We have seen that the accuracy of methods for computing integrals or derivatives of a function f(x) depends on the spacing between points at which f is evaluated, and that the approximation tends to the exact value as this spacing tends to 0. Suppose that a uniform spacing h is used. We denote by F (h) the approximation computed using the spacing h, from which it follows that the exact value is...

Abstract— There are several works dedicated to the investigation of Volterra integro-differential equations. In addition, there are theoretical and practical representations of stable methods that have a high order of accuracy and extended stability regions; these representations were constructed using the minimum values of arithmetic operations. Here, hybrid methods are proposed for the constr...

The integrity index Kv is the quantitative in CHN-BQ method, which can be determined by acoustic wave test, volume joint number Jv, or empirical judgment. However, these methods are not convenient and require practitioner to have extensive experience. In this study, a new evaluation of proposed determine accurately conveniently. A method for determining fractal dimension D based on structural p...

Background:In diagnostic radiology lead apron, are usually used to protect patients and radiology staff against ionizing radiation. Lead apron is a desirable shield due to high absorption and effective attenuation of x-ray photons in the diagnostic radiology range.Objective: Although lead aprons have good radiation protection properties, in recent years, researchers have been looking for altern...

The purpose of this work is to present a new method to extract the electron density ([Formula: see text]) and the effective atomic number (Z eff) from dual-energy CT images, based on a Karhunen-Loeve expansion (KLE) of the atomic cross section per electron. This method was used to calibrate a Siemens Definition CT using the CIRS phantom. The predicted electron density and effective atomic numbe...

PURPOSE A flat-panel detector based mobile isocentric C-arm for cone-beam CT (CBCT) has been developed to allow intraoperative 3D imaging with sub-millimeter spatial resolution and soft-tissue visibility. Image quality and radiation dose were evaluated in spinal surgery, commonly relying on lower-performance image intensifier based mobile C-arms. Scan protocols were developed for task-specific ...

Introduction: In radiotherapy treatment planning system (TPS), basic input is the data from computed tomography (CT) scan, which takes into account the effect of inhomogeneities in dose calculations. Measurement of CT numbers may be affected by scanner-specific parameters. Therefore, it is important to verify the effect of different CT scanning protocols on Hounsfield unit (HU) and its impact o...

Background: Breast is one of the main radiological sensitive organs, hence it is important to evaluate absorbed dose to this organ especially to the glandular parts. It is the aim of this study to measure mean glandular dose and image contrast in terms of different mammographic parameters. Materials and Methods: In this study two mammography machines located at Said-al Shohada (Giotto) ...

Background: In CT systems, the machine utilizes a bowtie filter to shape the X-ray beam and remove lower energy photons. The shape of this bowtie filter is complicated and its geometry is often not available in detail. These renders the CT dose index (CTDI) to have different values in measurement versus Monte Carlo simulation studies and other analytical calculations especially in dosimetry of ...

Introduction: The performance of computed tomography is routinely checked using phantoms, which are known as important diagnostic imaging tools. Depending upon the aim of the study, different phantoms are designed, while trying to satisfy certain levels of diversities in their application. Material and Methods: The present study describes the...