What is External Beam Radiation?

3D conformal radiation therapy images

In cancer treatment, external radiation (or external beam radiation) is the most common type of radiation therapy. External beam radiation therapy can be very carefully delivered with the help of radiation technology. By focusing the radiation beam on the cancer, the machines maximize the radiation reaching the cancer, while minimizing its effects on normal tissues.

What is External Beam Radiation Therapy?

External beam radiation therapy uses a high-energy x-ray machine — called a linear accelerator — to direct radiation to the tumor.

This outpatient cancer treatment lasts a few minutes, a few times a week over several months.

Before your radiation treatment begins, your UPMC Hillman Cancer Center radiation oncologist will:

  • Pinpoint the location of your tumor.
  • Take an image of the tumor.
  • Decide your course of treatment.

This involves an initial planning session.

Your Radiation Oncology Planning (Simulation) Session

Your planning session includes a simulated treatment session and takes about an hour.

During simulation, a radiation therapist may:

  • Create a thermoplastic or foam mold that supports your head, neck, back, pelvis, and thighs. This mold — sometimes called a cradle — ensures you're in the correct position over the course of your radiation treatments.
  • Take images or an x-ray of the tumor while you're lying in the mold.
  • Mark the treatment area on your skin, using the x-rays as a guide. These marks serve as a map of the treatment area.

External Beam Radiation Therapy Procedure: What to Expect

A radiation therapy session takes about 15 to 30 minutes total.

When you arrive, the radiation therapist will reproduce your set-up using the marks on your skin and molds from your planning session.

Then, you will lie in this position on the x-ray table.

The linear accelerator will move in a circular fashion around the target area. The actual radiation treatment lasts only a few minutes.

Your radiation oncologist will decide your treatment schedule and how often you will need to repeat the treatment process.

Types of External Beam Radiation Therapy

UPMC Hillman Cancer Center offers many types of external beam radiation therapy:

*On-Board Imager, Halcyon, and RapidArc are trademarks of Varian Medical Systems, Inc.

Contact Us About Radiation Oncology at UPMC Hillman Cancer Center

To learn more about radiation treatments or to make an appointment you can: