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Physics and Astronomy PhD Defense – Drew McCallister

July 2, 2019 @ 10:00 am - 12:00 pm

UNC-CH Physics and Astronomy PhD Defense

Drew McCallister

“Optimization of continuous flow Xenon-129 polarizer for biomedical imaging applications and the effect of magnetic field in homogeneities on fat fraction MR quantification”

Hyperpolarized 129Xe gas has been used in many different applications across the field of magnetic resonance and its applications are quickly expanding. For these applications, the largest barrier continues to be the low xenon polarization value that can be obtained with continuous flow spin exchange optical pumping. Work done in our lab using finite element analysis simulations of the spin exchange optical pumping (SEOP) process has highlighted major shortcomings in the current continuous-flow SEOP setup. To this end I have designed and constructed a new continuous-flow 129Xe polarizer to optimize the optical pumping process and reduce polarization losses. Some of the applications I have been working on are the detection of brown adipose tissue in humans as well as lung imaging in patients with cystic fibrosis. Fat fraction MR techniques have also been proposed as an alternative method to detect and quantify brown adipose tissue. We analyzed some of the shortcomings of these techniques, specifically the specificity of fat fraction and the effect of microscopic magnetic susceptibility gradients on quantification. Polarizer design, brown adipose tissue detection techniques and MR gas imaging in cystic fibrosis patients will be discussed.

Details

Date:
July 2, 2019
Time:
10:00 am - 12:00 pm

Venue

Phillips 277