We are pleased to announce that MIMRTL team member Eric Weber successfully passed his preliminary examination on November 26, 2024. This significant milestone marks his advancement to doctoral candidacy. Eric is co-advised by MIMRTL Principal Investigator Dr. Alan McMillan and by Dr. Nader Behdad. His examination committee also included Dr. Chu Ma and Dr. Kevin Johnson, whose expertise and guidance were invaluable.
Eric’s research focuses on the development and advancement of Electron Paramagnetic Resonance Imaging (EPRI), a noninvasive imaging technique with substantial potential for healthcare diagnoses, treatment guidance, and biomedical research. Unlike conventional magnetic resonance imaging (MRI) which typically images hydrogen nuclei, EPRI detects electron free radicals, often introduced via injectable spin probes. This allows for unique applications such as mapping tissue oxygenation, which is crucial for understanding tumor microenvironments and improving cancer therapies like radiation treatment, as hypoxic tissues show higher resistance. EPRI also shows promise for monitoring ischemia, studying antioxidant levels related to diseases like cancer and Alzheimer’s, performing dosimetry after radiation exposure, and even aiding pharmaceutical development by quantifying drug distribution and impurities.
In his preliminary examination, Eric presented his work on designing and building a novel Continuous-Wave (CW) EPRI system utilizing a Travelling-Wave (TW) architecture. This innovative approach diverges from traditional reflection-based EPRI systems by employing a waveguide structure for transmitting the radiofrequency (RF) excitation field, while a separate RF coil acts solely as a receiver. The core hypothesis is that this TW method will generate a more uniform excitation field across the sample, potentially overcoming challenges related to the limited penetration depth of RF signals at higher frequencies often used in EPRI for increased sensitivity.
Eric detailed the theoretical underpinnings and physical construction of the 1 GHz TW EPRI system developed within MIMRTL. He presented the design considerations for key components, including the main magnet, RF source, waveguide dimensions optimized for the dominant TE11 mode, receive RF coil, modulation coil, gradient coils for spatial encoding, and the RF bridge facilitating signal detection. He also discussed the custom programming interface developed using Python for system control and data acquisition. Initial experimental results were shared, demonstrating successful two-dimensional imaging of DPPH powder phantoms. Looking forward, Eric outlined the next aims for his doctoral research. A major goal is the development and construction of a multi-element receive coil array. Drawing inspiration from advancements in MRI technology, such an array is hypothesized to significantly improve image sensitivity, which is essential for imaging deeper within biological tissues and enabling future in vivo whole-body mouse imaging. Furthermore, he plans to investigate more structurally complex or multi-element antenna designs for exciting the waveguide. This could lead to improved excitation field uniformity over larger fields-of-view and potentially offer methods for field shaping to optimize imaging and reduce specific absorption rates (SAR), crucial steps towards the ultimate goal of performing three-dimensional murine imaging.
MIMRTL extends its warmest congratulations to Eric Weber on reaching this important academic milestone and eagerly anticipates his future contributions to advancing MRI and EPRI technology.