William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
What is radiation therapy?
In radiation therapy (also called radiotherapy), invisible high-energy rays or beams of subatomic particles are used to damage cancer cells and can stop them from growing and dividing. This ultimately can kill the cancer cells treated with radiation. A specialist in radiation therapy is called a radiation oncologist.
What are the types of radiation therapy?
Like surgery, radiation therapy can be a local treatment; it affects cancer cells only in the treated area. If the area treated is broader, we say it is then a regional treatment. Rarely, the whole body is given radiation therapy for a systemic or total-body effect. Radiation can come from a machine (external radiation). It can also come from an implant (a small container of radioactive material) placed directly into or near the tumor (internal or interstitial radiation). Some patients receive both kinds of radiation therapy.
External radiation therapy is usually given on an outpatient basis in a hospital or clinic with specialized equipment 5 days a week for a number of weeks. Patients are not radioactive during or after the treatment with external beam radiation therapy.
For internal radiation therapy, the patient often stays in the hospital for a few days. The implant may be temporary or permanent. Because the level of radiation is highest during the hospital stay, patients may not be able to have visitors or may have visitors only for a short time. Once an implant is removed, there is no radioactivity in the body. The amount of radiation given off to the outside from a permanent implant goes down to a safe level before the patient leaves the hospital.
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