Principles of radiotherapy

Abstract

Abstract This chapter discusses the evolution of cancer and the basic principles of treatment. While DNA damage predominates the radiation-induced cell kill, there are other mechanisms which might influence radiation damage. This chapter also discusses types of radiations and their interaction with tissues, and the fundamental principles of radiotherapy. Radiotherapy cannot distinguish between multiplying cancer and normal cells and therefore results in damage of both cells. However, fractionation of radiotherapy governed by the 5Rs (redistribution of cells, reoxygenation, repair of sublethal damage, repopulation and radiosensitivity) is helpful to maximise tumour kill with acceptable normal tissue toxicities. The concepts of tumour control and normal tissue complication probabilities and clinical application of altered fractionations are also included.