SU-E-T-525: Dosimetric Validation of the Algorithm Based on Linear Boltzmann Transport Equations for Photon 4MV Dose...

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Dosimetry

Background:

• Accurate dose calculation is crucial for effective radiotherapy.
• The AcurosXB (AXB) algorithm offers a potentially more accurate method for dose calculation.
• Evaluating AXB's performance against the established Anisotropic Analytical Algorithm (AAA) is essential.

Purpose of the Study:

• To assess the dosimetric accuracy of the AcurosXB algorithm for a 4 MV photon beam.
• To compare the performance of AcurosXB against the AAA algorithm in various phantom conditions and clinical scenarios.

Main Methods:

• Utilized a 4 MV photon beam (Clinac-6EX) with AAA and AcurosXB algorithms.
• Evaluated depth doses and dose profiles in water, lung-equivalent, and bone-equivalent phantoms.
• Analyzed clinical whole breast and head and neck IMRT plans, comparing AAA and AcurosXB calculations.

Main Results:

• AcurosXB demonstrated superior agreement with measurements in heterogeneous phantoms, particularly in lung and bone-equivalent materials.
• AXB showed better accuracy in the re-buildup region after lung phantom, with differences within 3% compared to AAA's ~10% overestimation.
• Clinical cases showed higher surface doses with AcurosXB, but dose-volume histogram (DVH) shapes for organs-at-risk were similar between algorithms within 2%.

Conclusions:

• AcurosXB exhibits enhanced dosimetric accuracy over AAA, especially in complex heterogeneous environments.
• Discrepancies in surface dose calculations between AcurosXB and AAA were noted in clinical applications.
• Further evaluation of AcurosXB's clinical agreement with Varian Medical Systems is recommended.