When John received his first opportunity to design a proton therapy center about 20 years ago, there were only five similar facilities in the entire country. No one at his firm had worked on proton therapy before, but they had extensive healthcare experience and a reputation for solving complicated problems.
Before meeting with the university president who would become his client, John did something that would shape his entire approach to proton therapy design: he traveled to all five existing centers. The teams running those facilities were generous with their time, sharing both their successes and their struggles. Those conversations revealed that every proton therapy project presents unique challenges, and the consequences of inexperience can be catastrophic.
Twenty years and dozens of projects later, we’ve accumulated lessons that span structural engineering, technological integration, construction sequencing, and team coordination. Some lessons came from our own problem-solving. Others came from witnessing failures at projects we didn’t design—including facilities that had to be abandoned entirely.
When Proton Therapy Center Projects Fail
The stakes in proton therapy construction are exceptionally high. These aren’t projects where you can easily correct mistakes after the fact.
At the China-Japan Friendship Hospital in Beijing, construction began in 2002 and was abandoned in 2004. Workers literally threw down their tools and walked away when they realized the equipment wouldn’t fit into the building they’d constructed. The structure sat for 13 years as an abandoned concrete shell on the hospital campus before being completely razed and reconstructed with a different system in 2017.
At King Fahd Medical City in Riyadh, construction began in 2012. The facility didn’t treat its first patient until 2024—twelve years later. Proton design experts had to be brought in after construction was complete to fix multiple problems: process cooling issues, incorrect piping materials, leaks, building control system failures, and overall poor quality and craftsmanship.
The McLaren Proton Therapy Center in Flint, Michigan, saw significant delays stemming from design and construction issues attributable to a lack of proton-specific knowledge on the team. This problem was compounded by the fact that this was the first installation for that equipment manufacturer, and a reliable building interface document wasn’t yet available.
At MD Anderson’s second proton therapy center in Houston, the equipment vendor arrived on site ready to begin installation, only to discover the critical equipment cooling water system wasn’t installed to specifications. The vendor refused to proceed until the system met proper specifications. This delay was significant because it required removing and changing pipes embedded in mass concrete, all due to a lack of proton knowledge on the team.
These failures share a common thread: teams without experience in the unique demands of proton therapy construction.
Early Lessons That Changed Everything
John’s tour of the country’s first proton therapy centers yielded insights that still inform our work today.
The University of Florida Health Proton Therapy Institute originally planned to put its patient treatment floor two levels below ground—standard practice at the time, since proton centers were modeled after radiation therapy facilities. But the architects didn’t understand the significance of Florida’s high water table. The project was delayed while the building was redesigned, raising it above the water table.
That failure prompted a fundamental question: Why do proton therapy centers need to be underground in the first place?
The answer at the time was simply “because that’s how it’s always been done.” There was no clinical reason. No operational reason.
This realization led to one of our most impactful design innovations—bringing proton therapy centers up to grade level. Today, most of our projects place treatment floors at ground level. Patients don’t navigate confusing basement corridors. They enter facilities with natural daylight, exterior views, and intuitive wayfinding. The healing environment improved dramatically, and construction became simpler and less expensive in most locations.
Processed Chilled Water: The Lifeblood of Precision
Process cooling is one of the most critical—and most frequently misunderstood—elements of proton therapy design. The equipment generates enormous heat that must be continuously removed with exceptional precision.
Processed chilled water (PCW) must be clean, predictable, and reliable. Any contamination, temperature fluctuation, or flow inconsistency can shut down the entire system. We’ve seen projects where incorrect piping materials were specified, leading to corrosion that contaminated the cooling system. Others used materials that couldn’t handle the thermal cycling, resulting in leaks within the massive concrete structures.
The lesson: PCW systems require stainless steel piping, proper water treatment, redundant pumps, and monitoring systems that catch problems before they impact equipment operation. This isn’t normal HVAC work—it’s precision engineering that must meet manufacturer specifications exactly.
Mass Concrete: Not Just Structure, But Shielding
The 14-foot concrete walls in proton therapy centers serve a dual purpose. They’re structural elements supporting massive equipment loads, but more importantly, they’re radiation shielding designed to contain neutrons produced during treatment.
Inside these walls are miles of electrical conduits, piping systems, HVAC ducts, and structural rebar—all of which must be precisely positioned before concrete is poured. Once that concrete sets, there’s no going back without extraordinary expense.
Think about what’s embedded within those walls. Enormous amounts of rebar create the structural integrity. Conduits carry power and data. Pipes transport cooling water and compressed air. Everything must be mapped in three-dimensional BIM models to ensure proper spacing. If components touch or interfere with each other, the consequences range from system failures to complete reconstruction.
The structural design must be built to the equipment manufacturer’s specific tolerance requirements. Tolerances are measured in millimeters. There’s no room for error once concrete is poured.
We’ve learned to approach mass concrete pours with industrial-level precision: embedded inspections, tolerance checks, and mock-ups verify critical dimensions before any concrete flows. The sequencing of these pours is critical—you can’t build everything at once, and the order matters.
Planning for Technology Evolution
One of the highest-priority lessons we’ve learned is this: technology doesn’t stand still. Proton therapy projects take 5-7 years from planning to first patient treatment. The technology that exists when you break ground may be obsolete by the time you open.
We design for flexibility wherever possible. Extra floor-to-floor heights accommodate future equipment with different dimensions. MEP capacity exceeds current requirements to handle upgraded systems. We build in pathways for equipment extraction and replacement—lessons that have become critical as we work on upgrade projects where 20-year-old facilities are now replacing their original equipment.
At Massachusetts General Hospital’s Francis H. Burr Proton Therapy Center, which opened in 2001 (three years later than planned due to design, construction, and technology issues), we’re now managing the world’s first major equipment upgrade. A tower was built above the center after the original construction, creating access challenges no one anticipated. Even though the new equipment from the same vendor has similar dimensions, we’ve had to blow out concrete walls to remove the old system.
These upgrade experiences now inform every new project we design. We ask: What happens in 20 years when this equipment needs replacement? How do we get it out? What access do we need to preserve?
BIM Coordination: Precision Modeling for Zero Conflicts
Building Information Modeling isn’t optional for proton therapy centers—it’s essential. The complexity of integrating shielding, gantries, beamlines, and building systems demands three-dimensional coordination at a level beyond any other kind of healthcare construction.
We model everything: the vault geometry, the gantry rotation envelope, the beam transport system, every pipe, every conduit, every duct. The model reveals conflicts before they appear in the field. It verifies clearances around rotating gantries weighing over 100 tons. It confirms that sliding shielded doors won’t interfere with utilities.
This level of coordination is what separates successful proton projects from failures. When the China-Japan Friendship Hospital team realized their equipment wouldn’t fit, they lacked the rigorous modeling that would have caught that problem during design.
Rigging and Extraction: Designing for Install and Future Removal
Getting massive proton therapy equipment into the building is a major design challenge. Cyclotrons can weigh up to 240 tons. Gantries exceed 100 tons. These components can’t roll through doorways.
Most installations require a removable roof section or a large wall opening. Special rigging systems—temporary railroad tracks, A-frame structures, massive cranes—move equipment into position. At the Texas Center for Proton Therapy in Irving, the cyclotron was so heavy it required a police escort and a three-day route avoiding bridges that couldn’t bear the load.
Many teams miss that you need to design for extraction, not just installation. Equipment eventually needs replacement or major service. If you don’t plan extraction pathways during initial design, you may have to demolish significant portions of the building decades later.
We now design removable wall plugs, access ramps, and rigging anchor points that will serve both installation and future extraction. This foresight is proving invaluable as we work on upgrade projects where original facilities never anticipated equipment removal.
The No-Fly Zone at Sliding Shielding Doors
Our Knoxville project introduced sliding shielded doors to replace traditional maze entrances—a significant innovation in proton therapy center design. These doors are engineering marvels: at least five feet thick, weighing multiple tons, using bi-parting mechanisms so they open twice as fast while providing fail-safe redundancy.
But these doors hang from above, occupying significant ceiling space that previously carried utilities. This created what we now call the “no-fly zone”—areas where utilities cannot be routed because door mechanisms need clearance.
Early iterations revealed mechanical challenges, too. The rollers supporting these massive doors didn’t last as long as expected under frequent use. Mechanisms eroded. We’ve continuously improved these systems, but the fundamental lesson remains: every innovation requires mapping out its spatial and operational requirements precisely.
The no-fly zone must be established early in design. Every trade must understand where they cannot route their systems. Violating this space can prevent doors from operating, creating a vulnerability in the facility’s radiation containment.
Sequencing Construction with Installation
Proton therapy projects involve parallel efforts by multiple teams: the general contractor building the facility, the equipment manufacturer installing their systems, and specialized subcontractors handling components like sliding doors or patient positioning systems.
Managing these overlaps requires structured sequencing. The building must reach certain completion milestones before equipment can arrive. Equipment installation often begins before building construction is complete. Multiple systems must be installed in a specific order within the treatment vault.
We’ve learned to create detailed sequence-of-operations documents that clarify responsibilities and timing. When does building work stop and equipment installation begin? Who has access to the space during overlapping phases? What happens if one party falls behind schedule?
Without this clarity, finger-pointing begins when problems arise. Clear sequencing, documented responsibilities, and regular coordination meetings keep all parties aligned.
MEP Engineering in Proton Therapy Centers
The mechanical, electrical, and plumbing systems in proton therapy centers operate at levels of complexity and reliability beyond typical healthcare facilities.
Electrical systems must provide extremely stable power—voltage fluctuations that wouldn’t affect normal equipment can disrupt particle accelerator operation. Uninterruptible power supplies, redundant feeds, and sophisticated monitoring ensure continuous operation.
Mechanical systems include the process cooling we discussed, but also precise HVAC, maintaining tight temperature and humidity tolerances. The equipment generates magnetic fields that can affect nearby electronics, requiring careful planning of control room locations.
Plumbing systems must use corrosion-resistant materials. Stainless steel is often required where traditional systems would use copper or PVC. Water quality matters—contamination that wouldn’t affect other systems can damage sensitive proton therapy components.
These details must be specified correctly from the beginning, with the design team understanding manufacturer requirements and long-term operational needs.
The Common Thread: Proton Expertise
Every lesson we’ve learned points back to the same fundamental principle: team expertise matters more in proton therapy construction than in perhaps any other healthcare facility type.
The construction costs for proton therapy centers are substantial—typically $250+ million for new facilities and $150-175 million for upgrades. With investments at this scale, there’s no margin for error.
You need architects who understand the unique requirements, engineers who can integrate complex systems within massive concrete structures, construction teams trained in the precision required, and project managers who can coordinate all these specialists while maintaining seamless communication with equipment manufacturers.
Proton therapy centers demand the precision of an instrument, not just the construction of a building. They’re 1,000 times more complex than a LINAC. These facilities aren’t buildings that hold machines—they are the machines.
The consequences of missing this understanding are too severe. Projects get abandoned. Facilities sit unusable for years. Costs multiply beyond recognition.
Building on Two Decades of Knowledge
Every project we complete adds to our institutional knowledge. We’ve learned from successes and from observing failures. We’ve learned from the five centers John visited 20 years ago and from the dozens of projects we’ve designed since then. We’re learning from the upgrade projects happening right now in Boston and Texas.
This accumulated expertise allows us to anticipate challenges before they become problems. We know which questions to ask equipment manufacturers. We understand how site conditions will impact construction. We can identify potential conflicts in three-dimensional space before concrete is poured.
Twenty years ago, proton therapy center design was largely uncharted territory. Today, we have proven methodologies, documented best practices, and hard-won insights that make success predictable rather than hopeful.
At Jessen Proton, those lessons inform every project we design. Questions about your proton therapy center project? Contact us to discuss how two decades of lessons learned can help ensure your facility’s success.
