Research Grant, Collaboration Initiated to Develop Advanced CT Imaging Technology

Scientists from Stanford University (Palo Alto, CA, USA) and from the Ginzton Technology Center at Varian Medical Systems, Inc. (Palo Alto, CA, USA) have jointly received a US$3.6 million five-year research grant from the U.S. National Institutes of Health (NIH; Bethesda, MD, USA) to develop advanced imaging technology for improving the quality of computed tomography (CT) images for patients with metal objects in their bodies such as hip implants and dental fillings.

The grant award is from the Cancer Imaging Program (CIP) of the National Cancer Institute (NCI) within NIH. The CIP made the grant under its program entitled Academic-Industrial Partnerships for Development and Validation of in vivo Imaging Systems and Methods for Cancer Investigations, which was set up to encourage interdisciplinary research by industry and academia into cancer-related imaging challenges. Josh Star-Lack, Ph.D., a senior scientist in Varian's Ginzton Technology Center for research and development, and Rebecca Fahrig, Ph.D., associate professor of radiological sciences at the Stanford University School of Medicine, will serve as coprincipal investigators on the project.

"Modern radiotherapy of cancer often relies on high quality CT images for planning advanced forms of treatment,” said Dr. Star-Lack. "You also need good cone-beam CT images from a machine-mounted imager for patient positioning and for assessing tumor response to treatment. These CT images are typically acquired at kilovoltage X-ray energies resulting in excellent soft tissue definition, which means you can distinguish tumor from muscle, fat, or other organs. Unfortunately, severe image distortions can be created when metal is present, making it harder to know what you're looking at.”

According to Dr. Star-Lack, it is possible to greatly reduce the distortions by using very high energy (megavoltage) X-rays that better penetrate the metal. However, megavoltage imaging also has significant disadvantages. "You need a lot of dose, and the quality of images is poor, particularly in soft tissues,” Dr. Star-Lack said. "Our research grant will be used to develop tools to achieve the best of both worlds by combining kilovoltage cone-beam CT data with a limited amount of megavoltage data to create a composite image with less distortion and good soft tissue resolution.”

As part of the project, researchers from Varian and Stanford will develop new megavoltage X-ray detection hardware and image reconstruction software, and will validate the new technology in a clinical trial to be conducted by Stanford. "The rapid translation of these advances into clinical practice could improve the accuracy of radiotherapy planning and image guidance for patients with metal objects near the targeted tumors,” Dr. Fahrig said. "This is a unique grant program that recognizes the special synergies that can happen when academic researchers, who often focus on pure science, collaborate with industrial researchers, who often emphasize product-oriented R&D with near-term commercial possibilities.”

The Ginzton Technology Center (GTC) serves as Varian Medical Systems' central R&D organization, incubating new technologies, supporting product development for the company's business units, and conducting government or industry-sponsored research projects. The GTC's mandate is to focus on the investigation of development of new, disruptive, cutting-edge technologies that will create considerably improved capabilities for Varian's customers.

Varian Medical Systems is a world-leading manufacturer of medical devices and software for treating cancer and other medical conditions with radiotherapy, radiosurgery, proton therapy, and brachytherapy. The company supplies informatics software for managing comprehensive cancer clinics, radiotherapy centers, and medical oncology practices.

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