September 17, 2014 — ViewRay announced the world’s first on-table adaptive radiation treatment program using the MRIdian system began at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine in St. Louis. The MRIdian system provides a patented combination of continuous magnetic resonance imaging (MRI) and simultaneous radiation therapy delivery for the treatment of cancer.
Siteman Cancer Center was the first in the world to offer MRI-guided radiation therapy using the MRIdian system, with the first patients treated in January 2014. Since then, the Siteman team of physicians and physicists has treated more than 20 different regions of the body using MRIdian’s intensity-modulated radiation therapy (IMRT), stereotactic body radiation therapy (SBRT) and 3-D conformal techniques. The team is now also the first in the world to utilize the adaptive capabilities of the MRIdian in an ongoing clinical service, enabling greater accuracy in treatment delivery and more personalized patient care.
“Medicine is moving towards personalized care, and we’re proud to have pioneered the most customized approach to radiation delivery available,” said Chris A. Raanes, ViewRay president and CEO. “The MRIdian system was designed to meet the demands of adaptive treatment planning and delivery, from its integrated MR imaging and high-contrast soft tissue images, to its ultra-fast Monte Carlo dose calculation algorithms. It’s gratifying to see the system enable a unique clinical service that benefits patients.”
The core technologies behind MRIdian’s adaptive capabilities are its MR imaging, soft tissue tracking and real-time treatment planning. These allow clinicians to truly adapt the treatment plan every day to the patients’ internal changes. Utilizing MRI not only improves soft tissue visualization, it eliminates X-ray exposure that is inherent in computed tomography (CT) scans.
“Based on what one sees on MRI, we can now evaluate the change in anatomy or change in dose distribution and then decide if the current plan is sufficient or if an adjustment is necessary,” said Jeffrey Olsen, M.D., radiation oncologist at Siteman Cancer Center and Washington University School of Medicine. “The component of re-planning or on-table adaptive planning is new in radiation therapy.”
MRIdian systems have been acquired by several leading cancer centers worldwide, including the Sylvester Comprehensive Cancer Center at University of Miami, the UCLA Jonsson Comprehensive Cancer Center and the University of Wisconsin Carbone Cancer Center.
For more information: www.viewray.com
March 09, 2026 
