Cancer Radiation Therapy
Principles of Radiation Therapy (Radiotherapy)
Radiation therapy is the treatment of cancer with ionizing radiation. Radiation works by damaging the DNA (genetic material) within the tumor cells, making them unable to divide and grow. Radiation is often given with the intent of destroying the tumor and curing the disease (curative treatment). However, although radiation is directed at the tumor, it is inevitable that the normal, non-cancerous tissues surrounding the tumor will also be affected by the radiation and therefore damaged (Burnet NG et al. 1996). The goal of radiation therapy is to maximize the dose to tumor cells while minimizing exposure to normal, healthy cells (Emami B et al. 1991).
Because no single therapy can provide complete treatment for a patient with a solid tumor, radiotherapy is often used in combination with surgery or chemotherapy to improve the chances of a successful treatment outcome. Sometimes radiation is used to relieve symptoms, such as pain or seizures; this is called palliative treatment (Hoskin PJ et al. 1992).