UPRIGHT RT SUMMIT 2026: FROM POSSIBILITY TO CLINICAL PRACTICE

Leo Cancer Care’s second annual Upright RT Summit brought the upright radiotherapy community together in Boston alongside ASTRO. The atmosphere reflected how much had changed in just twelve months.

At the previous summit, fundamental questions remained about treating patients upright, accommodating children and supporting those who needed general anesthesia. This year, Stanford Medicine’s experience of treating adults and children, both with and without anesthesia, gave those discussions a clinical foundation.

The focus is now expanding to workflow, imaging, immobilization and the lessons that will help other centers introduce upright treatment into practice.

CLINICAL EXPERIENCE CHANGES THE CONVERSATION

Leo Cancer Care CEO and co-founder Stephen Towe opened by sharing a patient’s perspective on upright treatment. The first upright patient, a young boy who had received treatment both lying down and sitting up, shared a preference for sitting up. His feedback brought the discussion back to what these developments can mean for the person receiving care.

Dr. Billy Loo described Stanford Medicine’s journey to delivering the world’s first clinical upright proton treatments using a Mevion S250-FIT in a converted linac vault, less than five years after the initial concept was sketched out.

At the time of the summit, Stanford Medicine had simulated 15 patients, including 6 children, and treated 9 patients, predominantly with head and neck conditions. 3 children had received treatment: 2 without anesthesia and one with. Treatment times had already reduced to approximately 20–30 minutes.

Dr. Loo’s advice to centers preparing to follow was practical: learn from established proton programs, rehearse extensively, increase clinical activity deliberately and learn from every patient.

BUILDING THE FOUNDATIONS FOR WIDER ACCESS

Stephen announced over 50 systems under contract globally and introduced two partnerships exploring new possibilities for upright care.

He introduced the partnership with Terapet looking to integrate PET imaging at the isocenter, illustrating the opportunities created by removing the gantry. The collaboration with GE HealthCare aims to combine Leo hardware with GE software to support simulation, planning and treatment in a single room, shortening the pathway to a patient’s first fraction.

Chief Commercial Officer Michael Bauer outlined further milestones:

• Regulatory and financial progress: the European CE marking for Marie and a Series D funding round that exceeded its $55 million target to reach $65 million.
• Expanded capacity: a new Crawley office and a 35% expansion of the Madison facility, tripling production capacity.
• Research and international growth: a real-time tumor tracking collaboration with Imperial College London and first system sales into Vietnam, India through Fortis, and Turkey.

Plans for the next 12–18 months include first carbon ion treatments at CNAO in 2027 and clinical go-lives at BayCare, UW Health, the University of Nebraska, McLaren and Atlantic Health.

PREPARING NEW CENTERS FOR UPRIGHT TREATMENT

Dr. Carri Glide-Hurst described UW Health’s approach to a program that pairs a Hitachi gantry room and beam line with a Leo Marie fixed-beam room.

Early measurements showed beam spot sizes matching between the rooms to within 0.5 mm. The team also reported stopping power ratios and dose calculations from the upright CT comparable to those obtained using a conventional Siemens scanner.

Commissioning was scheduled to begin in October, with upright treatments anticipated in winter 2027, subject to the necessary FDA clearances. The presentation offered a practical view of the integration and verification work involved in preparing a new center.

PREPARING CHILDREN, SUPPORTING FAMILIES

The pediatric session brought together patient preparation, clinical experience and engineering.

Stephen discussed the ambition to reduce the need for general anesthesia where appropriate by helping children become familiar with treatment beforehand. Initiatives include an augmented reality app, Leo the Lion as a familiar companion and Stanford Medicine’s AVATAR distraction system, licensed by Leo. A planned ambassador program would support knowledge sharing between pediatric centers of excellence.

Education and distraction are being developed alongside workflows for children who need anesthesia, recognizing that different patients require different support.

Chief Scientific Officer, Dr. Niek Schreuder shared updates on current pediatric immobilization development from a car seat concept to a forward-leaning device with an embedded screen. He also highlighted the newly published paper from the multi-institutional, multidisciplinary Upright Pediatric Radiotherapy Task Group, setting out the rationale, safety considerations and research priorities for treating children upright.

Dr. Lawrie Skinner presented Stanford Medicine’s 3D-printed tilting chair for children aged up to eight years. Key features include a supine-to-upright anesthesia workflow, a carbon backrest for craniospinal treatment and emergency extraction onto a gurney in approximately 5–10 seconds. He also described an ultra-thin OLED screen designed to allow photon beams to pass through it.

RESEARCH AND PLANNING SHAPE THE NEXT STEPS

Marc Mlyn, President of RaySearch Americas, outlined RayStation®’s support for the Mevion FIT upright configuration, including native handling of chair and backrest angles in Version 2025.

His presentation explored fallback planning, proton arcs, shoot-through beams and online adaptive replanning, including demonstrations of replanning in under a minute. Progress towards clinical use will depend on validation, integration and individual centers’ requirements. It was noted that some of the features and versions discussed were not yet available in the US and would need to be submitted to the FDA for clearance.

Niek’s review of 52 upright publications found that 36 had been published since 2021, with approximately two-thirds directly connected to Leo. The European UPLIFT consortium’s 19 PhD projects further illustrates the growing research activity.

For the first time, the summit invited researchers worldwide to compete for travel grants. Four finalists presented:

• Dr. Andrea Pella, CNAO, presenting on behalf of a PhD colleague Jiale Chen, examined how postural sway affects the relationship between respiratory surrogates and internal motion.
• Dr. Ye Zhang, PSI, presented synthetic upright patient models developed from paired upright and supine MRI scans of volunteers.
• Dr. Michelle Doherty, Mayo Clinic, introduced PoseLuna, a depth-camera system that uses body measurements to recommend initial chair settings.
• Dr. Jordan Slagowski, UW–Madison, presented UP-SNAP, combining chair rotation and vertical translation to create non-circular proton arcs for long treatment fields, including craniospinal irradiation.

Dr. Michelle Doherty received first place and a $10,000 travel grant, with Jiale, (presented by Dr. Andrea Pella), awarded second place and a $5,000 grant to support sharing their research.

LEARNING TOGETHER AS CLINICAL PRACTICE DEVELOPS

The closing panel brought Drs. Loo, Glide-Hurst and Schreuder together with Marc Mlyn to discuss lessons from development and early clinical use.

Verification and room design were central themes, including the value of orthogonal imaging, involving radiation therapists early and preparing installations for future capabilities. The panel also emphasized clinical champions, end-to-end testing and supporting staff through the learning curve.

Discussion of upright CT, motion quantification and adaptive therapy highlighted both current capabilities and priorities for further development. Across these topics, clinical experience and user feedback will help guide what comes next.

Boston marked a new phase for upright radiotherapy: patients are receiving treatment, and teams are sharing what they are learning. The summit demonstrated a commitment to building on that experience through research, careful preparation and collaboration.

We look forward to continuing those conversations at the Upright RT Summit 2027 in Chicago.