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What Happens During Radiation Therapy for Uterine Cancer

Whether you have endometrial cancer or uterine sarcoma, what happens during local radiation is basically the same. Where you get the radiation and its dose depend on the type and stage of tumor. You can get external radiation or intracavitary (internal) radiation as an outpatient at a hospital or a clinic. External beam radiation may come from a machine called a linear accelerator. Intracavitary radiation is administered as radioactive seeds or rods placed into the vaginal or uterine cavity for a period of time. Some patients will receive both.

A specialist doctor called a radiation oncologist decides where you need radiation and how much you need. Then a specialist called a radiation therapist gives you the radiation.

Preparing for radiation treatment

Before your first external beam radiation treatment, you’ll have an appointment to plan exactly where on your body the radiation beam needs to be directed. This process is called simulation. The appointment may take up to two hours. Here’s what you can expect to happen during it.

  • You’ll lie still on a table while the radiation therapist uses a machine to mark your treatment field. This field may also be called the treatment port. The field is the exact area on your body where the radiation will be aimed. You may have more than one treatment field if you have cancer in more than one place. The therapist will mark your skin with tiny dots of colored permanent ink or tattoos so that the radiation will be aimed at the same place each time.

  • You may have imaging scans, such as CT scans. These help your radiation therapy team find out exactly where your tumor is so that they can aim the radiation.

  • You may have body molds made. A body mold helps put you in the exact same position and keep you from moving during the treatment.

Intracavitary radiation also requires imaging scans that help the radiation therapy team plan the treatment, but it does not require a simulation. 

What happens during radiation

External beam radiation is administered in divided doses. On the days you get radiation, you’ll lie on a table while the machine is placed over you. You may have to wear a hospital gown. The experience is a lot like getting an X-ray, only it lasts longer. The whole process lasts about 15 to 30 minutes, with about one to five minutes spent actually getting the radiation. A radiation therapist may use special shields to cover parts of your body that don’t need to get the radiation. Or the machine itself may have built-in shields to protect you. The therapist will line up the machine exactly with the areas that were marked during the simulation.

The therapist will leave the room to turn on the machine. You will be able to talk to the therapist over an intercom. You can’t feel radiation. It is painless. You may hear whirring or clicking noises as the machine moves.

You will most likely get radiation treatments every day for five days in a row, Monday through Friday, for about four to six weeks.

You will not be radioactive afterward, so don’t worry about that.

Intracavitary radiation is administered as an outpatient in an outpatient surgery suite, usually in the hospital. It is placed in one procedure and removed in another. The period of time it remains in place is predetermined by your treatment team. You may be given instructions to limit radiation exposure to others. 


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