Author: Maria Jose Almada, Carlos Bohorquez, Maximiliano Musso, Rosa Petit, Carlos Daniel Venencia, Lucy D. Wolfsberger 👨🔬
Affiliation: LAP, Instituto Zunino - Fundacion Marie Curie 🌍
Purpose:
PSQA is crucial in maintaining patient safety, typically depending on dosimetric measurements. However, advancements in computational technology have highlighted the growing significance of independent calculation software. This study seeks to incorporate Radcalc into the clinical workflow as a PSQA system for photon beam energies from a TrueBeam STx accelerator, specifically 6X FFF and 10X FFF
Methods:
RadCalc v7.3 software was utilized in this work, and the dosimetric data from the TrueBeam STx linear accelerator were modeled. Dose profiles of open fields defined by the MLC were compared using Eclipse TPS v15.6 with the Anisotropic Analytical Algorithm dose calculation algorithm and Radcalc with the collapsed cone dose calculation algorithm with gamma passing rate criterion was 2%, 2mm, and a Th of 5%. A comparison was performed for four fields with modulation. TG-119 clinical cases were evaluated. Finally, ten clinical cases covering different anatomical locations were selected for each energy. The gamma passing rate criterion was 3%, 2mm, and a Th of 30%. The plans were verified using portal dosimetry, the Delta4 phantom, independent Radcalc dose calculations, and two in vivo dosimetry verification methods involving trajectory files, Radcalc logs, and RT plan reconstruction.
Results:
Dose profiles calculated by RadCalc and those obtained using Eclipse demonstrated a high level of agreement, and the gamma index exceeded 95% for all fields. Gamma analysis of modulation fields, performed using portal dosimetry, RadCalc dose calculations, RadCalc logs, and the reconstructed RT plan, yielded passing rates above 95%. The TG-119 clinical cases' gamma index exceeded 90% for all PSQA methods. Lastly, the gamma pass rate for the selected clinical cases was above 90% across all PSQA methods.
Conclusion:
This work confirms the usefulness and capability of RadCalc for clinical dosimetric verification of treatment plans with 6X FFF and 10X FFF beams.