For the first time, cancer patients in New England will have a cutting-edge option for radiation treatment of soft-tissue tumors. The new MR-Guided Radiation Therapy (MR-RT) treatment at Dana-Farber/Brigham and Women’s Cancer Center (DF/BWCC), launching this summer, will give physicians real-time, pinpoint accuracy for radiation planning and treatment.
Under the current standard of care, physicians use CT imaging to determine a tumor’s location and target it for subsequent radiation therapy. Depending on the tumor’s type and location, it can be difficult to accurately visualize the tumor, and the therapy planning process can take a week to complete. Moreover, variations in patient positioning or changes in the tumor’s size or position over time limit the ability of CT imaging to provide real-time guidance.
“MR-guided radiation therapy will likely make CT-based radiation planning and treatment obsolete for many cancer types within the next few years,” said Raymond H. Mak, MD, a thoracic radiation oncologist in DF/BWCC’s Radiation Oncology Department and the MR-RT lead. “As the first health system in New England, and one of the first in the country, to offer this cutting-edge therapy, DF/BWCC is revolutionizing the way radiation treatment is delivered. Our patients deserve access to the best, most advanced care.”
The new MR-Guided Radiation Therapy has two components: a wide-bore (70 cm) 3 Tesla MRI scanner modified for radiation therapy planning called the MR Advanced Procedure and Simulation (MAPS) unit and an integrated MR-guided linear accelerator (LINAC). The MAPS unit includes a high-field strength (3.0T) magnet for diagnostic quality imaging for initial radiation therapy planning. The MR-LINAC, meanwhile, is a state-of-the-art hybrid device that integrates a modified, lower-field (0.35T) MR scanner with a linear accelerator (radiation delivery machine) to reduce the magnetic interference on the radiation beam.
“Tumor resolution is vastly improved with MR imaging,” said Dr. Mak. “With MAPS, not only does MR imaging aid in the planning process, it also lets patients be immobilized and imaged in the treatment position, allowing us to target tumors and identify normal tissues more accurately and precisely, which will allow us to deliver higher doses of radiation to tumors while sparing normal healthy tissue.”
According to Dr. Mak, physicians at DF/BWCC will use the new MR-guided LINAC to see and track tumors in real time during treatment. The integrated MR technology will allow clinicians to adapt the radiation therapy to changes in the patient’s body and deliver radiation only when the tumor is in the proper position. This accuracy will help to reduce radiation toxicities and improve patient outcomes.
In addition, the MAPS unit will be part of a state-of-the-art procedure suite for brachytherapy: MR-guided implantation of radioactive sources.
“To put it simply, MR-guided therapy on this new MR-LINAC lets us adapt daily treatments to what we currently see instead of what we previously saw,” he said. “Plus, adaptive treatment plans that are personalized to the real-time location of the patient’s tumor and organs can be developed in an hour with the patient in the treatment room instead of taking a week.”
The new MR-guided radiation therapy will be used to treat many different cancer types with the greatest potential advantage for soft-tissue tumors — including breast, gastrointestinal, gynecological, sarcoma, prostate, and head and neck tumors — and for tumors that are highly mobile, such as lung cancers.