For Dr. Silvia Formenti, the most exciting aspect of the NewYork-Presbyterian David H. Koch Center is a linear accelerator with integrated magnetic resonance imaging (MRI), the MRIdian by ViewRay.
MRI enables the most precise targeting of radiation by accurately tracking the position and shape of a patient’s tumor. When internal organs move in response to respiratory and heart movement, this machine directs the treatment to precisely respond to the tumor’s change in position. The result is smaller and more precise fields of radiation, which spare the adjacent normal tissue. Best of all for patients, treatment courses can be shorter and more accurate.
The first on the East Coast, this state-of-the-art machine delivers “the classical photon radiotherapy, but in the context of MRI imaging,” says Dr. Formenti, the Sandra and Edward Meyer Chair for Cancer Research, professor and chairman of radiation oncology, and radiation oncologist in chief of NewYork-Presbyterian/Weill Cornell Medical Center, and a member of the NYP David H. Koch Center planning committee.
“The magnetic resonance imaging enables much more precision in defining the organs within the body, and with much more clarity. Also, [it offers] some functional information that you wouldn’t get with a normal CT scan and normal radiation machine. These unique characteristics enable the safe delivery of larger and more precisely targeted doses of radiation, reducing the number of visits needed to ablate a cancer.”
About two-thirds of cancer patients receiving treatment undergo a form of radiation therapy. But during a typical session, the patient’s tumors and internal organs move as a result of breathing or heartbeat. That means that although a radiologist positions the patient correctly at the start and end of the session, the radiation beam may not target the tumor as precisely as expected throughout the treatment.
“With the standard available technology, we can confirm the patient is in the correct position and verify that the organ and tumor are in the correct position before or after radiation — but not in real time,” says Dr. Formenti. The new linear accelerator improves upon this by relying on MR imaging to inform delivery of the dose only when the tumor is exactly in the position to be targeted by the radiation beam. Thus, the healthy tissues surrounding the tumor are largely spared.