What is radiation therapy?	Radiation therapy (also called radiotherapy) is a cancer treatment that uses high doses of radiation to kill cancer cells and stop them from spreading. At low doses, radiation is used as an x-ray to see inside your body and take pictures, such as x-rays of your teeth or broken bones. Radiation used in cancer treatment works in much the same way, except that it is given at higher doses.
How is radiation therapy given?	Radiation therapy can be external beam (when a machine outside your body aims radiation at cancer cells) or internal (when radiation is put inside your body, in or near the cancer cells). Sometimes people get both forms of radiation therapy. To learn more about external beam radiation therapy, see "External Beam Radiation Therapy" 1. To learn more about internal radiation therapy, see "Internal Beam Radiation Therapy" 2.
Who gets radiation therapy?	Many people with cancer need radiation therapy. In fact, more than half (about 60 percent) of people with cancer get radiation therapy. Sometimes, radiation therapy is the only kind of cancer treatment people need.
What does radiation therapy do to cancer cells?	Given in high doses, radiation kills or slows the growth of cancer cells. Radiation therapy is used to: Treat cancer. Radiation can be used to cure, stop, or slow the growth of cancer. Reduce symptoms. When a cure is not possible, radiation may be used to shrink cancer tumors in order to reduce pressure. Radiation therapy used in this way can treat problems such as pain, or it can prevent problems such as blindness or loss of bowel and bladder control.
How long does radiation therapy take to work?	Radiation therapy does not kill cancer cells right away. It takes days or weeks of treatment before cancer cells start to die. Then, cancer cells keep dying for weeks or months after radiation therapy ends.
What does radiation therapy do to healthy cells?	Radiation not only kills or slows the growth of cancer cells, it can also affect nearby healthy cells. The healthy cells almost always recover after treatment is over. But sometimes people may have side effects that do not get better or are severe. Doctors try to protect healthy cells during treatment by: Using as low a dose of radiation as possible. The radiation dose is balanced between being high enough to kill cancer cells yet low enough to limit damage to healthy cells. Spreading out treatment over time. You may get radiation therapy once a day for several weeks or in smaller doses twice a day. Spreading out the radiation dose allows normal cells to recover while cancer cells die. Aiming radiation at a precise part of your body. New techniques, such as IMRT and 3-D conformal radiation therapy, allow your doctor to aim higher doses of radiation at your cancer while reducing the radiation to nearby healthy tissue. Using medicines. Some drugs can help protect certain parts of your body, such as the salivary glands that make saliva (spit).
Does radiation therapy hurt?	No, radiation therapy does not hurt while it is being given. But the side effects that people may get from radiation therapy can cause pain or discomfort. This book has a lot of information about ways that you, your doctor, and your nurse can help manage side effects.
Is radiation therapy used with other types of cancer treatment?	Yes, radiation therapy is often used with other cancer treatments. Here are some examples: Radiation therapy and surgery. Radiation may be given before, during, or after surgery. Doctors may use radiation to shrink the size of the cancer before surgery, or they may use radiation after surgery to kill any cancer cells that remain. Sometimes, radiation therapy is given during surgery so that it goes straight to the cancer without passing through the skin. This is called intraoperative radiation. Radiation therapy and chemotherapy. Radiation may be given before, during, or after chemotherapy. Before or during chemotherapy, radiation therapy can shrink the cancer so that chemotherapy works better. Sometimes, chemotherapy is given to help radiation therapy work better. After chemotherapy, radiation therapy can be used to kill any cancer cells that remain.
Who is on my radiation therapy team?	Many people help with your radiation treatment and care. This group of health care providers is often called the "radiation therapy team." They work together to provide care that is just right for you. Your radiation therapy team can include: Radiation oncologist. This is a doctor who specializes in using radiation therapy to treat cancer. He or she prescribes how much radiation you will receive, plans how your treatment will be given, closely follows you during your course of treatment, and prescribes care you may need to help with side effects. He or she works closely with the other doctors, nurses, and health care providers on your team. After you are finished with radiation therapy, your radiation oncologist will see you for follow-up visits. During these visits, this doctor will check for late side effects and assess how well the radiation has worked. Nurse practitioner. This is a nurse with advanced training. He or she can take your medical history, do physical exams, order tests, manage side effects, and closely watch your response to treatment. After you are finished with radiation therapy, your nurse practitioner may see you for follow-up visits to check for late side effects and assess how well the radiation has worked. Radiation nurse. This person provides nursing care during radiation therapy, working with all the members of your radiation therapy team. He or she will talk with you about your radiation treatment and help you manage side effects. Radiation therapist. This person works with you during each radiation therapy session. He or she positions you for treatment and runs the machines to make sure you get the dose of radiation prescribed by your radiation oncologist. Other health care providers. Your team may also include a dietitian, physical therapist, social worker, and others. You. You are also part of the radiation therapy team. Your role is to: Arrive on time for all radiation therapy sessions Ask questions and talk about your concerns Let someone on your radiation therapy team know when you have side effects Tell your doctor or nurse if you are in pain Follow the advice of your doctors and nurses about how to care for yourself at home, such as: Taking care of your skin Drinking liquids Eating foods that they suggest Keeping your weight the same

Make a list of questions and problems you want to discuss with your doctor or nurse. Be sure to bring this list to your follow-up visits. See "Questions To Ask Your Doctor or Nurse" 7 for sample questions.

Glossary Terms

A procedure that uses a computer to create a 3-dimensional picture of the tumor. This allows doctors to give the highest possible dose of radiation to the tumor, while sparing the normal tissue as much as possible. Also called 3-dimensional radiation therapy.

A series of detailed pictures of areas inside the body taken from different angles. The pictures are created by a computer linked to an x-ray machine. Also called CAT scan, computed tomography scan, computerized axial tomography scan, and computerized tomography.

The things a person eats and drinks.

A type of radiation therapy that uses a machine to aim high-energy rays at the cancer from outside of the body. Also called external radiation therapy.

Monitoring a person's health over time after treatment. This includes keeping track of the health of people who participate in a clinical study or clinical trial for a period of time, both during the study and after the study ends.

In medicine, a process that makes pictures of areas inside the body. Imaging uses methods such as x-rays (high-energy radiation), ultrasound (high-energy sound waves), and radio waves.

A type of 3-dimensional radiation therapy that uses computer-generated images to show the size and shape of the tumor. Thin beams of radiation of different intensities are aimed at the tumor from many angles. This type of radiation therapy reduces the damage to healthy tissue near the tumor. Also called intensity-modulated radiation therapy.

A type of radiation therapy in which radioactive material sealed in needles, seeds, wires, or catheters is placed directly into or near a tumor. Also called brachytherapy, implant radiation therapy, and radiation brachytherapy.

Radiation treatment aimed directly at a tumor during surgery. Also called IORT.

Side effects of cancer treatment that appear months or years after treatment has ended. Late effects include physical and mental problems and second cancers.

A procedure in which radio waves and a powerful magnet linked to a computer is used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, NMRI, and nuclear magnetic resonance imaging.

A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

A procedure in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body. Also called positron emission tomography scan.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiotherapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiation therapy.

To eject some or all of the contents of the stomach through the mouth.