Groundbreaking Therapy Opens Window To See Cancerous Tumors In Motion
Posted Thursday, Nov. 14, 2014 – 8 p.m.
With the first MRI-guided radiotherapy system in the western U.S.— and one of only three locations in the world — UCLA radiation oncologists have an unparalleled ability to see and accurately target cancerous tumors, while making real-time adjustments to treatment delivery.
This technological advancement addresses a longstanding challenge for radiation oncologists, enabling them to see the targeted tumor and the surrounding healthy tissue during treatment and ensure that the radiation beam stays within desired margins as tumors and organs move.
Known as ViewRay, the technology incorporates magnetic resonance imaging (MRI) for pre-treatment imaging as well as continuous imaging during 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 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, ViewRay captures a steady stream of soft-tissue images and, in real time, compares them to the planned treatment margins. If the tumor strays outside prescribed margins, the machine can turn the beam off until the tumor returns to its prescribed location. Patients with such cancers as prostate, bladder and pancreas, as well as cancers of the head and neck and central nervous system, are expected to benefit from this non-stop MRI imaging.
Radiation oncologists traditionally design treatment plans based on images taken days or weeks before the treatment date. If doctors suspect tumor movement from weight loss or other reasons, redesigning a plan can take days. Using ViewRay, UCLA radiation oncologists can adapt radiation on the fly by creating a customized plan of the day for each patient. In doing so, radiation that otherwise would have hit healthy tissue is redirected to hone in on malignant tissue, increasing the probability of exact delivery and improving outcomes.
MRI-guided radiation therapy expands the personalized treatment options available at UCLA and supports all available advanced and traditional radiation-delivery techniques, including image-guided radiation therapy, intensity-modulated radiation therapy (IMRT), stereotactic radiosurgery, stereotactic body radiation therapy (SBRT), and 3D conformal therapy.
“We are excited to learn how real-time MRI-guided radiation can change the paradigm of how radiation therapy is delivered, with an eye toward benefiting our patients,” says Dr. Lee.