Precision treatment The precision of proton therapy cancer treatment is particularly important for tumors near critical organs, such as the brain, spinal cord, or lungs; and for treating pediatric cancers, when reducing radiation exposure to healthy tissues is paramount because young bodies are sensitive to radiation. The treatment is non-invasive, has reduced side effects compared to chemotherapy, and can be used alongside therapies like surgery or chemotherapy.

By Kevin Langan

The Carbone Cancer Center at UW Health Eastpark Medical Center in Madison, WI, is one of about just 50 cancer centers in the U.S. to offer proton therapy. It also soon will be one of the first facilities in the world to offer a new version of the treatment, upright proton therapy.

Unlike conventional radiation therapy that uses X-rays, proton therapy uses a beam of protons to more precisely target cancerous tumors, minimizing damage to surrounding healthy tissue. Traditional proton therapy is delivered to a patient lying on their back or stomach. When the Carbone Center begins offering upright therapy (pictured above), patients will be able to sit and receive their radiation treatment as a fixed proton beam rotates around them. This provides greater comfort, reduced patient anxiety, and improved clinical benefits for certain cancers.

IMEG provided mechanical, electrical, plumbing, fire protection, and low voltage engineering design for the new center, which, due to the needs of the proton therapy equipment, required specialized infrastructure, advanced systems, and detailed planning to ensure safety, reliability, and efficiency.

Specific engineering design considerations and challenges included:

Substantial space to accommodate the accelerator, gantries, treatment rooms, specialized shielding, support spaces, and associated mechanical and electrical equipment. Structural components, meanwhile, were required to withstand the weight and vibrations of the proton accelerators and concrete shielding.

Radiation shielding consisting of specialized walls, ceilings, and floors—often several feet thick—to absorb and contain radiation and strategically placed to prevent radiation leakage. IMEG worked closely with the radiation consultant to execute a confinement strategy that included routing ductwork and piping through the maze-like corridors used to access treatment and accelerator rooms and penetrations installed at 45-degree angles through the 7-foot-thick concrete walls.

Specialized HVAC systems capable of managing the cooling needs of the proton therapy equipment and the airflows required to maintain proper pressure differentials and ensure radiation safety. IMEG designed large capacity process water cooling and air conditioning systems to manage the extreme heat gain. Large exhaust systems were provided for the gantry, accelerator, and treatment rooms to remove potential radiation particles and support the high supply airflows needed to manage the heat.

Other key HVAC equipment included:

• A dedicated air handling unit, incorporating redundant components, to serve the space containing the high heat-load power supplies and control cabinets
• Centralized gas-fired humidifiers to maintain the required humidity levels throughout all proton therapy spaces during winter months
• Two process water cooling loops, one for the particle accelerator and the other for the magnets, power supplies, and associated equipment. Each process water loop has redundant cooling sources.
• Piping components made of corrosion resistant materials and deionized water processors to maintain water purity

High-capacity electrical systems with dedicated power supplies, backup generators, and uninterruptible power supplies (UPS) to ensure uninterrupted treatment. IMEG coordinated with the proton therapy vendors to make sure the systems could meet the demands of the center, minimize risk from fire or water damage, and carefully integrate the systems with the overall facility’s infrastructure to avoid electromagnetic interference.

An energy recovery chiller was designed by IMEG to allow the Eastpark Medical Center to use the heat generated by the proton therapy equipment to provide heat for the facility. In addition, a 1MW carport photovoltaic solar array, designed to match the energy use of the proton therapy center, effectively delivers carbon-free cancer care.

The Carbone Cancer Center’s proton therapy clinic and others like it require a large capital investment, both in equipment and infrastructure, and can take over 36 months from vendor selection to being available for patients. Faced with such an undertaking, owners should ensure their chosen design team understands the complexities of such a project.

Dr. Zachary Morris, professor and chair of the Department of Radiation Medicine at the University of Wisconsin School of Medicine and Public Health, summed up the project when the center began offering proton therapy on July 28, 2026.

“This achievement is a culmination of tremendous planning and teamwork,” he said, adding that the outcome has enabled UW Health to provide “one of the most precise forms of cancer therapy and a proton therapy center that is among the most technologically advanced anywhere.”

Senior Electrical Engineer John McGonegle contributed to this report. Read the IMEG case study on the UW Health Carbone Cancer Center and listen to a podcast.