Emory University School of Medicine's Department of Radiation Oncology has become the first health care facility in the U.S. to deliver new ultra-precise radiotherapy treatments using a fully robotic on-board imaging system for tracking tumor locations and positioning patients. Emory clinicians report that they have treated seven patients with image-guided radiation therapy (IGRT) using a newly developed On-Board Imager and Clinac linear accelerator from Varian Medical Systems.
The new Dynamic TargetingTM IGRT technology is expected to improve the precision and effectiveness of cancer treatments by giving doctors the ability to accurately track and adjust for tumor movements at the moment of treatment.
Emory clinicians treated the seven patients, four with brain or "CNS" (central nervous system) tumors and three with head and neck tumors, using the new device for the first time last week. Patients ranged in age from 29 to 63.
"The On-Board imager enables us to really take advantage of the precision of radiation therapy techniques like IMRT," said Dr. Lawrence Davis, chairman of the Department of Radiation Oncology at Emory. "With full confidence in our patient set-ups, we'll be able to start creating treatment plans with smaller margins around tumor volumes. That, in turn, will enable us to deliver higher doses to the tumor while reducing the dose to nearby critical structures, which can only translate into better tumor control and fewer complications."
"The use of the On-Board Imager allows for an efficient and accurate daily treatment setup based on actual tumor locations," said Dr. Timothy Fox, chief medical physicist in the Department of Radiation Oncology at Emory. "The entire process takes just three to five minutes, making it a clinically practical solution for improving patient care."
Fox added, "This is a new, integrated technology that performs as a fully automated patient positioning system for more accurate tumor targeting based on our image-guided treatment planning. Using Varian's On-Board Imager, the system generates images of the patient in the treatment position. The software then calculates how much the treatment table needs to move to align the tumor with the beam, and with the push of a button, we shift the patient into the correct position."
Varian's On-Board Imager is a digital imaging system mounted on the treatment machine via robotically controlled arms that operate along three axes of motion so that they can be positioned optimally for the best possible view of the tumor and surrounding anatomy. The device produces high-resolution images of the tumor, and it can also track tumor motion to provide doctors with a clear indication of exactly how a tumor will move during treatment due to normal breathing and other physiological processes.
Prior to the advent of IGRT tools like the On-Board Imager, radiation oncologists have had to contend with variations in patient positioning and with respiratory motion by treating a margin of healthy tissue around the tumor. IGRT is expected to enable doctors to minimize the volume of healthy tissue exposed to the treatment beam.
"This is another major milestone in radiation therapy, in keeping with our mission of putting powerful, cost-effective tools for image-guided radiation therapy into clinicians' hands," said Richard M. Levy, Chairman and CEO of Varian Medical Systems. "It is extremely gratifying to see Emory using this technology to benefit cancer patients."