Radiotherapy Planning Software With Motion-Management

New motion-management capabilities have been added to a radiotherapy treatment planning system, enabling clinicians to increase treatment precision for tumors in mobile areas of the body, such as the lung.

"We have enhanced the Eclipse system so that it can create treatment plans that compensate for tumor motion during treatment,” said Jeff Amacker, director, treatment planning systems, Varian Medical Systems (Palo Alto, CA, USA). "The system enables clinicians to see and assess the extent of any tumor motion, and to design treatment strategies that take the motion into account so that radiation doses can be concentrated more closely on the tumor even as it moves.”

While clinicians have been able, for some time, to treat moving tumors using Varian's RPM respiratory gating system to synchronize treatment with a patient's respiratory cycle, the enhancements to Eclipse will enable them to use tumor motion data at the outset, during the planning phase of treatment.

"To plan these kinds of treatment in the past, we had to manually import and co-register both PET [positron emission tomography] and CT [computed tomography] images from all of the phases of the respiratory cycle and work with these individually in a process that took about three hours per case,” said Allan Caggiano, MS, chief physicist at Holy Name Hospital (Teaneck, NJ, USA). "This new tool in Eclipse reduces that timeframe down to something quite manageable, by allowing the PET and CT images to be easily imported and automatically co-registered.

According to Mr. Caggiano, the new capabilities in Eclipse make three important things possible. "First, the system generates ‘animated' images that show exactly how a tumor is moving when the patient breathes. Second, the doctor can assess the magnitude of the motion, and plan the treatment to minimize the amount of tissue exposed to the treatment beam. Finally, for image-guided radiotherapy [IGRT], the moving images in Eclipse can be compared with images taken at the treatment machine later in a course of treatment, to make sure that the tumor motion due to respiration hasn't changed over time, or to make adjustments if it has. The new Eclipse capabilities were presented in November, 2006 at the American Society for Therapeutic Radiology and Oncology (ASTRO) meeting in Philadelphia (PA, USA).




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