background: exposure conditions in ct examinations are quite different from conventional xray. in ct examination higher dose is given to patient in comparison with the dose in other diagnostic examinations. in order to calculate organ effective dose in chest ct, monte carlo simulation has been used in this study. materials and methods: the impact survey data were used to determine the parameter...

introduction: radioiodine therapy is an effective method for treating thyroid cancer carcinoma, but it has some affects on normal tissues, hence dosimetry of vital organs are important to weigh the risks and benefits of this method. the aim of this study is to measure the absorbed doses of important organs by mcnp (monte carlo n particle) simulation and comparing the results of different method...

Monte Carlo simulation is a very powerful tool in understanding performances of positron tomographs as well as in assessing image reconstruction algorithms and their implementations. We present an object-oriented Monte Carlo simulator developed for 3D positron tomography. Results from phantom simulation studies including absorption and scattering of the photons in the field-of-view are presente...

In the last decade, sequential Monte-Carlo methods (SMC) emerged as a key tool in computational statistics (see for instance Doucet et al. (2001), Liu (2001), Künsch (2001)). These algorithms approximate a sequence of distributions by a sequence of weighted empirical measures associated to a weighted population of particles. These particles and weights are generated recursively according to ele...

We present two Monte Carlo sampling algo­ rithms for probabilistic inference that guarantee polynomial-time convergence for a larger class of network than current sampling algorithms pro­ vide. These new methods are variants of the known likelihood weighting algorithm. We use of recent advances in the theory of optimal stopping rules for Monte Carlo simulation to obtain an inference approximati...

Hypersonic blunt-body flowfields containing a mixture of continuum and nonequilibrium flow are investigated using a modular particle–continuum numerical method. The modular particle–continuum method solves the Navier–Stokes equations in near-equilibrium regions and uses the direct simulation Monte Carlo method in nonequilibriumregions.Hypersonicflowof nitrogen over a two-dimensional cylinder at...

Inverse problems in geophysics require the introduction of complex a priori information and are solved using computationally expensive Monte Carlo techniques where large portions of the model space are explored . The geostatistical method allows for fast integration of complex a priori information in the form of covariance functions and training images. We combine geostatistical methods and inv...

Background: For an effective treatment planning in brachytherapy, it is necessary to know the accurate source dosimetric information such as air kerma strength, exposure rate constant, dose rate constant and redial dose distribution. The usual method to determine these factors is thermo luminescent dosimeter (TLD) dosimetry. Nowadays, another more accurate method is known to be the Monte Carlo ...