Fig. 1.

(a) Photo of a HyperSense DNP system. The cabinet at the bottom is engineered to achieve temperatures near 1 K, where ¹³C sample doped with free radical is irradiated with microwaves to achieve solid-state hyperpolarization. The upper cabinet is used for sample insertion and retrieval, with the help of a long tube that is fitted with sample cup. (b) A preclinical Bruker 7 T MRI scanner. Due to the short decay time of HP pyruvate probe (less than 120 s), the HyperSense and MRI scanner must be in proximity, to allow instant injection of probe following hyperpolarization. In the setup at our laboratory, the two pieces of equipment are separated by a wall, which contains a small aperture for delivering the HP probe through a plastic hose