Many cancer centers, including Mercy’s David C. Pratt Cancer Center in St. Louis, are discovering that innovation isn’t just about acquiring the large radiotherapy equipment—it’s often about how advanced tools like surface guidance are integrated into existing workflows. We turned to C-RAD’s SGRT to bring more precision and confidence to our expanding proton therapy program. What started as a positioning aid has become a key part of how we deliver accurate, patient-focused care—building on the same principles that made surface guidance a staple in high-precision photon treatments.
Integrated for Impact: Patient-Focused Proton Therapy with C-RAD and Mevion
The combination of C-RAD’s SGRT system with the Mevion Proton Therapy system brought exciting potential—but also required our Mercy team to develop custom workflows. While the department had already expanded SGRT use across photon therapy on Elekta linacs, the move into proton therapy opened new opportunities to build on those strengths. Over time, our team uncovered practical applications that have meaningfully improved both patient experience and clinical outcomes.
Managing Motion with SGRT in Lung and GI Proton Cases
One of the most impactful innovations has been in proton treatments for lung and lower-GI gastrointestinal cases. These patients often exhibit subtle but significant internal motion, especially in the diaphragmatic region, which compromise target coverage. We found that incorporating DIBH with SGRT at simulation and during daily treatment stages helped ensure consistent external anatomy and respiratory patterns, reducing the variability that could compromise the precision of proton dose delivery. This approach enabled us to validate patient positioning with a level of confidence that would be difficult to achieve with free breathing or imaging alone—without increasing imaging dose or treatment time.
Same patient. Same plan. Two different breathing phases—two different outcomes.
SGRT with DIBH helps stabilize external anatomy and reduce internal variability, giving proton therapy the consistency it needs.
Streamlining Multi-Isocenter Proton Treatments
We also faced a challenging scenario: how to manage extended-field treatments, such as bilateral breast irradiation, which require multiple isocenters. Our current Oncology Information System (OIS) doesn’t natively support proton treatments with more than one isocenter, creating an obstacle that could potentially slow treatments and increase the margin for error.
Rather than accept this limitation, we adopted a technique used at Huntsman Cancer Institute (Salt Lake City, Utah), which relied on relative couch shifts. We took this one step further by integrating SGRT as a visual verification tool. After each couch shift, SGRT confirmed the patient’s surface alignment, allowing therapists to validate positioning at each isocenter before proceeding. The result was a dramatically shortened treatment time—nearly halved—and significantly increased confidence and consistency during treatment delivery.
Faster setup for multi-isocenter proton treatments
A Simple Fix for a Complex DIBH Challenge
DIBH patients who required repeat CT simulations, either for quality assurance or due to changes in anatomy, posed another unexpected challenge. SGRT reference surfaces rely on consistent placement of a respiratory marker because even minor deviations in this placement during a rescan can invalidate the reference surface, causing real-time troubleshooting and treatment delays.
A Broader Role for Surface Guidance in Radiation Therapy
Our team’s experience highlights just how adaptable SGRT can be when expertly integrated into complex treatment settings. While it’s often associated with breast cases, our work at Mercy shows that its true value lies in its versatility. Whether it’s enabling faster, more reliable multi-isocenter treatments, enhancing motion management in proton therapy, or ensuring consistency in DIBH, SGRT has proven to be a robust, multi-functional tool in our clinic.
More Than Efficiency: A Better Experience for Everyone
Beyond the technical achievements, these innovations have positively impacted the clinical environment:
- Treatment times are shorter, especially for complex proton cases.
- Therapists feel more empowered and less rushed, knowing they have tools that support efficient, accurate setup.
- Patients benefit from quicker treatments and more precise delivery, which can directly affect outcomes, especially in sensitive proton therapy scenarios.
Looking Ahead: Innovation Through Collaboration
At its core, Mercy’s SGRT journey isn’t about a single breakthrough—it’s about a team committed to asking, “How can we make this better?” and embracing trial, adaptation, and collaboration. In doing so, we’ve created a model for other centers looking to evolve their approach to radiation therapy. As more proton centers open around the world, the lessons we learned can continue to serve as a powerful example of what’s possible when radiation oncologist teams reimagine the potential of their technology.
Mercy Cancer Centers at a Glance
C-RAD surface guidance solutions are integrated across all Elekta linacs and the Mevion Proton Therapy system—supporting consistent workflows and patient care throughout the Mercy network.
Mercy St. Louis
• Elekta Versa HD
• Mevion s250i with Hyperscan Proton Therapy
• Accuray TomoTherapy Hi-Art
• Accuray Radixact
• Accuray CyberKnife S7
Mercy South
• Elekta Versa HD
• Accuray Radixact
Mercy Jefferson
• Elekta Versa HD
Mercy Washington
• Elekta Versa HD
Mercy/Anderson Cancer Center
• Elekta Infinity
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