Radiation Therapy

Radiation therapy, sometimes called radiotherapy, effectively treats cancer by using high-energy beams to pinpoint and destroy cancerous cells. Although radiation therapy is similar to an X-ray, the dose of radiation in cancer treatment is much stronger and is given over a longer period of time. Many forms of radiation are available. Your oncologist will choose the best therapy based on the type, stage and location of your cancer.


With careful planning, radiation can be directed to the cancer and away from most normal tissues. This means you may receive treatment on more than one side of your body or from different angles. You may also need more than one type of radiation, which may require the use of more than one machine.


Over 50% of cancer patients will undergo radiation therapy; for some, it will be the only cancer treatment they need. Radiation is often used in combination with other treatments. Used before or during other procedures, radiation shrinks the tumor to make surgery or chemotherapy more effective. Used afterward, it destroys any cancer cells that might remain.


There are two basic types of radiation therapy:

External beam radiation uses specialized machines to administer a high dose of radiation directly to the cancer site and a small amount of healthy tissue at the margins of the tumor. Different machines are used for tumors of various types or in different locations in the body. 

Internal radiation, or brachytherapy, involves radioactive material that is implanted in the body at the tumor site. Radiation implants are small tubes, seeds or capsules filled with different types of radioactive material and sealed. 


Frequently Asked Questions

No. However, the treatment table can be a little uncomfortable. If you do experience pain during treatment, tell the radiation therapist. He or she will turn off the machine and come into the room. The radiation stops when the machine is turned off.

Side effects are usually limited to the radiation site. Patients receiving radiation in the abdomen may have nausea, while radiation to the pelvis may trigger diarrhea. Other possible side effects include: 

  • Red, itching and peeling skin in the treatment area
  • Fatigue
  • Loss of appetite
  • Hair loss in the treatment area

Always let your health care team know about any side effects you may be experiencing, even if they seem minor. 

No. You can continue to enjoy the same contact with family and friends without fear of exposing them to radiation.

If you are hospitalized for insertion of internal radioactive sources, you will stay in a protected room until the source of radiation is removed. If you need this type of radiation, your doctor will explain it in detail.

The radiation oncologist is responsible for designing your treatment plan, including the amount of radiation you will receive and the total number of treatment days. The radiation oncologist will also manage any medical problems that may develop during your treatment.

A radiation therapist delivers the prescribed treatment and will help you before, during and after treatments. All radiation therapists at MD Anderson are licensed, certified professionals who have completed extensive education in radiation treatment delivery and patient care. A radiation therapy nurse works closely with the radiation oncologist to help you throughout treatment.

If radiation therapy is part of your cancer treatment plan, an appointment will be made for your treatment planning session, or simulation.

The simulation visit takes one to three hours. The radiation therapist will position you on the treatment table and take X-rays, CT scans and other images to confirm the area to be treated. Once the images are approved, the radiation therapist will mark reference points, either directly on your skin or on a plastic face mask. 

Actual treatments will start within the next 3-7 days. More X-rays will be taken to verify treatment fields. As the treatment progresses, the treatment area and marks may change.

Your daily treatments will probably be scheduled Monday through Friday, allowing you to rest on weekends. Your daily appointment schedule will be as convenient as possible. Your radiation therapist will notify you of any holidays on which you will not receive treatments.

The large doses of radiation necessary to treat cancer cannot be given at one time because of the severe side effects they would cause. On average, the course of treatment for radiation therapy takes 5 to 7 weeks. This allows your body to better tolerate the effects of the radiation.

If the radiation therapists stayed in the treatment room with every patient, they would be exposed to dangerous levels of radiation. Even though they are not in the treatment room, patients are constantly monitored by intercom and video camera. If you ever need assistance during your treatment, speak up. The radiation therapist can stop the treatment and attend to your needs.

You may have sex if it is comfortable for you. You are not radioactive, and your partner is in no danger from the radiation treatments or the cancer. If you are a woman of childbearing age and have sex during treatment, you must use some type of birth control. Your doctor can help you decide what kind of birth control is best for you.

If you need to talk with someone about other sexual health concerns, you may schedule an appointment with a social worker.

Provide your doctor or radiation therapy nurse with a complete list of prescription or over-the-counter medicines you are currently taking. He or she will review your current medications, which usually can be continued throughout your treatment. Your primary care doctor will still prescribe any medications you are taking for problems other than cancer.