Dosimetric Comparison of Anisotropic Analytical Algorithm and Acuros XB in Stereotactic Body Radiotherapy and Effect of Calculation Grid Size

Abstract

OBJECTIVEThis study aimed to determine the dose differences between Acuros XB (AXB) and anisotropic analytical algorithm (AAA) for patients with liver cancer who underwent stereotactic body radiotherapy (SBRT) and to investigate the dose-related effect of dose calculation grid size (CGS). METHODSSBRT treatment was planned for 10 patients with liver cancer using 1-mm and 2.5-mm CGS with AAA and AXB algorithms with 10 MV flattening filter-free (FFF) rays in Varian Trubeam STx. RESULTSWhen AAA 1-mm CGS plans and AAA 2.5-mm CGS plans were compared, 4% difference was observed; when AXB 1-mm CGS plans and AXB 2.5-mm CGS plans were compared, 1% difference was found. No significant difference was found between plans with AAA 1-mm CGS and plans with AXB 1-mm CGS (p>0.05). On the other hand, there was a significant difference between plans with AAA 2.5-mm CGS and plans with AXB 2.5-mm CGS (p<0.05). CONCLUSIONAs a result of the study, it was seen that the AXB algorithm gave more stable results than the AAA one in different intensity body regions. High doses are administered in a small number of fractions in SBRT. For SBRT, 1-mm CGS should be selected for calculation accuracy.