OHSU Knight Cancer Institute

Radiation Therapy

A doctor is helping a patient get comfortable before a radiation treatment. The patient is lying on a treatment bed. The doctor is leaning over them. The scene is framed by the circular opening of a radiation machine.

Radiation therapy is a powerful, lifesaving treatment that uses beams of energy to kill cancer cells. About half of all cancer patients get radiation therapy at some point in their treatment. New technology is making it safer and more effective than ever.

 At the OHSU Knight Cancer Institute, we offer: 

  • Nationally known experts in radiation therapy. 
  • The latest technology and techniques.
  • Advanced research and clinical trials.
  • A full range of support services, including a guest house for out-of-town patients.
Learn more about radiation therapy in this short video produced by the American Society for Radiation Oncology.

What is radiation therapy?

Radiation therapy uses beams of energy to treat cancer. The energy (called radiation) consists of subatomic particles such as photons, electrons, neutrons and protons.

The radiation damages the DNA inside the cancer cells. Normal cells can repair the damage, but cancer cells can’t. They stop growing and die.

Radiation can: 

  • Destroy tumors.
  • Shrink tumors before surgery. 
  • Kill cancer cells that remain after surgery. 
  • Ease pain and reduce symptoms. 

Your care team may use radiation alone or combine it with other treatment like surgery or chemotherapy.

Types of radiation therapy

Doctors have several ways to zero in on cancer while sparing healthy tissue. They’re divided into three broad types:

How it works

At your first visit, our team will go over treatment options and side effects. Your next visit involves detailed planning to find the best way to beam radiation at your tumor. Once you start treatment, you will see your radiation oncologist once a week to monitor your progress.

What are the side effects of radiation therapy?

The most common side effects are tiredness, loss of appetite, and skin redness, like a sunburn. Learn more about what to expect in our Radiation Therapy FAQ.

What makes us different

Expertise: Your care will be led by national experts who are dedicated to providing you with the safest, most effective treatment. They are also researchers who develop new treatments and train radiation doctors around the world.

Top minds together: Specialists from a wide range of fields will meet to discuss your case. You benefit from the knowledge of the entire team.

Advanced technology: We use advanced technology to deliver powerful doses of radiation with pinpoint precision. 

National recognition: We’ve earned the National Cancer Institute’s top designation for leadership in research.

Innovation: We’re leading the way in new therapies for prostate cancer, lung cancer, liver cancer, pancreatic cancer, NETs and many other conditions.

Sudershan Anand, Ph.D., is one of hundreds of OHSU cancer scientists.
Sudarshan Anand, Ph.D., is one of hundreds of cancer scientists at the Knight. His research is focused on figuring out how to make radiation therapy even more effective.

The whole you

We treat the whole person, not the disease. We offer a full range of resources, including: 

Learn about our support services for you and your family

Learn more

For patients

  • Request an appointment at our Marquam Hill location: 503-494-8756
  • Request an appointment at our Beaverton location: 971-262-9400

Visit our For Cancer Patients page to find a cancer doctor and links to diagnoses.


OHSU Knight Cancer Institute Radiation Medicine, Marquam Hill
Kohler Pavilion, fourth floor
808 S.W. Campus Drive
Portland, OR 97239

OHSU Knight Cancer Institute, Beaverton
15700 S.W. Greystone Court
Beaverton, OR 97006

OHSU Health Hillsboro Medical Center
299 S.E. 9th Ave.
Hillsboro, OR 97123

CMH-OHSU Knight Cancer Collaborative, Astoria
1905 Exchange Street
Astoria, OR 97103

OHSU Radiation Oncology at Roseburg Community Cancer Center
2880 N.W. Stewart Pkwy, #100
Roseburg, OR 97471

Free parking for patients and visitors

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Learn more about OHSU Knight Cancer Institute treatments: