10 years, 10,000 lives: Mayo Experts Highlight the Journey and Future of Proton Beam and Particle Therapy at Mayo Clinic

A decade after opening, the Mayo Clinic Proton Therapy Program­ in Rochester, Minnesota, has treated 10,000 patients. Annually, the program treats 30%–40% more patients than most comparable centers in the country. And, with new technology and facility expansions, it will soon be able to treat nearly 75% more patients each year with even more precise and effective therapies.

Nadia Laack, M.D., chair of the Department of Radiation Oncology at Mayo Clinic in Rochester, and Anita Mahajan, M.D., radiation oncologist and medical director of Mayo Clinic’s particle therapy center, discuss how Mayo is using tomorrow's standard of care today.

A bold step toward precision and efficiency

Mayo Clinic took a bold step by launching its program in 2015 with pencil beam scanning — an ultranarrow beam that conforms its radiation dose to the shape of the tumor. This allowed a focus on accuracy for complex tumors, many of which were considered untreatable due to their location.

Mayo Clinic, with technology vendors, has continued to elevate this therapy by developing precise tracking technology such as its custom eye-tracking device for melanoma of the eye.

The team's high level of fine-tuning extends to its scheduling. "Most proton systems have one accelerator for four rooms, treating only one at a time," explains Dr. Mahajan. "A patient could be set up in their room, but waiting an hour."

To solve this, Dr. Mahajan helped develop a system that radiation therapists use to communicate and coordinate beam use to minimize patient wait time and discomfort and allow more patients to be treated.

Locking in on a moving target

Heartbeats and breathing create constant movement in the body, making chest and abdominal tumors a moving target and previously impossible to treat safely.

"With our colleagues in Arizona and the vendor, we developed a way to track lung tumors to ensure the beam only turns on when it's within target," says Dr. Laack.

This technology helped extend proton beam therapy's effectiveness beyond cancer.

"Cardiac ablation with proton beam is an example of how we've taken everything to the next level," says Dr. Laack. "Our physicists and the Department of Cardiovascular Medicine developed tools that now allow us to confidently and accurately deliver radiation doses to the heart."

Automating an improved patient experience

Mobility restrictions and constant adjustment can be uncomfortable and time-consuming for patients. They can slow down treatment. Regular bodily functions, including gas, bowel movements and fluid retention, also require ongoing rescanning and radiation plan adjustments for treatment accuracy.

Plan adjustments previously delayed treatment by several days. Automation has helped reduce turnaround time to just one day.

"It's remarkable to have next-day planning because of automation," adds Dr. Laack. "But we can imagine a future where patients lie down comfortably, and we scan and treat them with a custom plan tailored to their current anatomy."

Building on a future-ready foundation

Mayo Clinic is amid a leap forward in heavy particle therapy, decades in the making.

"For 20 years, we've studied data and deepened our understanding of tumor genetics so we could offer the most comprehensive treatment portfolio," says Dr. Laack.

This commitment manifested in the June 2025 opening of the Duan Family Building in Jacksonville, Florida. The building will house the first carbon ion therapy facility in the Americas and introduce powerful radiation delivery for complex and proton-beam- resistant tumors.

In August 2025, the Andersen Building in Rochester also reached a major milestone, adding 360-degree gantry technology that delivers proton beam within a millimeter of accuracy and real-time CT imaging to enable faster, more precise treatment for nearly twice as many patients.

"It's an engineering marvel that represents innovation, collaboration and hope," says Dr. Laack. "It's the promise that every patient who walks through our doors will receive the most precise, personalized and compassionate care available anywhere in the world."