نتایج جستجو برای: dose accuracy dosecalculation algorithms
تعداد نتایج: 933128 فیلتر نتایج به سال:
According to the fundamental goal of remote sensing technology, the image classification of desired sensors can be introduced as the most important part of satellite image interpretation. There exist various algorithms in relation to the supervised land use classification that the most pertinent one should be determined. Therefore, this study has been conducted to determine the best and most su...
Background: Dose calculation algorithms play a very important role in predicting the explicit dose distribution. We evaluated the percent depth dose (PDD), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. Materials and Methods: The homogeneous and inhomogeneous virtual slab phantoms used in th...
An essential component in proton radiotherapy is the algorithm to calculate the radiation dose to be delivered to the patient. The most common dose algorithms are fast but they are approximate analytical approaches. However their level of accuracy is not always satisfactory, especially for heterogeneous anatomical areas, like the thorax. Monte Carlo techniques provide superior accuracy; however...
Aims: The aims of the present work are (1) to evaluate dose calculation accuracy of two commonly used algorithms for 15 MV small photon fields in a medium encompassing heterogeneity and (2) to compare them with measured results obtained from gafchromic film EBT2.Materials and Methods: Authors employed kailwood (Pinus Wallichiana) to mimic lung. Briefly, seven Kailwood plates, each measuring 25x...
Background: In radiation therapy, the peripheral dose is important when anatomical structures with very low dose tolerances are involved. In this study, the two available calculation algorithms of the Varian Eclipse 8.6 treatment planning system(TPS), the anisotropic analytic algorithm (AAA) and pencil-beam convolution (PBC) was used to compare measured and calculated peripheral dose distributi...
forest types mapping, is one of the most necessary elements in the forest management and silviculture treatments. traditional methods such as field surveys are almost time-consuming and cost-intensive. improvements in remote sensing data sources and classification –estimation methods are preparing new opportunities for obtaining more accurate forest biophysical attributes maps. this research co...
Background & Objective: Mixed outcomes arise when, in a multivariate model, response variables measured on different scales such as binary and continuous. In a bivariate modeling, when there are mixed response variables, the common methods in classic statistics have shortcomings. This study aimed at designing an appropriate ANN model for modeling and predicting the bivariate mixed responses i...
Background: Use of contrast agents (CAs) during CT simulation for treatment planing system leads to changes in electron density. In this study we aimed to investigate the effect on calculated dose of various concentrations of CAs on treatment planing systems in different dose calculation algorithms. Materials and Methods: Contrast agent (0.769 mg/ml Iopromid) - water mixtures at con...
Today, the global positioning systems (GPS) do not work well in buildings and in dense urban areas when there is no lines of sight between the user and their satellites. Hence, the local positioning system (LPS) has been considerably used in recent years. The main purpose of this research is to provide a four-layer artificial neural network based on nonlinear system solver (NLANN) for local pos...
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