His research has mostly to do with “radiation dosimetry” for radiation protection, medical imaging, and radiotherapy applications. His research has been continuously funded by governmental agencies and private industry. His publication list includes 2 books, 200 peer-reviewed papers/chapters, 400 abstracts, and 130 invited talks. Widely known for his work on “computational phantoms” and “advanced Monte Carlo simulations”, Prof. Xu is a fellow of American Nuclear Society (ANS), Health Physics Society (HPS), and American Association of Physicists in Medicine (AAPM), as well as a council member of the National Council on Radiation Protection and Measurement (NCRP) and a past president of the Council on Ionizing Radiation Measurements and Standards (CIRMS). He is currently on the editorial board of Medical Physics and Physics in Medicine & Biology. Prof. Xu has received numerous awards including most notably NSF’s CAREER Award, CIRMS Randal S. Caswell Award for Distinguished Achievements (2015), HPS Distinguished Scientific Achievement Award (2018), ANS Arthur Holly Compton Award in Education (2020), ANS Rockwell Lifetime Achievement Award in radiation protection and shielding (2020), and AAPM Edith H. Quimby Award for Lifetime Achievement in Medical Physics (2020). Prof. Xu is the co-founder and president of Virtual Phantoms Inc. which commercializes VirtualDose (a CT and IR patient dose reporting software) and ARCHER (a GPU-based Monte Carlo dose computing software for treatment planning and dose QA verification).