It may be delivered using machines called linear accelerators or via radioactive sources placed inside the patient on a temporary or permanent basis. Radiation therapy may be used to cure cancer, to relieve a cancer patient's pain or alleviate other symptoms.
Preparation for radiation therapy is focused on targeting the radiation dose to the cancer as precisely as possible to minimize side effects and avoid damaging normal cells.
Imaging tests may be used to help determine the exact shape and location of your tumor and define its boundaries. Your doctor will give you specific instructions based on the type of exam being performed. An increasing number of patients have their cancers treated successfully using radiation therapy. Modern technology has combined the use of three-dimensional imaging technology, computerized treatment planning and high-energy x-ray machines to make more precise treatment possible.
Professionals involved in radiation therapy treatment include:. More than half of cancer patients are treated with radiation at some time during their course of treatment. Radiation therapy is the use of high-energy radiation to treat cancer. A radiation oncologist may use radiation to cure cancer or to relieve a cancer patient's pain or alleviate other symptoms due to the cancer.
Radiation therapy works because the radiation destroys the cancer cells' ability to reproduce, and the body naturally gets rid of these cells.
Radiation affects cancer cells by damaging their DNA, so that the cancer cells can no longer divide and grow. Radiation is most effective at killing cells that are actively dividing. Cancer cells are more vulnerable to radiation for two reasons:. A radiation oncologist may use external beam radiation therapy or brachytherapy to treat cancer.
External beam radiation therapy can be generated by a linear accelerator a machine that accelerates electrons to produce x-rays or gamma rays. Proton therapy is another form of external beam radiation therapy that uses cyclotrons or synchrotrons to produce charged atoms that destroy tumors.
Radiation therapy given by radioactive sources that are put inside the patient is called brachytherapy. The radioactive sources are sealed in needles, seeds, wires, or catheters, and implanted directly into or near a tumor on a temporary or permanent basis. Brachytherapy is a common treatment for cancers of the prostate , uterus, cervix or breast. Some cancer patients may be treated with radiation as their primary treatment. In some cases, radiation therapy is given at the same time as chemotherapy.
In external beam radiation, the radiation comes from a machine outside of the body. A doctor may recommend radiation therapy for several purposes.
These include :. The National Cancer Institute NCI notes that doctors commonly use external beam radiation to treat the following types of cancer:. The NCI suggests that brachytherapy may be an especially effective treatment for cancers in certain parts of the body, including the:.
External beam radiation therapy and brachytherapy both start with a meeting to plan the treatment. A doctor will examine the individual, ask about their health, and discuss the therapy. In some cases, they may request imaging. A person who decides to have external beam radiation will typically meet with a radiation oncologist and a radiation therapist for a planning session called a simulation. These marks can be either temporary or in the form of a tattoo. In addition, healthcare professionals may create a body mold that they use to ensure that a person is in the correct position when receiving radiation therapy.
If a person is receiving radiation therapy to the head or neck, they may need to use a face mask to keep their head in place during treatment. What to expect during radiation therapy will differ depending on which type of therapy a person receives.
During an external beam radiation therapy session, a person will typically lie on a table beneath a large machine. The radiation therapist will position the individual in the machine and then go into a separate room. Although the person must try to stay still during the treatment, they generally do not have to hold their breath.
The machine will make whirring, clicking, and vacuum cleaner-like noises. A speaker system in the room allows the person to talk with the radiation therapist during the treatment. Once the catheter or applicator is in position, the doctor will place the radiation source inside it. In some cases, the implant may remain in the body for up to a few days before the doctor removes it.
In others, the doctor may place the implant in the body for a shorter time, such as 10—20 minutes, and repeat the treatment periodically for as long as several weeks. Sometimes an implant remains in the body permanently, but it will stop releasing radiation after some time.
When doctors use radiation therapy alongside other treatments, such as surgery or chemotherapy , they call it adjuvant treatment. Some people might receive radiation therapy before surgery to shrink a tumor and make it easier to remove.
Other individuals might receive it after surgery to destroy cancer cells that the surgery may have missed. Sometimes, doctors use radiation therapy as part of palliative care to help relieve symptoms of advanced cancer. These may include :. The ACS states that the most common side effects from radiation therapy are:. However, it notes that a person receiving radiation treatment can take steps to relieve these side effects.
Radiation treatment alone may be enough to cure certain early stage cancers. However, the NCI notes that studies suggest that cancer treatment outcomes are better if a person receives both radiation and chemotherapy following surgery. Radiotherapy can be done in many different ways, depending on your circumstances.
If you're diagnosed with cancer, you'll be cared for by a team of specialists. Your team will recommend radiotherapy if they think it's the best option for you, but the final decision is yours. Making this decision can be difficult. You may find it useful to write a list of questions to ask your care team. If you agree with your team's recommendation, they'll start to plan your treatment once you have given your consent to treatment.
Your treatment will be carefully planned to ensure the highest possible dose is delivered to the cancer, while avoiding damage to nearby healthy cells as much as possible. You will probably have a CT scan to work out exactly where the cancer is and how big it is. After the scan, some very small but permanent ink marks may be made on your skin to ensure the right area is targeted accurately each time.
If you're having radiotherapy to your head or neck, a plastic mask will be made for you to wear during treatment. The ink marks will be made on the mask. Most people have 5 treatments each week 1 treatment a day from Monday to Friday, with a break at the weekend. But sometimes treatment may be given more than once a day or over the weekend. Your doctor may call each dose a "fraction", although the term "attendance" is sometimes used to indicate how many hospitals visits you'll need to make during treatment.
During external radiotherapy, you lie on a table and a machine directs beams of radiation at the cancer. The machine is operated from outside the room, but you'll be watched through a window or a camera. There will be an intercom if you need to speak to the person treating you. You need to keep as still as possible throughout the treatment.
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