• 5/25/2005
  • Liverpool, England
  • press release
  • PR Newswire (www.prnewswire.com)

Clinicians at the Clatterbridge Oncology Center, near Liverpool, today announced that they have commenced delivering a new and more precise form of radiotherapy called image-guided radiation therapy (IGRT) using a new robotic imaging device from Varian Medical Systems.

A 75-year-old female cancer patient became the first person to be treated in the UK with an On Board Imager(TM) device, a new accessory that is designed to improve the precision and effectiveness of cancer treatments by giving doctors the ability to track and adjust for changes in tumor positions more accurately at the moment of treatment. Up to now, doctors have had to account for tumor motion by using broader beams that expose a significant margin of
healthy tissue in the treatment area. The On Board Imager at Clatterbridge is the first of seven such systems scheduled for delivery to UK hospitals in the coming year.

Dr. Philip Mayles, head of medical physics at Clatterbridge Oncology
Center, said, “We only have one chance to cure a tumor and giving it as big a dose as we can, while treating as little of the normal tissue as possible, is obviously the best thing we can do for the patient. Bigger treatment margins really compromise what you can do for the patient but the On-Board Imager will enable even more accurate radiotherapy delivery with much smaller margins.”

The fully automated Varian system makes it possible for clinical staff to complete the advanced IGRT treatments within the normal patient schedule. Radiographer Angela Heaton adds, “The biggest radiographer issue is to improve the quality of the patient’s treatment while maintaining the quantity. By using all the On-Board Imager’s automatic tools we can reap the considerable benefits of IGRT without impacting on treatment times, and thereby waiting
lists.”

Using the On-Board Imager, doctors can generate X-ray images of the
patient’s tumor and compare them with CT scans and DRR (digitally
reconstructed radiograph) images from the treatment plan to ensure that the patient’s tumor is exactly aligned with the beam immediately prior to treatment. This enables radiographers to verify the tumor location while the patient is in the treatment position, and automatically move the treatment couch to the correct position before delivering the daily treatment.

Clinicians at Clatterbridge intend to use the On-Board Imager during the treatment of approximately 20 prostate and head and neck cancer patients per day, although this number will increase as staff become more familiar with the device’s capabilities. They plan eventually to use the device to position patients for all IMRT (intensity modulated radiation therapy) treatments. They will also begin using Varian’s technology for respiratory gating, which involves monitoring the breathing patterns of patients with cancer of the lung
or breast and delivering the radiation beam in bursts timed to correspond exactly with the desired phase of the respiratory cycle, when the tumor is in the correct position.

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 area to be treated. 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 robotically-controlled On-Board Imager and control software to image and position the patient, doctors are treating cancer with the best of two critical technologies for Dynamic Targeting(TM) IGRT,” said Dow Wilson, 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.”