When you undergo external beam radiation therapy treatment, each session is painless, just like getting an X-ray. The radiation is directed at your tumor from a machine located away from your body, usually a linear accelerator. External beam radiation is noninvasive. One of the benefits of radiation therapy is that it is usually given as a series of outpatient treatments so you don’t have to stay in the hospital. You may not need to miss work or experience the type of recuperation period that may follow more invasive treatments.
The radiation therapist will deliver your external beam treatment following your radiation oncologist’s instructions. 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. Radiation therapists position you for treatment and set up the equipment. Time spent in the treatment room will vary depending on the type of radiation.
Once you are positioned correctly, the therapist will leave the treatment room and enter the control room next door to begin your treatment. During your treatment, your therapist will closely monitor you on a television screen. There is a microphone in the treatment room so you can always speak with the therapist if you have any concerns. The machine can be stopped at any time if you are feeling sick 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, knocking or whirring, but the radiation therapist is in complete control of the machine at all times.
Your radiation oncologist monitors your daily treatment and may alter your radiation dose based on these observations. Also, your doctor may obtain other tests such as blood tests and imaging to see how your body is responding to treatment. If the tumor shrinks or if your body changes significantly, another simulation may be required. This allows your radiation oncologist to change the treatment to destroy the rest of the tumor and spare even more normal tissue.
Sometimes a course of treatment may need to be interrupted for a day or more. This may happen if you develop side effects that require a break in treatment. Unscheduled machine maintenance may also cause a missed daily treatment. These missed treatments may be made up by adding treatments at the end. However, it is best to arrive on time and not miss any of your appointments.
Treatments are usually scheduled five days a week, Monday through Friday, and continue for multiple weeks. The number of radiation treatments you will need depends on the size, location and type of cancer you have, the goal of treatment, your general health and other medical treatments you may be receiving. Radiation oncologists will take all of this into account when determining your treatment course.
A portion of your external radiation therapy may be directed at the tumor and surrounding tissues at risk for harboring microscopic cancer cells. This might be followed by shrinkage of the volume of tissue treated to the tumor area itself, since this area may require a higher dose to eliminate the cancer cells. This is called a boost.
In some cases, you may receive chemotherapy and radiation therapy at the same time. The chemotherapy may be delivered daily, weekly, every three weeks or at an alternate schedule determined by the medical oncologist together with the radiation oncologist. The chemotherapy may work to sensitize the cancer cells in the target area to the radiation therapy and may also travel elsewhere in the body to help destroy or reduce microscopic cancer cells. Your treatment team will help coordinate these therapies and care for potential side effects.
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) and address any concerns you may have. Your doctor may also make changes in the schedule or treatment plan depending on your response or reaction to the therapy. Your radiation oncology team will gather on a regular basis with other health care professionals to review your case to ensure your treatment is proceeding as planned. During these sessions, all the members of the team discuss your progress and any concerns.
During your course of treatment, correct positions of the treatment beams will be regularly verified with images made using the treatment beam itself. These images (called port films, beam films or portal verification) represent an important quality assurance check but do not evaluate the tumor itself. Depending upon what kind of treatment you receive and what your doctor thinks will work best, the type of images used (e.g., X-ray, CT scan, ultrasound, etc.) may vary. These images assure your radiation oncologist that the treatment setup accurately matches the intended target.