CRYOGENICALLY COOLED SUPERCONDUCTOR RF HEAD COIL ARRAY AND HEAD-ONLY MAGNETIC RESONANCE IMAGING (MRI) SYSTEM USING SAME

• US 20110015078A1
• Filed: 04/20/2010
• Published: 01/20/2011
• Est. Priority Date: 04/20/2009
• Status: Abandoned Application

• Current Assignee: Time Medical Holdings Co. Ltd.
• Original Assignee: Time Medical Holdings Co. Ltd.
• Inventors: Gao, Erzhen, Ma, Qiyuan
• Application Number:
  US12/764,036
• Publication Number:
  US 20110015078A1
• Time in Patent Office: Days
• US Class Current: 505/162
• CPC Class Codes: G01R 33/34023 Superconducting RF coils
• CPC Class Codes: G01R 33/3403 Means for cooling of the RF coils, e.g. a refrigerator or a cooling vessel specially adapted for housing an RF coil
• CPC Class Codes: G01R 33/3415 comprising arrays of sub-coils , i.e. phased-array coils with flexible receiver channels
• CPC Class Codes: G01R 33/3635 Multi-frequency operation
• 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 33/3806 Open magnet assemblies for improved access to the sample, e.g. C-type or U-type magnets
• CPC Class Codes: G01R 33/3815 with superconducting coils, e.g. power supply therefor

Abstract

A superconducting main magnet system for a head-dedicated MRI system is provided, and a head-only MRI system may comprise such a superconducting main magnet and a cryogenically-cooled superconducting RF head-coil array. The superconducting main magnet may comprise a first and second set of high temperature superconductor coils which are configured to be coaxial relative to a common longitudinal axis. The first coil set includes at least two coils having an inner radius and disposed in a first region of a length along the common axis to cover a head and neck of a human body, and the second coil set includes at least one coil having an inner radius and disposed in a second region of a length along the common axis to cover a portion of a human torso, wherein the inner radius of the second coil set is greater than the inner radius of the first coil set. The first and second coils are configured to provide a uniform magnetic field in the first region to provide for imaging a region of interest of the individual'"'"'s head when positioned within the first region.

Claims

1. A system for head magnetic resonance imaging, comprising:

a first and second set of high temperature superconductor coils which are configured to be coaxial relative to a common longitudinal axis;

wherein the first coil set includes at least two coils having an inner radius and disposed in a first region of a length along the common axis to cover a head and neck of a human body, and the second coil set includes at least one coil having an inner radius and disposed in a second region of a length along the common axis to cover a portion of a human torso, wherein the inner radius of the second coil set is greater than the inner radius of the first coil set; and

wherein the first and second coils are configured to provide a uniform magnetic field in the first region to provide for imaging a region of interest of the individual'"'"'s head when positioned within the first region.

2. The system of claim 1, wherein the longitudinal position and extension, the number of turns, and electric current direction of each coil are designed to provide a 1-10 ppm uniform magnetic field within the first region for head imaging.

3. The system of claim 1, wherein the first set of coils includes at least two coils having an inner radius in a range of 25-35 cm and disposed in a first region of a length along the common axis in a range of 40-60 cm, and the second set of coils includes at least one coil having an inner radius in a range of 30-40 cm and disposed in a second region of a length along the common axis in a range of 15-25 cm to cover a portion of a human torso.

4. The system of claim 1, wherein the portion of human torso comprises the shoulders.

5. The system of claim 1 further comprising a vacuum thermal isolation housing comprising a double wall hermetically sealed high vacuum jacket at a pressure of about 10⁻

6 to 10<sup>−

12</sup> Torr, which encloses a low vacuum space at a pressure between 10<sup>−

3</sup> to 10<sup>−

6</sup> Torr, wherein the high temperature superconductor coils are disposed in said low vacuum space.

6. The system of claim 5, wherein the temperature in the low vacuum space is in the range of about 77K-80K.

7. The system of claim 1, wherein the high temperature superconductor coil comprises at least one superconductor material selected from the group consisting of YBaCuO, BiSrCaCuO, TlBiCaCuO, and MgB₂.

8. The system of claim 1, wherein at least one coil which are wound to carry current in the reverse direction relative to the rest of coils.

9. The system of claim 1, further comprising a shielding coil which surrounds said common longitudinal axis and is coaxial with said first and second coils.

10. The system of claim 9, wherein the shielding coil extends over the length of the first and second regions.

11. The system of claim 9, wherein the shielding coil has a radius in a range of 60-70 cm.

12. The system of claim 1, wherein the strength of the magnetic field is in the range of about 3.0-5.0 T.

13. The system of claim 1, wherein the length of the first and second region is 10-20 cm and 20-30 respectively.

14. The system of claim 1, wherein the inner radius of the first and second set of coils is 10-20 cm and 20-30 respectively.

15. The system of claim 1, further comprising a shielding coil, wherein the first coil set comprises six coils, the second coil set comprises two coils, and the dimensions and current direction for the first, second, and shielding coils are as follows:

16. The system according to claim 1, further comprising a superconductor radiofrequency head coil array module disposed coaxially with respect to said common longitudinal axis and configured to at least receive radiofrequency signals generated within said first region in which the individual'"'"'s head is positioned for imaging.

17. The system according to claim 16, wherein the head coil array comprises a plurality of high temperature superconductor coils disposed azimuthally about said common longitudinal axis.