background: the monte carlo method is the most accurate method for simulation of radiation therapy equipment. the linear accelerators are currently the most widely used machines in radiation therapy centers. methods: in this work, a monte carlo modelling of the siemens oncor linear accelerator in 6 mv and 18 mv beams was performed. the results of simulation were validated by measurements in wat...

Background: The lack of lateral electronic disequilibrium (LED) becomes a main problem in small field. This factor affects the dose in target volume cannot predict correctly. In addition, utilization of high-energy linear accelerator (10 MV) can emit some unwanted particles (electron contamination). Therefore, the aim of this study was to characterize head linear accelerator (linac) Varian Clin...

The reconstruction of the bioelectric field in the human brain from non-invasive measurements like electroencephalographic recordings (EEG) has the potential to become a powerful tool in neurology. From a mathematical point of view, the reconstruction can be considered as an inverse problem, which can be solved by repeated numerical simulations of the potential distribution for assumed dipolar ...

seismic inversion is a method that extracts acoustic impedance data from the seismic traces. sourcewavelets are band-limited, and thus seismic traces do not contain low and high frequency information.therefore, there is a serious problem when the deterministic seismic inversion is applied to real dataand the result of deterministic inversion is smooth. low frequency component is obtained from w...

Abstract This is a tutorial paper on the basics and applications of finite-difference time-domain (FDTD) method. Two types discretization linear governing equations, scalar-type FDTD method vector-type one, are first discussed. Then basic concept compact explicit-FDTD (CE-FDTD) described. By considering relationship between cutoff frequency computer resources, it shown that interpolated wide ba...