This masters level science course aims to give you an understanding of the application of physics to the techniques of radiotherapy, one of the key weapons in the fight against cancer. It is designed to enable you to develop a broad and balanced appreciation of this area of contemporary medicine, rather than a detailed ‘professional’ knowledge. The course explains the principles of applying basic physics to radiotherapy in dosimetry, external and internal treatment methods, treatment planning and radiation protection. You’ll also study radiobiology and consider the effects of ionising radiation on biological tissues. By the end of the course, your understanding of these topics will enable you to discuss confidently the ethical, social and financial constraints in delivering radiotherapy.This material is taken from The Open University course S819 Radiotherapy and its physics.