Ionizing radiation presents itself in the form of particles (alpha particles, beta particles, protons or neutrons) or electromagnetic radiation (gamma rays and X-rays) with characteristic ionizing power and penetration. Radiotherapy is an essential tool in the treatment of cancer. We can consider various forms of radiation such as external beam radiotherapy, brachytherapy and metabolic radiotherapy. When treating cancer with ionizing radiation all cells within the irradiation volume are more or less exposed.
