Clinical validation of the Acuros XB photon dose calculation algorithm, a grid-based Boltzmann equation solver

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Dosimetry

Background:

• External photon beam treatment planning requires accurate dose calculations.
• Traditional algorithms face challenges in heterogeneous media.
• A novel grid-based linear Boltzmann transport equation (LBTE) solver, Acuros XB, was developed.

Purpose of the Study:

• To evaluate the accuracy of the Acuros XB algorithm for dose calculations.
• To compare Acuros XB with the AAA convolution algorithm.
• To assess performance in both homogeneous and heterogeneous media.

Main Methods:

• Measured output factors, depth dose curves, and profiles using ionization chambers and diamond detectors.
• Calculated dose distributions in a CIRS thorax phantom with heterogeneous inserts using Acuros XB and AAA.
• Validated calculations against radiochromic film measurements.

Main Results:

• Acuros XB demonstrated excellent agreement with measurements (output factors within 1%, depth doses within 1%/1 mm DTA).
• Acuros XB showed superior performance in heterogeneous media (98-100% gamma passing rates) compared to AAA (94-96%).
• Acuros XB calculations were also in good agreement with AAA in homogeneous media.

Conclusions:

• The Acuros XB algorithm provides accurate dose calculations in homogeneous media.
• Acuros XB significantly outperforms AAA in heterogeneous environments, particularly in lung and bone.
• This advancement enhances the reliability of external beam treatment planning.