Intraoperative Radiation Therapy (IORT)

Intraoperative Radiation Therapy (IORT) is a procedure designed to deliver a single dose of radiation during surgery. IORT targets the area most at risk for cancer recurrence while protecting healthy tissues and organs around the area of the surgery. The radiation oncologist is present in the operating room and delivers the dose while you are asleep.

The procedure is called intraoperative because radiation is delivered during surgery, directly into the cavity where the tumor has just been removed. Most eligible patients won’t need to undergo any additional radiation therapy at a later date. Northwestern Medicine uses a team* of specialists who customize treatment for every patient, every time.

Benefits of IORT

  • Saves time: The entire therapeutic dose of breast radiation is given immediately at the time of lumpectomy (removal of the tumor) while you are still under anesthesia. This allows you to complete the therapy sooner and return to normal life more quickly.
  • Convenience for you: Traditionally, breast cancer patients would need to undergo radiation therapy for five days a week for up to three to six weeks after they heal from surgery. For most patients who undergo IORT, there are typically no return trips for radiation.
  • Targeted radiation therapy: Radiation is given directly to the tissue of the operative bed where the risk of recurrence is highest.
  • Team approach: The radiation oncologist is in the operating room with the surgeon.
  • Decreased side effects: IORT has been found to decrease side effects such as red rashes and skin irritations when compared to traditional radiation therapy.

Candidates for IORT

Breast cancer patients who would normally undergo a lumpectomy followed by radiation are ideal candidates for IORT. Candidates typically are in the early stages of breast cancer, are over the age of 60, and have small tumors.


During surgery, the tumor is removed with a lumpectomy. After the lumpectomy, your surgeon will do additional testing on the tumor. Depending on those results, your surgeon and radiation oncologist may need to discuss with you the need for additional radiation therapy.

Intraoperative radiation is delivered in a single treatment. A special applicator is used to target the area most at risk. Once the surgeon completes the lumpectomy, the radiation oncologist and surgeon determine what size applicator is best. The applicator is then placed in the area of the lumpectomy. The time it takes to deliver the radiation varies from person to person. Once the radiation is complete, the applicator is removed and the incision is closed.





The IORT procedure

  • Step 1: The surgeon removes the tumor, leaving a cavity where the tumor was located.
  • Step 2: The radiation oncologist places the applicator into the cavity.
  • Step 3: Radiation is given to the surrounding tissue for 20–50 minutes.
  • Step 4: The applicator is removed, and the surgeon closes the incision.

After surgery

Your surgeon will give you instructions about caring for your lumpectomy site while you're at home. 

Locations & Contact Information

    In the spirit of keeping you well-informed, the physician(s) identified are neither agents nor employees of Northwestern Memorial HealthCare or any of its affiliate organizations. They have selected our facilities as places where they want to treat and care for their private patients.