A method and an apparatus for producing hyperpolarized samples for use in
magnetic resonance imaging (MRI) are provided. The apparatus comprises an
ultra-compact cryogen-free cryostat structure for use in polarizing a
sample of selected material, wherein the cryostat structure comprises a
central bore being adapted to be evacuated to create a vacuum region, and
a cooling device inserted in the central bore or optionally close to the
central bore for maintaining a selected temperature of the sample.