Erno Sajo is a Professor and the Director of medical physics at the University of Massachusetts Lowell, where he also serves as the Director of biomedical engineering and biotechnology. His research areas are radiation transport computations at the nanoscale with emphasis on interfacial effects, including nanoparticle transport, the physiological translocation of nanoparticles, and nanoparticle enhanced radiation therapy. He is an Associate Editor of the Health Physics journal and has also served as an ad-hoc Editor of Medical Physics. Piotr Zygmanski is an Associate Professor of radiation oncology at the Harvard Medical School and a medical physicist at the Brigham and Women’s Hospital/Dana Farber Cancer Institute, Boston, Massachusetts. Prior to his present position he acquired his clinical training at the Massachusetts General Hospital, and the Harvard Cyclotron Laboratory. His research interests include multiscale radiation transport computations, detection of radiation and mathematical modeling for standard and nanoparticle enhanced radiotherapy.