Radiation Therapy Treatment

Radiation therapy uses beams of high-energy X-rays or other particles to kill cancer cells. It's a common part of cancer treatment. If the radiation therapy is given from a machine outside the body, it is called external-beam radiation therapy. It is the most common type for cancer. If you and your healthcare provider decide on radiation, you'll need a treatment planning visit called a simulation.

Simulation is the planning session that helps your healthcare provider map out and target the cancer in your body. The process re-creates the exact position you'll be in for each treatment. The radiation plan is made to protect your healthy tissues as much as possible from radiation. Your radiation therapy team uses a special machine called a simulator to plan your treatment. This might be an X-ray machine, CT scanner, MRI scanner, or PET-CT scanner machine. Laser lights are used to help put you in the right position. During this visit:

• The team figures out the best position for your body. It's often lying on your back. But you might be on your stomach or even on your side.

• Special devices might be made to keep you in the right position and still during treatment. These may include molds, masks, plaster casts, and blocks.

• Ink marks may be put on your skin. These are used to be sure you're in the same position and the radiation goes to the same spot for each treatment. (This part of your skin may be called the treatment field or port.) Tiny permanent tattoos may also be used. These tattoos may be removed later with laser treatments.

• Markers, such as metal balls or wires, may be put on or in your body. Sometimes these are taped to the skin to help with the imaging process. They're used along with the X-rays to position your body. The markers are removed after each visit.

After your team has the imaging scans and other data, all the information is sent into the computer planning system. Your healthcare team then makes your treatment plan. Your team figures out exactly where the radiation needs to go, the dose of radiation, how often treatments will be given, and what nearby tissues need to be protected. The goal is to get radiation to the tumor while limiting radiation to nearby normal tissues.