1970-2000 The largest separate unit
As a result of decades of research and development, modern radiation therapy is safe and effective nowadays. Radiotherapy of cancer is based on the ionizing effect of radiation. Its direct effect damages DNA and the structures of cell membranes. The indirect effect is due to the decomposition of water molecules in cells caused by radiation energy, which results in the creation of so called free radicals. These free radicals damage vital cell structures. Normal tissues have a remarkable ability to repair damages caused by radiation. Cancerous cells do not have this capability.