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If you are considering radiation therapy, you must first schedule a visit with a radiation oncologist to see if radiation therapy is right for you. During your initial visit, the doctor will evaluate your need for radiation therapy and its likely results. This includes reviewing your current medical problems, past medical history, past surgical history, family history, medications, allergies and lifestyle. The doctor will also perform a physical examination to assess the extent of your disease and judge your general physical condition. Depending on where your radiation oncologist practices, you may also be seen by a medical student, a resident (radiation oncologist in training), a nurse practitioner, a physician assistant or a nurse.
After reviewing your medical tests, including CT scans, MR scans and positron emission tomography scans (PET scans) and completing a thorough examination, your radiation oncologist will fully discuss with you the potential benefits and risks of radiation therapy and answer your questions.
Simulation and Treatment Planning
To be most effective, radiation therapy must be aimed precisely at the same target or targets each and every time treatment is given. The process of measuring your anatomy and marking your skin to help your team direct the beams of radiation safely and exactly to their intended locations is called simulation.
During simulation, your radiation oncologist and radiation therapist place you on the simulation machine in the exact position you will be in during the actual treatment. Your radiation therapist, under your doctor’s supervision, then marks the area to be treated directly on your skin or on immobilization devices.
Immobilization devices are molds, casts, headrests or other devices that are constructed and placed on a certain part of your body to help you remain in the same position during the entire treatment. The radiation therapist marks your skin and/or the immobilization devices either with a bright, temporary paint or a set of small permanent tattoos.
Your radiation oncologist may request that special blocks or shields be made for you. These blocks or shields are put in the external beam therapy machine before each of your treatments and are used to shape the radiation to your tumor and keep the rays from hitting normal tissue. Some treatment machines have built-in blocks or shutters called multileaf collimators, which also help shape the radiation.
Although simulation is typically only one session, your physician may schedule additional sessions depending on the type of cancer you have and the type of radiation therapy that is being used.
After simulation, your radiation oncologist and other members of the treatment team review the information they obtained during simulation along with your previous medical tests to develop a treatment plan. Often, a special treatment planning CT scan is done to help with the simulation and treatment planning. This CT scan is in addition to your diagnostic CT scan. Frequently, sophisticated treatment-planning computer software is used to help design the best possible treatment plan. After reviewing all of this information, your doctor writes a prescription that outlines the exact course of your radiation therapy treatment.
External beam radiation therapy is administered differently from brachytherapy. You may receive one or both of these treatments. The following sections describe what you may experience during treatment administration.
External Beam Radiation Therapy Treatments
When you undergo external beam radiation therapy treatment, each session is painless, like getting an X-ray. The radiation is directed to your tumor from a machine located outside of your body. One of the benefits of radiation therapy is that it is usually given as a series of outpatient treatments and you may not need to miss work or experience the type of recuperation period that can follow other treatments.
Treatments are usually scheduled five days a week, every day except Saturday and Sunday, and continue for three to 10 weeks. Some patients receive hyperfractionated radiation therapy, in which radiation treatments are given more than once a day. Other times, only one or a few treatments are required, such as for the treatment of cancer that has spread to the bone. This is called hypofractionated radiation therapy. The number of radiation treatments you will need depends on the size, location and type of cancer you have, your general health and other medical treatments you may be receiving.
The radiation therapist will administer your external beam treatment following your radiation oncologist’s instructions. It will take roughly five to 15 minutes for you to be positioned for treatment and for the equipment to be set up. If an immobilization device was made during simulation, it will be used during every treatment to make sure that you are in the exact same position every day.
Once you are positioned correctly, the therapist will leave the room and go into an adjoining control room to closely monitor you on a television screen while administering the radiation. There is a microphone in the treatment room so you can always talk with the therapist if you have any concerns. The machine can be stopped at any time if you are feeling ill or uncomfortable.
The radiation therapist may move the treatment machine and treatment table to target the radiation beam to the exact area of the tumor. The machine might make noises during treatment that sound like clicking or whirring. These noises are nothing to be afraid of, and the radiation therapist is in complete control of the machine at all times.
The radiation therapy team carefully aims the radiation to decrease the dose to the normal tissues surrounding the tumor. Still, radiation will affect some healthy cells. The time in between daily treatments allows your healthy cells to repair much of the radiation damage. Most patients are treated on an outpatient basis, and many can continue with normal daily activities.
Sometimes a course of treatment is interrupted for a day or more. This may happen if you develop side effects that require a break in treatment. These missed treatments may be made up by adding treatments at the end. Try to arrive on time and not miss any of your appointments.
Your radiation oncologist monitors your daily treatment and may alter your radiation dose based on these observations. Also, your doctor may order blood tests, X-ray examinations and other tests to see how your body is responding to treatment. If the tumor shrinks, another simulation may be done. This allows your radiation oncologist to change the treatment to destroy the rest of the tumor and spare even more normal tissue.
Brachytherapy, also called internal radiation or seed implants, is the placement of radioactive sources in or just next to a tumor. The radioactive sources may be left in place permanently or only temporarily, depending upon your cancer. To position the sources accurately, special catheters or applicators are used.
There are two main types of brachytherapy: intracavity treatment and interstitial treatment. With intracavity treatment, the radioactive sources are put into a space near where the tumor is located, such as the cervix, the vagina or the windpipe. With interstitial treatment, the radioactive sources are put directly into the tissues, such as the prostate.
Often these procedures require anesthesia and brief hospitalization. Patients with permanent implants may have a few restrictions at first and then can quickly return to their normal activities. Temporary implants are left inside of your body for several hours or days. While the sources are in place, you will stay in a private room. Doctors, nurses and other medical staff will continue to take care of you, but they will need to take special precautions to limit their exposure to radiation.
Devices called high dose rate remote afterloading machines allow radiation oncologists to complete brachytherapy quickly, in about 10 to 20 minutes. Powerful radioactive sources travel through small tubes called catheters to the tumor for the amount of time prescribed by your radiation oncologist. You may be able to go home shortly after the procedure. Depending on the area treated, you may receive several treatments over a number of days or weeks.
Most patients feel little discomfort during brachytherapy. If the radioactive source is held in place with an applicator, you may feel discomfort from the applicator. There are medications that can help this. If you feel weak or queasy from the anesthesia, your radiation oncologist can give you medication to make you feel better.
Weekly Status Checks
During radiation therapy, your radiation oncologist and nurse will see you regularly to follow your progress, evaluate whether you are having any side effects, recommend treatments for those side effects (such as medication or diet changes) and address any concerns you may have. As treatment progresses, your doctor may make changes in the schedule or treatment plan depending on your response or reaction to the therapy.
Your radiation therapy team may gather on a regular basis with other healthcare professionals to review your case to ensure your treatment is proceeding as planned. During this session, all the members of the team discuss your progress as well as any concerns.
Weekly Beam Films
During treatment, your treatment team will routinely use the treatment machines to take special X-rays called beam or port films. Your treatment team routinely reviews these films to be sure that the treatment beams remain precisely aimed at the proper target. These X-rays are not used to evaluate your tumor.
After treatment is completed, follow-up appointments will be scheduled so that your radiation oncologist can make sure your recovery is proceeding normally and can continue to monitor your health status. Your radiation oncologist may also order additional diagnostic tests. Reports on your treatment can be sent to your other doctors.
As time goes on, the frequency of your visits will decrease. However, you should know that your radiation oncology team will always be available should you need to speak to someone about your treatment.
Other Treatment Options
Systemic Radiation Therapy
Using radioactive isotopes to treat certain cancers is called systemic radiation therapy. The radioactive isotopes may be swallowed, given intravenously or injected into the body. For example, radioactive iodine (I-131) capsules are given to patients to treat some types of thyroid cancer. Another example is the use of intravenous radioactive strontium to treat pain due to cancer that has spread to the bone.
Recent research has focused on the use of radioactive monoclonal antibodies, also called radiolabeled antibodies, to deliver doses of radiation directly to a tumor. This process is known as radioimmunotherapy. Antibodies are made by the body in response to the presence of antigens (substances recognized as foreign by the immune system). Large quantities of particular types of antibodies, called monoclonal antibodies, can be made in the laboratory. These monoclonal antibodies can be attached to radioactive isotopes in a process called radiolabeling. When injected into the body, the radiolabled antibodies circulate in the bloodstream until they locate and bind to the surface of cancer cells. The cancer cells are then destroyed by the radiation carried in the antibody.
Intraoperative Radiation Therapy
Radiation therapy given during surgery is called intraoperative radiation therapy. Intraoperative radiation therapy is helpful when vital normal organs are dangerously close to the tumor. During an operation, a surgeon temporarily moves the normal organs out of the way so radiation can be applied directly to the tumor. This allows your radiation oncologist to avoid exposing those organs to radiation. Intraoperative radiation can be given as external beam therapy or as brachytherapy.
Investigational Radiation Therapies
Several specialized types of radiation therapy are available in a limited number of facilities in the United States. These treatments are currently being studied to determine their best use. You can discuss with your radiation oncologist whether these therapies may benefit you.