External Beam Radiation

Radiation therapy is given through different methods, depending on the type of cancer, the location of the cancer, and your health. Sometimes, radiation therapy is used in combination with other treatments.

With external beam therapy, radiation is administered by a large machine that points the energy waves directly at the tumor. The radiation therapist controls the machine. Since radiation is used to kill cancer cells, special shields may be made to protect the tissue surrounding the treatment area.

To give healthy cells time to recuperate, patients undergoing external beam therapy receive small doses (fractions) of radiation at one time. Most patients receive radiation treatments on an outpatient basis. A typical schedule for external beam therapy treatment is to receive therapy once a day for 5 days a week over 2 to 9 weeks. In some cases where the treatment is palliative (to relieve symptoms rather than cure), the length of treatment may last only 2 to 3 weeks. The treatment process usually takes 10 to 30 minutes a day with much of the time spent positioning the patient. Treatment duration depends on the method of treatment delivery and the prescribed dose.

As the treatment progresses, the radiation oncologist will monitor the patient's progress and response to the treatment. Depending on the response to treatment, changes may be made to the radiation dose, the number of treatments, or the length of treatment.

Advanced Technology
The Ella Milbank Foshay Cancer Center has some of the world’s leading technology for external beam radiation, allowing us to offer patients advanced methods to kill cancer cells and shrink or destroy tumors.

Varian Trilogy Linear Accelerator
The Varian Trilogy Linear Accelerator is the world's first Image-Guided Radiation Therapy (IGRT) system optimized for both conventional and stereotactic approaches to treating cancer. This cutting-edge equipment precisely targets tumors without affecting surrounding healthy tissues. This permits higher radiation doses and higher cure rates for early-stage cancer patients and supportive therapy with fewer side effects for advanced-stage cancer patients. The Trilogy System shortens daily treatment times and offers greater patient comfort. The Stereotactic Radiosurgery package enables physicians to treat tumors in a short course of only a few days or even in a single session.

On-Board Imaging (OBI)
The On-Board Imaging system is a cutting-edge technology that provides unparalleled capabilities to deliver precisely-targeted radiation therapy. It can pinpoint the exact location of the cancer on a daily basis, correcting for any patient or target motion, allowing high doses of radiation to be delivered while protecting adjacent healthy tissues.

Intensity Modulated Radiation Therapy (IMRT)
IMRT is a treatment technique that uses beams that change shape during the treatment creating many beamlets (beam segments) to vary the radiation intensity across each beam. Thus, allowing us to precisely confirm the dose to the target while sparing the nearby normal tissues. Consequently, tumors that could be treated using conventional techniques can now be treated in much higher doses, resulting in improved cure rates while reducing side effects. IMRT also enables the treatment of hard-to-get-to tumors that were considered untreatable using conventional techniques.

Varian RapidArc® Radiotherapy Technology
This technology is an effective cancer treatment representing an advanced new form of image-guided IMRT (Intensity Modulated Radiation Therapy). This technology enables clinicians to program a linear accelerator to deliver precise forms of IMRT up to eight times faster than other IMRT systems. It does this by delivering the complete IMRT treatment to the patient in fewer rotations than traditional IMRT. As a result, the tumor will receive the full radiation dose within less than two minutes compared with 10 minutes or longer for conventional IMRT. Treatment speed is important because it reduces the time that the patient must lie still and avoid any movement. As treatment time is reduced, Varian RapidArc® has the potential to improve the patient's quality of care and comfort.

Three-Dimensional Conformal Radiation Therapy (3-D CRT)
3-D CRT is an image-based computerized treatment planning and delivery technique that utilizes the beam's eye view (BEV) to shape the radiation fields to conform the dose to the target. The planning is performed using ADAC Pinnacle³ treatment planning systems that employ sophisticated three-dimensional dose calculation algorithms to determine the dose given to the patient.


PET/CT-Simulation and Three-Dimensional Reconstruction
This treatment process utilizes CT imaging to simulate the radiation treatment. All the necessary images and parameters for the treatment planning process are obtained during the simulation.


For more information about our Radiation Oncology Department, please call (561) 263-4400.