Dec. 09, 2025
Carbon ion therapy offers new hope for patients with the most aggressive, treatment-resistant cancers. Until now, only a handful of centers in Asia and Europe have provided this advanced form of radiation therapy, but that's about to change. Mayo Clinic in Florida is building the first carbon ion therapy facility in the Americas, scheduled to begin in 2028 inside the 228,000-square-foot Duan Family Building.
The new center will feature state-of-the-art technologies including carbon ion therapy and other next-generation radiation tools. These therapies will precisely target tumors while minimizing damage to healthy tissue.
Radiobiology research is a vital element of the carbon ion program's success. Michael D. Story, Ph.D., director of radiobiology at Mayo Clinic in Florida, is leading this work. Below, Dr. Story discusses how he and his team of top-level investigators are helping drive the next transformation in cancer care in the U.S.
You've spent decades studying heavy particle therapies such as carbon ions. What is carbon ion therapy, and what makes it so compelling?
Dr. Story: Carbon ion therapy is a type of radiation treatment that uses beams of carbon ions to target cancerous tumors. Scientists in the U.S. developed this approach in the 1970s. However, the technology was never adopted here, mainly because of the high financial investment required.
Currently, radiotherapy centers offer two types of external beam radiation therapy. The most common is conventional radiation therapy, which uses high-energy photons to kill cancer cells. The other is proton therapy, a technology that allows for more conformal treatment — meaning we can irradiate the tumor with better sparing of the surrounding normal tissue.
Carbon ions are yet more conformal, but they are also heavier and more powerful than photons or protons. They can kill cancer cells that resist proton or X-ray radiation, including sarcomas, pancreatic cancers, and some head and neck cancers, as examples. Carbon ions also appear to trigger an immune response, which is something that traditional and proton radiation therapies are less capable of.
In short, carbon ion therapy has the potential to treat radioresistant cancers more effectively, often with lower radiation doses and fewer treatments than other forms of radiation therapy.
What brought you to Mayo Clinic in Florida to lead the radiobiology research program?
Dr. Story: I've been intrigued by heavy-particle radiobiology since my graduate school days in the mid-1980s. For two decades, NASA funded my work studying how heavy particles in deep space increase the risk of lethal cancers for astronauts. Based on that research and the work of other scientists, I became convinced that carbon ion therapy could be an effective treatment for aggressive, treatment-resistant cancers.
Over the past 40 years, several institutions in the U.S. have attempted to build a carbon ion radiotherapy center, but Mayo Clinic is the first to make it happen. I was on the verge of retirement when I learned about the plans. It's gratifying to be part of the team bringing this vision to life.
Tell us about the research you and your colleagues are doing to advance your understanding of carbon ion therapy.
Dr. Story: Our research focuses on three main areas. First, we're attempting to identify genetic markers that can determine the level of radioresistance of a patient's cancer to know whether carbon ion radiotherapy is appropriate. Second, we're studying how carbon ion therapy affects both healthy and cancerous tissues to determine if there are vulnerabilities in cancer cells that can be exploited. Other researchers have studied this for different forms of radiation therapy, but there appear to be genetic vulnerabilities with carbon ions that may be exploitable.
Finally, we're exploring how to enhance treatment effectiveness by combining carbon ion therapy with other modalities, such as immunotherapy drugs. The goal is to deliver a one-two punch against treatment-resistant tumors whenever possible.
How will the carbon ion therapy Mayo Clinic offers differ from what's available in other countries?
Dr. Story: Clinicians in other countries have been using carbon ion radiation for years. We aim to build on that evidence-based foundation to achieve even better outcomes. For example, in Japan, patients typically receive 12 to 16 carbon ion treatments over several weeks. We're developing clinical trials to determine whether we can safely and effectively reduce the treatment duration — ideally to five days, or perhaps to once-a-month treatments.
Mayo Clinic is blazing new trails with carbon ion therapy in the U.S. What gives you confidence about the program's future success?
Dr. Story: Many institutions have talked about carbon ion therapy, but only Mayo has decided to invest in it. We're all in, and this is just the beginning of what we plan to do with emerging treatments. For example, we're also exploring other heavy particles, such as helium and neon, as potential alternative particles depending upon clinical circumstances. The driving force is our commitment to bring more cures to patients and help them live longer, healthier lives.
For more information
Learn about the science behind carbon ion therapy.
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