Internal Radiation Therapy at the Knight Cancer Institute

We offer you expertise in all types of internal beam radiation therapy. You’ll find:

  • The latest techniques to safely attack cancer cells while avoiding healthy tissue. 
  • Advanced technology to deliver internal radiation more quickly and with fewer side effects. 
  • Radiation experts who work with the rest of your cancer team to give you the best possible care. 
  • A brachytherapy program that attracts patients from all over Oregon. 
  • The first center in the U.S. to use a hybrid Geneva applicator.

What is internal radiation therapy?

Internal radiation therapy places a source of radioactive material in or near a tumor. It allows your cancer team to safely and effectively deliver a higher dose than with external beam radiation therapy. It can be permanent or temporary depending on your diagnosis and needs.

Your team may consider several kinds of internal radiation therapy. They will recommend the one that’s best for you based on your overall health and the type and stage of your cancer.

Five members of OHSU's Radiation team (four women and one man) stand smiling on a balcony with Portland's South Waterfront and Mt. Hood visible behind them.
Our radiation therapy specialists treat patients from all over Oregon. They include (from left): Amy Hamala, RTT; Anja Goerke, RN; Richard Crilly, Ph.D.; Jenna Kahn, M.D.; and Colleen Webb, RN.


What is brachytherapy? In brachytherapy, tiny radioactive implants in the shape of seeds, capsules or pellets are placed in the tumor (interstitial brachytherapy) or nearby (intracavity brachytherapy).

Treatment can be temporary, with your doctor removing the implants after treatment. Or it can be permanent, with the material staying in place. This is safe because the implants produce less radiation as time passes. Low-level radiation will not harm people around you.

Benefits over external radiation therapy alone:

  • Brachytherapy may be used as the primary treatment for some cancers. It might also be used along with other treatments, including external radiation therapy. Studies have shown that brachytherapy can increase survival rates.
  • Brachytherapy allows for much higher doses in the tumor or at the site of the tumor, with minimal radiation to healthy organs.
  • One study of cervical cancer patients showed that those who received brachytherapy had 10-year survival rates that were 25 percentage points above those who did not.

Types of brachytherapy:

  • Intracavity: Doctors place the radioactive implants in a body cavity near the tumor. They might be inside the vagina, for example, to treat cervical or uterine cancer. Our experts use special applicators with narrow tubes to place implants near the tumor. We often use this type of brachytherapy for smaller tumors.
  • Interstitial: Doctors use a special applicator to place the radioactive implants in the tumor itself. The applicator includes long, hollow needles that let us place the implants in more of the tumor. We often use this type of brachytherapy for larger tumors.
  • Hybrid: We have devices that are a combination of intracavity and interstitial. For example, we can place a device in a body cavity, and needles on the device can be inserted into the tumor. OHSU was the first center in the U.S. to use the hybrid Geneva applicator. We use it especially for cervical cancers.
  • MRI-guided brachytherapy: OHSU is the only center in Oregon with brachytherapy guided by MRI (magnetic resonance imaging). This precise imaging helps doctors see the tumor's exact location. We use the imaging both to plan and perform the procedure.

How is brachytherapy delivered?

  • High-dose rate (HDR): This treatment is temporary and given in repeat sessions. Because it uses powerful radiation, it usually takes less time than LDR brachytherapy. Your doctor may use thin flexible tubes called catheters to precisely place the implants. Or the implants can be placed with needles or a hybrid device. The implants are removed after a few minutes. You may have one or two HDR sessions in one day, or several in a week. This method is becoming the most common choice for many cancers. 
  • Low-dose rate (LDR): This treatment can be temporary or permanent. If temporary, it may take just a few minutes, or it can last several hours or days. You will stay in a room designed for the procedure. Your care team will limit exposure to others. If LDR treatment is permanent, the implants may be placed in your body during surgery. You may stay in the hospital overnight or for a few days to recover. The implants slowly release radiation over a few weeks or months. Eventually, almost all the radiation stops.

What cancers is it used for?

  • Breast cancer
  • Cervical cancer 
  • Endometrial cancer (the most common type of uterine cancer)
  • Eye cancer 
  • Head and neck cancer 
  • Sarcoma
  • Some skin cancers
  • Vaginal cancer 

Selective internal radiation therapy (SIRT)

What is it? Also called radioembolization, this therapy targets liver tumors by sending radioactive beads through your blood vessels directly to the cancer. It is used to treat tumors that can’t be removed through surgery.

How is it delivered? Most of the blood supplied to liver tumors comes from a blood vessel called the hepatic artery. Your doctor inserts a thin, flexible tube called a catheter into the artery, then uses it to send radioactive beads to the tumor. Because the beads emit radiation only over a short distance, they affect just the tumor, avoiding damage to the liver and other tissue.

What cancer is it used for?

  • Liver cancer 

Systemic radiation therapy

What is it? Systemic radiation uses medications with radioactive materials to distribute radiation to your whole body. These radiopharmaceuticals travel through your bloodstream and attach themselves to cancer cells. They give off small amounts of radiation that kills the cancer. In some cases, they may be given along with external radiation therapy.

How is it delivered? Radiopharmaceuticals can be taken in pill or liquid form. They also might be given in an IV. Some radioactive material will remain in your system during treatment, so you may stay in a special hospital room for a day or two to protect others from exposure. Everyone’s bodies eliminate radiation at different rates. Your doctor can help you take steps to protect friends and family in the days after you go home.

What cancers is it used for?  

  • Thyroid cancer 
  • Bone cancers 
  • Prostate cancer 
  • Non-Hodgkin lymphoma 

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.

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