New Technology Provides Faster, More Precise Radiotherapy Treatment

Using VMAT, clinicians were able to deliver a single treatment to their 72-year-old patient in less than two minutes.

The VMAT treatment, developed by Varian Medical Systems, Inc. (Palo Alto, CA, USA), is an advanced form of intensity modulated radiation therapy (IMRT), which has the potential to significantly improve treatment precision by sparing more healthy tissue in addition to making treatments much faster and more comfortable for patients. It was made possible by software innovations developed by BC Cancer Agency clinicians together with an advanced medical linear accelerator and beam-shaping accessory from Varian.

Karl Otto, Ph.D., a medical physicist at the BC Cancer Agency, developed a special software algorithm that made it possible for his clinic to deliver the VMAT treatment. "The algorithm is designed to generate highly conformal dose distributions while taking advantage of the specific capabilities of the Varian linear accelerator,” he said.

Building on Dr. Otto's work, Varian engineers have developed Varian's new RapidArc radiotherapy technology, which was exhibited for the first time at the American Society for Therapeutic Radiology and Oncology (ASTRO) in Los Angeles, CA, USA, in November 2007. Varian's RapidArc product for VMAT can provide intensity-modulated radiotherapy treatments two to eight times faster than was previously possible. It is currently pending U.S. Food and Drug Administration (FDA) 510(k) clearance and not yet available for sale in the United States.

"VMAT creates a precisely sculpted 3D [three-dimensional] dose distribution by tailoring the shape and intensity of the beam from a full 360º around the patient,” explained Dr. Otto. "It provides more flexibility in maximizing the dose of radiation targeting the tumor while minimizing damage to surrounding healthy tissue.”

Unlike more traditional treatment techniques where machines must rotate several times around the patient or make repeated intermittent stops and starts to treat individual fields from a number of different beam angles, VMAT technology makes it possible to deliver the dose to the entire tumor volume in a single rotation around the patient.

"This is certainly the next generation of radiation therapy delivery,” noted Dr. Ivo Olivotto, acting provincial radiation therapy program leader, BC Cancer Agency. "Besides the benefits to patients, what's really exciting about VMAT is that it maximizes the capabilities of our current technology.”

"These developments will make it possible for clinicians to deliver the most advanced and precise forms of radiation therapy like IMRT in a small fraction of the time it now takes,” said Dow Wilson, president of Varian's Oncology Systems business. "We have translated the BC Cancer Agency research into a product that can impact the quality of care around the world while reducing cancer patient waiting lists and making radiation therapy more affordable.”


Related Links:
BC Cancer Agency
Varian Medical Systems