Cone Beam CT ushering in new generation of image-guided radiation cancer therapy

Toronto (Oct. 23, 2003) - A new medical imaging system that will allow unparalleled precision for radiation treatment has been tested for the first time with a patient in Canada.

The imaging system, one of only four in the world, is called Cone Beam CT, and it is being pioneered at Princess Margaret Hospital. The breakthrough imaging technology is integrated with a radiation treatment machine to allow precision targeting of the cancer tumor.

The technology gets its name from the cone-shaped beam of x-rays used to collect a complete image. Conventional CT's (computed tomography) take a series of thin-sliced x-ray images, which are then stacked together like pancakes to produce a complete picture.

Cone Beam CT produces a more sophisticated image that requires less time and less x-ray exposure. The images are rapidly reconstructed into a 3D picture using a computer program called Sherpa - named after the famed mountain guides of the Himalayas.

"The images from our first test are striking," said Dr. David Jaffray, developer of Cone Beam CT, head of Radiation Physics at Princess Margaret Hospital, holds the Fidani Chair in Radiation Therapy Physics at PMH, and is Associate Professor at University of Toronto. "This technology offers a range of new possibilities even beyond high precision radiation therapy, to other applications such as real-time imaging for surgery."

A key aspect to using the new technology is its integration into the radiation treatment process. This will allow greater precision because the patient is imaged in the treatment position, just before actual treatment, thus allowing the treatment plan to be adjusted to for any shift of internal organs. That greater precision will translate into less side effects for the patient, and potentially reduce the number of treatment doses required.

The system is currently only approved by Health Canada for research purposes, but officials hope to soon begin combining the imaging with delivery of radiation treatment at the hospital.

"The results from initial testing are very promising and we are confident this new technology will soon allow us to make image-guided radiation therapy a reality," said Dr. Mary Gospodarowicz, head of the Radiation Medicine Program at Princess Margaret Hospital.

The Cone Beam CT was developed while Dr. Jaffray and his team worked at William Beaumont Hospital in Michigan. Last year, Dr. Jaffray and many in his team established the Image Guided Therapy Group at Princess Margaret Hospital, now one of four institutions in the world conducting research using Cone Beam CT and a radiation treatment machine (the others are in Michigan; the United Kingdom, and the Netherlands). The research work has lead to the development of Elekta's Synergy™ system, which combines Cone Beam CT with Elekta's digital linear accelerator used in radiotherapy.

About Princess Margaret Hospital

Princess Margaret Hospital and its research arm, Ontario Cancer Institute, have achieved an international reputation as global leaders in the fight against cancer. Princess Margaret Hospital is a member of the University Health Network, which also includes Toronto General Hospital and Toronto Western Hospital. All three are teaching hospitals affiliated with the University of Toronto.

Media Contact

Phone: 416 340 4636
Email: UHN.News@uhn.ca

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