Penn Medicine has broken ground on its fourth proton therapy center, located at Penn Presbyterian Medical Center in Philadelphia’s University City, to support clinical trials like the Radiotherapy Comparative Effectiveness (RadComp) study and ongoing work on FLASH radiotherapy, a technique under investigation for delivering ultra-high-dose radiation in seconds.

Scheduled to open in late 2027, the $224 million Roberts Proton Therapy Center will expand the health system’s radiation oncology services as it prepares for major renovations at its flagship proton facility.

The new center is part of Penn Medicine’s Abramson Cancer Center and will house two ProteusONE proton therapy systems from IBA in a 43,000-square-foot space. It will also include a new treatment room for photon therapy using a Varian TrueBeam system, which is expected to begin treating patients in fall 2025.
James Metz, M.D., chair of radiation oncology at the Perelman School of Medicine, said the center will help maintain patient care continuity during the planned update of the Roberts Proton Therapy Center at the Perelman Center for Advanced Medicine, where nearly 11,000 patients have been treated since 2010. The center will also support Penn’s collaboration with Children’s Hospital of Philadelphia, continuing pediatric proton therapy services at the new site.

Penn Medicine employs a centralized planning model in which physicists and dosimetrists based at the Perelman Center develop treatment plans that are executed by local radiation oncologists. This approach will be used at Penn Presbyterian, mirroring the setup at Penn’s other proton therapy locations in Lancaster and South Jersey.

FLASH therapy
The Roberts Proton Therapy Center will deepen Penn's commitment to pioneering FLASH radiotherapy, an experimental cancer treatment that delivers ultrahigh doses of radiation in less than a second. This technique, which remains in early-stage research and clinical trials globally, has drawn attention for its potential to reduce side effects while maintaining or improving tumor control.

The approach contrasts with conventional radiotherapy by dramatically shortening treatment time — compressing what typically takes several minutes into milliseconds. Laboratory studies suggest FLASH may spare more healthy tissue than traditional methods, though large-scale clinical validation is still needed.

Penn’s work builds on its history as a leader in proton therapy research, having trained staff from 27 centers worldwide and led multiple clinical trials in precision radiation. FLASH research at Penn spans both proton and photon platforms, with preclinical investigations underway to determine optimal dosing, safety, and efficacy parameters.

While several institutions in Europe and the United States are testing FLASH using photon beams, Penn is among a smaller group exploring proton-based FLASH delivery, leveraging its existing proton infrastructure and centralized treatment planning expertise. Though the timeline for routine clinical use remains uncertain, Penn’s investment in FLASH underscores a broader shift toward developing next-generation radiotherapy techniques aimed at improving patient outcomes.

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