Intraoperative radiation therapy (IORT) is a radiation treatment that's done during surgery.

IORT directs radiation to the target area while affecting the surrounding tissue as little as possible. IORT is used to treat cancers that are difficult to remove during surgery. And it's used when there's a concern that tiny amounts of unseen cancer might remain.

Intraoperative electron radiation therapy is the type of IORT most often used at Mayo Clinic. IORT is often combined with standard radiation therapy. Standard radiation therapy is usually done before surgery.

IORT delivers higher doses of radiation than does standard radiation therapy. It's not always possible to use such high doses during standard radiation therapy because of the possibility of radiation affecting nearby organs. IORT helps keep radiation away from nearby organs.

Intraoperative radiation therapy (IORT) care at Mayo Clinic

April 16, 2024
  1. Tepper JE, et al., eds. Intraoperative radiation. In: Gunderson & Tepper's Clinical Radiation Oncology. 5th ed. Elsevier; 2021. https://www.clinicalkey.com. Accessed Nov. 16, 2022.
  2. Jethwa KR, et al. The use of intraoperative radiation therapy in the management of locally recurrent rectal cancer. Seminars in Colon and Rectal Surgery. 2020; doi:10.1016/j.scrs.2020.100763.
  3. Mitin T. Radiation therapy techniques in cancer treatment. https://www.uptodate.com/contents/search. Accessed Dec. 1, 2022.
  4. Jethwa KR (expert opinion). Mayo Clinic. Dec. 16, 2022.

Intraoperative radiation therapy (IORT)