Dose distribution evaluation of various dose calculation algorithms in inhomogeneous media

Abstract

Background: Dose calcula on algorithms play a very important role in predic ng the explicit dose distribu on. We evaluated the percent depth dose (PDD), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calcula on algorithms and inhomogeneity correc on methods. Materials and Methods: The homogeneous and inhomogeneous virtual slab phantoms used in this study were manufactured in the radia on treatment planning system to represent the air, lung, and bone density with planned radia on treatment of 6 MV photons, a field size of 10 × 10 cm 2 , and a source-to-surface distance of 100 cm. Results: The PDD of air density slab for the Acuros XB (AXB) algorithm was differed by an average of 20% in comparison with other algorithms. Rebuild up occurred in the region below the air density slab (10-10.6 cm) for the AXB algorithm. The lateral dose profiles for the air density slab showed rela vely large differences (over 30%) in the field. There were large differences (20.0%-26.1%) at the second homogeneous-inhomogeneous junc on (depth of 10 cm) in the field for all calcula on methods. The surface dose volume histogram for the pencil beam algorithm showed a response that was approximately 4% lower than that for the AXB algorithm. Conclusion: The dose calcula on uncertain es were shown to change at the interface between different densi es and in varied densi es using the dose calcula on methods. In par cular, the AXB algorithm showed large differences in and out of the field in inhomogeneous media.

Investigation of the effects on dose calculations of correction-based algorithms in different tissue medium

“…In these treatment fields, vertical electronicequilibrium cannot be calculated effectively due to the fact that TPS algorithms have many heterogeneous in area close to the skin. Therefore, the calculated dose in the skin area is slightly different from the measured dose [18]. The PBC dose calculation algorithm calculates the absorbed dose faster because it does not effectively account for the horizontal electronic equilibrium and scattered electrons.…”

The dosimetric comparison using anisotropic analytical algorithm (AAA) and Acuros XB algorithms in the target overlapping with air cavity of pituitary carcinoma

“…In addition, the effect of dose for heterogeneity as lung and air is difference. From Kim et al (13) studied the dose comparison in heterogeneity phantom slab between AAA and AXB of about 2.8% and 20% in lung tissue and in air, respectively. AAA calculation is more overestimate dose in air than in lung too much that the results agreed with Fogliata et al (14).…”

Equivalent uniform dose and normal tissue complication probability of acute esophagitis in head-and-neck radiotherapy: Sensitivity to dose calculation accuracy

“…Sasani 4,5 , P. Jafari 6 , R. Fardid 1,3 algorithms can, therefore, be critical (11) . Many studies have evaluated the accuracy of different dose calculation algorithms for a wide range of different parameters and circumstances and have found various magnitudes of differences in the calculated dose depending on the algorithms and the extent and types of tissue heterogeneities and contour irregularities (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) . Radiobiological dose-response relationships are usually nonlinear (23) .…”