1,000th Patient Treated at Siteman with AI-Enabled Radiation Therapy System

Combining artificial intelligence (AI) with advanced imaging, the technology supports more precise, personalized daily treatments by WashU Medicine physicians

Siteman Cancer Center at Barnes-Jewish Hospital and WashU Medicine has treated its 1,000th patient using state-of-the art radiation therapy technology that allows physicians to update a patient’s treatment plan on each day of treatment.

Called adaptive technology, the system incorporates slight changes in tumor shape, size and location, as well as the movement of surrounding healthy organs and tissue, to adjust a patient’s daily radiation therapy treatment plan for the best possible outcome.

The system is used to treat a range of tumors, including head and neck, central nervous system, thoracic, abdominal and pelvic cancers.

“We are pleased to offer this advanced technology to our patients — from the first person we treated with this system in 2020, to the 1,000th person in August 2025,” said WashU Medicine radiation oncologist Hyun Kim, MD, associate professor of radiation oncology and chief of Adaptive Radiation Therapy at WashU Medicine and Siteman.

“The milestone of 1,000 patients treated on this platform is literally the result of thousands of hours dedicated by our faculty and staff to personalize treatment every day for every patient,” he said.

Also known as online adaptive radiation therapy, it requires a team of expert physicians, physicists and radiation therapists to develop and review a treatment plan after the patient’s arrival — all within minutes after the patient is positioned to receive treatment.

In addition to the AI component and machine learning, the platform is equipped with cone-beam computed tomography (CT). Cone-beam CT quickly provides high-quality images and leads to better visualization of the tumors and surrounding healthy organs and tissue, allowing the physician to develop even more accurate, personalized treatment plans than with some older radiotherapy platforms.

In clinical trials incorporating the new technology, patients experienced decreased times to treatment and, in some cases, improved cancer control with less damage to surrounding healthy organs and tissue.

For some gynecologic cancers, treatment can involve imaging the ovaries of pre-menopausal patients. As a result, some patients have experienced premature ovarian failure and early menopause when treated with older radiotherapy technologies. WashU Medicine physician-scientists are conducting an ongoing clinical trial using the new technology with the hope that they can spare these organs.

Known as Ethos, the platform is manufactured by Varian Medical Systems, which also makes the cone-beam CT imaging component, called HyperSight.