Proton Therapy at Stanford
On April 7th, 2026, Stanford Radiation Oncology unveiled the world's most compact proton therapy system, a moment that marks both a technological breakthrough and the beginning of a new chapter in cancer treatment.
.jpeg)
Radiation therapy uses energy to destroy cancer cells by damaging their DNA. Conventional radiation therapy accomplishes this with X-rays, which target the tumor and then pass through healthy tissue to exit the body. Proton therapy uses protons: charged particles that can be precisely controlled to deposit their energy directly in the tumor, with little or no spillover into nearby healthy tissues.
This precision is especially valuable for tumors located near critical organs such as the brain, heart, or spinal cord, as well as in pediatric patients, whose growing tissues are more sensitive to radiation.
Historically, proton therapy systems have been enormous and costly, often requiring custom-built facilities the size of gymnasiums, complete with thick concrete walls to contain the proton beam. Only a few dozen centers in the country currently offer it, and the nearest to Stanford is roughly an eight-hour drive away.
Stanford Health Care is bringing together one of the world’s leading proton therapy technology manufacturers, Mevion, with Leo Cancer Care, a company that is changing the paradigm of conventional patient imaging.
The result is a pioneering technology that reduces both the footprint and capital and operating costs of this most technologically advanced way to treat cancer, which can now fit into a common radiation therapy room. This eliminates the need for a dedicated 3-story building previously required to house these technologies.
Proton therapy is considered the gold standard for pediatric cancers needing radiation therapy. It can deliver improved outcomes while reducing the side effects of treatment at the same time. This technology positions Stanford to also be the first to develop programs for the routine delivery of “proton arc” and “proton flash”, two of the most promising advancements in the field of proton therapy.
90 Seconds with Lisa Kim
Stanford Medicine unveils the world’s first ultracompact proton therapy facility that will improve outcomes for cancer patients. Radiation oncologists Billy Loo, Jr., Susan Hiniker, and Yuan James Rao describe how the system destroys tumors while the patient is sitting upright. Not only will it increase access to care, but it will also minimize the footprint needed to deliver the precise radiation.
