• 10/10/2006
  • Leipzig, Germany
  • press release
  • Yahoo! Finance (biz.yahoo.com)

Leading oncology research establishments today gave examples of how advanced real-time imaging and respiration techniques are benefiting cancer patients through more accurate radiotherapy treatments. Their findings were presented at a symposium hosted by Varian Medical Systems at the annual ESTRO (European Society for Therapeutic Radiology and Oncology) meeting in Leipzig, Germany.

Advances in image-guided radiotherapy (IGRT) and respiratory gating, along with the move towards dynamic adaptive radiotherapy (DART), were presented to an audience of cancer treatment specialists by speakers from Clatterbridge Centre for Oncology in the UK, Aarhus University Hospital and Rigshospitalet Copenhagen in Denmark, and Clinique Sainte Catherine in Avignon, France.

In a session chaired by Professor Cai Grau from Aarhus University Hospital, speakers described a new treatment technique that makes it possible to deliver doses with greater precision using Varian’s On-Board Imager® for IGRT and RPM(TM) gating, a system that synchronizes treatments with the patient’s natural breathing cycle. These advanced treatments are also enabling radiation oncologists to reduce side effects.

Dr. Robin Garcia, of Clinique Sainte Catherine, presented the initial results of his team’s project on the use of IGRT for head and neck cancers. “Image-guided radiotherapy has enabled the possibility of investigating that which has never before been investigated in head and neck radiotherapy,” he said.

He said the need to begin dynamically adapting treatment plans on a daily basis was vital because of variations in weight loss during the course of treatment. In the case of head and neck cancer patients, weight loss can vary between just 1 or 2 kilograms up to 20 kilograms, resulting in the need to alter treatment plans accordingly, he said. Dr Garcia revealed early results of daily imaging using the 3D kV Cone Beam CT mode on the On-Board Imager, which is mounted on the treatment machine and enables automated repositioning of the treatment couch based on alterations between the image used to develop the plan and the newly-acquired image.

Angela Heaton, research radiographer at Clatterbridge Centre for Oncology, outlined the pioneering work her establishment is conducting using the radiographic, fluoroscopic and kV Cone Beam CT imaging modes of the On-Board Imager to improve treatment precision. Among the new techniques initiated at the hospital to date are the development of a supine patient position for spinal and head & neck treatments, kV Cone Beam CT for verifying stereotactic radiotherapy treatments, the use of IGRT in combination with seed markers for more tightly focused prostate treatments and the use of fluoroscopic imaging with Varian’s RPM gating system to account for respiratory motion. Clatterbridge was the first cancer center in the UK to begin clinical use of the On-Board Imager.

Dr Stine Korreman of Rigshospitalet detailed her center’s pioneering work using respiratory gating to help treat breast cancer patients and her hospital’s plans to introduce similar treatments for lung patients. “Gating has proven a great success at Rigshospitalet,” she said. “The patient is taught to breathe more deeply using audio coaching and the radiation is only on during maximum inspiration of breath. This inflation of the lung anatomically separates the heart from the target tumor and reduces the amount of lung tissue in the fields.”

Dr Korreman said that by using this method, the radiation dose to the lung can be reduced by 30-40 percent and the dose to the heart by 80-90 percent, with a corresponding decrease in the risk of complications such as pneumonitis and cardiac mortality.

Rolf Staehelin, head of Varian’s Oncology Systems marketing organisation in Europe, said, “With more than 250 installations in place Varian is the market and technology leader in IGRT and the institutions that have presented today give a good illustration of how these new technologies are enabling pioneering work to take place for the benefit of cancer patients around the world. Improvements in imaging technologies have enabled dramatic increases in the precision of radiotherapy treatments in recent years, allowing oncologists to adjust treatment plans based on daily imaging and to boost doses because they are more confident of being able to spare healthy tissue surrounding the tumor from any residual damage.”