Austin Center RADIATION Oncology

External Beam Radiation Therapy

external beam radiation therapy
Image courtesy of Varian Medical System, Inc. All rights reserved.

External Beam Radiation Therapy (EBRT) is a form of radiation treatment, also known as radiotherapy. External Beam Radiation Therapy can be used on any part of the body, and is the most common radiotherapy that is used. EBRT gets its name from the high energy beam that is delivered to the patient from outside the body.

The machine used to deliver the EBRT is called a linear accelerator or LINAC. When treating cancer patients, the linear accelerator dispenses high doses of radiation to destroy cancer cells. It accomplishes this by using specialized computer programs designed to target tumors while minimizing damage to surrounding tissue.

External Beam Radiation Therapy is administered at the Austin Center for Radiation Oncology on a daily basis (Monday through Friday). Most treatment plans range from 39 to 45 sessions and take approximately 15 minutes per treatment. Each treatment is similar to getting an x-ray, so the patient does not experience any discomfort. During delivery, the patient lies in the exact same position on the table (aided by a special body mold), and is asked to remain completely still.  This is to ensure that the radiation beam is consistently and precisely directed at the tumor.

Types of External Beam Radiation Therapy

Below is a short definition of three different forms of ERBT:

Three-Dimensional Conformal Radiation Therapy (3D-CRT) is a process in which CT imaging (computed tomography) is utilized to create a three-dimensional image of the tumor and surrounding organs. Information from the CT is entered directly into the radiotherapy planning computer to allow the Radiation Oncologist and Medical Physicist to see the treatment area in three-dimensions (3D). A treatment plan is then designed to target the radiation beam to the exact shape of the tumor, with the goal of sparing as much healthy surrounding tissue as possible.

external beam radiation therapy
Image courtesy of Varian Medical System, Inc. All rights reserved.

Intensity Modulated Radiation Therapy (IMRT) is a type of high-precision therapy that uses a computer-controlled linear accelerator to deliver precise radiation doses to the tumor. It is accomplished using a multi-leaf collimator that guides the radiation beams. The multi-leaf collimator is similar to the shutters on a window blind. You can change the amount of light coming in a window by opening and closing the blinds. With IMRT, the “leaves” can be moved to match the shape of each individual tumor. This allows the beams to target the shape of the tumor, from several directions, while reducing the radiation to surrounding tissue. With this form of radiation, the goal is to destroy the tumor and reduce adverse side effects.

Image Guided Radiation Therapy (IGRT) uses x-rays to view the cancer site on a daily basis. This is important when treating areas of tumor that may move around by pressure from surrounding organs – such as the prostate from the fullness of the bladder. This technology helps to ensure that the patient’s position is ideal for treating the tumor while sparing the surrounding tissue and organs. The radiation technicians are able to view these images on a computer console and adjust the treatment table accordingly.

If you have been diagnosed with prostate, bladder, testicular or bone cancer and would like to learn about the potential benefits of radiation therapy, contact us to schedule a consultation.