Textbook in PDF format This book provides a comprehensive overview of the use of artificial intelligence (AI) in radiation therapy (RT), with a particular focus on adaptive radiation therapy (ART). It covers key topics, including AI-driven image processing, automatic segmentation, adaptive replanning and delivery, AI-enhanced quality assurance, clinical decision support, and related safety, educational, regulatory and ethical considerations. As an emerging and rapidly evolving field, AI in ART holds immense potential to enhance precision, efficiency, and treatment outcomes in cancer care. Yet, comprehensive resources remain limited. This book bridges the gap by offering a detailed and practical guide, presenting the latest research and clinical applications to help practitioners and researchers effectively integrate AI into their practice and research. Key features: Comprehensive overview of artificial intelligence (AI) in radiation therapy (RT) and adaptive radiation therapy (ART) In-depth discussion of current developments in AI technologies facilitating ART Practical guidance for clinical practitioners and researchers AI in clinical trials Future perspectives