Effects of low magnetic fields on T1values for hyperpolarized 13 C Pyruvic Acid
description
Transcript of Effects of low magnetic fields on T1values for hyperpolarized 13 C Pyruvic Acid
Effects of low magnetic fields on T1values for hyperpolarized 13C
Pyruvic AcidBryan Addeman
April 6, 2010
Label specific metabolites with 13C
12C isotope is not magnetically active
Why use 13C instead of 1H?
Natural abundance of 13C is ≈ 1.11%
Amount of signal is related to gyromagnetic ratio (γ) & abundance◦ γH = 42.58 (Mhz/T)
◦ γ13C = 10.71 (Mhz/T)
Hyperpolarization can give a factor of 10,000x more initial signal
Why does the sample need to be hyperpolarized?
Hyperpolarization Process
Inject sample mixed with free radical
Cool to 1.4 K in a High magnetic field
Bombard sample with microwaves
Mix with heated solution
Duration: 1.5 hours
Amount of Hyperpolarization decays with time (T1)
Robarts DNP Hyperpolarizer
Hyperpolarized sample transport:◦ Bo: High (DNP) -> Low -> High (MRI)
What happens to the sample in transit?
T1 relaxation is a characteristic of the molecule that can be measured
Motivation
Measuring T1
SpinmasterOxford Instruments MQC
Variable magnetic field◦ Bo = 0.0-0.9 T
Desktop NMR system◦ Bo = 0.55 T
Both devices can measure Signal amplitude at time intervals
Spinmaster MQC (0.55 Static Field)
Field Strength (T)
T1 (s) Fit Error (s) T1 (s) Fit Error (s)
0.55 52.6 0.44 58.3 0.31
0.0235 68.7 0.25 87.0 0.82
0.0235 74.2 0.78 83.7 0.56
Results
Need to take more measurements to understand the effects low field strengths on T1 values
Conclusions
Acknowledgments Supervisors
Dr. Charles McKenzie Dr. Lanette Friesen-
Walder Dr. Tim Scholl Dr. Jake Onwuachi
Lab
Curtis Wiens Samantha Flood Steven Yange Elmer Soto Trevor Wade