Improving Radiation Therapy Through Motion Tracking

OF THE DISSERTATION Improving Radiation Therapy Through Motion Tracking by Hanlin Wan Doctor of Philosophy in Biomedical Engineering Washington University in St. Louis, 2016 Parag Parikh, Chair Radiation therapy is a widely-used cancer treatment method in which lethal doses of ionizing radiation are delivered to cancerous cells. Given the high dose requirements and the risk of associated complications, it is essential that radiation be targeted to cancerous cells while minimizing the dose to surrounding tissue. While current technology allows for accurate targeting of radiation dose, there is one major hurdle: Respiratory motion causes movement of up to a few centimeters of tumors in the abdomen and thorax, rendering even the most accurate radiation delivery machine highly inaccurate. Imaging devices integrated with the treatment machines allow us to visualize the moving tumors, either indirectly through x-ray imaging of nearby implanted fiducial markers, or directly through magnetic resonance imaging. The research presented here investigates two new methods of tracking the tumor motion on these modalities.