Clinical Experts Detail How They Use Technologies From Varian Medical Systems To Improve The Precision And Speed Of Cancer Treatment

Main Category: Cancer / Oncology
Also Included In: Radiology / Nuclear Medicine
Article Date: 02 Nov 2007 - 14:00 PDT

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Two noted cancer treatment specialists reported yesterday about how they are using technologies from Varian Medical Systems (NYSE: VAR) to target tumors more accurately and to speed up delivery of ultra-precise intensity-modulated radiotherapy (IMRT) treatments. An expert from the BC Cancer Agency in British Columbia presented an approach to volumetric arc radiotherapy, which makes it possible to deliver an IMRT treatment up to eight times faster than is possible with conventional treatment approaches. And an expert from Stanford University discussed novel image-guided motion management techniques for accurately treating lung cancer and other tumors that move during treatment as the patient breathes. The presentations were part of an "Emerging Technologies Symposium" sponsored by Varian in connection with the annual meeting here of the American Society for Therapeutic Radiology and Oncology (ASTRO).

Using Volumetric Modulated Arc Therapy at the BC Cancer Agency

W. James Morris, MD, associate professor at the University of British Columbia and radiation oncologist with the BC Cancer Agency, presented an approach to volumetric arc therapy (VMAT) that has been developed and used at his agency to deliver an ultra-precise IMRT treatment for prostate cancer in less than two minutes. This type of treatment normally would take at least ten minutes to deliver. A VMAT treatment is faster because it delivers a full dose to the entire targeted tumor volume with just a single rotation of the treatment machine around the patient.

"The treatments are delivered with high levels of dosimetric accuracy," Morris said. "The dose distributions with VMAT are equal or better to the ones you can get using conventional IMRT delivery techniques, and much faster to deliver."

Motion Management in the Thorax

Billy W. Loo, Jr., M.D., Ph.D. of Stanford University, Palo Alto, California, described how his team uses 4D CT scans, which are images that correspond with particular phases of the patient's respiratory cycle, to create a respiratory gating strategy for triggering the treatment beam on and off in timed bursts that are synchronized with the patient's breathing. Prior to each treatment, Loo's team verifies that the programmed respiratory gating strategy is still valid by studying fluoroscopic (moving) and cone-beam CT (volumetric) images of the targeted area and surrounding anatomy, generated using Varian's On-Board Imager® device.

"Near-real-time image guidance tools are the wave of the future, because they will enable us to be much more accurate in how we address motion and reduce treatment margins to spare more healthy tissue," Loo said.

Varian's RapidArc™ Radiotherapy Technology

Varian CEO Tim Guertin introduced Varian's new RapidArc™ radiotherapy*, the company's new VMAT technology that will enable clinicians to deliver highly-conformal treatments much faster than is possible with conventional or helical IMRT (tomotherapy). Guertin said that Varian's goal is "to reduce the amount of time it takes to deliver these treatments -- the best available -- to less than five minutes. Two minutes to set the patient up for treatment, and two to treat -- that's where we're headed," he said. "Faster imaging and faster treatment, with no sacrifice in terms of accuracy or precision, are going to be the cornerstones of effective, affordable cancer care."

*RapidArc is pending FDA 510(k) clearance, and not yet available for sale in the U.S.

About Varian Medical Systems

Varian Medical Systems, Inc., of Palo Alto, California, is the world's leading manufacturer of medical devices and software for treating cancer and other medical conditions with radiotherapy, radiosurgery, proton therapy, and brachytherapy. The company supplies informatics software for managing comprehensive cancer clinics, radiotherapy centers and medical oncology practices. Varian is a premier supplier of tubes and digital detectors for X-ray imaging in medical, scientific, and industrial applications and also supplies X-ray imaging products for cargo screening and industrial inspection. Varian Medical Systems employs approximately 4,500 people who are located at manufacturing sites in North America and Europe and approximately 60 sales and support offices around the world.

http://www.varian.com/.

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