PALO ALTO, Calif.,June 22, 2004 Varian Medical Systems (NYSE: VAR) has announced the first installation and clinical use of the company’s On-Board Imager ™ system for image-guided radiation therapy (IGRT).The world-famous Karolinska University Hospital in Stockholm, Sweden, has become the first treatment center to use Varian's new imaging accessory, designed to improve the precision and effectiveness of cancer treatments by giving doctors the ability to track and adjust for tumor positions more accurately at the moment of treatment.
A 55-year-old lung cancer patient from Stockholm was the first person to be positioned for treatment using the new On-Board Imager accessory, a digital imaging device that has been mounted on Varian’s Clinac® medical linear accelerator, the machine that delivers radiation therapy treatments.
Professor Ingemar Naslund, head of the radiotherapy unit at Karolinska, said, “The On-Board Imager worked very well and we will be increasing its use as we go forward. The image quality is extremely good and images can be integrated automatically and easily into the treatment process to make it very practical for use in a busy radiotherapy unit.”
Using the On-Board Imager, doctors generated X-ray images of the patient's tumor and compared them with CT scans and DRR (digitally reconstructed radiograph) images to ensure that the patient’s tumor was aligned with the beam according to the treatment plan.This enabled radiotherapists to verify the tumor location within two minutes while the patient was in the treatment position, and automatically make adjustments before delivering his daily treatment.
Head physicist Aris Tilikidis added, “Integration of all the elements for image-guided radiation therapy is essential for this approach. Otherwise, it would take too much time to move information and treatment data back and forth between different systems, and you could never be certain the information was absolutely correct. With this system, everything is integrated seamlessly, and that makes it clinically viable.”
“We congratulate the team at Karolinska for reaching a major milestone in radiation therapy with this treatment,” said Richard M. Levy, Chairman and CEO of Varian Medical Systems.“It is extremely gratifying to see this technology being put to use to benefit patients. It demonstrates that we have been able to create a clinically practical system to treat patients routinely with the world’s most advanced cancer treatments.”
On-Board Imager and IGRT
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. This device produces high-resolution images of the tumor.In addition, it can track tumor motion to provide doctors with a clear indication of exactly how a tumor will move during treatment due to respiration or other normal physiological processes.
“By using our robotic technology and control software to position the On-Board Imager, we give doctors the best of two critical technologies for Dynamic Targeting ™ IGRT,” said Timothy Guertin, president of Varian's Oncology Systems business. “We have combined two important technologies on one platform: low-dose, high resolution, kilovoltage X-ray imaging and integrated software control of all treatment parameters. This enables improved, fast, cost-effective, automated treatments that are conducive to patient comfort.”
Prior to the advent of IGRT, 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.
The new On-Board Imager is available as an option on all Varian’s newly installed high-energy Clinacä linear accelerators and as an upgrade for most digital Clinac accelerators already in place at clinical sites around the world. It is a standard feature on all Trilogy™ linear accelerators.
About Karolinska Institute
The Karolinska University Hospital serves a catchment area of 1.9 million people in Stockholm and the neighboring island of Götland. Almost 4,500 patients receive external beam radiation treatment at Karolinska each year (about 26 per machine per day) and about 240 prostate cancer patients receive brachytherapy per annum followed by external beam radiation. Among the radiotherapy unit’s 100 staff are 20 medical physicists and six full time radiation oncologists.
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