The Elekta Unity MR-linac, a high-field (1.5 Tesla) MR-guided linear accelerator, is the world’s first radiation therapy technology to combine an MRI scanner with a linear accelerator in a single system. Previously, experts thought it would be nearly impossible to combine MRI and linear accelerator devices, because the powerful MRI magnets could interfere with radiation beams. The Unity MR-linac was developed by Elekta and its MRI technology partner Philips.

Christopher Schultz, MD, radiation oncologist, explains how Elekta Unity MR-linac technology works and the ways it could change radiation therapy for cancer patients in the future.

With the Elekta Unity MR-linac, doctors can “see” tumor tissue more clearly — and adapt the radiation dose while a patient is being treated. Because it can safely deliver higher doses of radiation to a tumor, treatment is expected to be more precise and more effective than ever before. It could also reduce the number of treatment sessions, providing more convenience for patients.

Froedtert & MCW researchers, along with other members of the global consortium, are continuing to collect data and analysis to further define the practical applications of the Elekta Unity MR-linac with the goal of improving outcomes of cancer patients treated with radiation therapy around the world.

William Hall, MD, talks about the Elekta Unity MR-linac and its potential to be a "game-changer" in cancer patient care. Dr. Hall is part of the team studying the Elekta Unity MR-linac’s capabilities at the Clinical Cancer Center at Froedtert Hospital in collaboration with the Elekta global consortium.

Personalized Medicine: Elekta Unity MR-Linac Adapts to Each Patient

Installation of the MR_Linac technology

To install the technology, two components — a magnet, weighing about 5.75 tons, and a gantry, weighing about 10 tons — were lowered through an opening in the roof of the Clinical Cancer Center.

MRI, with its fine-detail imaging capabilities, provides a clear picture that distinguishes tumor tissue from normal tissues — for radiation therapy planning and treatment delivery. MRI provides excellent soft-tissue visualization of tumors deep within the body and has real-time imaging capabilities.

The Elekta Unity MR-linac allows doctors to see a tumor clearly and treat it precisely every time. The technology provides real-time information on tumor location, organ function and therapeutic targeting that has not been available before: Physicians can monitor and assess the tumor’s position while a patient is being treated.

With its state-of-the-art visual capabilities, Elekta Unity MR-linac technology allows doctors to:

  • Clearly see soft tissues, distinguishing tumors from normal tissues, blood vessels and bony structures.
  • Precisely locate tumors during every treatment session.
  • Shape the radiation beam to the tumor each day or as needed over a course of treatment, taking into account the tumor’s position, shape, biology and its relationship to sensitive organs, such as the stomach, kidneys, heart, spinal cord, bladder, bowel or brain.
  • Accurately deliver higher, more effective doses of radiation to the tumor.
  • Offer treatment in fewer sessions. Since daily radiation doses could be higher, patients may not need as many treatments.
  • Avoid radiation dose to normal, healthy tissues, blood vessels and organs.

How Elekta Unity MR-Linac Works

Potential to Improve Patient Outcomes

With MR-enhanced imaging, Elekta Unity MR-linac-based radiation therapy may be appropriate for many cancer patients who are typically treated with radiation therapy. Going a step further, it may also treat patients who have cancers previously considered unsuitable for or hard to treat with radiation therapy.

For example, because of its ability to adapt, the Elekta Unity MR-linac can be particularly effective for patients with tumors that are in constant motion. This includes a tumor in the lung that moves with each breath — or pancreatic, liver and other upper abdominal tumors that also move with a patient’s breath — and which may wrap around blood vessels or lie close to organs such as the stomach that don’t tolerate radiation therapy well.

International Database Created to Track MR-Linac Treatment Results

The international MR-linac Consortium, of which the Froedtert & MCW Cancer Network is a member, has developed a database for evaluating different ways to use Elekta Unity MR-linac technology

The database is called MOMENTUM and focuses on applications for MR-linac technology. This five-year study aims to collect data from about 6,000 patients undergoing treatment with Elekta Unity MR-linac. The study is novel in its approach of gathering clinical and technical data as the technology is being implemented.

In addition to data from patients within the Froedtert & MCW Cancer Network, researchers from a consortium of cancer institutions around the world will contribute data to the MOMENTUM study. Consortium members from this global research team are studying the advanced capabilities of Elekta Unity MR-linac, collaborating to further develop its applications for patient treatment.