Radiation Therapy
The treatment of disease using penetrating beams of high energy waves or streams of particles called radiation.
Introduction
This online booklet is for patients who are receiving radiation therapy for cancer. It describes what to expect during therapy and offers suggestions for self-care during and after treatment. It explains the two most common types of radiation therapy, external radiation and internal radiation therapy. Information is included about the general effects of treatment and how to deal with specific side effects. You may not want to read everything here at one time. Browse through it, read the sections that are of interest to you right now, and look at the others as needed. Because your doctor will plan the treatment specifically for you and the type of cancer you have, some information may not apply to you. Radiation therapy may vary somewhat among different doctors, hospitals, and treatment centers. Therefore, your treatment or the advice of your doctor (the radiation oncologist) may be different from what you read here. Be sure to ask questions and discuss your concerns with your doctor, nurse, or radiation therapist. Ask whether they have any additional written information that might help you.

Fast Facts About Radiation Therapy
- Radiation treatments are painless.
- External radiation treatment does not make you radioactive.
- Treatments are usually scheduled every day except Saturday and Sunday.
- You need to allow 30 minutes for each treatment session although the treatment itself takes only a few minutes.
- It’s important to get plenty of rest and to eat a well-balanced diet during the course of your radiation therapy.
- Skin in the treated area may become sensitive and easily irritated.
- Side effects of radiation treatment are usually temporary and they vary depending on the area of the body that is being treated.
What is Radiation Therapy?
Radiation therapy (sometimes called radiotherapy, x-ray therapy, or irradiation) is the treatment of disease using penetrating beams of high energy waves or streams of particles called radiation. Many years ago doctors learned how to use this energy to “see” inside the body and find disease. You’ve probably seen a chest x-ray or x-ray pictures of your teeth or your bones. At high doses (many times those used for x-ray exams) radiation is used to treat cancer and other illnesses. The radiation used for cancer treatment comes from special machines or from radioactive substances. Radiation therapy equipment aims specific amounts of the radiation at tumors or areas of the body where there is disease.

How Does Radiation Therapy Work?
Radiation in high doses kills cells or keeps them from growing and dividing. Because cancer cells grow and divide more rapidly than most of the normal cells around them, radiation therapy can successfully treat many kinds of cancer. Normal cells are also affected by radiation but, unlike cancer cells, most of them recover from the effects of radiation. To protect normal cells, doctors carefully limit the doses of radiation and spread the treatment out over time. They also shield as much normal tissue as possible while they aim the radiation at the site of the cancer.
What Are the Goals and Benefits of Radiation Therapy?
The goal of radiation therapy is to kill the cancer cells with as little risk as possible to normal cells. Radiation therapy can be used to treat many kinds of cancer in almost any part of the body. In fact, more than half of all people with cancer are treated with some form of radiation. For many cancer patients, radiation is the only kind of treatment they need. Thousands of people who have had radiation therapy alone or in combination with other types of cancer treatment are free of cancer. Radiation treatment, like surgery, is a local treatment – it affects the cancer cells only in a specific area of the body. Sometimes doctors add radiation therapy to treatments that reach all parts of the body (systemic treatment) such as chemotherapy, or biological therapy to improve treatment results. You may hear your doctor use the term, adjuvant therapy, for a treatment that is added to, and given after, the primary therapy. Radiation therapy is often used with surgery to treat cancer. Doctors may use radiation before surgery to shrink a tumor. This makes it easier to remove the cancerous tissue and may allow the surgeon to perform less radical surgery.
Radiation therapy may be used after surgery to stop the growth of cancer cells that may remain. Your doctor may choose to use radiation therapy and surgery at the same time. This procedure, known as intraoperative radiation, is explained more fully in this booklet in Section 2, “External Radiation Therapy.” In some cases, instead of surgery, doctors use radiation along with anticancer drugs (chemotherapy) to destroy the cancer. Radiation may be given before, during, or after chemotherapy. Doctors carefully tailor this combination treatment to each patient’s needs depending on the type of cancer, its location, and its size.
The purpose of radiation treatment before or during chemotherapy is to make the tumor smaller and thus improve the effectiveness of the anticancer drugs. Doctors sometimes recommend that a patient complete chemotherapy and then have radiation treatment to kill any cancer cells that might remain.
When curing the cancer is not possible, radiation therapy can be used to shrink tumors and reduce pressure, pain, and other symptoms of cancer. This is called palliative care or palliation. Many cancer patients find that they have a better quality of life when radiation is used for this purpose.
What Are the Risks of Radiation Therapy?
The brief high doses of radiation that damage or destroy cancer cells can also injure or kill normal cells. These effects of radiation on normal cells cause treatment side effects. Most side effects of radiation treatment are well known and, with the help of your doctor and nurse, easily treated. The risk of side effects is usually less than the benefit of killing cancer cells. Your doctor will not advise you to have any treatment unless the benefits – control of disease and relief from symptoms – are greater than the known risks.

How is Radiation Therapy Given?
Radiation therapy can be given in one of two ways: external or internal. Some patients have both, one after the other. Most people who receive radiation therapy for cancer have external radiation. It is usually given during outpatient visits to a hospital or treatment center. In external radiation therapy, a machine directs the high-energy rays at the cancer and a small margin of normal tissue surrounding it. The various machines used for external radiation work in slightly different ways. Some are better for treating cancers near the skin surface; others work best on cancers deeper in the body. The most common type of machine used for radiation therapy is called a linear accelerator. Some radiation machines use a variety of radioactive substances (such as cobalt-60, for example) as the source of high-energy rays. When internal radiation therapy is used, the radiation source is placed inside the body. This method of radiation treatment is called brachytherapy or implant therapy. The source of the radiation (such as radioactive iodine, for example) sealed in a small holder is called an implant. Implants may be thin wires, plastic tubes (catheters), capsules, or seeds. An implant may be placed directly into a tumor or inserted into a body cavity. Sometimes, after a tumor has been removed by surgery, the implant is placed in the ‘tumor bed’ (the area from which the tumor was removed) to kill any tumor cells that may remain. Another type of internal radiation therapy uses unsealed radioactive materials which may be taken by mouth or injected into the body. If you have this type of treatment, you may need to stay in the hospital for several days. More information about internal radiation therapy can be found in Section 3.
Who Gives Radiation Treatment?
A doctor who specializes in using radiation to treat cancer – a radiation oncologist – will prescribe the type and amount of treatment that is right for you. The radiation oncologist is the person referred to as “your doctor” throughout this booklet. The radiation oncologist works closely with the other doctors and health care professionals involved in your care. This highly trained health care team may include:
- The radiation physicist who makes sure that the equipment is working properly and that the machines deliver the right dose of radiation. The physicist also works closely with your doctor to plan your treatment.
- The dosimetrist who works under the direction of your doctor and the radiation physicist and helps carry out your treatment plan by calculating the amount of radiation to be delivered to the cancer and normal tissues that are nearby.
- The radiation therapist who positions you for your treatments and runs the equipment that delivers the radiation.
- The radiation nurse, who will coordinate your care, help you learn about treatment, and tell you how to manage side effects.
- The nurse can also answer questions you or family members may have about your treatment. Your health care team also may include a physician assistant, radiologist, dietitian, radiation oncologist, physical therapist, social worker, or other health care professional.

External Radiation Therapy:
What to Expect
How Does the Doctor Plan My Treatment?
The high energy rays used for radiation therapy can come from a variety of sources. Your doctor may choose to use x-rays, an electron beam, or cobalt-60 gamma rays. Some cancer treatment centers have special equipment that produces beams of protons or neutrons for radiation therapy. The type of radiation your doctor decides to use depends on what kind of cancer you have and how far into your body the radiation should go. High-energy radiation is used to treat many types of cancer. Low-energy x-rays are used to treat some kinds of skin diseases.
After a physical exam and a review of your medical history, the doctor plans your treatment. In a process called simulation, you will be asked to lie very still on an examining table while the radiation therapist uses a special x-ray machine to define your treatment port or field. This is the exact place on your body where the radiation will be aimed. Depending on the location of your cancer, you may have more than one treatment port.Simulation may also involve CT scans or other imaging studies to plan how to direct the radiation.
Depending on the type of treatment you will be receiving, body molds or other devices that keep you from moving during treatment (immobilization devices) may be made at this time. They will be used each time you have treatment to be sure that you are positioned correctly. Simulation may take from a half hour to about 2 hours. The radiation therapist often will mark the treatment port on your skin with tattoos or tiny dots of colored, permanent ink. It’s important that the radiation be targeted at the same area each time. If the dots appear to be fading, tell your radiation therapist who will darken them so that they can be seen easily.
Once simulation has been done, your doctor will meet with the radiation physicist and the dosimetrist. Based on the results of your medical history, lab tests, x-rays, other treatments you may have had, and the location and kind of cancer you have, they will decide how much radiation is needed, what kind of machine to use to deliver it, and how many treatments you should have.
After you have started the treatments, your doctor and the other members of your health care team will follow your progress by checking your response to treatment and how you are feeling at least once a week. When necessary, your doctor may revise the treatment plan by changing the radiation dose or the number and length of your remaining radiation sessions.
Your nurse will be available daily to discuss your concerns and answer any questions you may have. Be sure to tell your nurse if you are having any side effects or if you notice any unusual symptoms.
How Long Does the Treatment Take?
For most types of cancer, radiation therapy usually is given 5 days a week for 6 or 7 weeks. (When radiation is used for palliative care, the course of treatment is shorter, usually 2 to 3 weeks.) The total dose of radiation and the number of treatments you need will depend on the size, location, and kind of cancer you have, your general health, and other medical treatments you may be receiving.Using many small doses of daily radiation rather than a few large doses helps protect normal body tissues in the treatment area. Weekend rest breaks allow normal cells to recover.
It’s very important that you have all of your scheduled treatments to get the most benefit from your therapy. Missing or delaying treatments can lessen the effectiveness of your radiation treatment.

What Happens During the Treatment Visits?
Before each treatment, you may need to change into a hospital gown or robe. It’s best to wear clothing that is easy to take off and put on again. In the treatment room, the radiation therapist will use the marks on your skin to locate the treatment area and to position you correctly. You may sit in a special chair or lie down on a treatment table.
For each external radiation therapy session, you will be in the treatment room about 15 to 30 minutes, but you will be getting radiation for only about 1 to 5 minutes of that time. Receiving external radiation treatments is painless, just like having an x-ray taken. You will not hear, see, or smell the radiation. The radiation therapist may put special shields (or blocks) between the machine and certain parts of your body to help protect normal tissues and organs. There might also be plastic or plaster forms that help you stay in exactly the right place.
You need to remain very still during the treatment so that the radiation reaches only the area where it’s needed and the same area is treated each time. You don’t have to hold your breath – just breathe normally.
The radiation therapist will leave the treatment room before your treatment begins. The radiation machine is controlled from a nearby area. You will be watched on a television screen or through a window in the control room.
Although you may feel alone, keep in mind that the therapist can see and hear you and even talk with you using an intercom in the treatment room. If you should feel ill or very uncomfortable during the treatment, tell your therapist at once. The machine can be stopped at any time.
The machines used for radiation treatments are very large, and they make noises as they move around your body to aim at the treatment area from different angles. Their size and motion may be frightening at first. Remember that the machines are being moved and controlled by your radiation therapist. They are checked constantly to be sure they’re working right.
If you have concerns about anything that happens in the treatment room, discuss these concerns with the radiation therapist.
What Can I Do To Take Care of Myself During Therapy?
Each patient’s body responds to radiation therapy in its own way. That’s why your doctor must plan, and sometimes adjust, your treatment. In addition, your doctor or nurse will give you suggestions for caring for yourself at home that are specific for your treatment and the possible side effects.
Nearly all cancer patients receiving radiation therapy need to take special care of themselves to protect their health and to help the treatment succeed. Some guidelines to remember are given on the following pages:
- Before starting treatment, be sure your doctor knows about any medicines you are taking and if you have any allergies. Do not start taking any medicine (whether prescription or over-the-counter) during your radiation therapy without first telling your doctor or nurse.
- Fatigue is common during radiation therapy. Your body will use a lot of extra energy over the course of your treatment, and you may feel very tired. Be sure to get plenty of rest and sleep as often as you feel the need. It’s common for fatigue to last for 4 to 6 weeks after your treatment has been completed.
- Good nutrition is very important. Try to eat a balanced diet that will prevent weight loss. For patients who have problems with eating or diet planning, the section, “Managing Side Effects,” offers practical tips.
- Check with your doctor before taking vitamin supplements or herbal preparations during treatment.
- Avoid wearing tight clothes such as girdles or close-fitting collars over the treatment area.
- Be extra kind to your skin in the treatment area
- Ask your doctor or nurse if you may use soaps, lotions, deodorants, sun blocks, medicines, perfumes, cosmetics, talcum powder, or other substances in the treated area.
- Wear loose, soft cotton clothing over the treated area.
- Do not wear starched or stiff clothing over the treated area.Do not scratch, rub, or scrub treated skin.
- Do not use adhesive tape on treated skin. If bandaging is necessary, use paper tape and apply it outside of the treatment area. Your nurse can help you place dressings so that you can avoid irritating the treated area.
- Do not apply heat or cold (heating pad, ice pack, etc.) to the treated area. Use only lukewarm water for bathing the area.
- Use an electric shaver if you must shave the treated area but only after checking with your doctor or nurse. Do not use a pre-shave lotion or hair removal products on the treated area.
- Protect the treatment area from the sun. Do not apply sunscreens just before a radiation treatment. If possible, cover treated skin (with light clothing) before going outside. Ask your doctor if you should use a sunscreen or a sun blocking product. If so, select one with a protection factor of at least 15 and reapply it often. Ask your doctor or nurse how long after your treatments are completed you should continue to protect the treated skin from sunlight.
If you have questions, ask your doctor or nurse. They are the only ones who can properly advise you about your treatment, its side effects, home care, and any other medical concerns you may have.
Internal Radiation Therapy:
What to Expect
When Is Internal Radiation Therapy Used?
Your doctor may decide that a high dose of radiation given to a small area of your body is the best way to treat your cancer. Internal radiation therapy allows the doctor to give a higher total dose of radiation in a shorter time than is possible with external treatment.
Internal radiation therapy places the radiation source as close as possible to the cancer cells. Instead of using a large radiation machine, the radioactive material, sealed in a thin wire, catheter, or tube (implant), is placed directly into the affected tissue.
This method of treatment concentrates the radiation on the cancer cells and lessens radiation damage to some of the normal tissue near the cancer. Some of the radioactive substances used for internal radiation treatment include cesium, iridium, iodine, phosphorus, and palladium.
Internal radiation therapy may be used for cancers of the head and neck, breast, uterus, thyroid, cervix, and prostate. Your doctor may suggest using both internal and external radiation therapy.
In this booklet, “internal radiation treatment” refers to implant radiation. Health professionals prefer to use the term “brachytherapy” for implant radiation therapy. You may hear your doctor or nurse use the terms, interstitial radiation or intracavitary radiation; each is a form of internal radiation therapy. Sometimes radioactive implants are called “capsules” or “seeds.”
How Is the Implant Placed in the Body?
The type of implant and the method of placing it depend on the size and location of the cancer. Implants may be put right into the tumor (interstitial radiation), in special applicators inside a body cavity (intracavitary radiation) or passage (intra-luminal radiation), on the surface of a tumor, or in the area from which the tumor has been removed.
Implants may be removed after a short time or left in place permanently. If they are to be left in place, the radioactive substance used will lose radiation quickly and become non-radioactive in a short time.
When interstitial radiation is given, the radiation source is placed in the tumor in catheters, seeds, or capsules. When intracavitary radiation is used, a container or applicator of radioactive material is placed in a body cavity such as the uterus. In surface brachytherapy the radioactive source is sealed in a small holder and placed in or against the tumor. In intra-luminal brachytherapy the radioactive source is placed in a body lumen or tube, such as the bronchus or esophagus.
Internal radiation also may be given by injecting a solution of radioactive substance into the bloodstream or a body cavity. This form of radiation therapy may be called unsealed internal radiation therapy.
For most types of implants, you will need to be in the hospital. You will be given general or local anesthesia so that you will not feel any pain when the doctor places the holder for the radioactive material in your body.
In many hospitals, the radioactive material is placed in its holder or applicator after you return to your room so that other patients, staff, and visitors are not exposed to radiation.
How Are Other People Protected From Radiation While the Implant is in Place?
Sometimes the radiation source in your implant sends its high energy rays outside your body. To protect others while you are having implant therapy, the hospital will have you stay in a private room.
Although the nurses and other people caring for you will not be able to spend a long time in your room, they will give you all of the care you need. You should call for a nurse when you need one, but keep in mind that the nurse will work quickly and speak to you from the doorway more often than from your bedside.
In most cases, your urine and stool will contain no radioactivity unless you are having unsealed internal radiation therapy.
There also will be limits on visitors while your implant is in place. Children younger than 18 or pregnant women should not visit patients who are having internal radiation therapy. Be sure to tell your visitors to ask the hospital staff for any special instructions before they come into your room. Visitors should sit at least 6 feet from your bed and the radiation oncology staff will determine how long your visitors may stay. The time can vary from 30 minutes to several hours per day. In some hospitals a rolling lead shield is placed beside the bed and kept between the patient and visitors or staff members.
What Are the Side Effects of Internal Radiation Therapy?
The side effects of implant therapy depend on the area being treated. You are not likely to have severe pain or feel ill during implant therapy. However, if an applicator is holding your implant in place, it may be somewhat uncomfortable. If you need it, the doctor will order medicine to help you relax or to relieve pain.
If general anesthesia was used while your implant was put in place, you may feel drowsy, weak, or nauseated but these effects do not last long. If necessary, medications can be ordered to relieve nausea. Be sure to tell the nurse about any symptoms that concern you. In Section 4, “Managing Side Effects,” you will find tips on how to deal with problems that might occur after implant therapy.
How Long Does the Implant Stay in Place?
Your doctor will decide the amount of time that an implant is to be left in place. It depends on the dose (amount) of radioactivity needed for effective treatment. Your treatment schedule will depend on the type of cancer, where it is located, your general health, and other cancer treatments you have had.
Depending on where the implant is placed, you may have to keep it from shifting by staying in bed and lying fairly still.Temporary implants may be either low dose-rate (LDR) or high dose-rate (HDR). Low dose-rate implants are left in place for several days; high dose-rate implants are removed after a few minutes. For some cancer sites, the implant is left in place permanently.
If your implant is permanent, you may need to stay in your hospital room away from other people for a few days while the radiation is most active. The implant becomes less radioactive each day; by the time you are ready to go home, the radiation in your body will be much weaker. Your doctor will advise you if there are any special precautions you need to use at home.
What Happens After the Implant Is Removed?
Usually, an anesthetic is not needed when the doctor removes a temporary implant. Most can be taken out right in the patient’s hospital room.Once the implant is removed, there is no radioactivity in your body.
The hospital staff and your visitors will no longer have to limit the time they stay with you. Your doctor will tell you if you need to limit your activities after you leave the hospital. Most patients are allowed to do as much as they feel like doing. You may need some extra sleep or rest breaks during your days at home, but you should feel stronger quickly.
The area that has been treated with an implant may be sore or sensitive for some time. If any particular activity such as sports or sexual intercourse cause irritation in the treatment area, your doctor may suggest that you limit these activities for a while.
Followup Care: What Does “Followup” Mean?
Once you have completed your radiation treatments, it is important for your doctor to monitor the results of your therapy at regularly scheduled visits. These checkups are necessary to deal with radiation side effects and to detect any signs of recurrent disease. During these checkups your doctor will examine you and may order some lab tests and x-rays.
The radiation oncologist also will want to see you for followup after your treatment ends and will coordinate followup care with your doctor.
Follow up care might include more cancer treatment, rehabilitation, and counseling. Taking good care of yourself is also an important part of following through after radiation treatments.
Who Provides Care After Therapy?
Most patients return to the radiation oncologist for regular follow-up visits. Others are referred to their original doctor, to a surgeon, or to a medical oncologist. Your followup care will depend on the kind of cancer that was treated and on other treatments that you had or may need.

Questions to Ask
Following are some questions that you may want to ask your doctor after you have finished your radiation therapy
- How often do I need to return for checkups?
- Why do I need more x-rays, CT-scans, blood tests, and so on? What will these tests tell us?
- Will I need chemotherapy, surgery, or other treatments?
- How and when will you know if I’m cured of cancer?
- What are the chances that it will come back?
- How soon can I go back to my regular activities? Work? Sexual activity? Sports?
- Do I need to take any special precautions like staying out of the sun or avoiding people with infectious diseases?
- Do I need a special diet?
- Should I exercise?
- Can I wear a prosthesis?
- Can I have reconstructive surgery ? How soon can I schedule it?
It’s a good idea to write down the questions you want to ask your doctor. Use the “Notes” page at the back of this booklet for your questions and take it with you when you have your appointment with the doctor. Some patients find that it’s helpful to take a family member with them to help remember what the doctor says.
How Can I Help Myself After Radiation Therapy?
Patients who have had radiation therapy need to continue some of the special care they used during treatment, at least for a short while. For instance, you may have skin problems for several weeks after your treatments end. Continue to be gentle with skin in the treatment area until all signs of irritation are gone. Don’t try to scrub off the marks in your treatment area.
If tattoos were used to mark the treatment area, they are permanent and will not wash off. Your nurse can answer questions about skin care and help you with other concerns you may have after your treatment has been completed.
You may find that you still need extra rest after your therapy is over while your healthy tissues are recovering and rebuilding. Keep taking naps as needed and try to get more sleep at night. It may take some time to get your strength back, so resume your normal schedule of activities gradually.
If you feel that you need emotional or social support, ask your doctor, nurse, or a social worker for information about support groups or other ways to express your feelings and concerns.
When Should I Call the Doctor?
After treatment for cancer, you’re likely to be more aware of your body and to notice even slight changes in how you feel from day to day. The doctor will want to know if you are having any unusual symptoms. Promptly tell your doctor about:
- A pain that doesn’t go away, especially if it’s always in the same place.
- New or unusual lumps, bumps, or swelling.
- Nausea, vomiting, diarrhea, or loss of appetite.
- Unexplained weight loss.
- A fever or cough that doesn’t go away.
- Unusual rashes, bruises, or bleeding.
- Any symptoms that you are concerned about.
- Any other warning signs mentioned by your doctor or nurse.
Conclusion
We hope that the information in this booklet will help you understand how radiation therapy is used to treat cancer. If you know what to expect when you go for your treatments, you may not feel as anxious. Remember to talk with your nurse, doctor, or other members of your health care team whenever you have questions or feel that you need more information.