Résumé
Radiotherapy mainly involves treatment of patients with malignant tumors. Even with recognition of the risks of late skin injury, carcinogenesis, leukemogenesis, and genetic damage from all ionizing radiation; radiation therapy also continues to be accepted treatment for benign diseases. Before initiation, the quality of irradiation, total dose, overall time, underlying organs at risk, and shielding factors should be considered. Children should be treated with ionizing radiation only in very exceptional cases and after weighing the pros and cons of the therapy. Direct irradiation of skin areas overlying organs that are particularly prone to late effects (e.g. thyroid, eye, gonads, bone marrow and breast) should be avoided. Radiation protection techniques should be used in all instances. The depth of penetration of the x-ray beam should be chosen according to the depth of the pathologic process. Choice of beam energy usually depends on the depth of the target volume; every effort is made to spare normal underlying tissue in superficial lesions. There are a number of other benign conditions that can be treated with radiotherapy; we present a brief overview of some of the commonly encountered conditions.