Patent ID: 7246939

Claim:
A method of measuring the thermal diffusivity in a substance by nuclear magnetic resonance, said method comprising: a. providing a nuclear magnetic resonance imaging and spectroscopy apparatus, b. placing said substance in said nuclear magnetic resonance imaging and spectroscopy apparatus, c. measuring one or more nuclear magnetic resonance properties comprising nuclear magnetic resonance frequency ω or nuclear spin phase shift φ or nuclear magnetization M(t e ,T) or equilibrium nuclear magnetization M(0,T) or spin-lattice relaxation time T 1 (T) or spin-lattice relaxation rate R 1 (T) or spin—spin relaxation time T 2 (T) or spin—spin relaxation rate R 2 (T) or effective spin—spin relaxation time T 2 *(T) or effective spin—spin relaxation rate R 2 *(T) or spin diffusion coefficient D(T) in said substance, d. providing a thermal energy to heat a volume in said substance or to heat an absorber placed in close contact with said substance or within said substance, e. measuring and normalizing the temporal variation of one or more said nuclear magnetic resonance properties in step (c) in said substance in imaging voxels perpendicular to the direction of the heat propagation at multiple distances from the heated volume or absorber by acquiring multiple nuclear magnetic resonance images, f. determining the time for the maximal change in said temporal variation of one or more said nuclear magnetic resonance properties in step (e) at multiple distances, g. determining said thermal diffusivity in said substance using the relation between said square of the distance and said time for the maximal change in said temporal variation of one or more said nuclear magnetic resonance properties in step (f).