Real-Time Polarimetry of Hyperpolarized 13C Nuclear Spins Using an Atomic Magnetometer

We introduce a method for nondestructive quantification of nuclear spin polarization, of relevance to hyperpolarized spin tracers widely used in magnetic resonance from spectroscopy to in vivo imaging. In a bias field of around 30 nT we use a high-sensitivity miniaturized 87Rb-vapor magnetometer to measure the field generated by the sample, as it is driven by a windowed dynamical decoupling pulse sequence that both maximizes the nuclear spin lifetime and modulates the polarization for easy detection. We demonstrate the procedure applied to a 0.08 M hyperpolarized [1-13C]-pyruvate solution produced by dissolution dynamic nuclear polarization, measuring polarization repeatedly during natural decay at Earth's field. Application to real-time and continuous quality monitoring of hyperpolarized substances is discussed.

Automated summary

We present a nondestructive method for quantifying nuclear spin polarization, which is relevant for hyperpolarized spin tracers commonly used in magnetic resonance imaging. Using a miniaturized 87Rb-vapor magnetometer with high sensitivity, we measure the magnetic field generated by the sample under a bias field of around 30 nT. The polarization is modulated and detected using a windowed dynamical decoupling pulse sequence that maximizes nuclear spin lifetime. We demonstrate the application of this method to measure the polarization decay of a hyperpolarized [1-13C]-pyruvate solution produced by dynamic nuclear polarization, and discuss its potential use for real-time quality monitoring of hyperpolarized substances.