Radiation Oncology MRI-Guided Radiotherapy Opens Window to See Tumors in Real Time STORY HIGHLIGHTS UCLA is the only center in the western United States to offer new technology that allows radiation oncologists to see and accurately target cancerous tumors, while making immediate adjustments to treatment delivery in real time. The new technology, approved for clinical use by the FDA in 2012, combines MRI with radiation therapy. As home to the first MRI-guided radiotherapy system in the western United States — and one of only three locations in the world — UCLA physicians in the Department of Radiation Oncology have an unparalleled ability to see and accurately target cancerous tumors, while making immediate adjustments to treatment delivery in real time. This technological advance addresses a long-standing challenge for radiation oncologists, enabling them to see the targeted tumor and the surrounding healthy tissue during treatment and to ensure that the radiation beam stays within desired margins as tumors or organs move. Prior to this advance, imaging could only take place before or after the treatment. This meant that treatment plans were often based on images that had been captured minutes, days or even weeks beforehand; during treatment, when the beam was on, clinicians could not see exactly where the therapy target was located inside a patient’s body. Numerous studies showed that soft-tissue motion can shift the positions of the tumor and nearby organs, creating the possibility that the beam would miss the tumor’s edges or unnecessarily irradiate healthy tissue. UCLAHEALTH.ORG 1-800-UCLA-888 (1-800-825-2888) Known as ViewRay, this new technology combines continuous magnetic resonance imaging (MRI) with radiation therapy for cancer patients. It was approved by the U.S. Food and Drug Administration in 2012 for clinical use. “The ability to image in real time with high-quality MRI during therapy is new and a game-changer in all aspects,” says radiation oncologist Percy Lee, MD. MRI is the preferred method for imaging soft tissue because it can produce a clearer, more detailed view of internal organs than computed tomography (CT) without the radiation exposure associated with CT. In areas of the body such as the abdomen, pelvis and breast, MRI allows physicians to more easily differentiate a tumor from healthy tissue, and it is especially useful for mobile tumors, which often change position in unpredictable ways, Dr. Lee explains. The clearer visualization potentially allows for more precise therapy. During treatment, the technology’s integrated MRI-guided radiotherapy system captures a steady stream of soft-tissue images and, in real time, compares them to the planned treatment