Session D21: Focus Session: Novel Instrumentation & Measurements for Biomedical Research
2:30 PM–5:30 PM, Monday, March 21, 2011
Room: D161
Sponsoring Unit:
GIMS
Chair: Larry Nagahara, National Institutes of Health
Abstract ID: BAPS.2011.MAR.D21.9
Abstract: D21.00009 : Producing $>$60,000-fold room-temperature $^{89}$Y NMR signal enhancement
4:30 PM–4:42 PM
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Abstract 
Authors:
Lloyd Lumata
(UT Southwestern Medical Center)
Ashish Jindal
(UT Southwestern Medical Center)
Matthew Merritt
(UT Southwestern Medical Center)
Craig Malloy
(UT Southwestern Medical Center)
A. Dean Sherry
(UT Southwestern Medical Center)
Zoltan Kovacs
(UT Southwestern Medical Center)
$^{89}$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.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2011.MAR.D21.9