• Radiooncology
  • Irradiation
  • Tumour irradiation


Radiation therapy is the treatment of benign and malignant (cancer) diseases using high-energy radiation. The medical field of radiotherapy exists independently as a third radiological specialty besides diagnostic radiology and nuclear medicine.

Physical principles of radiotherapy

The term radiation stands for a physical form of energy. Visible light is a well-known form of radiation. The term radiation combines a multitude of different types of radiation.

In principle, wave radiation (photon radiation) can be distinguished from particle radiation (corpuscular radiation). The wave radiation contains many small energy carriers, the photons. The special thing about photons is that they do not have their own mass.

In the broadest sense it is pure energy in the form of electromagnetic waves. In contrast to this, the energy carriers in particle radiation have their own mass. As an example, the electron beam, which is composed of many small electrons.

Both particle radiation and wave radiation continue to be collective terms that summarize physically different types of radiation used in radiation therapy. Individual photons can be distinguished physically by their wavelength. The wavelength describes the distance that exactly one wave travels from its beginning to its end point.

The intrinsic energy and the possibilities of interactions depend strongly on the wavelength in the case of wave radiation. Particle beams differ in the type of particle. All are used in radiation therapy.

Examples are:

  • Electron beams
  • Proton beams
  • Neutron beams
  • Heavy ion beams

Electron beams (negatively charged particle from the atomic shell)Proton beams (positively charged particle from the atomic nucleus)Neutron beams are uncharged particles from the atomic nucleus. Heavy ions can consist of carbon ions C12, for example.