Frequently Asked Questions about Cancer
How is radiation therapy given?
- Published: 27 June 2012
Radiotherapy can be delivered using one of two approaches: external or internal radiotherapy. Some patients, however, may require both forms.
Most patients who receive treatment undergo external beam radiotherapy. Such treatment is typically delivered as an outpatient visits once daily (Monday through Friday) over several weeks. In some cases, your doctor may choose to deliver several treatments per day. In external therapy, a machine known as a linear accelerator (linac) is used to direct high-energy x-rays or particles (electrons) at the cancer. At WellSpring we also offer tomotherapy, which is a more precise delivery method of radiation.
When internal radiation therapy, also known as brachytherapy, is indicated, a radioactive substance, or source, is used. Another name for internal radiation therapy is an “implant”. During the implant procedure, a radioactive source is placed either next to (intracavitary implant) or within (interstitial implant) the tumor.
To aid in the delivery of the treatment, a small plastic or metal apparatus may be temporarily inserted into the body which holds the radioactive source in its proper place.
Two primary methods are used to deliver brachytherapy: low-dose-rate (LDR) and high-dose-rate (HDR) techniques. For much of the last century, patients were treated with LDR brachytherapy which delivered treatment slowly over several days. LDR required the patient to be admitted to the hospital and typically placed at strict bed rest.
Today, patients undergoing brachytherapy are treated predominantly with HDR techniques administered over a few minutes on an outpatient basis.