How Radiation Therapy Works
Radiation Therapy is a clinical specialty that utilizes high-energy x-rays, gamma rays, electrons, or other ionizing radiation to manage and treat many types of cancer (and occasionally non-malignant conditions). Radiation can be administered externally or internally.
Radiation works by damaging the DNA and other parts of cells in the treatment area. Healthy cells of your body are able to better recover from this damage than malignant cells are. Radiation is therefore delivered so that the cancer cells are compromised, while the healthy cells are able to repopulate and heal the exposed area. External radiation treatments are painless (there is no burning or other sensation while receiving treatment) and do not make you radioactive.
Radiation is prescribed the same way any kind of medicine is, and it varies for each person. At the consultation, you and your radiation oncologist will determine the overall radiation dose and treatment plan that will benefit you most. Most people receiving radiation therapy will come to the Radiation Therapy Center daily, Monday through Friday, for treatments that take five to thirty minutes each. This may last anywhere from one to eight weeks depending on your treatment plan.
What is Radiation Therapy?
Radiation is a special kind of energy carried by waves or streams of particles. It can come from special machines or from radioactive substances. Many years ago, doctors learned how to use this energy to see inside the body and find disease (examples include chest x-rays or x-rays of your teeth or bones). When radiation is used at higher energies and doses (many times those used for x-ray exams), it can be used to treat cancer and other illnesses. Special equipment is used to precisely aim the radiation at tumors or areas of the body where there is disease. This use of high-energy rays or particles to treat disease is called radiation therapy. It is also sometimes called radiotherapy, x-ray therapy, cobalt therapy, electron beam therapy, or irradiation.
High doses of radiation can kill cells or keep them from growing and dividing. Radiation therapy is a useful tool for treating cancer because cancer cells grow and divide more rapidly than many of the normal cells around them. Although some normal cells of the body are affected by radiation, most normal cells are able to better recover from the effects of radiation than cancer cells can. Doctors carefully limit the intensity of treatments and the area being treated so that the cancer will be affected more than normal tissue.
What Are the Benefits and Goals of Radiation Therapy?
Radiation therapy is an effective way to treat many kinds of cancer in almost any part of the body. At least half of all people with cancer are treated with radiation, and the number of cancer patients who have been cured is rising every day. For many patients, radiation is the only kind of treatment needed. Thousands of people are free of cancer after having radiation treatments alone or in combination with surgery, chemotherapy, immunotherapy, or biological therapy.
Doctors may recommend radiation before surgery to shrink a tumor. After surgery, radiation therapy may be used to stop the growth of any cancer cells that remain. In some cases, doctors use radiation, along with anticancer drugs to destroy the cancer, instead of surgery.
Even when curing the cancer is not possible, radiation therapy still can bring relief. Many patients find the quality of their lives improve when radiation therapy was used to shrink tumors and reduce pressure, bleeding, pain, or other symptoms of cancer. This is called palliative care.
Are There Risks Involved?
Like many other treatments for disease, there are risks for patients who are receiving radiation therapy. The brief high doses of radiation that damage or destroy cancer cells also can hurt normal cells. When this happens, the patient has side effects. The risk of side effects is usually outweighed by the benefits of killing cancer cells.
Your doctor will not advise you to have any treatment unless the potential benefits (control of disease and relief from symptoms) are greater than the known risks.
How Is Radiation Therapy Given?
Radiation therapy can be in either of two forms: external or internal. Some patients have both forms, one after the other.
Most people who receive radiation therapy for cancer have the external type. It is usually given during outpatient visits to the treatment center. In external therapy, a machine directs the high-energy rays or particles at the known sites of cancer. The primary machine that is used for external radiation therapy is called a linear accelerator.
When internal radiation therapy is used, a radioactive substance, or source, is sealed in small containers such as thin wires or tubes called implants. The implant is placed directly into a tumor or inserted into a body cavity. Sometimes, after a tumor has been removed by surgery, implants are put into the area around the incision to kill any tumor cells that may remain. Another type of internal radiation therapy uses unsealed radioactive sources. The source is either taken by mouth or is injected into the body.
How Do I Know the Radiation Treatment Will Be Safely Delivered?
To ensure the safety of all patients treated at every Minneapolis Radiation Oncology clinic site, we perform a rigorous program that tests all equipment and assures the quality of every treatment.
All members of the team, including radiation oncology physicians, radiation physicists, and radiation therapists, perform safety checks throughout all steps of the treatment process. This detailed process ensures that radiation therapy treatments are appropriate for each patient.
Our safety process begins before a treatment machine is put into service, at which time an extensive set of measurements is performed to ensure it is working properly and complies fully with the treatment modeling system. These measurements are verified by an independent assessment by the Radiological Physics Center, which provides auditing services to radiation oncology departments across the country.
Regular testing and quality assurance checks are performed at consistent intervals. Each morning, radiation therapists conduct safety checks of the machine’s radiation output, beam-shaping devices, imaging technology, and body-positioning features to ensure they are all in compliance.
More extensive testing is done monthly and annually according to state and national standards. All machines also have redundancy systems to control and monitor radiation dose and shape, and the machine is automatically shut off if it is not performing to specifications.
All individual patient treatments also undergo extensive safety checks. Patient charts undergo a review to ensure treatment accuracy and absence of errors, and each patient’s treatment plan is peer-reviewed to ensure that it complies with standards of care.
Settings for the dose and shape of the radiation beams are automatically transferred from the treatment planning systems to the treatment machines to avoid errors and miscommunications. Intensity modulated radiation therapy (IMRT) plans are first tested on a treatment verification device to ensure the machine delivers the planned treatment accurately.
During treatment, video monitors enable radiation therapists to view the treatment’s progress. Patient positioning is regularly verified with imaging that is reviewed by the physician.
Finally, all patients are monitored by nurses and physicians at regular intervals over the course of their treatment to ensure there are no unexpected side effects.
Minneapolis Radiation Oncology prides itself on its strong record of safety and its system-wide culture where safety is an intrinsic part of treatment.