[Radiation therapy for malignant tumors]

Radiation therapy uses ionizing radiation to kill cancer cells and shrink tumors, with consideration to minimize harmful damages to health tissues. About 30% of all people with cancer are treated with radiation therapy, either alone or in combination with chemotherapy. Radiation therapy may be internal or external. In brachytheraphy as the internal radiation therapy the radioisotope is implanted into or near the tumor by tubes as the container. And it is often used for patients with the tongue cancer. External radiation, the type most often used, comes from a machine outside the body. It is usually used for shrinking tumors with bony invasions such as gingival cancer and improving the pain in patients with bony metastasis. For the primary bone tumor the radiation therapy is not always used because the radiosensitivity of the almost primary bone tumor is low.