This Paediatric Oncology online workshop is an interactive case-based course aimed to improve the delineation of target volumes for paediatric brain tumours and Hodgkin lymphoma. Participants are asked to delineate two cases according to the latest European guidelines and and during the course the participants’ delineations are compared to the teachers delineations while discussing the differences. At the workshop you will learn about craniospinal target volumes, including delineation of organs at risk, principles of target volume delineation for lymphoma in children, teenage, and young adults and radiotherapy planning. The workshop will also discuss the optimal use of MRI and PET/CT for target volume delineation. The course aims to reduce variability and inconsistency in delineation for tumours in children, teenage and young adults to improve the safety and quality of radiotherapy.