This book summarizes recent advances in radiation oncology, many of which originated in physics and engineering sciences. These new technologies have a complex physical, mathematical and technical background that technical assistants, dosimetrists, and physicians frequently find difficult to comprehend. This book is specifically designed to be readily understandable by professionals and students with a medical background as well as by newcomers to radiation oncology from the field of physics. All relevant areas of the subject are covered in detail, including 3D imaging and image processing, 3D treatment planning, modern treatment techniques, patient positioning, and aspects of verification and quality assurance.