A comparison of two dose calculation algorithms-anisotropic analytical algorithm and Acuros XB-for radiation therapy planning of canine intranasal tumors

2017 ◽  
Vol 58 (4) ◽  
pp. 479-485 ◽  
Author(s):  
Koichi Nagata ◽  
Timothy D. Pethel
2018 ◽  
Vol 18 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Ashfaq Zaman ◽  
Muhammad Basim Kakakhel ◽  
Amjad Hussain

AbstractBackgroundA comparison of anisotropic analytical algorithm (AAA) and Acuros XB (AXB) dose calculation algorithms with Electron Gamma Shower (EGSnrc) Monte Carlo (MC) for modelling lung and bone heterogeneities encountered during enhanced dynamic wedged (EDWs) radiotherapy dose deliveries was carried out.Materials and methodsIn three heterogenous slab phantoms: water–bone, lung–bone and bone–lung, wedged percentage depth doses with EGSnrc, AAA and AXB algorithms for 6 MV photons for various field sizes (5×5, 10×10 and 20×20 cm2) and EDW angles (15°, 30°, 45° and 60°) have been scored.ResultsFor all the scenarios, AAA and AXB results were within ±1% of the MC in the pre-inhomogeneity region. For water–bone AAA and AXB deviated by 6 and 1%, respectively. For lung–bone an underestimation in lung (AAA: 5%, AXB: 2%) and overestimation in bone was observed (AAA: 13%, AXB: 4%). For bone–lung phantom overestimation in bone (AAA: 7%, AXB: 1%), a lung underdosage (AAA: 8%, AXB: 5%) was found. Post bone up to 12% difference in the AAA and MC results was observed as opposed to 6% in case of AXB.ConclusionThis study demonstrated the limitation of the AAA (in certain scenarios) and accuracy of AXB for dose estimation inside and around lung and bone inhomogeneities. The dose perturbation effects were found to be slightly dependent on the field size with no obvious EDW dependence.


2021 ◽  
Author(s):  
Zhangkai Cheng ◽  
Regina Bromley ◽  
Brad Oborn ◽  
Jeremy Booth

BACKGROUND Despite spinal metastases accounting for 10% to 30% of new tumors diagnoses annually, and radiation therapy is a standard treatment technique, the studies discussing the effects of small-size spinal prostheses on spinal radiation therapy are limited. OBJECTIVE To compare the accuracies of the AAA and AcurosXB dose calculation algorithms and to predict the change in the down-stream and lateral dose deposition of high energy photons in the presence of material with densities higher that commonly found in the body. METHODS Metal rods of titanium (d =4.5g/m2), stainless steel (d=8g/cm2) and tungsten (d=19.25 g/cm2) were positioned in a phantom. Film was position behind and laterally to the rods to measure the dose distribution for a 6 MV, 18 MV and 10 FFF photon beams. A DOSXYZnrc Monte Carlo simulation of the experimental setup was performed The AAA and AcurosXB dose calculation algorithms were used to predict the dose distributions. The dose from film and DOSXYZnrc were compared with the dose predicted by AAA and AcurosXB. RESULTS AAA overestimated the dose behind the rods by 15-25% and underestimated the dose laterally to the rods by 5-15% depending on the range of materials and energies investigated. AcurosXB overestimated the dose behind the rods by 1-18% and underestimated the dose laterally to the rods by up to 5% depending on the range of material and energies investigated. CONCLUSIONS AAA cannot deliver clinically acceptable dose calculation results at a distance less than 10 mm from metals, for a single field treatment. Acuros XB is able to handle metals of low atomic numbers (Z ≤ 26), but not tungsten (Z = 74). This can be due to the restriction of the CT-density table in EclipseTM TPS, which has an upper HU limit of 10501.


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