Comparison between Acuros XB and Brainlab Monte Carlo algorithms for photon dose calculation

Area of Science:

• Medical Physics
• Radiation Oncology

Background:

• Accurate dose calculation is crucial for effective radiation therapy planning.
• Advanced algorithms like Acuros® XB (AXB), XVMC (Monte Carlo), and Anisotropic Analytical Algorithm (AAA) are used for this purpose.

Purpose of the Study:

• To compare the dose calculation accuracy of Varian's Acuros® XB (AXB) and Brainlab's XVMC (Monte Carlo) algorithms against Varian's AAA algorithm.
• To evaluate the performance of these algorithms in both artificial phantom and clinical patient scenarios.

Main Methods:

• Dose calculations were performed using AXB, XVMC, and AAA algorithms.
• Comparisons were made using a slab phantom (water-bone-lung layers) and a lung phantom.
• Depth-dose curves and profiles were analyzed in phantoms.
• Clinical patient CT data was used to recalculate plans and compare dose-volume histograms (DVHs).

Main Results:

• AXB and XVMC showed minimal differences in depth doses and profiles within artificial phantoms.
• AAA exhibited deviations up to 13% in depth dose and a few percent in lung phantom profiles.
• In clinical cases, DVHs for all three algorithms were comparable for open fields.

Conclusions:

• AAA demonstrates differences at tissue boundaries in artificial phantoms compared to AXB and XVMC.
• These discrepancies were not observed in the dose-volume histograms of planning target volumes for real patient CTs.
• AXB and XVMC show good agreement, suggesting their reliability in clinical applications.