CERAMIC CAMERA FOR MRI

• US 20140354282A1
• Filed: 11/14/2012
• Published: 12/04/2014
• Est. Priority Date: 11/18/2011
• Status: Active Grant

• Current Assignee: UWM Research Foundation
• Original Assignee: UWM Research Foundation
• Inventors: Kusik, Todd P., Armstrong, Brian S. R., Barrows, Robert T.
• Granted Patent: US 9,599,683 B2
• Time in Patent Office: Days
• US Class Current: 324/322
• CPC Class Codes: G01R 33/283 Intercom or optical viewing arrangements, structurally associated with NMR apparatus
• CPC Class Codes: G01R 33/5673 Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/65 Control of camera operation in relation to power supply

Abstract

A camera assembly for use in a MRI machine. The camera assembly includes a Faraday cage defining a shielded cavity and an optical path mount constructed of a highly stiff, dense, and non-electrically-conductive material in the shielded cavity. The camera imager and lens are mounted to the optical path mount. The camera assembly includes a capacitor-based power regulation circuit. The optical path mount is not subject to eddy currents because it is non-electrically-conductive. The capacitor-based power regulation circuit includes very little ferrous material and is within the shielded cavity, to reduce eddy currents. The resulting camera assembly reduces vibrations and shaking in the magnetic field environment of the MRI machine.

Claims

1. A camera comprising:

an optical path mount integrally formed with an imager mounting surface and a lens mounting surface, the optical path mount being a massive element constructed of a highly stiff and non-electrically-conductive material, with mass at least twice as great as that of the imager and lens, modulus of elasticity of at least 2 giga-Pascals, and resistivity of at least 10⁶ Ohm-centimeters;

an imager directly mounted to the imager mounting surface; and

a lens directly mounted to the lens mounting surface.

2. The camera of claim 1, wherein the optical path mount is constructed of ceramic.

3. The camera of claim 1, wherein the mass of the optical path mount is at least five times as great as the combined mass of the imager and lens.

4. The camera of claim 1, wherein the lens collects images of an imaging volume, the camera further comprising a lighting system to illuminate the imaging volume.

5. The camera of claim 4, wherein the lens collects the images along a direct axis.

6. The camera of claim 5, wherein the lighting system includes a ring light surrounding the direct axis.

7. The camera of claim 1, further comprising:

a light source producing light; and

a partially silvered mirror;

wherein the light shines through the partially silvered mirror to illuminate an imaging volume; and

wherein the partially silvered mirror reflects an image of the imaging volume to the lens.

8. The camera of claim 7, wherein the optical path mount includes a mirror mounting surface;

and wherein the partially silvered mirror is directly mounted to the mirror mounting surface.

9. The camera of claim 1, further comprising a Faraday cage enclosing the imager and optical path mount and at least partially enclosing the lens;

wherein said lens forms a portion of the Faraday cage.

10. A camera assembly comprising:

a digital camera; and

a capacitor-based power regulation circuit that does not incorporate inductors;

wherein the capacitor-based power regulation circuit provides power for operation of the digital camera.

11. The camera assembly of claim 10, wherein said digital camera includes a fiber-optic interface for transmitting images.

12. The camera assembly of claim 11, wherein said fiber-optic interface for transmitting images includes lasers and said lasers are non-ferrous.

13. The camera assembly of claim 10, further comprising a Faraday cage enclosing the digital camera and circuit.

14. The camera assembly of claim 10, further comprising a lighting system;

wherein said digital camera includes a lens; and

wherein said lens and lighting system are arranged to permit imaging a range of depths from 100 mm to 700 mm.

15. A magnetic resonance imaging (MRI) apparatus, comprising:

a MRI scanner for accommodating a patient;

a magnet generating a magnetic field, gradient coils generating dynamic magnetic field gradients within the MRI scanner;

radio-frequency (RF) coils generating RF energy within the MRI scanner;

a camera assembly including a Faraday cage defining a shielded cavity, an imager, a lens, and an optical path mount constructed of a material with mass at least twice as great as the combined mass of the imager and lens, the optical path mount having a modulus of elasticity of at least 2 giga-Pascals and resistivity of at least 10⁶ Ohm-centimeters, the optical path mount being positioned within the shielded cavity, the imager and lens being mounted to the optical path mount within the shielded cavity; and

a mounting assembly for mounting the camera assembly within the MRI scanner;

wherein the Faraday cage includes an aperture through which the camera lens receives images of the patient within the MRI scanner; and

wherein the Faraday cage shields all elements within the shielded volume from the RF energy generated by the RF coils.

16. The MRI apparatus of claim 15, wherein the optical path mount is constructed of ceramic.

17. The MRI apparatus of claim 15, wherein the mass of the optical path mount is at least five times as great as the combined mass of the imager and lens.

18. The MRI apparatus of claim 15, wherein the lens receives images of the patient along a direct axis;

the MRI apparatus further comprising a ring light surrounding the direct axis and illuminating the patient.

19. The MRI apparatus of claim 18, wherein the ring light is mounted on an external surface of the Faraday cage and surrounds the aperture.

20. The MRI apparatus of claim 15, wherein the camera includes a light source producing light and a partially silvered mirror;

wherein the light shines through the partially silvered mirror to illuminate the patient; and

wherein the partially silvered mirror reflects an image of the patient to the lens.

21. The MRI apparatus of claim 20, wherein the optical path mount includes a mirror mounting surface;

and wherein the partially silvered mirror is directly mounted to the mirror mounting surface.

22. The MRI apparatus of claim 15, further comprising a capacitor-based power regulation circuit that does not incorporate inductors;

the circuit being mounted within the shielded cavity and providing power for operation of the digital camera assembly.

23. A camera assembly comprising:

a Faraday cage defining a shielded cavity;

an imager;

a lens;

a massive optical path mount constructed of a highly stiff and non-electrically-conductive material with mass at least twice as great as that of the combined imager and lens, modulus of elasticity of at least 2 giga-Pascals and resistivity of at least 10⁶ Ohm-centimeters in the shielded cavity, the imager and lens being mounted to the optical path mount; and

a capacitor-based power regulation circuit that does not incorporate inductors mounted within the shielded cavity and providing power for operation of the camera assembly;

wherein the Faraday cage includes an aperture through which the camera lens receives images of the patient within the MRI scanner; and

wherein the Faraday cage shields all elements within the shielded volume from RF energy surrounding the Faraday cage.