The 3rd Virtual Summer School in Medical Physics will first introduce standard data science tools in the field of medical physics with overview talks by specialists in the field. After that, we want to focus on some key applications: treatment planning, Monte Carlo Simulations, radiobiological and biophysical modelling as well as medical image analysis and processing. We will also touch some applications in radiomics and radiology in general. Our virtual summer school is dedicated to national and international young scientists and graduates (BSc or MSc or PhD students) with a degree in physics, medical physics or medical technology, computer science, radiation oncology or similar. Participation is free of charge but limited to a certain number of participants. The teaching language is English.