After the first year of theoretical physics course marathon in my PhD study, I found myself more attracted by the work of my engineering peers, so I started taking engineering classes. Professor Jeffrey Fessler’s course “Medical Imaging Systems” intrigued me and brought me into the field of medical imaging – I never knew so many wonderful things I could do with my physics knowledge. After a short summer rotation, I joined Professor Larry Antonuk’s group, in the hope that the balanced flavors of theoretical and empirical investigations within the group would give me a relatively broad doctoral training.
My thesis project concentrates on the development of high quantum efficiency megavoltage X-ray imagers. The quantum efficiency of conventional portal imager with phosphor screens is only ~2%, leading to a detective quantum efficiency (DQE) of only ~1%. To capture a much larger fraction of the treatment radiation, imagers incorporating thick and optically isolated segmented scintillators have been proposed and investigated by our group. Such scintillators provide over an order of magnitude increase in DQE.
One of the implications of such significant DQE increase is the possibility of megavoltage cone-beam CT (CBCT) with clinically practical doses using the treatment beam itself and portal imager, as an alternative to the kilovoltage CBCT currently performed in image-guided radiotherapy. My research focuses on the theoretical optimization of segmented scintillator designs for MV CBCT through Monte Carlo simulations, as well as empirical characterization of scintillator prototypes.
During my five-year stay in Professor Larry Antonuk's group, I have collaborated with researchers from around the world, and contributed new knowledge to the frontier of the battle against cancer – I have authored or co-authored four peer-reviewed papers, and presented my studies at international conferences. More importantly, I have fostered analytical and interpersonal skills that are essential for a research scientist. It has been a very rewarding experience of my graduate life.