Dr. Bortfeld received his Ph.D. in Physics from the University of Heidelberg, Germany, in 1990. He started his career at the German Cancer Research Center (DKFZ) in Medical Physics, interrupted by a short postdoctoral fellowship at the MD Anderson Cancer Center in Houston. He was instrumental in the early development of intensity modulated radiation therapy (IMRT), including inverse planning algorithms and delivery of IMRT with multileaf collimators (MLC). His work enabled the first clinical deployment of MLC-based IMRT at the Memorial Sloan Kettering Cancer Center in New York in 1995. Since 2001 Dr. Bortfeld has been at the Massachusetts General Hospital (MGH) in Boston, where he developed and deployed multi-criteria optimization and robust optimization of treatment plans. In 2008 he was promoted to Professor at the Harvard Medical School and Chief of the Radiation Biophysics Division at MGH. His current research interests are imaging-guided temporo-spatial optimization of treatment delivery, better ways to define the clinical target volume, and making the benefits of proton therapy available to more patients.