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:

This technique shapes the radiation beams to match the shape of the tumor. This makes it possible to locate and treat the tumor more precisely than older technologies. It also spares the healthy tissue around the tumor from the damaging effects of radiation.

Learn more about 3D Conformal Radiation Therapy.

IGRT is a method of disease management that uses On-Board Imager®* or Cone Beam CT to image your tumor or target region before radiation therapy. This helps optimize the accuracy of treatment delivery.

Learn more about IGRT.

IMRT technology allows radiation oncologists to sculpt the edges of the tumor and match the radiation beam to the exact shape of the tumor. This delivers a precise dose of radiation while reducing the damage to adjacent healthy tissue and side effects.

Learn more about IMRT.

The Halcyon system delivers precise image-guided, volumetric, intensity-modulated radiation therapy (IMRT) up to four times faster than standard technology. Images can be acquired in less than 15 seconds, and treatment can be administered in about two minutes.

Learn more about the Halcyon™ Radiation Therapy System.

RapidArc radiotherapy technology is a fast and precise form of IMRT that delivers more radiation to the tumor and potentially less to surrounding healthy tissue. RapidArc treatment uses a single 360° rotation of the linear accelerator, which takes less than five minutes.

Learn more about RapidArc®.

SRS and SABR function much like surgery but do not involve incisions or anesthesia. These methods are good options for certain types of cancers and for people with tumors in previously irradiated sites. These precise and effective approaches allow the radiation oncologist to target tumors with high doses of radiation and minimal effects on nearby healthy tissues.

Learn more about SRS and SABR.

TrueBeam uses sophisticated imaging technology to take pictures of tumors, even when they move. It can alter the shape of the radiation beam to match the shape of the tumor. This makes the radiation treatment more precise and helps avoid targeting healthy tissue nearby.

Learn more about TrueBeam Radiosurgery.

*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: