ABSTRACT
This chapter describes dose quantities with their units used in radiation protection aspects. It explains principles which are used in radiation safety: justification, optimisation and the as low as reasonably achievable (ALARA) principle. The chapter examines briefly how they are implemented within a radiation oncology department. All sources of ionising radiation should have the best possible safety systems set in place so that magnitude and likelihood of exposure is kept ALARA taking into account the local economic and social factors being taken into account. The chapter discusses the differences between external and internal exposures and the implications for radiation safety. It highlights different types of radiation which may be present in a radiotherapy bunker containing a linear accelerator. The most commonly used material for bunker design is concrete. However, in situations where space is limited, then the use of the higher density concrete, steel or lead may be used.
