Radiation therapy involves the use of high-energy ionizing radiation to kill cancer cells. Cancer cells are destroyed in the anatomic area being treated so it is considered a local therapy. Radiation breaks down one or both strands of the DNA molecule inside of cells, preventing cell growth and division. Radiation therapy is delivered with machines administering high ionizing radiation. The machine used will depend on the tumor itself.
Radiation therapy is planned according to clinical status.
The desired dosage of radiation should be delivered in the least amount of fraction possible in order to promote patient comfort. In palliative radiation, high doses with small daily fractions are administered over one or two weeks. However, studies have shown that low dose, short course radiation is just as effective as high dose protocols. The first phase of radiation is known as simulation. Healthy tissue may be protected from radiation therapy by using customized shields, known as blocks.