“The challenge in radiotherapy has always been how to treat these moving targets very accurately without causing a lot of collateral damage,” said Billy Loo, MD, PhD, associate professor, thoracic radiation oncology program. “Advances in image guidance and motion management technologies, coupled with state-of-the-art equipment, have made radiation more precise.”
“Radiation oncology is a major, curative modality of therapy for a large percentage of cancer patients,” said Quynh-Thu Le, the Katharine Dexter McCormick & Stanley McCormick Memorial Professor, and Chair, Department of Radiation Oncology. “New technologies allow us to visualize the tumor more clearly and deliver radiation more precisely, so we can treat patients in a faster and much more targeted approach.”
One such innovation developed at Stanford is a video biofeedback system that controls patient movement by helping patients hold their breath to freeze their tumor in a specific position while radiation is delivered. Patients see a visual representation of their breathing on a screen, and focus on hitting a target when asked to hold their breath. This motion management technique stabilizes the position of their body and their tumor, making treatment more reproducible. This predictability allows doctors to deliver higher, curative doses of radiation directly to the targeted area, with minimal collateral damage to surrounding areas caused by movement.
“The system shortens treatment times because we can keep the beam turned on for more of the time and deliver the dose faster and more precisely,” said Loo.
The same video display used for biofeedback in adults was modified to become a movie screen for kids undergoing radiation therapy. The Audio-Visual Assisted Therapeutic Ambience in Radiotherapy (AVATAR) system uses a paper screen and a wireless projector, so kids can watch their favorite movie and relax during treatment, without the need for anesthesia. In the first six months of using the AVATAR system, more than 450 anesthesia administrations were avoided, reducing the potential risks, side effects and costs associated with daily anesthesia.
“We believe the treatment experience matters, especially for our youngest patients,” said Le. “We are committed to making advances in this important area.”
Another motion management method used at Stanford is respiratory gating. Doctors first monitor a patient’s natural breathing pattern, and then program the gating equipment to only turn on the radiation beam when the tumor is in the right position as the patient is breathing. Stanford has refined this approach by using image guidance during treatment to ensure that the beam is turning on at precisely the right time.
“The ability to deliver higher, curative doses of radiation to precise targets has been a game changer,” said Loo. Stanford radiation oncologists are now redefining the role of radiotherapy for tumors in the lungs, liver and pancreas, tumors that were once only treatable with surgery.
“Now we have treatments that work with comparable effectiveness to surgery that create a new treatment option for patients who cannot undergo surgery,” said Daniel Chang, MD, professor, radiation oncology.