Pre-clinical evaluation of a novel surface-guided radiation therapy (SGRT) system
Pre-clinical evaluation of a novel surface-guided radiation therapy (SGRT) system
“All test results were within the manufacturer’s specifications and ESTRO guideline tolerances. A comparison of LUNA 3D with traditional lasers and CBCT demonstrates that the system offers accurate patient positioning guidance.”
Authors
Hui Khee Looe, Björn Poppe, Kay C. Willborn
University Clinic for Medical Radiation Physics and Clinic for Radiation Therapy, Medical Campus Pius Hospital,
Carl von Ossietzky University, Oldenburg, Germany
ECMP 2024
Introduction
Surface-guided radiation therapy (SGRT) has become a standard of care in modern radiotherapy. In addition to providing dose-free, markerless patient positioning, SGRT systems enable real-time monitoring and advanced respiratory motion management. Recently, a new SGRT system was introduced. This work presents the initial results from our pre-clinical evaluation of this system, which features a browser-based user interface, fast GPU parallel computing, and an innovative virtual lasers concept.
Materials and Method
The novel SGRT system LUNA 3D (LAP, Germany) was installed at a C-arm linac (Synergy, Elekta) with three pods. The acceptance tests were implemented according to the ESTRO-ACROP guideline1. Both static and dynamic accuracies have been evaluated using the EASY CUBE phantom (LAP) in combination with a translational and dynamic platform. The End-to-End (E2E) testing using the RUBY phantom (PTW, Germany) was adapted to accommodate the laser-free positioning. The isocenter of the plan was arbitrarily set within the phantom, and the phantom was positioned solely using LUNA 3D guidance. The plan was then irradiated, and the dose was measured using the microDiamond detector (PTW). Additionally, pre-clinical evaluations were conducted to compare patient positioning accuracy using LUNA 3D versus traditional laser guidance, as well as the required CBCT-based corrections.
Results
The static accuracy with translational and rotational shifts was found to be better than 0.4 mm, even when accounting for the uncertainty introduced by manually shifting the phantom. Dynamic accuracy was assessed based on amplitude deviation (< 0.2 mm) and cycle period variation (< 0.2 s). In the E2E testing, positioning with LUNA 3D agreed with CBCT results within 1.4 mm and 0.5°. Additionally, the measured dose of the delivered plan was consistent within 1.2%. The concept of virtual lasers has proven to be an invaluable feature during pre-clinical evaluations (Figure 3), offering intuitive guidance for patient setup. Additionally, the extended field of view provided by LUNA 3D ensures reliable patient monitoring throughout the entire treatment process.
Conclusion
All test results were within the manufacturer’s specifications and ESTRO guideline tolerances. A comparison of LUNA 3D with traditional lasers and CBCT demonstrates that the system offers accurate patient positioning guidance.