This book equips readers with detailed knowledge on the current status of image-guided radiotherapy with photons and particles and highlights issues that need to be addressed in order to further improve treatment outcomes. The opening chapters cover clinical and technical aspects of target volume definition using anatomic (computed tomography and magnetic resonance imaging; MRI) as well as functional (MRI and positron emission tomography) imaging. Up-to-date information is then provided on the full range of image-guided high-precision radiotherapy techniques, including IMRT/VMAT, stereotactic body radiation therapy, MR-guided linear accelerators, MR-guided brachytherapy, and particle therapy. The role of ultrasonography in image-guided radiotherapy is discussed, as are the available means for target volume demarcation and stabilization and adaptive radiation therapy. Finally, outcome evaluation is explored in depth, with a particular focus on the role of multimodality imaging in predicting tumor control and normal tissue toxicity. The authors are experts in different specialties and the book will be of high value for radiation oncologists, medical physicists, radiologists, nuclear medicine physicians, and radiation technicians.