III.11 — Radiation oncology: biology, physics and clinical applications

Ionizing radiation is one of the main modalities used for cancer treatment and has been used in the clinic since the discovery of X-rays and radioactivity at the end of the 19th century. The development of linear accelerators (linacs) in the 1950s allowed treatment of deeply seated tumours and sparing of the skin. Further improvements in imaging, computer-assisted planning, dose-delivery techniques and globally treatment equipment, allowed vast improvements in curability and reduced toxicity; nowadays, over 50% of cancer patients receive radiotherapy. The majority of radiotherapy treatments globally are delivered with megavoltage electron linacs. Access to radiotherapy and improvement of available technology remain key issues of global health.