Discovery Boosts Cancer Radiation Therapy Effectiveness

Canadian medical physicists are the first in the world to successfully take a magnetic resonance (MR) image at the same time radiation therapy is being delivered. This advance has the potential to increase the likelihood of tumor control by an estimated 20-40%. The technology should make radiation therapy more accessible for cancers that are hard to treat with radiation because of organ movement, such as the liver, stomach, and pancreatic cancers.

Dr. Gino Fallone, the director of medical physics at the Cross Cancer Institute (Edmonton, Alberta, Canada) and professor of oncology at the University of Alberta (Canada), said, "We were told by some that it couldn't be done.” Mutual interference (magnetic and RF [radio frequency] fields) make the linear accelerator (linac) and the MR systems ‘allergic' to each other, an obstacle previously thought to be insurmountable. "However, we've now proved our design principle and can proceed to developing a larger [whole body system] prototype and eventually to clinical trials,” stated Dr. Fallone.

Dr. Fallone and his team of medical physicists are the first to develop and build a prototype linac-MR hybrid (head system) that has successfully taken MR images of objects while linac radiation is being delivered. The prototype gives the ability to guide the curative radiation to the tumor at the same time the image is being taken.

Current state-of-the-art equipment allows for a computed tomography (CT) scan moments before delivering the radiation. According to Dr. Fallone, it is similar to relying on a blurry image that does not capture soft tissue well. The linac-MR prototype provides clear video images, including soft tissue, and allows one to guide radiation in real time to the tumor.

The prototype will also minimize the need to radiate a margin of healthy tissue, currently required to ensure the entire tumor has been treated and will allow for a higher dose of radiation.

Related Links:
Cross Cancer Institute
University of Alberta