Artificial intelligence has been utilized to automate and improve various aspects of medical science. For radiotherapy treatment planning, many algorithms have been developed to better support planners. The book provides applications of artificial intelligence (AI) in radiation therapy according to the clinical radiotherapy workflow. An introductory section explains the necessity of AI regarding accuracy and efficiency in clinical settings followed by a basic learning method and introduction of potential applications in radiotherapy. Some chapters also include typical source codes which the reader may use in their original neural network.