Squid detected NMR and MRI at ultralow fields

US7218104B2 · kind B2 · utility

Inventors

• John M. Clarke · Dunlap, US
• Robert McDermott · Lompoc, US
• Alexander Pines · Berkeley, US
• Andreas Trabesinger · Zürich, CH

Key dates

• Filing date: Sep 25, 2006
• Grant date: May 15, 2007
• Expiry date: Sep 25, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G01R33/445
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.