Roadblock after roadblock

That’s how Dr. Billy W. Loo Jr. describes Stanford Medicine’s pursuit of proton therapy. The hospital, in the heart of Silicon Valley, chased the technology for years, but projects kept stalling. By 2016, it came closest to building a proton and carbon ion facility on Palo Alto VA land, with federal approvals in hand. Rising construction costs and a tech-driven real estate boom, however, shelved the project.

Simply put, proton therapy centers are enormous. Loo notes that a single large accelerator — the most expensive component — often feeds several treatment rooms, each with a gantry that rotates around the patient. The structure alone can rise three stories, with a footprint that can stretch to the size of a football field and more with the addition of clinical infrastructure. “You can imagine, given our location, what the building costs would be,” Loo quips.
One breakthrough came from startup Leo Cancer Care, which reimagined both the physics and the footprint. Rather than rotating a massive gantry around a patient lying flat, Leo’s system keeps the beam fixed while the patient sits upright and rotates. Combined with a compact accelerator from Mevion Medical Systems, “another major breakthrough,” Loo says, the required space drops from 29,000 square feet to roughly 1,700, a reduction of more than 90%. In the end, Stanford brought Mevion and Leo together, integrating the compact accelerator with the upright positioning system.

The reduced footprint let Stanford fit the system into an existing X-ray vault, fully integrating proton therapy into the cancer center. “Typically, bringing in proton therapy means building across town,” Loo says. “You separate facilities, need new nursing rooms and CT scanners, and split your staff. With this system, it’s fully integrated.”

March marks the start of patient treatments at Stanford. “We’re just getting started with proton therapy,” he says.

How proton therapy works
Unlike X-rays, which deposit radiation along their entire path through the body, protons stop at a specific depth. The result: reduced exposure to surrounding healthy tissue, an advantage particularly relevant for pediatric cancers and tumors near critical structures such as the brain and spinal cord.

More Magazine Features

Proton Therapy Homepage