This paper investigates a method of reconstructing images from energy-resolved CT data with negligible beam-hardening artifacts and improved contrast-to-nosie ratio (CNR) compared to conventional energy-weighting methods. Conceptually, the investigated method first reconstructs separate images from each energy bin. The final image is a linear combination of the energy-bin images, with the weigh...

Aim: The purpose of this study was to make a comparison between measured and calculated physical wedge dose distributions using the superposition algorithm. Settings and Design: The accurate determination of absorbed dose is important radiotherapy because of the relatively steep sigmoidal dose response curves for both tumor control and normal-tissue damage. Materials and Methods: High-energy ph...

Artifacts are commonly encountered in clinical computed tomography (CT), and may obscure or simulate pathology. There are many different types of CT artifacts, including noise, beam hardening, scatter, pseudoenhancement, motion, cone beam, helical, ring, and metal artifacts. We review the cause and appearance of each type of artifact, correct some popular misconceptions, and describe modern tec...

In computed tomography (CT) the quality of reconstructed images depends on several reasons: the quality of the set-up calibration; precision of the mathematical model, used in the reconstruction procedure; the reconstruction technique used; quality of the numerical implementation of the reconstruction algorithm. Most of fast reconstruction algorithms use the X-ray monochromaticity assumption. I...

Traditionally, most MDCT systems employ a post collimation anti-scatter grid (ASG) in the angular (X) direction to compensate for the scatter radiation. However, with increasing Z-axis coverage offered by advanced state-of-the-art multi-slice CT (MSCT) scanners, the scatter level increases significantly and there is an opportunity to use software algorithms to further decrease the impact of sca...

This paper aims at investigating the nonlinear behavior of a system which is consisting of two free-free beams which are connected by a nonlinear joint. The nonlinear system is modelled as an in-extensional beam with Timoshenko beam theory. In addition, large amplitude vibration assumption is taken into account in order to obtain exact results. The nonlinear assumption in the system necessities...

As the turbine industries need to manufacture turbine blades made of martensitic stainless steel AISI 420 with high toughness and wear resistance, local laser hardening has become more and more important. In this research, surface of the samples was initially hardened by high-power pulsed laser beam; then, optimum parameters of hardening were calculated and wear resistance of surface hardened s...

Recommended Citation Mohapatra, Sucheta. "Development and quantitative assessment of a beam hardening correction model for preclinical micro-CT." MS his contributions of time, ideas, and funding to make my graduate study experience so productive and stimulating. accomplishments shall continue to inspire me towards my future goals. I owe a lot to all my friends and colleagues in Iowa City, who h...

In this paper we describe and evaluate an image-based spectral CT method. Its central formula expresses measured CT data as a spectral integration of the spectral attenuation coefficient multiplied by a Local Weighting Function (LWF). The LWF represents the local energy weighting in the image domain, taking into account the system and reconstruction properties and the object self attenuation. A...

ABSTRACT In this paper, we propose a novel method for beam hardening correction in polychromatic transmission tomography. A family of polynomials is firstly determined in a training phase, which forms a complete set in the sense of X-ray physics of medical diagnostic imaging. In particular, every polynomial in the set is indexed by a beam hardening factor, i.e. effective atomic number, which is...