External radiation therapy (also called external beam radiation therapy) delivers a beam of high-energy X-rays directly to your tumor to destroy cancer cells or slow their growth. A machine outside the body produces the radiation.

Advanced radiation therapy delivered with compassion

Cooper offers the most advanced external radiation therapy treatments and approaches available — delivered with compassion. From your first appointment to the completion of your care, we will be there to support you and answer all of your questions. 

By using state-of-the-art linear accelerators to deliver external radiation therapy, including intensity modulated radiation therapy (IMRT), we treat your cancer aggressively, while minimizing the side effects of radiation therapy. Using a state-of-the-art image-based planning system, we precisely locate your tumor and design treatments with pinpoint accuracy. Then we deliver the most effective dose of radiation to your tumor while sparing as much healthy tissue as possible.

Uses of external radiation therapy

External radiation therapy can be used to:

  • Treat cancer
  • Control cancer by slowing its growth
  • Relieve symptoms caused by the growth of the tumor. 

External radiation therapy may be used alone or with other treatments, like surgery or chemotherapy. 

How external radiation therapy works

External radiation therapy is like getting an X-ray. A large machine that moves around you aims radiation at the cancer. External radiation therapy doesn't hurt.
External radiation therapy is done on an outpatient basis for 2 to 8 weeks, depending on your type and stage of cancer.  The average length of external radiation therapy is about 6 weeks.  Treatments are usually done 5 days a week (Monday through Friday). 

Each treatment lasts only a few minutes, but the setup time — getting you into place for treatment —takes longer.  An average treatment visit takes about 30 to 60 minutes.

The radiation that destroys cancer cells also injures nearby healthy cells. This can cause side effects, like feeling very tired (fatigue), skin changes, and loss of appetite. To reduce the chance that you’ll have side effects, your doctors will carefully figure out the exact dose of radiation you need and aim the radiation as accurately as possible. If you do have side effects, your doctors can help you manage them.

Types of external radiation therapy

Cooper offers two types of external radiation therapy:

Intensity modulated radiation therapy (IMRT)
Cooper is one of a few centers in the region to offer IMRT — the most advanced form of external radiation therapy available. It delivers high doses of radiation directly to cancer cells very precisely while sparing more of the nearby healthy tissue. 

IMRT uses computer-generated images to deliver tightly focused, high-dose radiation to a tumor or to specific areas within the tumor. The images create a 3-dimensional (3D) map of the location of the tumor. 

The radiation beams are shaped (or conformed) to match the shape of the tumor. This is done by modulating (or controlling) the intensity of the radiation beam to focus more radiation on the tumor while minimizing the radiation exposure of surrounding healthy tissue. 

3D computerized tomography (CT) images and computerized dose calculations are used to determine the best dose intensity pattern for your tumor. A CT scan combines a series of X-rays taken from different angles to produce detailed images of bones, organs, soft tissues, and blood vessels. 

IMRT delivers higher and more effective radiation doses safely with fewer side effects than conventional external radiation therapy.

Image-guided radiation therapy (IGRT)
Some types of tumors can move. For example, lung tumors move when you breathe.  

IGRT uses repeated imaging scans taken during treatment to track your tumor, adjust your position, and more precisely target the radiation.  It delivers higher radiation doses to the tumor while sparing the nearby healthy tissue. 

The scans used in IGRT can be:

  • CT scan (computerized tomography)
  • MRI (magnetic resonance imaging)
  • PET scan (positron emission tomography)
  • Ultrasound
  • X-ray (radiograph)

Contact Us

For an appointment with an MD Anderson Cooper radiation therapy expert, please call 855.MDA.COOPER (855.632.2667).