Professor Xu's laboratory is interested in imaging and dosimetry simulations of cancer stem cells (CSCs) for potential applications in radiotherapy. An understanding of how CSCs respond to ionizing radiation such as x-rays, electrons and protons would provide unprecedented opportunity for more effective methods of radiation treatment of cancers. CSCs have been recently found to resist radiation during radiotherapy. It is possible that these cancer-initiating cells are responsible for previous failures of radiotherapy involving leukemia, breast tumors, brain tumors, and bone tumors. We are hoping to integrate the latest experimental radiobiologic information with novel imaging as well as radiation transport modeling to develop better cancer treatment methods.