Closer to Care Series: Making Particle Therapy More Accessible with Marie®

Particle therapy is widely regarded as one of the most advanced and precise forms of cancer treatment available today. By delivering radiation with exceptional accuracy, proton beam therapy and carbon ion therapy can target tumors while reducing unnecessary dose to surrounding healthy tissues.

Yet despite its clinical promise, access to particle therapy remains limited for many patients due to cost, infrastructure requirements, and operational complexity.

Across the industry, researchers, clinicians and technology developers are exploring new approaches to make particle therapy more accessible.

One such approach is Marie®, Leo Cancer Care’s upright radiotherapy solution, which seeks to address some of the infrastructure challenges associated with conventional particle therapy systems.

The Access Challenge in Particle Therapy

Particle therapies such as proton and carbon ion therapy offer significant advantages for many cancer indications. However, global adoption has been slower than many anticipated given its clinical advantages.

Despite growing clinical adoption, access remains limited. According to Particle Therapy Co-Operative Group (PTCOG) data, there were approximately 120 proton therapy centres and 14 carbon ion therapy centres operating worldwide in 2024, highlighting the relatively limited availability of particle therapy compared with conventional radiotherapy services [1].

A key reason is infrastructure.

Conventional particle therapy systems rely on large rotating gantries. These are complex mechanical structures that can weigh hundreds of tonnes and require purpose-built facilities, extensive shielding, and substantial capital investment.

For many healthcare providers, introducing particle therapy remains a significant undertaking. For many patients, access is not just limited; it can require travelling long distances or relocating temporarily to receive treatment.

Why Accessibility Matters

Improving access to advanced cancer treatment is about more than expanding technology.

Expanding access to proton therapy has the potential to reduce travel burdens for patients and support treatment decisions based on clinical need rather than geographic availability [2]. When treatment is available closer to where patients live, it may minimize disruption to family and work life, while enabling more patients to benefit from innovations in radiation oncology.

As demand for precision cancer treatments continues to grow, healthcare systems are increasingly seeking solutions that can deliver high-quality care without requiring entirely new facilities or major infrastructure projects [3].

One approach to addressing these challenges is to rethink how treatment is delivered.

Rethinking How Particle Therapy Is Delivered

An alternative approach is to keep the treatment beam fixed while rotating the patient in an upright position.

This principle forms the basis of the Marie® system. Which challenges one of the long-standing assumptions in radiation therapy: that the treatment beam must rotate around the patient.

Instead, the radiation beam remains fixed while the patient is gently rotated in an upright position.

By eliminating the need for a rotating gantry, this approach introduces several practical advantages:

• Reduced system size, potentially up to one-third of conventional particle therapy configurations
• Lower infrastructure and construction requirements
• Compatibility with existing treatment environments, including LINAC vaults [4]

By simplifying system design, particle therapy has the potential to become more attainable for healthcare providers looking to expand access to advanced treatment options.

Designed Around the Patient

At the heart of Marie® is a patient-centred approach to treatment delivery.

Patients are treated in a seated, upright position which is closer to the body’s natural posture than conventional supine treatment approaches.

This may offer several advantages, including improved comfort and reduced feelings of vulnerability during treatment [5]. Emerging research also suggests that upright positioning may support greater anatomical stability and reduce organ motion in certain treatment sites, particularly in the thoracic and abdominal regions [6].

The design also enables a more direct, eye-level interaction between patients and clinicians, helping create a treatment environment that feels more connected and supportive.

Supporting Adaptive and Personalised Treatment

Advances in imaging and adaptive radiotherapy are helping clinicians respond more effectively to the day-to-day anatomical changes that can occur throughout a course of treatment.

Marie® incorporates an upright fan-beam CT scanner within the treatment environment, enabling imaging and treatment to be integrated into a single workflow. This approach supports:

• Daily imaging and online adaptive therapy, allowing treatment plans to respond to anatomical changes over time
• Image-guided verification to support accurate treatment delivery
• Future opportunities for particle arc therapy and enhanced dose conformity

Online adaptive radiotherapy enables treatment plans to be modified in response to anatomical changes identified through onboard imaging, helping maintain treatment accuracy throughout the course of therapy [7]. Daily image guidance and adaptive workflows have become increasingly important in modern radiotherapy as clinicians seek to account for anatomical variation and organ motion between treatment fractions [8].

As imaging technologies become more closely integrated with treatment delivery, they have the potential to support increasingly adaptive and personalised approaches to cancer care.

From Innovation to Global Impact

Marie® achieved FDA 510(k) clearance in 2025 and CE marking in 2026, demonstrating readiness for clinical implementation in both the United States and Europe. This regulatory progress was followed by treatment of the first patient using the system, marking an important transition from development and validation to clinical adoption.

Interest in upright treatment delivery and gantry-less particle therapy approaches is growing across multiple regions, reflecting a broader focus on improving accessibility and reducing infrastructure requirements.

As healthcare systems continue to seek ways to expand access to advanced radiation oncology technologies, innovations that reduce infrastructure barriers may play an increasingly important role.

Expanding Access to Advanced Cancer Treatment

Marie® reflects a broader trend within radiation oncology towards solutions that aim to reduce infrastructure barriers while maintaining treatment precision.

By fitting within existing LINAC vaults and reducing facility requirements compared with conventional proton therapy systems, Marie® has the potential to simplify implementation while maintaining a focus on patient experience and treatment precision.

Whether through upright treatment delivery, adaptive workflows, or new facility models, the broader challenge remains the same: how can advanced cancer treatments become available to more patients?

Addressing that challenge will require continued collaboration between clinicians, researchers, healthcare providers and technology developers.

Because the future of cancer treatment is not only about advancing technology, but also about ensuring that more patients have the opportunity to benefit from it.

Reference

1. Durante, M. Current status and future trends in particle therapy – lessons from an interdisciplinary workshop. Health Technol. 14, 819–821 (2024). https://doi.org/10.1007/s12553-024-00855-6
2. NAPT News. 2026. Expanding Global Access to Proton Therapy on World Cancer Day. Available at: https://proton-therapy.org/expanding-global-access-to-proton-therapy-on-world-cancer-day/?utm_source=chatgpt.com
3. Yan S, Ngoma T, Ngwa W et al. Global democratisation of proton radiotherapy. The Lancet Oncology. 2023. 24 (6), e245-e254
4. Underwood T, et al. A Strengths, Weaknesses, Opportunities, and Threats (SWOT) Analysis for Gantry-Less Upright Radiation Therapy. International Journal of Radiation Oncology, Biology, Physics. 2025; 122, 1337-1343
5. Ulman, J, et al. Exploring patient perceptions of the current breast radiotherapy pathway and a future upright radiotherapy solution. Radiography. 2025. 31(6). ISSN 1078-8174. https://doi.org/10.1016/j.radi.2025.103157.
6. Marano J, et al. Relative thoracic changes from supine to upright patient position: A proton collaborative group study. J Appl Clin Med Phys. 2023 Dec;24(12):e14129. doi: 10.1002/acm2.14129.
7. Lu, L, et al. A Review of Online Adaptive Radiation Therapy. Appl Rad Oncol. 2024;(4). doi:10.37549/ARO-D-24-00037
8. Liu, H., Schaal, D., Curry, H. et al.Review of cone beam computed tomography based online adaptive radiotherapy: current trend and future direction. Radiat Oncol18, 144 (2023). https://doi.org/10.1186/s13014-023-02340-2