Stanford Medicine Opens New Proton Therapy Facility

The advanced cancer treatment will be more accessible to patients in Northern California.

Apr. 7, 2026 at 10:52pm

Got story updates? Submit your updates here. ›

An extreme close-up X-ray photograph revealing the intricate internal components of a compact proton therapy machine, conceptually illustrating the advanced technology that is making this targeted radiation therapy more widely available.Stanford Medicine's new proton therapy facility uses innovative compact equipment to make this advanced cancer treatment more accessible to patients.Palo Alto Today

Stanford Medicine is opening a first-of-its-kind facility to deliver proton therapy, a form of radiation therapy that precisely targets tumors while minimizing damage to healthy tissues. The new facility uses innovative, compact equipment that drastically reduces the size and cost of traditional proton therapy setups, making the advanced treatment more accessible to patients in the region.

Why it matters

Proton therapy offers significant advantages over traditional X-ray radiation, especially for tumors located near critical structures like the brain, heart, and nerves. By precisely targeting the tumor while sparing healthy tissues, proton therapy can reduce long-term side effects, which is especially important for pediatric cancer patients. The new compact equipment will make this advanced treatment available to more Northern California residents who previously had limited access.

The details

Stanford Medicine's innovation, developed in collaboration with two medical technology companies, is to drastically shrink the size and cost of the machinery used to deliver proton therapy. The new equipment fits into a standard linear accelerator vault of 1,200 square feet, compared to the football-field-sized footprint of traditional proton therapy setups. This will allow Stanford Medicine to offer the advanced treatment at its cancer center in Palo Alto without constructing a new building.

  • Stanford Medicine will cut the ribbon on the new proton therapy facility on April 7, 2026.
  • The compact proton therapy equipment is being adopted at other health care systems around the world over the next several months to years.

The players

Billy Loo

Professor of radiation oncology and co-director of particle therapy at Stanford Medicine, who played a key role in the innovation.

Susan Hiniker

Associate professor of radiation oncology at Stanford Medicine who treats children receiving radiotherapy.

Yuan James Rao

Associate professor of radiation oncology at Stanford Medicine.

Mevion Medical Systems

A medical device company that offered the most compact cyclotron in the industry, a key component of the new proton therapy equipment.

Leo Cancer Care Inc.

A medical technology company that developed a system to position patients upright for proton therapy treatment, enabling a smaller footprint.

Got photos? Submit your photos here. ›

What they’re saying

“For our patients, the key is being able to eliminate their cancer without causing unacceptable collateral damage. Proton therapy helps us balance that equation by making radiotherapy more precise.”

— Billy Loo, Professor of radiation oncology and co-director of particle therapy

“With proton therapy, the particles are able to stop on a dime. We expect similar rates of tumor control to what we see with X-rays. But with protons, the volume of tissue receiving radiation is smaller, and in many cases, this will lead to fewer long-term side effects.”

— Susan Hiniker, Associate professor of radiation oncology

What’s next

Stanford Medicine plans to explore the advantages of delivering radiation treatment to patients sitting upright instead of lying down, as well as studying different patterns of radiation delivery like FLASH treatment to improve precision and reduce collateral damage.

The takeaway

By making proton therapy equipment smaller, less expensive, and easier to install, Stanford Medicine is breaking the bottleneck that has previously limited access to this advanced cancer treatment in Northern California. The new facility will bring the benefits of proton therapy, including reduced long-term side effects, to more patients in the region.