This book provides an overview of recent advances in radiation oncology, many of which have originated from physics and engineering sciences. After an introductory section on basic aspects of 3D medical imaging, the role of 3D imaging in the context of radiotherapy is explored in a series of chapters on the various modern imaging techniques. A further major section addresses 3D treatment planning for conformal radiotherapy, with consideration of both external radiotherapy and brachytherapy. Subsequently the modern techniques of 3D conformal radiotherapy are described, including stereotactic radiotherapy, intensity-modulated radiation therapy, image-guided and adaptive radiotherapy, and radiotherapy with charged particles. More clinically oriented chapters explore the use of brachytherapy in patients with prostate cancer, cardiovascular disorders and breast cancer. The book concludes with sections on patient positioning and quality assurance. The text is specifically designed to be accessible to professionals and students with a medical background as well as to newcomers to radiation oncology from the field of physics.