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Published on: July 29, 2013
Comprehensive quality assurance of a surface-guided radiotherapy system using a new anthropomorphic add-on phantom in
Mathias Dierl1, Andreas A Schönfeld2, Oscar Casares-Magaz2
1Klinikum Bayreuth GmbH, Department of Medical Physics, Bayreuth, Germany; Department of Radiation Oncology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany; Comprehensive Cancer Center Erlangen-EMN (CCC ER-EMN), Erlangen, Germany.
A new anthropomorphic phantom add-on enables comprehensive quality assurance for surface-guided radiotherapy (SGRT) systems. This advanced phantom ensures accurate positioning and precise dose delivery, meeting ESTRO-ACROP guidelines for SGRT QA.
Area of Science:
- Medical Physics
- Radiotherapy Technology
- Quality Assurance
Background:
- Surface-guided radiotherapy (SGRT) systems are increasingly used for precise patient positioning during radiation therapy.
- Ensuring the quality assurance (QA) of SGRT systems is critical for treatment accuracy and patient safety.
- Existing QA methods may not fully capture the end-to-end performance of SGRT in complex treatment scenarios.
Purpose of the Study:
- To evaluate the suitability of a novel anthropomorphic phantom add-on for comprehensive QA of SGRT systems.
- To validate the phantom's performance against established ESTRO-ACROP guidelines for SGRT QA.
- To assess the end-to-end accuracy and precision of an SGRT system using the new phantom.
Main Methods:
- Positional accuracy of the SGRT system was assessed in 6 degrees-of-freedom using cone-beam computed tomography (CBCT) as ground truth.
- End-to-end tests were performed using the phantom on a dynamic platform to simulate dynamic dose delivery for sinusoidal and deep-inspiration breath hold (DIBH) treatments.
- The phantom-detector setup was integrated with a C-arm linac equipped with an SGRT system.
Main Results:
- The SGRT system demonstrated positioning accuracy within ±0.5mm/±0.5°.
- For gated delivery with a 5mm tolerance, the 2%/3mm gamma metric achieved 100% pass rates for sine waveforms and 96.5% for DIBH waveforms.
- End-to-end tests with a 2%/1mm gamma criterion showed 100% pass rates for single-target plans and 95.3% for multi-metastasis target plans.
Conclusions:
- The new anthropomorphic phantom add-on provides a robust solution for comprehensive SGRT system QA.
- The phantom facilitates thorough evaluation of end-to-end positioning accuracy and delivery precision.
- The integrated approach aligns with ESTRO-ACROP guidelines and utilizes widely adopted stereotactic radiotherapy equipment.
