In this paper, first the limitations of the ray-based method and the one-way wave-field extrapolation migration (WEM) in imaging steeply dipping structures are discussed by some examples. Then a new method of the reverse time migration (RTM), used in imaging such complex structures is presented. The proposed method uses a new wave-field extrapolator called the Leapfrog-Rapid Expansion Method (L...

Background: X- ray images provide accurate and reliable data in different foot pathologies. However, the accompanied complications will limit its use for epidemiological studies and research purposes, especially in children.  Therefore, simple, accessible, and cost- effective methods such as footprint, with a good correlation with x-ray images, are needed to help diagnose different foot pa...

Introduction: The purpose of the current study was to investigate the effect of X-ray spectra on the sensitivity of a polymer gel dosimeter imaged with a conventional computed tomography (CT) scanner. Material and Methods: The whole process of CT imaging of an irradiated polymer gel was simulated by MCNPX Monte Carlo (MC) code. The imaging of polyacrylamide gel was accomplished by means of a co...

Recent advances in imaging techniques and position-sensitive -y-ray detectors have made feasible hard x-ray and -y-ray telescopes with arc-second resolution [ 1]. Above an energy of 100 keY, past instrumentation has been limited to a typical angular resolution of a few degrees. A -y-ray imaging device with 1 arc-second resolution would be a dramatic improvement over conventional, non-imaging in...

Abstmd--We present three terahertz wave (T-ray) tomographic imaging modalities: T-ray computed tomography (T-ray CT), T-ray dinractive tomography (T-ray DT), and tomographic imaging with a Fresnel binaly lens. T-ray CT provides 3-dimensional (3D) images and reveals information about the target for functional imaging. T-ray DT achieves suhmm spatial resolution, and a Binary lens leads a novel im...