US6159444A
Expired / Lapsed
US
⏱️ 0.0 years remaining
NMR/MRI with hyperpolarized gas and high Tc SQUID
Assignee: University of California
•
Filing: 1999-09-10
•
Granted: 2000-12-12
•
Expires: 2019-09-10
Abstract
Abstract A method and apparatus for the detection of nuclear magnetic resonance (NMR) signals and production of magnetic resonance imaging (MRI) from samples combines the use of hyperpolarized inert gases to enhance the NMR signals from target nuclei in a sample and a high critical temperature (Tc) superconducting quantum interference device (SQUID) to detect the NMR signals. The system operates in static magnetic fields of 3 mT or less (down to 0.1 mT), and at temperatures from liquid nitrogen (77K) to room temperature. Sample size is limited only by the size of the magnetic field coils and not by the detector. The detector is a high Tc SQUID magnetometer designed so that the SQUID detector can be very close to the sample, which can be at room temperature.
Inventors
- 👤 Klaus Schlenga
- 👤 Ricardo E. de Souza
- 👤 Annjoe Wong-Foy
- 👤 John Clarke
- 👤 Alexander Pines
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:50
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/323; G01R33/326; G01R33/281; Y; Y10; Y10T; Y10T436/00; Y10T436/24
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
59 words
A method for magnetic resonance imaging (MRI) of a sample, comprising: introducing a hyperpolarized inert gas into the sample to transfer spin polarization from the inert gas to target nuclei; detecting nuclear magnetic resonance (NMR) signals from the target nuclei with a high critical temperature (Tc) superconducting quantum interference device (SQUID); forming an image from the detected NMR signals.
Claim 2
Independent Claim
59 words
A method for magnetic resonance imaging (MRI) of a sample, comprising: introducing a hyperpolarized inert gas into the sample to transfer spin polarization from the inert gas to target nuclei; detecting nuclear magnetic resonance (NMR) signals from the target nuclei with a high critical temperature (Tc) superconducting quantum interference device (SQUID); forming an image from the detected NMR signals.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein the inert gas is hyperpolarized by optical pumping.
Claim 4
Dependent Claim
11 words
The method of claim 2 wherein the inert gas is xenon.
Claim 5
Dependent Claim
15 words
The method of claim 1 further comprising operating the SQUID in a flux locked mode.
Claim 6
Dependent Claim
33 words
The method of claim 4 wherein the output of the SQUID is passed through a preamplifier, an amplifier, and an integrator, and then back to a flux modulating coil positioned near the SQUID.
Claim 7
Dependent Claim
14 words
The method of claim 1 further comprising operating the SQUID with additional positive feedback.
Claim 8
Dependent Claim
34 words
The method of claim 1 wherein the NMR signals from target nuclei in the sample are produced by applying a magnetic field to the sample and directing radio frequency (RF) waves into the sample.
Claim 9
Dependent Claim
15 words
The method of claim 7 wherein the magnetic field is less than about 3 mT.
Claim 10
Dependent Claim
16 words
The method of claim 8 wherein the magnetic field is as low as about 0.1 mT.
Claim 11
Dependent Claim
18 words
The method of claim 7 wherein the RF waves have a frequency of less than about 100 kHz.
Claim 12
Dependent Claim
14 words
The method of claim 1 wherein the SQUID is maintained at liquid nitrogen temperature.
Claim 13
Dependent Claim
19 words
The method of claim 11 wherein the SQUID is positioned in a vacuum enclosure containing a liquid nitrogen reservoir.
Claim 14
Dependent Claim
30 words
The method of claim 12 further comprising mounting the SQUID on one end of a sapphire rod and immersing the other end of the rod in the liquid nitrogen reservoir.
Claim 15
Dependent Claim
25 words
The method of claim 11 further comprising positioning a sapphire window adjacent the SQUID and positioning the sample on the other side of the window.
Claim 16
Dependent Claim
21 words
The method of claim 14 wherein the SQUID and sample are separated by a distance of about 1.5 mm or less.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-12-12 | 2004-06-12 | 2004-12-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-12-12 | 2008-06-12 | 2008-12-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-12-12 | 2012-06-12 | 2012-12-12 | $7700.00 | Window Closed / Lapsed |