TORONTO, Oct. 8, 2002 (PRIMEZONE) -- An innovative radiotherapy treatment platform that integrates advanced imaging technologies and treatment delivery into one system is ready for installation at Princess Margaret Hospital. The new Elekta SYNERGY(TM) research system represents a new class of treatment machines that will address the long-standing challenges of organ motion and set-up error in radiotherapy, through high-quality, volumetric imaging and target localization. Ontario's Princess Margaret Hospital (PMH) is the first Canadian installation of the research system, which is equipped with X-ray volume imaging (XVI) technology.
"The precision this device will allow us to achieve will be unprecedented in radiotherapy. It will provide sub-millimeter resolution and with proper calibration, promises comparable precision in treatment delivery," said David A. Jaffray, Ph.D., PMH Head of Radiation Physics. As a staff physicist at William Beaumont Hospital (Royal Oak, Mich.), he led the effort to develop the new technology with support from Elekta.
In September 2002, PMH received the new Elekta SYNERGY(TM) research system -- and it is currently undergoing installation testing. The September acquisitions also included an additional "conventional" Precise Treatment System(TM) and upgrades of two existing Elekta linacs to Precise Treatment System(TM). PMH's present complement of radiotherapy machines is 16 linear accelerators, a cobalt-60 machine, three CT simulators, and two conventional simulators.
The XVI systems technology enables clinicians to take single radiographic exposures in addition to simulator-like fluoroscopic exposures. An exciting capability will be cone-beam reconstructions, which produce a set of 3-D images of the patient in the treatment position. While this treatment machine's "expanded vision" is clearly advantageous to visualize the region of interest, the sheer volume of images that can be made available creates its own challenge -- one that PMH physicists will address as a top priority.
"We have funding from various sources to explore ways to clinically exploit the new information that this system provides," Dr. Jaffray explained. "That means we need to develop, in collaboration with a number of institutions, tools and methods of using the data, such as automatic marker detection schemes and high speed methods of adjusting the treatment plan to accommodate changes in patient position."
According to Dr. Jaffray, use of the Elekta SYNERGY(TM) research system will include developing plans for the treatment of relatively "easy" cases, such as head and neck tumors and sarcomas, prostate cancer -- a more challenging cancer site -- and even lung tumors, the most challenging of all due to intrafraction mobility.
While plans for the new system move forward, the standard platform, which forms the basis for the new system, will still be put into service as a conventional linear accelerator to share in PMH's tremendous yearly volume of over 6,000 patient treatments (300-400 daily).
"The plans for integration of this imaging technology into an advanced, commercially available linear accelerator makes it the ideal device for moving from conventional practice to high-precision radiotherapy," Dr. Jaffray said.
About Princess Margaret
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.
About Elekta
Elekta is a world-leading supplier of advanced and innovative radiation oncology and neurosurgery solutions and services for precise treatment of cancer and brain disorders. Elekta's solutions are clinically effective and cost efficient and gentle to the patient.
Expanding RT's vision
In conjunction with its clinical partners, Elekta is taking a leadership role in the development of technology that will enhance the precision of radiotherapy. The linac at Princess Margaret Hospital and other sites represents a new breed of treatment machines possessing "expanded vision." Integrating imaging devices into the treatment machine effectively gives improved sight to a system whose sole purpose until recently has been megavoltage treatment and megavoltage portal imaging. And this technological solution is the leading approach for what has been termed image-guided radiotherapy.
The addition of the kilovoltage imager, the bedrock of x-ray imaging technology for decades, is crucial. Clinicians have been struggling many years with an inappropriate type of radiation for taking images. Mounting a kilovoltage system directly on the accelerator's gantry means radiation oncologists now have the same frame of reference for imaging as they have for treating. It's like having a simulator and accelerator on the same gantry -- the patient doesn't have to be moved.
Using the kilovoltage system allows x-ray volume imaging providing high-quality images in orientations normally associated with MRI, but without the attendant problems of geometric distortion. Acquisition using XVI technology is fast, with the full volume acquired in approximately 60 seconds, resulting in minimal impact on treatment schedules. Anatomy can be reviewed at different image resolutions appropriate to the task being undertaken.
Many scientists and researchers believe that integrating flat panel detectors, and MV and kV x-ray devices and fluoroscopic imaging systems into treatment systems will go a long way toward reducing errors related to organ motion and set-up during and between fractions. Radiation therapy today relies on assumptions clinicians make about target locations, based on data or images that are old relative to the time of treatment -- creating uncertainty. Radiation oncologists employ larger treatment margins to accommodate that uncertainty, erring on the side of sparing normal tissue by restricting dose escalation.
The bottom line is that the increased precision afforded by image-guided techniques will allow physicians to unleash the full potential of radiotherapy.
Giving the treatment machine a more proactive role in the patient's treatment -- by incorporating on-board imaging systems and thereby expanding its vision -- promises to improve precision in radiotherapy.