Courtesy of Varian Oncology Systems Radiation therapy can also be given internally to administer higher doses of radiation directly to the tumor. In some cases, the radioactive substance is sealed in small containers such as thin wires or tubes, which are held in place by mechanical devices. In other situations, the radioactive substance is swallowed by mouth or injected into the body. Most patients who receive internal radiation therapy are admitted to the hospital for 3-7 days. The side effects of radiation therapy vary from patient to patient.
Most patients have no side effects at all or only mild ones that are easily managed.
Acute side effects, or those that occur during treatment phase and typically go away a few weeks after treatment is finished, include fatigue, skin reactions, and side effects specific to the area being treated. Chronic side effects occur months to years after radiation therapy. They differ according to the area treated and the total dose of radiation therapy received, and may be permanent. Advances in technology and computers now allow radiation oncologists to be more precise than before in treating cancer. Called conformal beam therapy, intensity modulated radiation therapy, or IMRT, this new approach allows for the radiation beams to be more closely tailored to the shape of the entire tumor.