In external radiation therapy the patient is usually needed to attend a daily treatment session. In these sessions, the patients are exposed to radiations with different energy range, with the use of single or different machines, depending on the energy required.
In radiotherapy, the radiation source is usually a machine containing a natural radioactive source such as a bar of cobalt, or an X-ray tube that emit radiation of different types.
Types of External Radiation Therapy
The different types of external radiotherapy are as follows:
- Superficial radiotherapy: it is used in cases of superficial lesions, usually of the skin. The energy range used is lower and therefore it is less pervasive.
- Ortovoltage radiation therapy: given with X-ray equipment with energy slightly above the surface radiation and therefore a slightly higher penetration.
- Cobalt: it is done with a radioactive cobalt source and has an energy range higher than that of ortovoltage, allowing us the opportunity to improve the distribution of energy within the tumor and the body. A few years ago, it was the standard treatment for most tumors.
- High energy: sophisticated X-ray machines, known as linear accelerators, can treat patients with very high energies, improving the penetration and distribution in deep internal organs, with minimization of the effect of radiation on the skin.
Side effects of External Radiation Therapy
Thanks to technical progress, the side effects of radiation therapy today are very limited and no long term side effects occur. Localized redness of the skin may appear after 3 or 4 weeks of treatment, it is called radiation sunburn. Other common side effects include loss of hair, occasional lose motion, vomiting sensations, soaring of throat or mouth, swelling of the areas exposed to radiation and so on. There are other long-term side effects of external radiation therapy that occur in patients who are exposed to radiations for a long time.