame.

21. The assembly of claim 20 , wherein the conductor comprises a plurality of conducting fingers affixed to one or more of the inside surface of the door and the outer surface of the door frame.

22. The assembly of claim 20 , wherein the conductor comprises a conductive gasket affixed to one or more of the inside surface of the door and the outer surface of the door frame.

23. The assembly of claim 20 , wherein the conductor is sufficiently compressible to deform over lines connected between the patient's treatment or monitoring equipment received within the Faraday cage interior and the patient and extending through the door-opening when the door is closed.

24. The assembly of claim 1 , further comprising a window enclosing a window pane providing visual access to the Faraday cage interior, the window pane being formed from a conductive material.

25. The assembly of claim 24 , wherein the window is provided on the door.

26. The assembly of claim 1 , further comprising a screened window providing audible access to the Faraday cage interior, the screen being comprised of a conductive mesh electrically coupled to at least one of a Faraday cage wall and a Faraday cage door.

27. The assembly of claim 1 , further comprising an audio transmission system for transmitting audio sounds emanating from the Faraday cage interior to a point outside of the Faraday cage.

28. The assembly of claim 27 , wherein the audio transmission system includes a microphone positioned within the Faraday cage interior.

29. The assembly of claim 28 , wherein the audio transmission system includes a Bluetooth repeater in electrical communication with the microphone.

30. The assembly of claim 28 , wherein the audio transmission system includes an electronic intercom.

31. The assembly of claim 1 , further comprising:
a 2 mm×2 mm slot opening and extending into at least one of (a) an outer side edge of the door and (b) an inner side edge of the door-opening, the slot providing an opening into the Faraday cage interior when the door is closed that is sized to receive lines extending between the patient and patient's treatment or monitoring equipment.

32. The assembly of claim 1 , wherein the Faraday cage is constructed primarily from non-ferromagnetic materials.

33. The assembly of claim 32 , wherein the non-ferromagnetic material include copper.

34. The assembly of claim 32 , wherein the non-ferromagnetic material include aluminum.

35. The assembly of claim 32 , wherein the non-ferromagnetic material include brass.

36. A method for performing a Magnetic Resonance exam on a patient connected by a line to a piece of medical equipment, comprising the steps of:
providing a Faraday cage assembly including:
a Faraday cage having an interior sized for receiving the piece of medical equipment, the Faraday cage having a door-opening into the interior and a door adapted to cover the door-opening; and
a slot opening and extending into at least one of (a) an outer side edge of the door and (b) an inner side edge of the door-opening, the slot providing an opening into the Faraday cage interior when the door is closed tha

Assignees

• Children'S Hospital Medical Center
• Childrens Hospital Med Ct

Inventors

• Dumoulin Charles L
• Pratt Ronald

Classifications

• A61M2209/084

  Supporting bases, stands for equipment · CPC title

• A61B5/055

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title

• A61B2562/182

  Electrical shielding, e.g. using a Faraday cage · CPC title

• A61B5/0046

  Arrangements of imaging apparatus in a room, e.g. room provided with shielding or for improved access to apparatus · CPC title

• A61M5/1415

  Stands, brackets or the like for supporting infusion accessories · CPC title