Comparison of Anisotropic Analytical Algorithm and Acuros XB Calculation Algorithms on Intensity-modulated Radiotherapy and Volumetric Modulated Arc Therapy Techniques for Nasal Cavity and Paranasal Sinus Tumors: Effects on Integral Radiation Dose
Aydın ÇAKIR1,Züleyha AKGÜN2
1İstanbul Bilgi University, Vocational School, İstanbul-Turkey
2Department of Radiation Oncology, Memorial Şişli Hospital, İstanbul-Turkey
DOI : 10.5505/tjo.2019.2075 OBJECTIVE
This study aims to investigate the dosimetric effects of Acuros XB (AXB) and Anisotropic Analytical algorithms (AAA) on intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) techniques for nasal cavity and paranasal sinus tumors.

This study included 10 patients with the nasal cavity and paranasal sinus tumors, and 7-field non-coplanar IMRT plan and VMAT plans were generated with 6-MV photon beams specially selected for each patient anatomy. The effects on planning target volume (PTV) and organ-at-risk (OAR) were evaluated using AXB and AAA in each treatment technique to compare the accuracy of the calculation.

Conformity Index (CI) values for PTV were found to be 1.02±0.02 and 1.03±0.03 for VMATAAA and VMATAXB plans, respectively and 1.18±0.03 and 1.20±0.02 for IMRTAAA and IMRTAXB plans, respectively. Regarding heterogeneity index (HI) values, VMATAAA and VMATAXB plans (0.025±0.02; 0.029±0.02) were found to have better HI values than IMRTAAA and IMRTAXB plans (0.246±0.02; 0.335±0.03). Depending on the technique and algorithm used, a dose difference of 4%-14% was detected between PTV Dmin values.

The selection of AXB algorithm in treatment regions with high tissue heterogeneity will give more accurate dose calculation results for PTV and healthy tissues. Keywords : Anisotropic analytical algorithm; Acuros XB; nasal cavity, radiotherapy for paranasal sinus; integral dose