Medical Physics Seminar – Monday, March 7, 2022
Fluorine-19 MRI for Quantitative In Vivo Tracking of Murine Natural Killer Cells Within Lymphoma
Lawrence Lechuga
Graduate Research Assistant to Prof. Sean Fain
In recent years, cancer immunotherapies have demonstrated great success against multiple forms of cancer. One treatment approach utilizes adoptive cellular transfer (ACT) of Natural Killer cells to elicit cytotoxic activity and tumor infiltration. A growing number of studies suggest that the presence of NK cells within solid tumors is associated with more positive clinical outcomes. Although this information may hold prognostic value and inform the timing of cellular infusions, the biodistribution and persistence of these cells after infusion are generally unknown. Fluorine-19 (19F) MRI has the potential to track and quantify labeled cells for days to weeks after adoptive transfer. 19F MRI is a highly specific and quantitative imaging technique of perfluorocarbon nanoemulsions that are used to directly label cell populations with ex vivo. This work will demonstrate the ability of 19F MRI to track and quantify intratumorally injected PFPE-red labeled GFP+ NK cell populations within lymphoma-bearing mice out to 6 days post injection and verify both NK cell viability and label retention within the injected cells via flow cytometry of the dual-fluorescent cells.
Motion Compensation in Pulmonary Ultra-short Echo Time MRI
Luis Torres
Graduate Research Assistant to Prof. Sean Fain
Idiopathic Pulmonary Fibrosis (IPF), a chronic restrictive lung disease, and Bronchopulmonary Dysplasia (BPD), a disease of premature birth, are progressive pulmonary diseases that could benefit from structural MRI to allow for more frequent imaging without accruing ionizing radiation dose. A significant challenge to applying structural pulmonary MRI clinically is the long scan times and resulting motion corruption in the images. Recently, 3D radial ultrashort echo-time (UTE) MRI has shown promise for application in these subjects, however, due to long acquisition times and inconsistent tidal breathing in disease, motion corruption is still frequently observed. Recently, more advanced motion correction techniques have been proposed to retrospectively improve image quality. The purpose of this study was to evaluate these strategies in the highly challenging setting of infants with BPD and longitudinal imaging of older adults with IPF. Our goal is to identify the current best approach for compensating for respiratory motion and capturing respiratory dynamics using 3D radial UTE MRI.