?Gokhan Ozyigit graduated from Hacettepe University Faculty of Medicine (English) in 1996 and then obtained ECFMG Certification in the USA. In 2001 he completed his residency in the Department of Radiation Oncology at Hacettepe University. He later became a Research Fellow in the Departments of Radiation Oncology at Washington University and The University of Texas M.D. Anderson Cancer Center. In 2004 he was appointed Assistant Professor in the Department of Radiation Oncology at Hacettepe University and in 2006 became an Associate Professor there. He is currently Chair and Professor of the Department of Radiation Oncology and Director of the Advanced Cancer Technologies Research & Application Center at Hacettepe University. Dr. Ozyigit is an editorial board member of several international journals. He is also a reviewer or advisor for a number of other international journals, co-editor of eight previous books, and author of numerous articles in peer-reviewed journals and book chapters. He has received several national awards in the field of Oncology and is a member of the Board of Directors of the Turkish Society for Radiation Oncology. Ugur Selek graduated from Hacettepe University, Faculty of Medicine (English), in 1997, and was certified by ECFMG in USA. He completed his Radiation Oncology Residency Program in Hacettepe University in 2001. Between 2001 and 2003, he worked at University of Texas, M.D. Anderson Cancer Center, Department of Radiation Oncology, as a Clinical Fellow focusing on IMRT and Stereotactic Radiotherapy, and was awarded with "First Annual M.D. Anderson Radiation Oncology Fellow Research Award" in 2003. After his appointment as Assistant Professor in 2004, he became an Associate Professor in the Department of Radiation Oncology at Hacettepe University in 2006. Dr Selek is currently Professor & Chair of Department of Radiation Oncology at Koc University School of Medicine, as well as being an adjunct Professor of U.T. M.D. Anderson Cancer Center, Department of Radiation Oncology, and Chair of American Hospital-MD Anderson Radiation Treatment Center in Istanbul. Dr. Selek is an editor of Turkish Journal of Oncology, reviewer for a number of international journals, co-editor of 3 previous books, and has authored numerous articles in peer-reviewed journals and book chapters. He is a member of ASTRO International Education Subcommittee, and member of Board of Directors of both Turkish Society for Radiation Oncology & Turkish Society of Lung Cancer.