Producing $>$60,000-fold room-temperature $^{89}$Y NMR signal enhancement

$^{89}$Y in chelated form is potentially valuable in medical imaging because its chemical shift is sensitive to local factors in tumors such as pH. However, $^{89}$Y has a low gyromagnetic ratio $\gamma_{n}$ thus its NMR signal is hampered by low thermal polarization. Here we show that we can enhance the room-temperature NMR signal of $^{89}$Y up to 65,000 times the thermal signal, which corresponds to 10 \% nuclear polarization, via fast dissolution dynamic nuclear polarization (DNP). The relatively long spin-lattice relaxation time $T_{1}$ ($\sim$500 s) of $^{89}$Y translates to a long polarization lifetime. The $^{89}$Y NMR enhancement is optimized by varying the glassing matrices and paramagnetic agents as well as doping the samples with a gadolinium relaxation agent. Co-polarization of $^{89}$Y-DOTA with a $^{13}$C sample shows that both nuclear spin species acquire the same spin temperature $T_{s}$, consistent with thermal mixing mechanism of DNP. The high room-temperature NMR signal enhancement places $^{89}$Y, one of the most challenging nuclei to detect by NMR, in the list of viable magnetic resonance imaging (MRI) agents when hyperpolarized under optimized conditions.