External beam radiation therapy is an outpatient procedure. It takes place in a hospital or clinic. As an outpatient, you won't need to spend the night in the treatment center. Treatment is often done 5 days a week. It can take 3 to 7 weeks, depending on the type of radiation used and the reason it's being given.
Stereotactic body radiation therapy (SBRT) is one type of external radiation therapy. It uses higher doses of radiation. The beams are directed at the tumor from many different angles.
SBRT is often used when lung cancer is affecting the brain. It may also be used to focus on small tumors within the lungs. This is often the case if surgery is not part of your treatment plan. Because of the high dose, this type of therapy takes less time. It can be done in 1 to 5 treatments.
Whole-brain radiation therapy (WBRT) is another approach used when lung cancer is affecting the brain. It is used when there are many cancer lesions in the brain. This treatment is often given 10 times over 2 weeks.
How do I get ready for external beam radiation therapy?
Before the first treatment, you'll meet with your doctors to figure out where the radiation beam will focus on your body and how you will be positioned during treatment. This session is called simulation. It can take up to 2 hours. No radiation is used in the simulation.
During this session, the radiation therapist will ask you to lie on a table. They will find the treatment area. They will mark the area with small dots of semi-permanent ink or with very tiny tattooed dots. The marks will help make sure the radiation is angled in the right direction. This area is also called the treatment port.
You may have more than one treatment port depending on the plan you and your doctor talked about.
You might also have imaging tests,such as CT scans, during simulation. Before the test, you may be given a contrast dye through an I.V. (intravenous) line in your hand or arm. Or you may be asked to swallow the contrast. This dye makes the CT images clearer. These tests give your doctors more information about the exact location of any tumors.
Your doctor might also make body molds.These are plastic or plaster forms of a part of your body. Using these can help you lie in the same position for each treatment. They make the treatment more precise and effective.
What happens during external beam radiation therapy?
On treatment days, you'll lie down on a table while a machine scans your body. It focuses on the treatment ports marked during simulation. You may have to wear a hospital gown.
Your radiation therapist helps you get in the right position. They might use the body molds made for you. They also might use blocks or shields. These objects prop up your body or cover parts of it that don't need radiation. All these items help support your body during the process and can make the treatment safer.
Next, the therapist will adjust the machine so that the radiation beam will be in line with the treatment port. When you're ready, the therapist will leave the room and turn on the machine. You may hear whirring or clicking noises while the machine moves. The machine won't touch you.
The machine will scan your body. It will focus on the treatment ports marked during simulation. During treatment, you'll be able to hear and communicate with the therapist over an intercom.
You can't feel radiation, so it doesn't hurt. You won't be radioactive afterward. The session might feel like getting an X-ray. The treatment itself is short. But you may be at the clinic or hospital for about 1 hour.