Makoto Hosono, MD, PhD, is a Professor of Radiology and Nuclear Medicine, Institute of Advanced Clinical Medicine, Kindai University Faculty of Medicine, Japan, and serves as a member of Committee 3, International Commission on Radiological Protection. Jean-François Chatal, MD, PhD, is an Emeritus Professor of Nuclear Medicine at the University of Nantes, France. He is one of the international leaders who developed radioimmunotherapy, that is, therapy using radiolabeled anti-tumor antibodies. He created and headed an INSERM research laboratory and also initiated the installation of a cyclotron institute termed ARRONAX for the production of novel radionuclides for nuclear medicine.