SAN DIEGO, September 27, 2017 /PRNewswire/ -- Elekta (EKTA-B.ST) today announced that members of the Elekta MR-linac Consortium reported data related to the advancement of the company's transformative MR/RT system at the American Society for Radiation Oncology (ASTRO) Annual Meeting, September 24-27 in San Diego.

The Elekta MR-linac is the only MR/RT system that integrates a high-field (1.5 Tesla) MR scanner with an advanced linear accelerator and intelligently-designed software. The system is expected to deliver precisely targeted radiation doses while simultaneously capturing the highest-quality MR images. These features are expected to allow clinicians to visualize tumors at any time and adapt treatment.

"The Consortium continues to make excellent progress in establishing MR/RT as a new approach to radiation therapy," said Kevin Brown, Global VP Scientific Research at Elekta. "In bringing together clinicians, researchers and medical physicists and leading international cancer centers, the Consortium has developed truly innovative approaches to integrating the most advanced MR imaging and linear accelerator technologies. We deeply value their ongoing efforts to enable MR/RT as the next step in the evolution of radiation therapy."
Researchers at the Odette Cancer Centre, Sunnybrook Health Sciences Centre in Toronto, presented preliminary results of a study evaluating the potential of MR-linac in adapting to changes in tumor volume that can be observed using MR imaging during treatment of glioblastoma multiforme, an aggressive form of brain cancer (Abstract #3706). The study is designed to capture MR images from 20 patients at the treatment planning stage, at 10 and 20 days of radiation therapy and at one month following completion of treatment. Imaging data showing relative and absolute changes in gross tumor volume (GTV) are then used to simulate a new planning target volume (PTV) to assess the feasibility of treatment plan adaptation.

Data for the first three patients evaluated in this study were presented by Sunnybrook's Mark Ruschin, PhD, MCCPM. Two of the three patients showed decreases in GTV of 14% and 20% at Day 20 and 51% and 42% one month following completion of treatment. The image set containing the 20% GTV shrinkage at Day 20 was used to generate an adapted plan, resulting in a new PTV that was 31% smaller than the original. In the adapted plan, the smaller PTV contributed to a reduction in the maximum dose to the brainstem and optic chiasm by 37% and 39%, respectively. In addition to demonstrating a dosimetric advantage of adaptive brain radiotherapy, the present work is an important first step towards developing the tools and processes needed for clinical implementation of the new MR/RT technology. Future work involves the use of functional imaging to improve the quantification of tumor and normal tissue response to radiation and ultimately leads toward adapting treatment based on an individual patient's biological response.

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