External Beam Radiation Therapy for Cancer

External beam radiation therapy comes from a machine that aims radiation at your cancer. It is a local treatment, which means it treats a specific part of your body. For example, if you have cancer in your lung, you will have radiation only to your chest, not to your whole body.

External beam radiation therapy is used to treat many types of cancer.

 What To Know About External Beam Radiation Therapy
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Radiation therapy is one of the most important aspect of cancer treatment. Sixty to seventy percent of all cancers will eventually have to undergo various forms of radiation therapy. All the videos provided below are in the public domain and is for educational purposes and should help understand the procedures involved in radiation therapy.

The videos below can be expanded to full screen. They will give you a very good understanding of what radiation therapy is all about.

What to Expect When Having External Beam Radiation Therapy

How Often You Will Have External Beam Radiation Therapy

Most people have external beam radiation therapy once a day, five days a week, Monday through Friday. Radiation is given in a series of treatments to allow healthy cells to recover and to make radiation more effective. How many weeks you have treatment depends on the type of cancer you have, the goal of your treatment, the radiation dose, and the radiation schedule.

The span of time from your first radiation treatment to the last is called a course of treatment.
Researchers are looking at different ways to adjust the radiation dose or schedule in order to reach the total dose of radiation more quickly or to limit damage to healthy cells. Different ways of delivering the total radiation dose include:

• Accelerated fractionation, which is treatment given in larger daily or weekly doses to reduce the number of weeks of treatment.
• Hyperfractionation, which is a smaller dose than the usual daily dose of radiation given more than once a day.
• Hypofractionation, which is larger doses given once a day or less often to reduce the number of treatments.

Researchers hope these different schedules for delivering radiation may be more effective and cause fewer side effects than the usual way of doing it or be as effective but more convenient.

Where You Go for External Beam Radiation Therapy

Most of the time, you will get external beam radiation therapy as an outpatient. This means that you will have treatment at a clinic or radiation therapy center and will not stay the night in the hospital.

What Happens Before Your First External Beam Radiation Therapy Treatment

You will have a 1- to 2-hour meeting with your doctor or nurse before you begin radiation therapy. At this time, you will have a physical exam, talk about your medical history, and maybe have imaging tests. Your doctor or nurse will discuss external beam radiation therapy, its benefits and side effects, and ways you can care for yourself during and after treatment. You can then choose whether to have external beam radiation therapy.

If you decide to have external beam radiation therapy, you will be scheduled for a treatment planning session called a simulation. At this time:

• A radiation oncologist (a doctor who specializes in using radiation to treat cancer) and radiation therapist will figure out your treatment area. You may also hear the treatment area referred to as the treatment port or treatment field. These terms refer to the places in your body that will get radiation. You will be asked to lie very still while x-rays or scans are taken.
• The radiation therapist will tattoo or draw small dots of colored ink on your skin to mark the treatment area. These dots will be needed throughout your course of radiation therapy. The radiation therapist will use them to make sure you are in exactly the same position for every treatment. The dots are about the size of a freckle. If the dots are tattooed, they will remain on your skin for the rest of your life. Ink markings will fade over time. Be careful not to remove them and tell the radiation therapist if they fade or lose color.
• A body mold may be made of the part of the body that is being treated. This is a plastic or plaster form that keeps you from moving during treatment. It also helps make sure that you are in exactly the same position for each treatment

• If you are getting radiation to the head and neck area you may be fitted for a mask. The mask has many air holes. It attaches to the table where you will lie for your treatments. The mask helps keep your head from moving so that you are in exactly the same position for each treatment.

What to Wear for Your Treatments

Wear clothes that are comfortable and made of soft fabric, such as fleece or cotton. Choose clothes that are easy to take off, since you may need to expose the treatment area or change into a hospital gown. Do not wear clothes that are tight, such as close-fitting collars or waistbands, near your treatment area. Also, do not wear jewelry, adhesive bandages, or powder in the treatment area.

What Happens During a Treatment Session

• You may be asked to change into a hospital gown or robe.
• You will go to the treatment room where you will receive radiation. The temperature in this room will be very cool.
• Depending on where your cancer is, you will either lie down on a treatment table or sit in a special chair. The radiation therapist will use the dots on your skin and body mold or face mask, if you have one, to help place you in the right position.
• You may see colored lights pointed at your skin marks. These lights are harmless and help the therapist position you for treatment.
• You will need to stay very still so the radiation goes to the exact same place each time. You will get radiation for 1 to 5 minutes. During this time, you can breathe normally.

The radiation therapist will leave the room just before your treatment begins. He or she will go to a nearby room to control the radiation machine. The therapist watches you on a TV screen or through a window and talks with you through a speaker in the treatment room. Make sure to tell the therapist if you feel sick or are uncomfortable. He or she can stop the radiation machine at any time. You will hear the radiation machine and see it moving around, but you won't be able to feel, hear, see, or smell the radiation.

Most visits last from 30 minutes to an hour, with most of that time spent placing you in the correct position.

How to Relax for Treatment Sessions

Keep yourself busy while you wait.

• Read a book or magazine.
• Work on crossword puzzles or needlework.
• Use headphones to listen to music or recorded books.
• Meditate, breathe deeply, pray, use imagery, or find other ways to relax.

External Beam Radiation Therapy Will Not Make You Radioactive

People often wonder if they will be radioactive when they are having treatment with radiation. External beam radiation therapy will not make you radioactive. You may safely be around other people, even pregnant women, babies, and young children.

How Radiation Therapy Works Against Cancer
At high doses, radiation therapy kills cancer cells or slows their growth by damaging their DNA. Cancer cells whose DNA is damaged beyond repair stop dividing or die. When the damaged cells die, they are broken down and removed by the body.

Radiation therapy does not kill cancer cells right away. It takes days or weeks of treatment before DNA is damaged enough for cancer cells to die. Then, cancer cells keep dying for weeks or months after radiation therapy ends.

Types of Radiation Therapy
There are two main types of radiation therapy, external beam and internal.

The type of radiation therapy that you may have depends on many factors, including:

• The type of cancer
• The size of the tumor
• The tumor’s location in the body
• How close the tumor is to normal tissues that are sensitive to radiation
• Your general health and medical history
• Whether you will have other types of cancer treatment
• Other factors, such as your age and other medical conditions

External Beam Radiation Therapy

External beam radiation therapy comes from a machine that aims radiation at your cancer. The machine is large and may be noisy. It does not touch you, but can move around you, sending radiation to a part of your body from many directions.

External beam radiation therapy is a local treatment, which means it treats a specific part of your body. For example, if you have cancer in your lung, you will have radiation only to your chest, not to your whole body.

Internal Radiation Therapy

Internal radiation therapy is a treatment in which a source of radiation is put inside your body. The radiation source can be solid or liquid.

Internal radiation therapy with a solid source is called brachytherapy. In this type of treatment, seeds, ribbons, or capsules that contain a radiation source are placed in your body, in or near the tumor. Like external beam radiation therapy, brachytherapy is a local treatment and treats only a specific part of your body.

With brachytherapy, the radiation source in your body will give off radiation for a while.

Internal radiation therapy with a liquid source is called systemic therapy. Systemic means that the treatment travels in the blood to tissues throughout your body, seeking out and killing cancer cells. You receive systemic radiation therapy by swallowing, through a vein via an IV line, or through an injection.

With systemic radiation, your body fluids, such as urine, sweat, and saliva, will give off radiation for a while.

Why People with Cancer Receive Radiation Therapy

Radiation therapy is used to treat cancer and ease cancer symptoms.

When used to treat cancer, radiation therapy can cure cancer, prevent it from returning, or stop or slow its growth.

When treatments are used to ease symptoms, they are known as palliative treatments. External beam radiation may shrink tumors to treat pain and other problems caused by the tumor, such as trouble breathing or loss of bowel and bladder control. Pain from cancer that has spread to the bone can be treated with systemic radiation therapy drugs called radiopharmaceuticals.

Types of Cancer that Are Treated with Radiation Therapy:

External beam radiation therapy is used to treat many types of cancer.

Brachytherapy is most often used to treat cancers of the head and neck, breast, cervix, prostate, and eye.

A systemic radiation therapy called radioactive iodine, or I-131, is most often used to treat certain types of thyroid cancer.

Another type of systemic radiation therapy, called targeted radionuclide therapy, is used to treat some patients who have advanced prostate cancer or gastroenteropancreatic neuroendocrine tumor (GEP-NET). This type of treatment may also be referred to as molecular radiotherapy.

How Radiation Is Used with Other Cancer Treatments
For some people, radiation may be the only treatment you need. But, most often, you will have radiation therapy with other cancer treatments, such as surgery, chemotherapy, and immunotherapy. Radiation therapy may be given before, during, or after these other treatments to improve the chances that treatment will work. The timing of when radiation therapy is given depends on the type of cancer being treated and whether the goal of radiation therapy is to treat the cancer or ease symptoms.

When radiation is combined with surgery, it can be given:

• Before surgery, to shrink the size of the cancer so it can be removed by surgery and be less likely to return.
• During surgery, so that it goes straight to the cancer without passing through the skin. Radiation therapy used this way is called intraoperative radiation. With this technique, doctors can more easily protect nearby normal tissues from radiation.
• After surgery to kill any cancer cells that remain.

Lifetime Dose Limits
There is a limit to the amount of radiation an area of your body can safely receive over the course of your lifetime. Depending on how much radiation an area has already been treated with, you may not be able to have radiation therapy to that area a second time. But, if one area of the body has already received the safe lifetime dose of radiation, another area might still be treated if the distance between the two areas is large enough.

Radiation Therapy Can Cause Side Effects
Radiation not only kills or slows the growth of cancer cells, it can also affect nearby healthy cells. Damage to healthy cells can cause side effects.

Special Diet Needs
Radiation can cause side effects that make it hard to eat, such as nausea, mouth sores, and throat problems called esophagitis. Since your body uses a lot of energy to heal during radiation therapy, it is important that you eat enough calories and protein to maintain your weight during treatment.

If you are having trouble eating and maintaining your weight, talk to your doctor or nurse. You might also find it helpful to speak with a dietitian. For more information about coping with eating problems see the booklet Eating Hints or read more about side effects.

Working During Radiation Therapy
Some people are able to work full-time during radiation therapy. Others can work only part-time or not at all. How much you are able to work depends on how you feel. Ask your doctor or nurse what you may expect from the treatment you will have.

You are likely to feel well enough to work when you first start your radiation treatments. As time goes on, do not be surprised if you are more tired, have less energy, or feel weak. Once you have finished treatment, it may take just a few weeks for you to feel better—or it could take months.

Radiation Therapy Side Effects