Modern Radiotherapy is becoming increasingly conformal with the development of advanced beam delivery techniques such as VMAT, IMRT, and SABR, as well as image-guided radiotherapy (IGRT). However, routine radiotherapy treatment planning heavily depended on manual target delineation and planning simulation. The goal of this research project is to develop AI-based algorithms in target delineation and dose prediction for automatic radiotherapy treatment planning and applied aspects of clinical practice of radiotherapy. Our research mainly focus on AI-based approaches to provide better target definition, the usage of AI-based methods for multi-modality image segmentation, and target localization based on 2D and 3D imaging using AI approaches that rapidly provide high-quality personalized treatment for cancer patients.