Radiation Therapy at the Knight Cancer Institute

A male doctor feeling the glands on a male patient's throat.
Dr. Nima Nabavizadeh is a radiation oncologist who specializes in caring for patients with lymphoma and gastrointestinal cancer. He is an expert in treating a wide variety of cancers with radiation therapy.

Radiation therapy has long been a pillar of cancer care. Advances have made it more effective with fewer side effects. At the OHSU Knight Cancer Institute, we offer: 

  • Nationally known radiation therapy experts who work with your full cancer team to give you outstanding care. 
  • Doctors who continually research how to provide the best results with the least amount of radiation. 
  • Detailed treatment planning and follow-up so you know exactly what to expect. 
  • The latest technology to safely and accurately deliver radiation. 
  • Innovative techniques to precisely target cancer and spare healthy tissue. 

What is radiation therapy?

Radiation therapy uses high-energy beams such as X-rays or electrons to destroy cancer cells. After radiation exposure, cancer cells can’t grow or spread. Normal cells can recover from radiation, repairing themselves over time.

Your care team may use radiation alone or combined with surgery or medication such as chemotherapy. Radiation has been a treatment option for cancer for more than 100 years. Recent advances have made it safer and more precise than ever.

Radiation may be used to: 

  • Shrink tumors before surgery. 
  • Kill cancer cells that remain after surgery. 
  • Eliminate tumors that have not spread. 
  • Ease pain or other symptoms by reducing tumor size. 

Radiation therapy schedule

Your treatment schedule will depend on the type and stage of your cancer. Most people have radiation therapy five days a week. Most cancers need to be treated for five to eight weeks.  

Radiation therapy types

External: Radiation therapy delivered from a machine outside your body is called external beam radiation.

Internal: Radiation therapy from material placed inside your body is called brachytherapy, internal radiation or nuclear medicine.

Intraoperative: Radiation therapy delivered during surgery is called intraoperative radiation therapy, or IORT for short.

These broad categories include many types of radiation therapy and ways to deliver it. At OHSU, we specialize in treatments that zero in on cancer while avoiding healthy tissue.  

Radiation therapy technology

We use the most advanced technology to make radiation treatment as effective as possible. If you receive care at the Tuality/OHSU Cancer Center in Hillsboro, your team may show you a 3D simulation of your treatment.

Radiation therapist Estel Hayes runs through a virtual simulation presentation prepared for patients at Tuality/OHSU Cancer Center.
Radiation therapist Estel Hayes runs through a virtual simulation presentation prepared for patients at the Tuality/OHSU Cancer Center. The system gives patients and their families a 3D view of what to expect.

What makes us different

Expertise: Your care will be led by radiation oncologists, doctors who specialize in radiation therapy for cancer. Our specialists are dedicated to providing the safest, most effective radiation treatment and care. They are also well-known researchers who develop new treatments and train radiation oncologists around the world.

Top minds together: Our experts meet regularly to discuss each patient, so you benefit from the entire team’s expertise. Your care team also includes:

  • Medical physicists to safely plan treatment. 
  • Certified dosimetrists to calculate your ideal dose. 
  • Radiation therapists, cancer nurses and technicians.  

Advanced technology: Our sophisticated imaging systems allow us to precisely match radiation to the shape and location of your tumor. 

Comprehensive care: At your first visit, our team will spend up to two hours going over treatment options and side effects. Your next visit involves detailed planning to find the best way to send radiation to your tumor. Once you start treatment, you will see your radiation oncologist once a week to monitor your progress. 

National recognitionWe’ve earned the National Cancer Institute’s top designation for leadership in research. We’re consistently ranked among the best cancer hospitals in the nation by U.S. News & World Report, which also gives us top rating for advanced technology.

Sudershan Anand, Ph.D., is one of hundreds of OHSU cancer scientists.
Sudarshan Anand, Ph.D., is one of hundreds of OHSU cancer scientists. He hopes his research leads to a way to detect whether a patient’s cancer will respond to radiation therapy.

Commitment to research: The Knight Cancer Institute, as part of Oregon’s only academic health center, is dedicated to finding better ways to treat cancer. We translate our findings into patient care as quickly as possible.

Innovative techniques: Our team has the knowledge and expertise to tailor treatment to your needs. For prostate cancer treatment, we use Calypso technology, also called GPS for the body, to adjust radiation in real time based on the prostate’s position. For lung, liver and pancreatic cancer treatment, we offer stereotactic radiation therapy. This delivers a high dose of radiation over fewer treatments.

Support services: When you seek care from the Knight Cancer Institute you benefit from the full menu of OHSU resources, including: 

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.


Parking is free for patients and their visitors.

Marquam Hill
Kohler Pavilion, fourth floor
808 S.W. Campus Drive
Portland, OR 97239
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OHSU Beaverton
15700 S.W. Greystone Court
Beaverton, OR 97006
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