Comparison of surface dose and peripheral dose with radiochromic film measurements in different treatment plans that calculated different calculation algorithms

Accurate modeling of the peripheral doses and surface doses have great importance for the clinical results in radiation therapy. Therefore, peripheral dose and surface dose distribution must be modeled accurately by calculation algorithms in the treatment planning system (TPS). The aim of this study to compare Analytic Anisotropic Algorithm (AAA), Acuros XB (AXB) and Pencil Beam Convolution Algorithm (PBC) with Radiochromic Film measurements and check the authenticity of the calculation algorithms. In this study, three dimensional conformal radiotherapy (3DCRT), intensity modulated radiotherapy (IMRT) and volumetric arc therapy (VMAT) plans were created on the TPS for the estimation of peripheral and surface dose. 3DCRT plans were created in three different field sizes (5x5 cm2, 10x10 cm2,20x20 cm2) and depths (1.5 cm, 5 cm,10 cm). Each treatment plans, created on the Eclipse TPS, were calculated by the different calculation algorithms. Two dimensional dose distribution of the plans that created for estimation of peripheral and surface dose, were exported. After these dose distributions exported, they had been compared with Radiochromic Films which were irradiated by Varian Trilogy Tx linear accelerator. The comparisons have been made via Film QA. Pro. software. In the estimation of 3DCRT's peripheral dose, it was observed that calculation algorithms could model better unless increasing field sizes and depths. Peripheral dose was underestimated by the calculation algorithms in the each of 3DCRT, IMRT and VMAT plans. However, AAA calculation algorithm calculated peripheral dose better than the other calculation algorithms in these three treatment techniques. The results were similar in the surface dose estimation. Each of Eclipse TPS calculation algorithms underestimated surface dose in all 3DCRT, IMRT and VMAT plans. Although all calculation algorithms underestimated the surface dose, AAA was the closest calculation algorithm to the Radiochromic Film but there was a little difference between AAA and AXB calculation algorithms.