Introduction Welcome Message of Congress Presidents On behalf of the Organizing Committee, we would like to extend our warmest welcome to all colleagues participating in the World Congress on Medical Physics and Biomedical Engineering 2006. We hope you will join us, taking advantage of this opportunity to learn the latest advancements in the field, to reconnect with old friends and meet new ones, and to take in the sights and sounds of Seoul. WC 2006 offers a strong and diverse scientific program covering a wide range of issues and challenges that are currently present in Medical Physics and...