![]() However, as the tube ages further, resulting in images with more pronounced artifacts. ![]() Among the types of artifacts on CBCT scans, those derived from the beam-hardening effect may critically impact diagnosis and are caused by high-density materials located inside 1, 2 or outside 3 the field of view. The purpose of this study was to describe a novel technique to characterize BH artifacts in CBCT images produced by 3 root canal filling materials and to evaluate the effects of a zirconium (Zr)-based root filling material with a lower K edge (17.99 keV) on the production of BH artifacts. In the early stages the arcing may be infrequent, and small artifacts begin to appear in the images. Artifacts impair the image quality of cone-beam computed tomography (CBCT) scans and may hinder the diagnosis of numerous conditions. Introduction: The beam hardening (BH) artifact produced by root filling materials in cone-beam computed tomographic (CBCT) images is influenced by their radiologic K absorption edge values. The arcing causes a momentary loss of xray output, which contaminates the xray signal collected at the detectors, affecting proper image reconstruction and hence producing artifacts. This results in two effects: cupping and streaking, both of which are physics-based artifacts. As the beam passes through an object, the beam hardens (i.e. ![]() ![]() Once an xray tube starts to arc, a cascade -type effect may occur that sets event in motion that contribute to yet more frequent arcing. Physics Based Artifacts Beam Hardening The X-ray beam is composed of a spectrum of energies. Arcing can also occur through the oil in the xray tube housing. As an xray tube ages, the tendency to arc often increases owing to such factors as degradation of the vacuum within the tube, which results in increased gas pressure. In a xray tube, arcing can occur through residual gas molecules present within the evacuated envelop of the xray tube. Arcing tends to occur whenever there is a large difference in electrical potential, such as the case between the anode and cathode in an xray tube. This is referred to as either high voltage arcing or tube arcing. Iterative correction of beam hardening artifacts in CT. All rights reserved.A common cause of equipment induced artifact occurs when there is a undesired surge of electrical current like a short-circuit, within the xray tube. A computed tomography scan is a medical imaging technique used to obtain detailed internal. Root canal filling materials with lower K edge material properties reduce BH artifacts along the entire length of the root canal and reduce the contribution of the dark artifact.īeam hardening artifact CBCT cone beam computed tomography dark artifact gutta-percha light artifact zirconium.Ĭopyright © 2018 American Association of Endodontists. Moreover, statistically significant differences between the areas of both the light and dark artifacts were observed within all regions of the tooth root, with the greatest artifact being generated in the coronal third of the root (P <. Beam hardening artifact and its influence on blood flow estimation in a. GP generated a significantly greater dark but not light artifact area compared with Zr (P <. Comparison of mean myocardial flow between 120 kVp and 70 keV under baseline. By combining the data from the two scans, synthetic monoenergetic images can be obtained in which beam hardening artifacts are accurately corrected (Stonestrom et al., 1981). Mixed-design analysis of variance was used to evaluate differences in the artifact area for the light and dark elements of the BH artifacts.Ī statistically significant difference in the area of the dark portion of the BH artifact was found between all fill materials and in all regions of the phantom tooth root (P <. Beam hardening can be a pernicious artifact because it changes the CT value of a material (or void) depending upon its location in an image. A possible procedure to remove the beam hardening errors is to perform a dual-energy scan in which the same sample is scanned at two different source energy levels. Beam hardening artifact meaning software#The "light" and "dark" components of the BH artifacts were quantified separately using ImageJ software (National Institutes of Health, Bethesda, MD) in 3 regions of the root. Each phantom tooth was individually imaged using the CS 9000 CBCT unit (Carestream, Atlanta, GA). The palatal root canals of 3 phantom model teeth were prepared and root filled with gutta-percha (GP), a Zr root filling material, and calcium hydroxide paste. ![]() The beam hardening (BH) artifact produced by root filling materials in cone-beam computed tomographic (CBCT) images is influenced by their radiologic K absorption edge values. ![]()
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