What is radiation therapy?
Radiation therapy is a type of cancer treatment that uses beams of intense energy to kill cancer cells. Radiation therapy most often uses X-rays, but protons or other types of energy also can be used. The term "radiation therapy" most often refers to external beam radiation therapy. During this type of radiation, the high-energy beams come from a machine outside of your body that aims the beams at a precise point on your body.
During a different type of radiation treatment called brachytherapy (brak-e-THER-uh-pee), radiation is placed inside your body. Radiation therapy damages cells by destroying the genetic material that controls how cells grow and divide.
While both healthy and cancerous cells are damaged by radiation therapy, the goal of radiation therapy is to destroy as few normal, healthy cells as possible. Normal cells can often repair much of the damage caused by radiation.
- 3D conformal radiation therapy: Computed tomography (CT) scans and special computer software help create a three-dimensional computer model of the area to be treated. Treatments are more precisely targeted to the tumor, sparing surrounding normal tissue.
- Intensity-modulated radiation therapy (IMRT)/volumetric modulated arc therapy (VMAT): Intensity modulated radiotherapy provides even more precise radiation therapy. This multi-beam system varies dose intensity and narrows in on diseased cells. VMAT does this over an arc, which tends to be faster.
- Image guided radiotherapy (IGRT): Sometimes three dimensional imaging done before treatment can help ensure the best alignment to the target. This is usually done by getting a CT scan prior to each treatment. Other imaging options include X-rays, ultrasound, systems that track internal seeds and cameras that track a surface as it moves.
- Stereotactic radiosurgery/Gamma Knife radiosurgery: The Gamma Knife is considered the "gold standard" for radiation treatment for brain tumors or lesions. The Gamma Knife provides results comparable to or better than conventional surgery in many cases, without the need for a surgical incision or long recovery in the hospital. Radiosurgery is usually a single treatment, although in some cases you may have treatment broken up into a few treatments over separate days.
- Stereotactic body radiation therapy (SBRT): This type of treatment focuses high doses of intense radiation to targets outside the head. This type of treatment is usually given in one to five treatments. Sometimes special systems that control or track your breathing are necessary to further minimize radiation to the healthy parts of your body.
- Intraoperative radiation: Intraoperative radiation therapy (IORT) allows for radiation to be delivered at the time of surgery, which may help avoid the need for external radiation later. The radiation is better focused to areas that have some tumor left behind.