Published Study Highlights MRIdian System’s Value in Sparing Healthy Tissue from Radiation

Use in Accelerated Partial Breast Irradiation Enables Margin Reduction
and Demonstrates Early Positive Cosmesis Results


CLEVELAND, November 30, 2016 — ViewRay, Inc. (Nasdaq: VRAY), makers of the world’s first and only clinical MRI-guided radiation therapy system,announced today the results of a study published in the November 2016 issue of the International Journal of Radiation Oncology, Biology, Physics (the official journal of the American Society for Radiation Oncology), highlighting the value of the MRIdian system in delivering accelerated partial breast irradiation (APBI). The study, conducted by researchers from Washington University School of Medicine in St. Louis, Mo., demonstrated the ability to reduce planning target volumes (PTV) using MRIdian, thereby dramatically reducing the amount of healthy tissue exposed to radiation.


The study evaluated thirty women with breast cancer (stages 0-I) who had previously undergone

breast-conserving surgery. The women received APBI using the MRIdian system. The goal of the study was to determine intrafractional motion of the breast surgical cavity and assess delivered dose versus planned dose.

Results of the study indicate that there is minimal intrafractional motion and good agreement between delivered and planned dose (a mean difference of less than 1 percent). Given the clinicians’ confidence in the MRIdian system’s real-time tracking and MR-guidance, no additional margin was added for the PTV, thereby reducing the PTV by 52 percent, compared with a 1-cm PTV margin that is used conventionally.

“In addition to the exciting findings published in our recent study, we’re also seeing extremely promising cosmesis results,” said Maria Thomas, M.D., Ph.D., Assistant Professor of Radiation Oncology at Washington University. “To date, 100 percent of the patients treated with APBI using MRIdian have good to excellent cosmetic outcomes.”

Approximately 100 patients have been treated with this approach by Dr. Thomas and Dr. Imran Zoberi at Washington University to date.

Dr. Thomas discussed these results and her center’s clinical experience with MRIdian during the recent American Society for Radiation Oncology 2016 Annual Meeting. A video of her presentation is available at

About ViewRay

ViewRay®, Inc. (Nasdaq: VRAY), designs, manufactures and markets the MRIdian® radiation therapy system. MRIdian integrates MRI technology, radiation delivery and proprietary software to locate, target and track the position and shape of soft-tissue tumors during radiation. ViewRay believes this combination of enhanced visualization and accuracy will significantly improve outcomes for patients.

ViewRay and MRIdian are registered trademarks of ViewRay, Inc.

This press release contains forward-looking statements. Statements in this press release that are not purely historical are forward-looking statements. Such forward-looking statements include, among other things, references to the benefits of the MRIdian system and clinical studies by certain MRIdian users. Actual results could differ from those projected in any forward-looking statements due to numerous factors. Such factors include, among others, the ability to raise the additional funding needed to continue to pursue ViewRay’s business and product development plans, the inherent uncertainties associated with developing new products or technologies, competition in the industry in which ViewRay operates and overall market conditions. These forward-looking statements are made as of the date of this press release, and ViewRay assumes no obligation to update the forward-looking statements, or to update the reasons why actual results could differ from those projected in the forward-looking statements, except as required by law. Investors should consult all of the information set forth herein and should also refer to the risk factor disclosure set forth in the reports and other documents ViewRay files with the SEC available at