Billy W. Loo, Jr., M.D., Ph.D. is a Professor of Radiation Oncology, a member of the Molecular Imaging Program at Stanford (MIPS) in the Department of Radiology, and a member of the Stanford Cancer Institute, in the School of Medicine. He is a physician-scientist Radiation Oncologist and Bioengineer who directs the Thoracic Radiation Oncology Program at Stanford. His clinical specialties are state-of-the-art radiation therapy for lung/thoracic cancers, including stereotactic ablative radiotherapy (SABR) and 4-D image-guided radiation therapy for lung tumors. Dr. Loo is a recognized expert in thoracic cancers serving on multiple national committees (including as writing member, chair, or vice-chair) that publish clinical guidelines on the treatment of lung cancer and other thoracic malignancies, including the National Comprehensive Cancer Network (NCCN), American College of Radiology (ACR), and American Society of Radiation Oncology (ASTRO). His clinical research is in clinical trials and implementation of new treatment techniques for lung cancer, and development of new medical imaging methods for measuring organ function and predicting response to cancer treatment. As part of this work, he leads a clinical and preclinical research program in molecular imaging, particularly using novel PET tracers for tumor hypoxia (EF5), tumor proliferation (FLT), and neuroinflammation (PBR06). He also co-leads clinical trials of novel applications of SABR including treatment of pulmonary emphysema and cardiac arrhythmias. Since conceiving of a fundamentally new approach to delivering ultra-rapid, ultra-precise radiation therapy, pluridirectional high-energy agile scanning electronic radiotherapy (PHASER), Dr. Loo's major laboratory research focus has been to co-lead a collaborative effort between the Stanford Cancer Institute and SLAC National Accelerator Laboratory to develop PHASER into a transformative yet clinically practical technology. This program comprises both technology development and fundamental research on the radiobiology of extremely rapid FLASH radiation therapy to optimize the biological therapeutic index. Dr. Loo received his MD from University of California, Davis and his PhD in Bioengineering from University of California, San Francisco and Berkeley. He completed his Radiation Oncology residency training at Stanford University. He is certified by the American Board of Radiology in Radiation Oncology.