Radiation Therapy


When you’ve been diagnosed with cancer, it’s important to review your treatment options with your health care team. One possible option for solid tumors is radiation therapy. You should always discuss all options for treating your cancer with your health care team. They can help you decide the best treatment for you.

This patient guide will provide a general overview of the various types of radiation oncology. This includes both radiation therapy (also called radiotherapy) and radiosurgery treatments. Be sure to talk about any questions with your health care team.

Radiation oncology teams use advanced software and very specialized equipment to give patients different types of treatments. Which treatment you get will depend on what’s best for your case. Your radiation oncologist, or cancer doctor who specializes in radiation therapy, will talk with you about your radiation treatment options. He or she will also help you decide which the best one for your particular cancer.

How Does Radiation Therapy Fight Cancer?

Radiation therapy uses focused X-rays, which are a type of energy, to kill cancer cells. Because they are focused, this reduces the risk to your healthy tissue. Radiation damages the DNA in cancer cells. This breaks up their ability to reproduce, which makes them die, shrinking the tumor. Most normal cells can repair themselves and recover from the radiation. If normal cells near the tumor area receive radiation, it can cause some side effects.

Side effects vary from patient to patient. Many side effects can build up over time. This means they can get worse as the radiation accumulates in the tumor. They can be minor or severe, depending on three main things:

  • How big the tumor is
  • Where it’s located
  • How healthy you are

You’re most likely to have two side effects: irritation or damage to the skin near the treatment site, and fatigue. But you may also have more serious side effects. These can include:

  • Diarrhea
  • Nausea
  • Swelling at the treatment site
  • Lymphedema (swelling in the arms and legs)
  • Secondary cancer

Your treatment team will help you manage any side effects you may experience.

Radiation Treatment Techniques

There are two types of radiation therapy: radiation therapy — also called radiotherapy — and radiosurgery. Neither of these require an incision, or cut. Instead, they focus a beam of radiation right on the tumor while lessening exposure to healthy tissue around it.

There are two main differences between the treatments: how many treatments you get and how strong the radiation is. If you get radiotherapy, you’ll usually have treatment sessions five days a week, for four to six weeks. Each treatment session lasts between two and 15 minutes.

If you get radiosurgery, you’ll have it in five or fewer sessions over one or two weeks. Most treatments will last from a few minutes to 30 minutes. Also, the strength of each dose is much higher in radiosurgery. This makes it a better treatment for deep tumors, small tumors, and cancers that have spread, or metastasized, to other parts of the body.

Each of these two types of treatment can given in different ways. It all depends on what’s most appropriate for you. Here are the most common ways that doctors use radiation.

Types of Radiation Therapy Treatments

Three-dimensional conformal radiotherapy (3DCRT) takes detailed digital images of a tumor. It also lets doctors see the surrounding area, including bones and organs. It gives highly “conformed” (focused) radiation to match the shape of a tumor.
Two more types of treatments are intensity-modulated radiotherapy (IMRT) and intensity-modulated radiosurgery (IMRS). These allow doctors to change the strength of a radiation beam. That way, the tumor gets a very high dose of radiation, while lessening damage to the normal tissue around it. Your treatment team will make three-dimensional scans of the tumor area. That way, they can see the area that needs to be treated from many different angles. At each of these angles, the strength and the shape of the beam are changed to match the shape of the tumor. This technique was introduced in the early 1990’s. It was considered to be a major advance in the treatment of cancer. Today, this technique is being used by most cancer treatment centers in North America.
You might also get two other types of treatment, image-guided radiotherapy (IGRT) or Image-guided radiosurgery (IGRS). These let your health care team see a tumor’s location before and during treatment. This helps when they’re treating tumors in the chest or stomach areas, because the tumor may move when you breathe. IGRT and IGRS use advanced imaging techniques and motion management technology. These help to check the tumor’s exact location during treament.
Volumetric arc therapy (VMAT) is an advanced form of radiation treatment. It is also called RapidArc radiotherapy technology. RapidArc’s special software can be used to give IMRT treatments quickly. Normal IMRT treatments can take anywhere from 15 minutes to 30 minutes. With RapidArc, most people can be treated in less than two minutes.
SRS, or stereotactic radiosurgery is another type of radiation therapy. It treats tumors or other abnormalities in the brain and spine, or central nervous system. When radiosurgery treats body parts outside the central nervous system, it is called stereotactic body radiotherapy (SBRT). Doctors use SBRT to treat the prostate, lungs, pancreas or kidneys. Because radiosurgery has a much higher dose, it isn’t the best treatment for all cancer types. Your health care team will decide the best way to treat your cancer.

Your Clinical Team

A team of specialists will give you radiotherapy. The team may include:

  • Radiation oncologist — A cancer doctor who specializes in radiation therapy
  • Medical physicist —  A scientist who knows the latest information about radiation
  • Dosimetrist — The person who decides how much radiation you get and for how long)
  • Radiation therapist — The person who gives you your radiation therapy
  • Radiation nurse — The person who takes care of you during your treatment

If you’re getting radiosurgery, your team will include:

  • Radiation oncologist — A cancer doctor who specializes in radiation therapy
  • Neurosurgeon — A doctor who specializes in the central nervous system, or brain and spine
  • Specialty surgeons — Doctors who focus on different parts of the body, like a thoracic pulmonologist, who treats lung disease

Whether you’re getting radiosurgery or radiotherapy, you may also have these people on your team:

  • Physician assistant — A health care professional who works with doctors to give patients medical care
  • Radiologist — Doctors that specialize in radiation therapy
  • Dietitian — An nutrition expert
  • Physical therapist — A medical expert who helps injured or ill people improve their movement and manage their pain
  • Social worker — An expert who supports patients, families and caregivers who are dealing with cancer
  • Other people who specialize in the area of the body being treated (like a urologist, or prostate cancer doctor)

Treatment Process

Each type of therapy, radiotherapy or radiosurgery, includes the same basic steps. They are:

  • Tumor visualization
  • Treatment planning
  • Treatment delivery
  • Follow up

Your clinical team will decide on the best treatment for you. In addition, they will answer any questions you may have before, during or after treatment.

Tumor Visualization

To design your treatment plan, your treatment team will take images to show the exact location of the tumor. This includes its size and position in relationship to the tissues and organs around it. The team typically does this with a CT scan. Depending on the tumor’s location and other factors, they may also take other scans, like an MRI, PET scan or ultrasound. With the help of these scans or images, your clinical team can see details of the tumor from different angles.

Depending on your treatment, you may have a custom body-mold (or mask if your head is being treated). You may also get tiny skin marks to help make sure you’re in exactly the same position for each session.


When the scans are completed, your clinical team will use advanced treatment planning software. This will create a 3D, or three-dimensional “picture” of the area where you will get treatment. They’ll determine how much radiation to deliver, the best angle to give it from, and how many sessions you’ll need. They’ll also take into account many other factors, like:

  • The type of cancer you have
  • Its location and size
  • Your medical history
  • Your lab test results

They will use this information to create a plan just for you.


You’ll get radiation on a machine called a linear accelerator, or linac for short. This machine makes the X-rays used to treat cancer. Before each session, your radiation therapist, or RT for short, will position you on the linac’s treatment table, or “couch.”

Once you’re in the right position, the therapist may use the machine to take a new image of the tumor. That will help them make sure it’s in the right position for that day’s treatment. During the imaging, the robotic imager arms on each side of the linac will stick out and begin to move in a circle around you. The RT may change your position so that it matches the position your team planned for you. The RT will leave the room before your treatment begins. You will be in constant contact with your RT through the cameras and microphones set up in the treatment room.

During the treatment, you will not see the radiation beam. You may hear the quiet buzz or shuffling of the beam-shaping device. It’s located inside the head, or gantry, of the machine. This beam-shaping device is called a multileaf collimator (MLC). It makes a uniquely shaped opening for the radiation beam to pass through. As the head, or gantry, rotates around you, it gives you radiation from different angles. The MLC continuously adjusts the beam. This lets it conform to, or match the shape of the tumor, and helps to deliver precise treatment. The linac will rotate around you as it delivers radiation right to the tumor.

Follow-Up Care

After you finish your treatment, your radiation oncologist and health care team will monitor your progress with a series of follow-up visits. These visits can include:

  • A physical examination
  • Blood screening
  • More imaging
  • Other tests that may be needed

Your follow-up appointments are also a good time for you and your caregivers to ask any questions about your progress. Your team can also answer questions about your overall health.


Use this information as a general guide to radiation therapy for cancer. It doesn’t replace a full discussion with your doctor and health care team. You should know that radiotherapy and radiosurgery aren’t appropriate for cancer types. Actual treatment times may vary. Patients usually get radiotherapy treatments once a day for a series of weeks. If you have radiosurgery, you’ll usually have it during one day or for a series of days. That depends on your particular case. You may have serious side effects like: diarrhea, nausea, swelling at the treatment site, lymphedema (swelling in the arms and legs) and secondary cancer. Talk to your doctor about what you can expect from your treatment. They will help you decide whether radiotherapy or radiosurgery are right for you.

Radiation Therapy FAQs

Doctors use radiation therapy to treat a variety of tumors. These include cancers of the: 1. Brain 2. Breast 3. Cervix 4. Larynx 5. Lung 6. Pancreas 7. Prostate 8. Skin 9. Spine 10. Stomach 11. Throat/neck 12. Uterus 13. Soft-tissue sarcomas Medical teams use radiosurgery to treat tumors of the central nervous system, which includes tumors of the brain and spine. They most often use stereotactic body radiotherapy (SBRT) to treat other areas like: the prostate, lungs, liver, pancreas or kidneys. Doctors and scientists are always researching whether radiosurgery will work for other types of cancer. Radiotherapy and radiosurgery are not right for all people or all tumors. Only your health care team can decide if it’s right for you. It’s important to talk with your health care team about all your treatment options. This includes whether radiotherapy or radiosurgery is an appropriate option for you.
No. In situations where it isn’t possible to complete get rid of the cancer, radiotherapy therapy can be used to shrink the tumor. This will help relieve pain, pressure and other symptoms and make your quality of life better. When radiation is used in this way, it is called palliative radiation therapy.
Side effects vary from patient to patient. Many side effects can be cumulative. That means they get worse over the course of treatment as the radiation builds up in the tumor. They can be minor or severe. This depends on the size of the tumor, where it’s located, and your overall health. There are two common side effects of radiation treatments: irritation or damage to the skin near the treatment site, and fatigue, or tiredness. You can ask your team about what side effects you may expect during your treatment.
You will not be able to feel or see the radiation beam as it works. You may hear some low-level sounds as the machine rotates around you or as parts in it move. If you have trouble staying still during treatment, you may, at times, feel discomfort. However, your clinical team will work with you to make you as comfortable as they can. After treatment, side effects can be minor or severe, That depends on the size and location of the tumor and your overall health. There are two common side effects of radiation, irritation or damage to the skin near the treatment site, and tiredness. If you’re having head and neck treatment, your mouth or throat might hurt.
Many patients continue most of their usual activities during treatment, including work and mild exercise. However, your energy level may go down toward the end of your treatment. If so, you should get extra rest. Fatigue usually goes away within weeks after treatment ends. Again, you talk with your doctor and health care team. Learn more from them about the type of activities and exercise you may continue during your radiotherapy.
Many patients are able to drive during their treatment and. In many cases, they also continue normal daily activities, including work. You should, however, ask your doctor about your own situation and what activities you can do during your treatment.
Radiation treatment can cause temporary hair loss, but only in the area being treated. You shouldn’t lose your hair unless your treatment targets a part of the body that grows hair, like your scalp. The amount of hair that grows back depends on the strength of the radiation you receive.
Generally, radiation treatment affects only those areas being treated. So, if you are not receiving radiation to your stomach, you probably won’t have nausea as a result of treatment. In some cases, you might have nausea from other types of treatment, like chemotherapy or pain medication.
External-beam radiation treatment — where the source of the radiation is a machine outside your body — will not make you radioactive. After you finish a session, the radiation disappears.

Treatment Locations

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